Vulkan-Docs/ChangeLog.txt

Update Log for the Vulkan-Docs repository on Github. Updates are in reverse
chronological order starting with the latest public release.

This summarizes the periodic public updates, not individual commits. Updates
on Github are done as single large patches at the release point, collecting
together the resolution of many Khronos internal issues, along with any
public pull requests that have been accepted.

-----------------------------------------------------

Change log for March 5, 2018 Vulkan 1.1.72 spec update:

  * Update release number to 72.

Github Issues:

  * Restructure the repository to put the specification `Makefile` and
    associated spec source material at the top level, `vk.xml` and
    associated scripts material in `xml/`, and generated include and source
    files in `include/vulkan/` and `src/ext_loader/`, respectively (public
    issue 436).
  * Add missing bullet point markup to flink:vkCmdCopyImage valid usage
    statement, so it gets a VUID assigned (public issue 627).
  * Fix broken links in a couple of extension appendices (public pull
    request 665).
  * Add the \<platform> tag to the index in section 4.1 of the registry
    schema documentation, and add the protect= attribute of \<extension>
    tags to the comments in `registry.rnc` (public issues 673, 678).
  * Add missing valid usage statements for sparse image interactions to
    flink:VkImageCreateInfo (public pull request 675).
  * Fix improper usage and grammar of "`can: not`" (public pull request
    681).
  * Remove duplicate spec language and NOTE on present layout between the
    flink:vkAcquireNextImageKHR and flink:vkAcquireNextImage2KHR commands
    (public pull request 685).
  * Fix some typos and markup issues (public pull request 689; public issues
    642, 667, 687).
  * Fix typo etext:VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_FENCE_FD_BIT ->
    ename:VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT in the
    <<external-semaphore-handle-types-compatibility, External semaphore
    handle types compatibility>> table (public pull request 691).

Internal Issues:

  * Remove the need for the "`noautovalidity`" attribute on extension
    structures in `vk.xml`. It is now implied by the "`structextends`"
    attribute instead (internal issue 942).
  * Replace uses of "`currently bound`" with "`bound`", since "`currently`"
    is redundant and distracting, and add a corresponding rule to the style
    guide (internal issue 993).
  * Fixed subtle issues with the last updates to flink:vkAcquireNextImageKHR
    language that had resulted in ambiguities (internal issue 1178).
  * Make it clear that only one query of a given type is allowed at a time
    by reordering valid usage statements for flink:vkCmdBeginQuery and
    flink:vkCmdEndQuery, and removing redundant ones (internal issue 1213).
  * Swapped OL1 and OL3 in `tessparamUL.svg` to match previous version, and
    fixed where "`(no edge)`" appears (internal issue 1215).

Other Issues:

  * Fixed a minor problem with the valid usage statement extraction script,
    and corresponding markup in the spec source.

New Extensions:

  * `VK_AMD_shader_core_properties`
  * `VK_EXT_descriptor_indexing`
  * `VK_NV_shader_subgroup_partitioned`

-----------------------------------------------------

Change log for March 16, 2018 Vulkan 1.1.71 spec update:

  * First public update for Vulkan 1.1.

Github Issues:

  * Refer to standard sparse image block shape format tables explicitly in
    the <<sparsememory-standard-shapes, Standard Sparse Image Block Shapes>>
    section (public issue 93).
  * Add the missing definition of the code:LocalInvocationIndex decoration
    in the <<interfaces-builtin-variables, Built-In Variables>> section
    (public issue 532).
  * Clarify dynamic state definition in the introduction to the <<pipelines,
    Pipelines>> section and the new <<pipelines-dynamic-state, Dynamic
    State>> subsection (public issue 620).
  * Clarified deprecation statement in the `VK_AMD_negative_viewport_height`
    appendix (public issue 674).
  * Fix parameter descriptions for flink:vkCreateIndirectCommandsLayoutNVX
    (public issue 677).

Internal Issues:

  * Remove description of <<primsrast-points, rasterization point size>>
    being taken from the tessellation control shader, since there are no
    circumstances under which you can have TCS without TES (internal issue
    522).
  * Define <<copies-images-format-size-compatibility, _size-compatible_
    image formats>> for flink:vkCmdCopyImage, add it to the glossary, and
    use that definition for slink:VkImageViewCreateInfo (internal issue
    771).
  * Change brief descriptions of enumerant names, and of parameters which
    are enumerants, from "`enum *indicates*`" to "`enum *specifies*`" for
    consistency, and add a markup style guide rule (internal issue 862).
  * Clarify how execution dependencies interact with
    <<synchronization-submission-order, submission order>> at numerous
    places in the <<renderpass, Render Pass>> and <<synchronization,
    Synchronization>> chapters (internal issue 1062).
  * Clarify statement in the <<interfaces-resources-setandbinding,
    DescriptorSet and Binding Assignment>> section that only interface
    variables statically used by the entry point used in a pipeline must be
    present in the descriptor set layout (internal issue 1172).
  * Flip sparse image diagrams with partially full mip levels vertically, to
    match graph origins of other image diagrams (internal issue 1176).
  * Update new SVG diagrams to have consistent style and base font size,
    increase consistency of primitive topology diagrams, and add a section
    to the style guide on creating and editing images in a consistent style
    (internal issue 1177).
  * Resolve problems with valid usage statement extraction by fixing
    existing VUID tags for interfaces promoted to version 1.1 and fixing
    conditional directives around
    VUID-VkMemoryDedicatedAllocateInfo-image-01797 (internal issue 1184).
  * Strip `KHR` suffixes from a few interfaces promoted to Vulkan 1.1 that
    were missed previously (internal issue 1185).
  * Restrict code:OpImageQuerySizeLod and code:OpImageQueryLevels to only
    work on code:Image operands with their code:Sampled operand set to 1. In
    other words, these operations are not defined to work with storage
    images (internal issue 1193).
  * Recycle extension slot for extension #82 in `vk.xml`. This extension was
    never published (internal issue 1195).
  * Add an issue to the `VK_KHR_maintenance1` appendix noting that zero
    height viewports are allowed when this extension is enabled (internal
    issue 1202).
  * Fix slink:VkDescriptorSetLayoutBinding description so that shader stages
    always use descriptor bindings, not the other way around (internal issue
    1206).
  * Fix field name for
    slink:VkInputAttachmentAspectReference::pname:inputAttachmentIndex
    (internal issue 1210).

Other Issues:

  * Fix a few broken links in the <<versions-1.1, Version 1.1>> appendix.
  * Replace a few old refBegin/refEnd tags with open block markup around
    interfaces, and remove old KHX VUID tags that were breaking the valid
    usage statement extraction.
  * Fix error codes accidentally tagged as success codes in `vk.xml` for
    flink:vkGetSwapchainCounterEXT.
  * Added valid usage statements for ftext:vkBind*Memory2 input structures
    stext:VkBind*MemoryInfo, and fix a pname:image -> pname:buffer typo in a
    couple of places.
  * Fix swapped descriptions of elink:VkDescriptorType enums
    ename:VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE and
    ename:VK_DESCRIPTOR_TYPE_STORAGE_IMAGE (reported via tweet).

New Extensions:

  * `VK_ANDROID_external_memory_android_hardware_buffer`

-----------------------------------------------------

Change log for March 7, 2018 Vulkan 1.1.70 spec update:

  * Vulkan 1.1 initial release. Bump API patch number and header version
    number to 70 for this update. The patch number will be used for both
    Vulkan 1.1 and Vulkan 1.0 updates, and continues to increment
    continuously from the previous Vulkan 1.0.69 update.

    NOTE: We are not publishing an updated 1.0.70 specification, or 1.1
    reference pages, along with 1.1.70. There are still minor issues to work
    out with those build targets. However, we will soon generate all three
    types of documents as part of the regular spec update cycle.

    NOTE: The GitHub KhronosGroup/Vulkan-Docs repository now maintains the
    current specification in the `master` branch. The `1.0` branch is out of
    date and will not be maintained, since we will be generating both 1.1
    and 1.0 specifications from the `master` branch in the future.

Github Issues:

  * Clarify how mapped memory ranges are flushed in
    flink:vkFlushMappedMemoryRanges (public issue 127).
  * Specify that <<synchronization-pipeline-stages, Pipeline Stages>> are a
    list of tasks that each command performs, rather than necessarily being
    discrete pieces of hardware that one task flows through. Add a
    "`synchronization command`" pipeline type which all synchronization
    command execute (it's just TOP + BOTTOM), with an explanatory note
    (public issue 554).

Internal Issues:

  * Regenerate all images used in the spec in Inkscape with a consistent
    look-and-feel, and adjust image size attributes so they're all legible,
    and not too large with respect to the spec body text (internal issue
    701).
  * Document in the <<extensions,extensions>> appendix and in the style
    guide that `KHX` extensions are no longer supported or used in the
    Vulkan 1.1 timeframe (internal issue 714).
  * Remove the leftover equations_temp directory after PDF build completes
    (internal issue 925).
  * Update the <<credits, Credits (Informative)>> appendix to include
    contributors to Vulkan 1.1, and to list them according to the API
    version(s) they contributed to (internal issue 987).
  * Add a NOTE to the introduction explaining that interfaces defined by
    extensions which were promoted to Vulkan 1.1 are now expressed as
    aliases of the Vulkan 1.1 type (internal issue 991).
  * Instrument spec source conditionals so spec can be built with 1.1
    features, extensions promoted to 1.1, or both (internal issues 992,
    998).
  * Modify the XML schema and tools to support explicit aliasing of types,
    structures, and commands, and use this to express the promotion of 1.0
    extensions to 1.1 core features, by making the extension interfaces
    aliases of the core features they were promoted to. Mark up promoted
    interfaces to allow still generating 1.0 + extension specifications
    (internal issue 991).
  * Platform names, along with corresponding preprocessor symbols to enable
    extensions specific to those platforms, are now reserved in vk.xml using
    the <platform> tag. Update the registry schema and schema specification
    to match (internal issue 1011).
  * Updated the <<textures-texel-replacement, Texel Replacement>> section to
    clarify that reads from invalid texels for image resources result in
    undefined values (internal issue 1014).
  * Modify description of patch version so it continues to increment across
    minor version changes (internal issue 1033).
  * Clarify and unify language describing physical device-level core and
    extension functionality in the <<fundamentals-validusage-extensions,
    Valid Usage for Extensions>>, <<fundamentals-validusage-versions, Valid
    Usage for Newer Core Versions>>, <<initialization-functionpointers
    Command Function Pointers>>, <<initialization-phys-dev-extensions,
    Extending Physical Device From Device Extensions>>
    <<extended-functionality-instance-extensions-and-devices, Instance
    Extensions and Device Extensions>> sections and for
    flink:vkGetPhysicalDeviceImageFormatProperties2. This documents that
    instance-level functionality is tied to the loader, and independent of
    the ICD; physical device-level functionality is tied to the ICD, and
    associated with device extensions; physical devices are treated more
    uniformly between core and extensions; and instance and physical
    versions can be different (internal issue 1048).
  * Updated the <<commandbuffers-lifecycle, Command Buffer Lifecycle>>
    section to clarify the ability for pending command buffers to transition
    to the invalid state after submission, and add a command buffer
    lifecycle diagram (internal issue 1050).
  * Clarify that some flink:VkDescriptorUpdateTemplateCreateInfo parameters
    are ignored when push descriptors are not supported (internal issue
    1054).
  * Specify that flink:vkCreateImage will return an error if the image is
    too large, in a NOTE in the slink:VkImageFormatProperties description
    (internal issue 1078).
  * Remove near-duplicate NOTEs about when to query function pointers
    dynamically in the <<initialization, Initialization>> chapter and
    replace by extending the NOTE in the <<fundamentals-abi, Application
    Binary Interface>> section (internal issue 1085).
  * Restore missing references to "`Sparse Resource Features`" in the
    flink:VkBufferCreateFlagBits description (internal issue 1086).
  * Tidy up definitions of descriptor types in the `GL_KHR_vulkan_glsl`
    specification, the <<descriptorsets, Resource Descriptors>> section and
    its subsections, and the <<interfaces-resources-descset, Descriptor Set
    Interface>> for consistency, reduction of duplicate information, and
    removal of GLSL correspondance/examples (internal issue 1090).
  * Correctly describe code:PrimitiveId as an Input for tessellation control
    and evaluation shaders, not an Output (internal issue 1109).
  * Relax the requirements on chroma offsets for nearest filtering in
    <<textures-implict-reconstruction, Implicit Reconstruction>> (internal
    issue 1116).

Other Issues:

  * Clarify the intended relationship between specification language and
    certain terms defined in the Khronos Intellectual Property Rights
    policy. Specific changes include:
  ** Rewrote IP/Copyright preamble and introduction to better agree with
     normative language both as laid out in the introduction, and the
     Khronos IPR policy.
  ** Added notion of fully informative sections, which are now tagged with
     "`(Informative)`" in their titles.
  ** Removed non-normative uses of the phrase "`not required`"
  ** Clarified the distinction between terms "`optional`" and "`not
     required:`" as they relate to the IPR Policy, and updated specification
     text to use terms consistent with the intent.
  ** Reduced additions to RFC 2119, and ensured the specification agreed
     with the leaner language.
  ** Removed the terms "`hardware`", "`software`", "`CPU`", and "`GPU`" from
     normative text.
  ** Moved several paragraphs that should not have been normative to
     informative notes.
  ** Clarified a number of definitions in the Glossary.
  ** Updated the document writing guide to match new terminology changes.
  * Explicitly state in the <<fundamentals-objectmodel-lifetime-acquire,
    application memory lifetime>> language that that for objects other than
    descriptor sets, a slink:VkDescriptorSetLayout object used in the
    creation of another object (such as slink:VkPipelineLayout or
    slink:VkDescriptorUpdateTemplateKHR) is only in use during the creation
    of that object and can be safely destroyed afterwards.
  * Updated the <<textures-scale-factor, Scale Factor Operation>> section to
    use the ratio of anisotropy, rather than the integer sample rate, to
    perform the LOD calculation. The spec still allows use of the sample
    rate as the value used to calculate the LOD, but no longer requires it.
  * Update `vulkan_ext.c` to include all platform-related definitions from
    the Vulkan platform headers, following the split of the headers into
    platform-specific and non-platform-specific files.
  * Fix bogus anchor name in the <<commandbuffers, Command Buffers>> chapter
    which accidentally duplicated an anchor in the pipelines chapter. There
    were no reference to this anchor, fortunately.
  * Add valid usage statement for slink:VkWriteDescriptorSet and
    slink:VkCopyDescriptorSet requiring that the slink:VkDescriptorSetLayout
    used to allocate the source and destination sets must not have been
    destroyed at the time flink:vkUpdateDescriptorSets is called.
  * Document mapping of subgroup barrier functions to SPIR-V, and clarify a
    place where subgroupBarrier sounds like it's execution-only in the
    standalone `GL_KHR_shader_subgroup` specification.
  * Use an HTML stylesheet derived from the Asciidoctor `colony` theme, with
    the default Arial font family replaced by the sans-serif Noto font
    family.
  * Numerous minor updates to README.adoc, build scripts, Makefiles, and
    registry and style guide specifications to support Vulkan 1.1 outputs,
    use them as defaults, and remove mention of `KHX` extensions, which are
    no longer supported.


New Extensions:

  * `VK_EXT_vertex_attrib_divisor`

-----------------------------------------------------

Change log for February 19, 2018 Vulkan 1.0.69 spec update:

  * Bump API patch number and header version number to 69 for this update.

Github Issues:

  * Clean up description of synchronization for flink:vkAcquireNextImageKHR
    (public issue 626).
  * Move valid usage statements requiring offset and extent to respect image
    transfer granularity requirements of the queue family they are submitted
    against from slink:VkImageCopy and slink:VkBufferImageCopy to the
    corresponding flink:vkCmdCopyImage, flink:vkCmdCopyBufferToImage, and
    flink:vkCmdCopyImageToBuffer commands, where are relevant information is
    known (public issue 654).
  * Clarify that flink:vkGetDeviceProcAddr only supports device-level
    commands (public issue 655).

Internal Issues:

  * Associate each elink:VkDescriptorType with a type of descriptor, and
    link to descriptions of those types (internal issue 860).
  * Rework valid usage extraction script to better utilize and respond to
    spec markup, and fix some spec markup accordingly (internal issues 846,
    909, 945).
  * Rephrase flink:vkCmdPushConstants valid usage to allow overlapping push
    constant ranges in different shader stages (internal issue 1103).
  * Fix problem with diff_html target in extension.rb (internal issue 1104).
  * Modify valid usage statements for slink:VkClearDepthStencilValue,
    slink:VkGraphicsPipelineCreateInfo, slink:VkViewport, and
    flink:vkCmdSetDepthBounds, and the description of vkCmdSetDepthBias, to
    clarify that clamping is applied if and only if the
    `VK_EXT_depth_range_unrestricted` is not enabled (internal issue 1124),
    in versions of the specification built with that extension included.
  * Resolve contradictions and use of undefined "`per-sample shading`" term
    in the <<primsrast-sampleshading, Sample Shading>> and
    <<shaders-fragment-execution, Fragment Shader Execution>> sections; for
    the <<features-features-sampleRateShading, sampleRateShading feature>>;
    for code:FragCoord, code:SampleId, and code:SamplePosition; and for
    slink:sname:VkPipelineMultisampleStateCreateInfo (internal issue 1134).
  * Clarify the meaning of the ptext:maxDescriptorSet* limits in footnote 8
    of the <<features-limits-required,Required Limits>> table (internal
    issue 1139).
  * Fix broken NOTE markup in slink:VkSamplerCreateInfo.txt (internal issue
    1140).
  * Remove extend comparison language from valid usage statement for
    slink:VkImageCreateInfo, turning it into a simple validation of
    pname:mipLevels against pname:maxMipLevels (internal issue 1151).
  * Update valid usage statements for slink:VkImageCopy when the
    `VK_KHR_maintenance1` extension is enabled to allow multi-slice 2D <->
    3D copies when the pnaem:extent.depth parameter specifies the number of
    layers being copied, and matches the
    slink:VkImageSubresourceLayers.layerCount of the 2D image (internal
    issue 1152).
  * Rephrase memory / control barrier rules in the
    <<spirvenv-module-validation, Validation Rules within a Module>> section
    to avoid "`not use none`", which could be misconstrued to allow no
    synchronization semantics, and only storage class semantics (internal
    issue 1154).

Other Issues:

  * Move GLSL extension specifications to the KhronosGroup/GLSL repository
    on Github.
  * Add missing description of ename:VK_FILTER_CUBIC_IMG enum to
    slink:VkFilter.
  * Update description of code:PrimitiveId in the
    <<interfaces-builtin-variables,Built-In Variables>> section to clarify
    its behavior.
  * Disallow disjoint images from being used with dedicated-memory images in
    slink:VkMemoryDedicatedAllocateInfoKHR.
  * Update README to suggest older versions of "mathematical" and
    "ruby-gems" packages for use on Cygwin.
  * Fix typos

New Extensions:

  * `VK_AMD_buffer_marker`

-----------------------------------------------------

Change log for January 15, 2018 Vulkan 1.0.68 spec update:

  * Bump API patch number and header version number to 68 for this update.

Github Issues:

  * Added more details in the
    <<extended-functionality-extensions-compatibility, Extension
    Compatibility>> section, allowing explicit incompatibilities, and
    simplify corresponding language in the style guide, which now defers to
    the API Specification on this point (public issue 638).
  * Fix typo in description of slink:VkCommandBufferLevel::pname:level
    (public issue 651).
  * Only include extension-dependent valid usage statement for
    slink:VkImageSubresourceRange, and note that the extension names for
    header files described in the <<boilerplate-wsi-header, Window
    System-Specific Header Control>> section are only valid links, when the
    specification being viewed is built with the corresponding extensions
    enabled (public issue 652).

Internal Issues:

  * Add language to elink:VkResult specifying that when commands return an
    error, output parameter contents are undefined instead of unmodified
    (except for pname:sType and pname:pNext). Note that this is a behavior
    change. Add notes calling out slink:VkImageFormatProperties as an
    exception (internal issue 1118).
  * Add "`general-purpose`" to the style guide, and correct existing uses of
    "`general purpose`" as an adjective (internal issue 1121).
  * Add the ename:VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT_EXT token
    for the `VK_EXT_validation_cache` extension, following the same naming
    pattern as other tokens in the extension, but keep the old
    ename:VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT token around for
    backwards compatibility (internal issue 1126).

Other Issues:

  * Specify that flink:vkCmdSetDiscardRectangleEXT does not affect copies or
    clears, matching existing language for the scissor rectangle test.
  * Move the <<boilerplate-sType, pname:sType>> definition from the
    boilerplate appendix to the Fundamentals chapter, putting it together
    with the valid usage of pname:sType rather than having the definition
    split across two places.
  * Inline all of the etext:Vk*Flags definitions, moving each one from the
    boilerplate appendix to appear either after the corresponding
    etext:Vk*FlagBits value if one is defined, or after the first structure
    that includes them if not.

-----------------------------------------------------

Change log for January 5, 2018 Vulkan 1.0.67 spec update:

  * Bump API patch number and header version number to 67 for this update.
  * Update copyright dates to 2018

Github Issues:

  * Fix texture lookup functions in `GL_KHR_vulkan_glsl` specification
    (public pull request 363).
  * Clarify the state waited semaphores are left in when a call to
    flink:vkQueuePresentKHR fails (public issue 572).
  * Cleanup descriptions of slink:VkObjectTablePushConstantEntryNVX and
    slink:VkObjectTableDescriptorSetEntryNVX (public issue 583)
  * Remove redundant flink:vkCmdSetDiscardRectangleEXT valid usage
    statements (public pull 586).
  * Make dynamic state array length valid usage statements implicit for
    flink:vkCmdSetViewportWScalingNV, flink:vkCmdSetDiscardRectangleEXT, and
    flink:vkCmdSetViewport (public pull 589).
  * Clarify meaning of window extent (0,0) in slink:VkSwapchainKHR for the
    Windows and X11 platforms, in their respective extensions (public issue
    590).
  * Allow flink:vkGetPastPresentationTimingGOOGLE to return
    ename:VK_INCOMPLETE (public issue 604).
  * Add synchronization valid usage statements to flink:vkAcquireNextImage
    (public pull 611).
  * Fix some broken external links and internal xrefs (public pull 613).
  * Clean up slink:VkViewport valid usage statements in the presence or
    absence of relevant extensions (public pull 623).
  * Remove
    ename:VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR
    token from VK_KHR_maintenance2 from the non-extension VU path for
    slink:VkGraphicsPipelineCreateInfo (public issue 628).
  * Miscellaneous minor markup fixes - extension name strings (public pull
    631), Notes (pull 633), queue names emitted by generator scripts (pull
    634), block formatting in slink:VkDescriptorUpdateTemplateEntryKHR (pull
    635), ename:VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG (pull
    641), quotes and apostrophes (pull 643),
  * Miscellaneous minor grammar fixes (public pull 644).
  * Fix markup macros so usage like ptext:*Src* works (public pull 647).

Internal Issues:

  * Clarify in the `VK_KHR_surface` and `VK_KHR_swapchain` extensions that
    parameter combinations which aren't supported for normal images are also
    unsupported for presentable images, even if the parameter values are
    individually supported as reported by the surface capability queries
    (internal issue 1029).
  * Fixed XML typo in the valid value field of the pname:sType member of
    slink:VkPhysicalDeviceExternalMemoryHostPropertiesEXT (internal issue
    1100).

Other Issues:

  * Add memory semantics validity rules to the <<spirvenv-module-validation,
    Validation Rules within a Module>> section of the SPIR-V environment
    appendix, and specify that sequentiality consistency is not supported.
    This forbids certain cases like "`Load+Release`" that we don't expect to
    ever be meaningful.
  * Document mapping of OpenGL Shading Language barriers to SPIR-V scope and
    semantics in the `GL_KHR_vulkan_glsl` specification.

New Extensions:

  * `VK_EXT_conservative_rasterization`

-----------------------------------------------------

Change log for November 27, 2017 Vulkan 1.0.66 spec update:

  * Bump API patch number and header version number to 66 for this update.

Github Issues:

  * Clarified how and when ename:VK_ERROR_TOO_MANY_OBJECTS is generated in
    flink:vkAllocate Memory, and remove incorrect valid usage statement
    about exceeding the API limit (public issue 356).
  * Minor clarification of the description of
    flink:vkUpdateDescriptorSetWithTemplateKHR::pname:descriptorUpdateTemplate
    (public issue 564).
  * Minor fixes for flink:vkCmdSetViewportWScalingNV (public pull request
    588).
  * Fix random name markup issues (public pull request 603).
  * Fix code:BuiltIn decoration typo in the <<fxvertex-attrib, Vertex
    Attributes>> section (public pull request 606).
  * Fix synchronization language following the definition of
    flink:vkAcquireNextImageKHR (public issue 607).
  * Restore descriptions of several commands and structures missing from the
    generated spec due to a mistyped asciidoctor conditional (public issue
    612).
  * Fix 1.0.41 changelog to refer to public issues 403/404 (public issue
    618).

Internal Issues:

  * Refactor valid usage statements with internal conditionals in
    `copies.txt`, `pipelines.txt`, `renderpass.txt`, and `resources.txt` so
    each branch of the conditional appears as a standalone statement which
    can contain a separate VUID. This should have no impact on the generated
    specs, but is necessary given the present state of the VU extractor and
    the validation layer code that consumes them (internal issue 1043).
  * Fix VkQueueGlobalPriorityEXT enum values missing _EXT suffix (internal
    issue 1045).
  * Clarified initial ownership of resources bound to shared memory objects,
    (internal issue 1068).
  * Fix duplicated valid usage ID tag for flink:vkCmdCopyImage, and make the
    required layouts include ename:VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL in
    both cases (internal issue 1084).

Other Issues:

  * Remove the noise functions from GLSL for SPIR-V for Vulkan in the
    `GL_KHR_vulkan_glsl.txt` extension.

New Extensions:

  * `VK_EXT_external_memory_host`
  * `VK_EXT_external_memory_dma_buf`
  * `VK_EXT_queue_family_foreign`

-----------------------------------------------------

Change log for October 27, 2017 Vulkan 1.0.65 spec update:

  * Bump API patch number and header version number to 65 for this update.

Github Issues:

  * Replaced inaccurate "`pixel`" with "`texel`" or "`compressed texel
    block`" as appropriate in the <<sparsememory, Sparse Resources>> chapter
    (public issue 86).
  * Attempt to clarify security/integrity guarantees in the
    <<fundamentals-errors, Errors>> section (public issue 147).
  * Update the <<memory-device,Device Memory>> section with clarifications
    and markup fixes (public pull request 194).
  * Fix typo VkDeviceCreateInfo -> slink:VkDebugMarkerObjectNameInfoEXT in
    sample code for `VK_EXT_debug_marker` extension (public pull request
    227).
  * Clarified slink:VkFramebufferCreateInfo language regarding concurrent
    use of attachment resources during a render pass instance (public issue
    299).
  * Added overlap rules for destination regions in <<copies,copy commands>>.
    Also unified the sparse and non-sparse source-destination overlap rules,
    since the non-sparse rules were technically inaccurate in the face of
    aliasing in flink:vkBindMemory2 - the new rules are true regardless
    (public issue 317).
  * Clarified the <<features-features-samplerAnisotropy,
    pname:samplerAnisotropy feature>> to only affect the
    slink:VkSamplerCreateInfo::pname:anisotropyEnable value, and that
    pname:maxAnisotropy is ignored when pname:anisotropyEnable is VK_FALSE
    (public issue 503).
  * Clarify pointer valid usage statements to use "`valid pointer to valid
    _object_`" terminology and update the
    <<fundamentals-validusage-pointers,Valid Usage for Pointers>> section
    accordingly (public pull request 547).
  * Some operations that use integer coordinates can also accept a LOD to
    sample from. Add a description of that selection and the validity
    conditions in the new <<textures-integer-coordinate-operations, Integer
    Texel Coordinate Operations>> section (public issue 548).
  * Update stext:VkImageSubresource* valid usage statements (public pull
    request 550).
  * Added text tying ename:VK_OUT_OF_POOL_MEMORY error for
    flink:vkAllocateDescriptorSets to the number of descriptor types in the
    allocating pool. Removed redundant "`length`" text about number of
    descriptors returned (public issue 582).
  * Update slink:VkSwapchainCreateInfoKHR descriptions (public pull request
    585).
  * Update slink:VkPipelineViewportWScalingStateCreateInfoNV and related
    structures' valid usage statements (public pull request 587).
  * Change some dates to conform to ISO 8601 as specified in the style guide
    (public pull request 601).
  * Fix some math markup problems and be more consistent in use of asciidoc
    math markup (public pull request 602).

Internal Issues:

  * Clarified that attribute reads from incomplete vertex buffer elements
    are considered out of bounds accesses, in the
    slink:VkPhysicalDeviceFeatures and flink:vkCmdBindVertexBuffers.txt
    sections (internal issue 842).

-----------------------------------------------------

Change log for October 20, 2017 Vulkan 1.0.64 spec update:

  * Bump API patch number and header version number to 64 for this update.

Github Issues:

  * Add chapter name to the PDF page footer (public pull request 458).
  * Fix several mistaken references to the nonexistent etext:VK_DEVICE_LOST
    status to etext:VK_ERROR_DEVICE_LOST (public pull request 502).
  * Fix description of the tlink:PFN_vkDebugReportCallbackEXT debug report
    callback function pointer to match the validation layer behavior (public
    issue 534).
  * Document experimental KHX extensions and alternate vendor author IDs
    also ending in X in more detail in the <<extensions, Layers &
    Extensions>> appendix, the extensions section of the style guide, and
    the registry schema description document (public issues 536, 580).
  * Fix references to ptext:pDepthStencil to properly refer to
    pname:pDepthStencilState or pname:pRasterizationState as appropriate in
    the slink:VkGraphicsPipelineCreateInfo description (public issue 542).
  * Fix wrong parameter name in slink:VkPipelineMultisampleStateCreateInfo
    valid usage (public pull request 571).

Internal Issues:

  * Update the style guide to describe how to write LaTeX math expressions
    in table cells (internal issue 908).
  * Define how framebuffer-local dependencies work between subpasses with
    the same or different numbers of samples, in the
    slink:VkSubpassDescription and <<synchronization-framebuffer-regions,
    Framebuffer Region Dependencies>> sections. This clarifies which samples
    in an input attachment you are allowed to access after a
    framebuffer-local dependency (internal issue 915).
  * Specify which storage classes can have an initializer in the
    <<spirvenv-module-validation, Validation Rules within a Module>> section
    (internal issue 1023).
  * Use "LOD" consistently for "level-of-detail", to eliminate spelling
    inconsistencies. The term is already standardized in the Glossary
    (internal issue 1027).

Other Issues:

  * Fix false positives in Makefile dependencies when rules fail, by
    deleting partially-made targets.

New Extensions:

  * `VK_AMD_shader_info`

-----------------------------------------------------

Change log for October 13, 2017 Vulkan 1.0.63 spec update:

  * Bump API patch number and header version number to 63 for this update.

Github Issues:

  * Add missing valid usage statements for ptext:maxDescriptorSets*,
    ptext:maxPerStageDescriptorInputAttachments, and
    ptext:maxPerStageResources to slink:VkPipelineLayoutCreateInfo.txt,
    flink:VkComputePipelineCreateInfo, and
    flink:VkGraphicsPipelineCreateInfo (public issue 546).
  * Fix typos in ftext:vkCmdDraw*AMD descriptions (public pull request 549).
  * Fixed flink:vkCmdWriteTimestamp so it is not unnecessarily restricted to
    queues supporting graphics or compute operations (public issue 558).
  * Improvements to valid usage generator for output `*Flags` pointer
    parameters and for some `void *` parameters (public pull requests 560,
    562).
  * Document `altlen` attribute in XML schema as valid C99 syntax and tweak
    `vk.xml` to match (public pull request 566).
  * Clarify when pname:fence is signaled by flink:vkQueueSubmit in a more
    obvious place (public issue 577).

Internal Issues:

  * Specify a whitelist of supported SPIR-V Storage Classes in the
    <<spirvenv-module-validation, Validation Rules within a Module>>
    appendix (internal SPIR-V issue 166).
  * Relax the shared semaphore wait timeout requirement in the
    <<synchronization-semaphores-importing, Importing Semaphore Payloads>>
    section (internal issue 820).
  * Update the <<textures-image-level-selection, Image Level(s) Selection>>
    equations so that the parameters returned by the level-of-detail query
    appear explicitly, also fixing the issue that linear filtering would
    select a level below the base level for magnification (internal issue
    926).
  * Disallow creation of a swapchain with zero pname:imageExtent in
    slink:VkSurfaceCapabilitiesKHR and slink:VkSwapchainCreateInfoKHR
    (internal issue 1020).

Other Issues:

  * Clarify in <<textures-operation-validation,Image View Validation>> that
    the layout of subresources in an image view must have a layout that
    matches that written into the descriptor, and that this section is about
    validating image views, not images.

New Extensions:

  * `VK_EXT_global_priority`

-----------------------------------------------------

Change log for October 6, 2017 Vulkan 1.0.62 spec update:

  * Bump API patch number and header version number to 62 for this update.

Github Issues:

  * Move asciidoc conditionals for `VK_KHR_maintenance1` in
    slink:VkDescriptorSetAllocateInfo so valid usage statements for
    `VK_KHR_push_descriptor` aren't accidentally removed when the first
    extension isn't enabled (public issue 573).

Internal Issues:

  * Specify constraints on concurrent access to fences that share payload in
    the <<synchronization-fences-importing, Importing Fence Payloads>> and
    <<synchronization-semaphores-waiting-state, Semaphore State Requirements
    For Wait Operations>> sections (internal issue 820).
  * Define the term "`retired swapchain`", reorganize some swapchain
    language, and improve language for pname:oldSwapchain in
    flink:VkSwapchainCreateInfoKHR, the <<swapchain-wsi-image-create-info>>
    table, flink:vkDestroySwapchainKHR, and flink:vkAcquireNextImage2KHX
    (internal issue 869).
  * Describe in the <<writing-arrays, Describing Properties of Array
    Elements>> section of the style guide how and when to use "`each`" and
    "`any`" to refer to properties of array elements, and make those uses in
    the specification consistent (internal issue 884).
  * Clarified that events cannot be used for cross-queue synchronization in
    the <<synchronization-events, Events>> section and for
    flink:vkCmdWaitEvents (internal issue 970).
  * Add success and error codes to +vk.xml+ for
    flink:vkCreateValidationCacheEXT (internal issue 995).
  * Clarify aspect mask usage for image memory barriers of multi-plane
    images in slink:VkImageSubresourceRange, slink:VkImageMemoryBarrier, and
    the <<textures-layout-validation, Layout Validation>> section (internal
    issue 996).

Other Issues:

  * Fixed typo in flink:VkRenderPassSampleLocationsBeginInfoEXT (renamed
    field pname:pSubpassSampleLocations to
    pname:pPostSubpassSampleLocations).
  * Add missing buffer usage requirements for indirect draws in
    flink:vkCmdDrawIndirect, flink:vkCmdDrawIndirectCountAMD,
    flink:vkCmdDrawIndexedIndirect, and
    flink:vkCmdDrawIndexedIndirectCountAMD.
  * Modify Makefile to allow specification to build in git "`detached HEAD`"
    state.
  * Update valid usage ID generation script to allow recursively operating
    on all `.txt` files in a specified directory, and move the `startVUID`
    tracking information into a separate python file that is automatically
    updated by the script.
  * Fixed errors in API example code for
    flink:vkUpdateDescriptorSetWithTemplateKHR and
    flink:vkCmdPushDescriptorSetWithTemplateKHR.

New Extensions:

  * Add +vk.xml+ entries for pending `VK_ANDROID_native_buffer` extension
    (note, this extension is not yet enabled).
  * `VK_AMD_shader_image_load_store_lod`

-----------------------------------------------------

Change log for September 15, 2017 Vulkan 1.0.61 spec update:

  * Bump API patch number and header version number to 61 for this update.

Github Issues:

  * Provide alternate length attributes (altlen=) in the XML schema, for
    those using length attributes to generate code instead of documentation
    (public issue 555).
  * Fix erroneous references to `latex:` being used for asciidoc math
    markup, rather than `latexmath:` (public pull request 556).
  * Add author ID to XML for Kazan software renderer (public pull request
    557).

Internal Issues:

  * Add the <<fundamentals-abi,Application Binary Interface>> section
    describing platform ABI requirements and recommendations, add examples
    of function and function pointer declarations to the
    <<boilerplate-platform-specific-calling-conventions, Platform-Specific
    Calling Conventions>> section, and remove related language that existed
    elsewhere in the specification (internal issue 64).
  * Describe where to document valid usage interactions of chained
    structures in the style guide, and fix one case now appearing in
    slink:VkBufferCreateInfo instead of the child
    slink:VkDedicatedAllocationBufferCreateInfoNV structure (internal issue
    715).
  * Add example to the style guide of describing enumerated types which are
    empty when the spec is built without relevant extensions enabled, and
    apply it to existing examples for
    elink:VkDescriptorSetLayoutCreateFlagBits and
    elink:VkSubpassDescriptionFlagBits (internal issue 864).
  * Add a note to the <<fundamentals-validusage-enums, Valid Usage for
    Enumerated Types>> section that the special values suffixed with
    etext:_BEGIN_RANGE, etext:_END_RANGE, etext:_RANGE_SIZE and
    etext:_MAX_ENUM are not part of the API and should: not be used by
    applications (internal issue 872).
  * Added note to flink:vkCmdUpdateBuffers explaining the performance
    penalty for copies done in this way, and why the upper copy limit is
    what it is (internal issue 952).
  * Update `VK_KHX_device_group` to split some functionality into the new
    `VK_KHR_bind_memory2` extension, and rename that functionality (internal
    issue 969).
  * Remove *Status* fields from extension appendices, since they are by
    definition published and complete by the time they reach the public
    github repository (internal issue 973).

Other Issues:

  * Update Data Format specification dependency to version 1.2 and change
    references to DF sections accordingly.
  * Update XML to make the pname:pAllocator parameter of
    flink:vkRegisterDeviceEventEXT and flink:vkRegisterDisplayEventEXT in
    the `VK_EXT_display_control` extension as optional.

New Extensions:

  * `VK_KHR_bind_memory2`
  * `VK_KHR_image_format_list`
  * `VK_KHR_maintenance2`
  * `VK_KHR_sampler_ycbcr_conversion`

-----------------------------------------------------

Change log for September 5, 2017 Vulkan 1.0.60 spec update:

  * Bump API patch number and header version number to 60 for this update.

Github Issues:

  * Document that <<queries-timestamps, Timestamp Queries>> can only be
    meaningfully compared when they are written from the same queue (public
    issue 216).
  * Document that the `<extension>` tag `type` attribute is required for
    non-disabled extensions (derived from, but does not close public issue
    354).
  * Clean up registry schema length attribute descriptions to be consistent
    and correct (public issue 555).

Internal Issues:

  * Replace as much of the hand-written extension appendix metadata as
    possible with asciidoc includes generated from corresponding attributes
    of +vk.xml+, and enhance the style guide to match. This avoids
    inconsistencies between +vk.xml+ and the appendices, and produces a more
    uniform style (internal issue 137).
  * Remove the generated extDependency.{py,sh} files from the tree and
    create them dynamically on demand instead, reducing merge conflicts
    (internal issue 713).
  * Add a prototype tool for generating in-place difference markup for
    sections guarded by asciidoc conditionals, and new syntax for open
    blocks to support it (internal issue 833).
  * Remove unnecessary restriction of etext:*SYNC_FD_BIT_KHR external handle
    types to the same physical device in the
    slink:VkPhysicalDeviceIDPropertiesKHR,
    flink:VkImportMemoryWin32HandleInfoKHR,
    slink:VkImportFenceWin32HandleInfoKHR, slink:VkImportFenceFdInfoKHR,
    slink:VkImportSemaphoreWin32HandleInfoKHR,
    slink:VkImportSemaphoreFdInfoKHR
    <<external-memory-handle-types-compatibility, External memory handle
    types compatibility>>, <<external-semaphore-handle-types-compatibility,
    External semaphore handle types compatibility>>, and
    <<external-fence-handle-types-compatibility, External fence handle types
    compatibility>> sections (internal issue 956).

Other Issues:

  * Remove dependency of +VK_KHX_device_group+ on +VK_KHR_swapchain+ (there
    is an interaction, but not a strict dependency), and add a new
    `extension` attribute to the `<require` XML tag to allow classifying a
    subset of interfaces of an extension as requiring another extension.
    Update the registry schema and documentation accordingly.

New Extensions:

  * `VK_AMD_shader_fragment_mask` (and related `GL_AMD_shader_fragment_mask`
    GLSL extension)
  * `VK_EXT_sample_locations`
  * `VK_EXT_validation_cache`

-----------------------------------------------------

Change log for August 19, 2017 Vulkan 1.0.59 spec update:

  * Bump API patch number and header version number to 59 for this update.

Github Issues:

  * Fix a few missing Implicit Valid Usage statements to indicate that a
    common parent of two objects is required (public issue 497).
  * Clarify render pass synchronization language for
    slink:VkSubpassDependency and \<\<renderpass,render passes>> (public
    issue 531).
  * Rename ename:VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES2_EXT to
    ename:VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT for consistency, and
    add an alias for backwards compatibility (public issue 539).

Internal Issues:

  * Add an explanation to the \<\<interfaces-builtin-variables-layer,
    code:Layer>> description explaining that writing to invalid layers
    results may or may not result in primitives being processed and fragment
    shaders being run, and gives undefined results in the framebuffer
    (internal issue 614)
  * Add valid usage statement for slink:VkDescriptorSetLayoutBinding
    requiring that input attachment descriptor bindings must not use
    non-fragment stages (internal issue 933).

Other Issues:

  * Makes description of pname:loadOp and pname:storeOp easier to read in
    the \<\<renderpass-load-store-ops>> section.

New Extensions:

  * `VK_EXT_shader_stencil_export`

-----------------------------------------------------

Change log for August 14, 2017 Vulkan 1.0.58 spec update:

  * Bump API patch number and header version number to 58 for this update.

Github Issues:

  * Update the <<interfaces-resources-descset,Descriptor Set Interface>>
    section to allow multiple variables with the same descriptor set/binding
    decorations, and require that all variables that are statically used
    must be consistent with the pipeline layout. Allow
    ename:VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER to be used with texture
    and sampler variables (public issues 522, 524).

Internal Issues:

  * Replace networkx package used for extension dependency generation with a
    homegrown network dependency traverser (internal issue 713).
  * Specify in the <<interfaces-fragmentoutput, Fragment Output Interface>>
    section that if a fragment shader writes integers that cannot be
    represented in the format of the colour attachment, then the result is
    undefined (internal issue 893).
  * Separate malformed valid usage statement for
    slink:VkPipelineRasterizationStateCreateInfo into two (internal issue
    918).
  * Fix cases where the term 'pNext chain' is incorrectly used in reference
    to functions, rather than their parameters. Replace 'pNext list' with
    'pNext chain'. Fixed typo in the example code of
    +VK_KHR_dedicated_allocation+ (internal issue 944).
  * Fix typo in elink:VkExternalSemaphoreHandleTypeFlagBitsKHR enum
    descriptions, replacing
    etext:VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_FENCE_FD_BIT_KHR with
    ename:VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT_KHR, and make the
    description more consistent with
    VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT_KHR (internal issue 950).

Other Issues:

  * Clarify how pipeline stage masks affect
    <<synchronization-pipeline-stages-masks, access and synchronization
    scopes>>.
  * Clarify that dedicated allocations do not allow aliasing in the
    flink:vkBindBufferMemory and flink:vkBindImageMemory valid usage
    statements.
  * Correct specification of pname:dynamicCount for push_constant token in
    slink:VkIndirectCommandsLayoutNVX.

New Extensions:

  * `VK_EXT_shader_viewport_index_layer`

-----------------------------------------------------

Change log for August 1, 2017 Vulkan 1.0.57 spec update:

  * Bump API patch number and header version number to 57 for this update.

Github Issues:

  * Fix error in description of ename:VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK
    block size (public issue 342).
  * Update documentation of ename:VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT
    to explicitly mention both graphics and compute pipelines (public issue
    525).

Internal Issues:

  * Document that
    slink:VkPhysicalDeviceLimits::pname:framebufferColorSampleCounts does
    not cover integer formats (internal issue 550).
  * Add a note under slink:VkImageViewCreateInfo describing how values meant
    for one format can be sanitized when used via another format (internal
    issue 927).
  * Add valid usage statements to ftext:vkCmd* documenting that image
    subresources used as attachments must not be accessed as non-attachments
    in a render pass (internal issue 929).
  * Remove obsolete 'validextensionstructs' attribute from +vk.xml+, the XML
    schema, and the schema documentation (internal issue 946).

New Extensions:

  * `VK_AMD_mixed_attachment_samples`
  * `VK_EXT_post_depth_coverage`
  * `VK_KHR_relaxed_block_layout`

-----------------------------------------------------

Change log for July 21, 2017 Vulkan 1.0.56 spec update:

  * Bump API patch number and header version number to 56 for this update.

Github Issues:

  * Add valid usage statements for commands introduced by
    `VK_EXT_debug_report` and `VK_EXT_debug_marker` extensions, regarding
    the valid pname:object and pname:objectType values (public issue 495).
  * Modify `GL_KHR_vulkan_glsl` specification to document that uniform and
    buffer block arrays each take only a single binding (public issue 514).
  * Add `KHX` author tag to +vk.xml+ (public issue 526).

Internal Issues:

  * Document use of code: macro for non-Vulkan APIs in the style guide
    (internal issue 863).
  * Document that reference page open block delimiters must not contain
    asciidoc section markup in the style guide (internal issue 898).
  * Fix <<spirvenv,SPIR-V appendix>> to say
    code:VariablePointersStorageBuffer instead of
    code:VariablePointersUniformBufferBlock (internal issue 928).

Other Commits:

  * Add missing extension structures to dependency attributes in +vk.xml+.

New Extenions:

  * `VK_EXT_depth_range_unrestricted`

-----------------------------------------------------

Change log for July 15, 2017 Vulkan 1.0.55 spec update:

  * Bump API patch number and header version number to 55 for this update.

Github Issues:

  * Removed unintended optional parameter in +vk.xml+ from the
    pname:pWaitSemaphores member of slink:VkPresentInfoKHR, which resulted
    in the generation of an incorrect implicit valid usage clause allowing
    pname:pWaitSemaphores to be NULL even when pname:waitSemaphoreCount is
    non-zero (public issue 491).
  * Add missing attribute to +vk.xml+ documenting that
    slink:VkSwapchainCounterCreateInfoEXT extends
    slink:VkSwapchainCreateInfo (public issue 510).
  * Add const qualifier for some `VK_EXT_debug_market` extension command
    parameters that were missing it (public issue 513).
  * Fix definition of q and level~base~ in
    <<textures-image-level-selection,Image Level(s) Selection>> (public
    issue 515).
  * Clarify lifetime requirement for slink:VkRenderPass objects used in
    object creation (public issue 516).
  * Fix link to floating/normalized fixed-point conversion from
    <<interfaces-fragmentoutput,Fragment Output Interface>> (public issue
    521).

Internal Issues:

  * Update the style guide to include the general structure of a Vulkan
    command name, the specific rule for using "`Get`" vs. "`Enumerate`" in
    names, and a table of verbs commonly used in command names (spinoff of
    internal issue 753).
  * Clarified the behavior of automatic layout transitions in case of
    attachment views that are 2D or 2D array views of 3D images. In
    addition, restructured the valid usage clauses corresponding to the
    members of the slink:VkImageSubresourceRange structure and added missing
    valid usage clauses for its pname:baseMipLevel and pname:baseArrayLayer
    members (internal issues 803, 849).
  * Modify `GL_KHR_vulkan_glsl` specification to allow explicit std430 on a
    push_constant declaration (internal issue 919).

Other Commits:

  * Modify <<synchronization-framebuffer-regions, Framebuffer Region
    Dependencies>> to use synchronization scope terminology.
  * Add ename:VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT to the
    `VK_EXT_swapchain_colorspace` extension.
  * Replace XML comments with `comment` attributes and/or tags, to enable
    tools which transform the XML without loss of information.
  * Replace `validextensionstructs` with `structextends`, which is tagged in
    the child structure instead of the parent. This makes it slightly
    simpler to add new structs to the XML, causes fewer merge conflicts, and
    the information is kept localized to the extension structures where it
    belongs. The old `validextensionstructs` attributes will be retained
    until we're certain this doesn't cause problems with known consumers of
    +vk.xml+.

-----------------------------------------------------

Change log for July 13, 2017 Vulkan 1.0.54 spec update:

  * Bump API patch number and header version number to 54 for this update.

Github Issues:

Internal Issues:

  * Fix tessellation domain to have an upper-left origin in the
    <<img-tessellation-topology-ul, tessellation toplogy image>> and related
    language. CTS and all implementations were already doing this, it was
    just a documentation bug that it was flipped to lower-left (internal
    issue 603).
  * Add a section to the style guide describing how VUID tags are changed
    and removed when the corresponding Valid Usage statements are modified
    (internal issue 829).
  * Add explicit Valid Usage statement to
    slink:VkPipelineDynamicStateCreateInfo to require that members of
    pname:pDynamicStates must be unique (internal issue 851).

New Extensions:

  * `VK_KHR_16bit_storage`
  * `VK_KHR_dedicated_allocation`
  * `VK_KHR_external_fence`
  * `VK_KHR_external_fence_capabilities`
  * `VK_KHR_external_fence_fd`
  * `VK_KHR_external_fence_win32`
  * `VK_KHR_get_memory_requirements2`
  * `VK_KHR_storage_buffer_storage_class`
  * `VK_KHR_variable_pointers`

Extensions Promoted From KHX To KHR Status:

  * `VK_KHR_external_memory`
  * `VK_KHR_external_memory_capabilities`
  * `VK_KHR_external_memory_fd`
  * `VK_KHR_external_memory_win32`
  * `VK_KHR_external_semaphore`
  * `VK_KHR_external_semaphore_capabilities`
  * `VK_KHR_external_semaphore_fd`
  * `VK_KHR_external_semaphore_win32`
  * `VK_KHR_win32_keyed_mutex`

-----------------------------------------------------

Change log for June 24, 2017 Vulkan 1.0.53 spec update:

  * Bump API patch number and header version number to 53 for this update.

Github Issues:

Internal Issues:

  * Clarify mappings of coordinates for mutable, compatible image views in
    slink:VkImageViewCreateInfo (internal issue 815).
  * Make ename:VK_BIND_SFR_BIT require a logical device with multiple
    physical devices, so that standard sparse image block dimensions are
    only required on systems that support multi-GPU (internal issue 835).
  * Convert all files from use of // refBegin .. // refEnd comments to
    delimit ref pages, to use of open blocks, and update style guide
    accordingly (internal issue 839).
  * Add valid usage for slink:VkWriteDescriptorSet when performing updates
    to a ename:VK_STORAGE_IMAGE descriptor with layout
    ename:VK_IMAGE_LAYOUT_GENERAL.
  * Add a hack to the validity generator script to support an odd
    interaction between flink:vkCmdFillBuffer and an extension (internal
    issue 853).
  * Remove redundant text describing slink:VkBufferCreateInfo::pname:usage,
    which was already covered by implicit valid usage (internal issue 854).
  * Update implicit validity generator script to properly handle the
    pname:sType and pname:pNext members of "returnedonly" structures
    (internal issue 874).
  * Note that slink:VkApplicationInfo::pname:pApplicationName &
    slink:VkApplicationInfo::pname:pEngineName are optional, and add missing
    implicit valid usage statements for flink:vkDestroyInstance.
  * Added missing valid usage for flink:vkCmdWriteTimestamp to require a
    timestamp query pool.
  * Simplify and/or split "`non-atomic`" valid usage statements.

New Extensions:

  * `VK_AMD_gpu_shader_int16`
  * `VK_EXT_blend_operation_advanced`
  * `VK_EXT_sampler_filter_minmax`
  * `VK_NV_framebuffer_mixed_samples`

-----------------------------------------------------

Change log for June 13, 2017 Vulkan 1.0.52 spec update:

  * Bump API patch number and header version number to 52 for this update.

Github Issues:

Internal Issues:

  * Clarify behavior when non-coherent memory has
    <<memory-device-unmap-does-not-flush, not been flushed before being
    unmapped>> (internal issue 819).
  * Fix description of code:WorkgroupSize builtin to note it decorates an
    object, not a variable (internal issue 836).
  * Fix asciidoc attributes so that trailing '{plus}' symbols in [eq] style
    equations are rendered properly (internal issue 845).
  * Add language to the "`Extension Handles, Objects, Enums, and Typedefs`"
    section of the Procedures and Conventions document stating that any new
    handle type requires a corresponding entry in the elink:VkObjectType
    enumerated type (internal issue 856).
  * Update style guide to use slink macro for Vulkan handle type names, and
    define narrow conditions under which to use the *name and *text macros
    instead of *link (internal issue 886).
  * Add a dependency of the <<VK_KHX_device_group,VK_KHX_device_group>>
    extension on VK_KHX_device_group_creation to +vk.xml+ and the extension
    appendix.
  * Change the copyright on Vulkan specification asciidoc *source* files to
    CC-BY 4.0, and update the proprietary Khronos copyright applied to the
    generated *output* formats (internal issue 327). This enables broader
    re-use and modification of the Vulkan specification sources, while not
    affecting the Reciprocal IP License between Vulkan Adopters and Working
    Group Members.

New Extensions:

  * `VK_NV_fill_rectangle`
  * `VK_NV_fragment_coverage_to_color`

-----------------------------------------------------

Change log for June 4, 2017 Vulkan 1.0.51 spec update:

  * Bump API patch number and header version number to 51 for this update.

Github Issues:

  * Add Valid Usage statement to flink:vkCmdResolveImage to require that
    source and destination image formats match (public issue 492).
  * Specify that a code:char* parameter must: be a valid null-terminated
    string in the <<fundamentals-implicit-validity, implicit valid usage>>
    section (public issue 494).
  * Removed unnecessary VU for slink:VkPhysicalDeviceFeatures which is
    covered by ename:VK_ERROR_FEATURE_NOT_PRESENT already (public issue
    496).
  * Clarify valid usage of pname:pQueueFamilyIndices in
    slink:VkBufferCreateInfo, slink:VkImageCreateInfo, and
    slink:VkSwapchainCreateInfoKHR (public issue 501).
  * Document that dependencies of enabled extensions must also be enabled in
    the <<extended-functionality-extensions-dependencies, Extension
    Dependencies>> section (public issue 507).

Internal Issues:

  * Change slink:VkMappedMemoryRange valid usage to allow pname:offset +
    pname:size == size of the allocation. Also, if ename:VK_WHOLE_SIZE is
    used, require the end of the mapping to be aligned to a multiple of
    pname:nonCoherentAtomSize (internal issue 611).
  * Add issue to `VK_KHR_win32_surface` about reusing window objects from a
    different graphics API or Vulkan ICD (internal issue 639).
  * Require locations on user in/out in `GL_KHR_vulkan_glsl` (internal issue
    783).
  * Added version info to the json validation output, and updated the schema
    to match (internal issue 838).
  * Restructure enumerated type descriptions separately from the command or
    structure they are used in, allowing better reference page generation
    (internal issue 841).
  * Re-sort extension appendices to be in alphabetical order within each
    author ID section.
  * Fix enum naming and clarify behavior for
    `VK_NVX_device_generated_commands` extension.

-----------------------------------------------------

Change log for May 20, 2017 Vulkan 1.0.50 spec update:

  * Bump API patch number and header version number to 50 for this update.

Github Issues:

  * Fix numerous minor issues with the VK_EXT_debug_report extension (public
    issues 478, 483, 486, 489, 490).

Internal Issues:

  * Update flink:vkAllocateDescriptorSets to specify conditions under which
    to return ename:VK_ERROR_FRAGMENTED_POOL or
    ename:VK_ERROR_OUT_OF_POOL_MEMORY instead of
    out-of-host/out-of-device-memory, and improve the
    <<fundamentals-errorcodes, description of those errors (internal issue
    654).
  * Add a NOTE documenting that flink:vkAcquireNextImageKHR can only signal
    a single semaphore, and how to deal with that when multiple physical
    devices in a logical device need to wait on it (internal issue 730).
  * Improve description of pname:pNext chains of
    slink:VkPhysicalDeviceImageFormatInfo2KHR and
    slink:VkImageFormatProperties2KHR (internal issue 814).
  * Clean up math markup issues in the <<textures, Image Operations>>
    chapter (internal issue 818).
  * Update validusage target to use more robust code for preprocessing, by
    making direct use of Asciidoctor's preprocessor. Added uniqueItems check
    to JSON vu schema and add clean_validusage target (internal issue 826).
  * Update style guide to prohibit writing non-self-contained (on a single
    bullet point) Valid Usage statements, and modify offending Valid Usage
    statements in the Specification to match, to assist with automatic
    extraction for the validation layers (internal issue 828).
  * Add ename:VK_VALIDATION_CHECK_SHADERS_EXT to elink:VkValidationCheckEXT
    of the `VK_EXT_validation_flags` extension, to selectively disable
    shader validation.
  * Remove duplicate valid usage statement for slink:VkImageMemoryBarrier.
  * Modify reflow.py script to place VUID tag anchors standalone on a line
    following their corresponding bullet point, and reflow the spec text
    accordingly (this had been pending since the initial tag deployment).

New Extensions:

  * `VK_AMD_texture_gather_bias_lod`

-----------------------------------------------------

Change log for May 12, 2017 Vulkan 1.0.49 spec update:

  * Bump API patch number and header version number to 49 for this update.

Github Issues:

  * Modify reference page extraction script to make internal links to spec
    anchors refer to the core specification instead of being dangling links
    (public issue 455).
  * Fix GL_KHR_vulkan_glsl typo and add a nor-normative mapping to the newly
    published StorageBuffer class (public issue 466).
  * Both flink:vkEnumerateInstanceExtensionProperties and
    flink:vkEnumerateDeviceExtensionProperties return
    ename:VK_ERROR_LAYER_NOT_PRESENT, which covers the error case of an
    application providing a layer name that wasn't returned by
    ftext:vkEnumerate{Instance|Device}LayerProperties (public issue 487).
  * The specification for flink:VkApplicationInfo::apiVersion says that the
    driver must return ename:VK_ERROR_INCOMPATIBLE_DRIVER in the case that
    pname:apiVersion specifies a non-supported version. That means that the
    valid usage should not also state that, and so the VU statement is
    removed. The VU had language about "`an effective substitute`" that
    would have been lost, and so it was moved to the pname:apiVersion
    description (public issue 488).

Internal Issues:

  * Modify implicit validity generator script to assign asciidoc anchors to
    all valid usage statements it generates, and reflow.py script to insert
    Valid Usage ID (VUID) tags into the specification source files for
    explicit valid usage statements. This has no semantic effects on the
    specification, but will support the validation layer's detection of
    valid usage violations and allow it to link into the corresponding part
    of the specification (internal issue 583).
  * Assign VUID tags to all explicit VU statements and document
    the process and tag format in the style guide (internal issue 583).
  * Clarify the rules of whether to structure new functionality as instance
    extensions, device extensions, or both in the
    <<extended-functionality-instance-extensions-and-devices, Instance
    Extensions and Device Extensions>> section (internal issue 749).
  * Require that SPIR-V run-time arrays are only used with the
    code:BufferBlock decoration (internal issue 750).
  * Fix implicit and explicit valid usage statements for
    slink:VkWriteDescriptorSet::pname:dstSet (internal issue 767)
  * Fix SPIR-V code sample for ename:VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER
    in the <<descriptorsets-uniformtexelbuffer, Uniform Texel Buffer>>
    section (internal issue 770).
  * Clarify that disabling depth testing also disables depth writes in the
    <<fragops-ds-state, Depth and Stencil Operations>> section (internal
    issue 775).
  * flink:VkDescriptorImageInfo::pname:imageLayout must match the actual
    imageLayout at the time the image is accessed. This was in the spec
    text, but needed an associated valid usage statement.
  * Note that only 32-bit atomic operations are supported in the
    <<spirvenv-module-validation, Validation Rules within a Module>>
    section.
  * Note that code:UniformConstant variables must not have initializers in
    the <<spirvenv-module-validation, Validation Rules within a Module>>
    section.
  * Add a new elink:VkObjectType enumeration to the core API, promoted from
    elink:VkDebugObjectTypeEXT, since it is used for much more than just the
    debug_report extension.

New Extensions:

  * `VK_KHR_get_surface_capabilities2`
  * `VK_KHR_shared_presentable_image`

-----------------------------------------------------

Change log for April 15, 2017 Vulkan 1.0.48 spec update:

  * Bump API patch number and header version number to 48 for this update.

Internal Issues:

  * Add missing VU statements for flink:vkUpdateDescriptorSets (internal
    issue 333).
  * Correct swapped ifdef/ifndef blocks for `VK_KHR_maintenance1` extension
    (internal issue 776).

-----------------------------------------------------

Change log for April 8, 2017 Vulkan 1.0.47 spec update:

  * Bump API patch number and header version number to 47 for this update.

Github Issues:

  * Allow <<synchronization-pipeline-barriers-subpass-self-dependencies,
    self-dependencies>> (also described for slink:VkSubpassDependency) to
    have earlier stages depend on later stages if all stages are
    framebuffer-space (public issue 125).
  * Clarify when pipeline state structures are ignored in the
    slink:VkGraphicsPipelineCreateInfo strucure, when the tessellation
    structure must be valid, and remove 'if `NULL`' descriptions from the
    valid usage statements (public issue 445).
  * Remove the obsolete "validextensionstructs" attribute for
    flink:VkPresentRegionsKHR. This caused a pname:pNext valid usage
    statement to be generated which wasn't consistent with what is stated in
    the spec (public issue 481).

Internal Issues:

  * Clarify facingness of non-polygon fragments for slink:VkStencilOpState
    and in the code:FrontFacing <<interfaces-builtin-variables,built-in
    variable description>>. Define 'facingness' of a fragment as a distinct
    term from facingness of a polygon (internal issue 662).
  * Clarify that the texture compression features (e.g.
    pname:textureCompressionBC) means that all formats of that type
    (<<features-features-textureCompressionASTC_LDR,ASTC>>,
    <<features-features-textureCompressionETC2,ETC2>>,
    <<features-features-textureCompressionBC,BC>>) are supported, and that
    support for individual formats may: queried separately (internal issue
    663).
  * Clarify in the valid usage for slink:VkBindImageMemoryInfoKHX that each
    SFR rectangle must be a multiple of the sparse block size for each
    aspect, e.g. in a depth/stencil image using separate depth/stencil
    planes (internal issue 721).
  * Re-remove KHX variants of KHR structure types after promotion (internal
    issue 762).

-----------------------------------------------------

Change log for March 31, 2017 Vulkan 1.0.46 spec update:

  * Bump API patch number and header version number to 46 for this update.

Github Issues:

  * Add language to the <<fundamentals-validusage-enums, Valid Usage for
    Enumerated Types>> section allowing values to be returned from Vulkan
    that are not present in extensions explicitly enabled by the
    application, similar to existing language for bit flags in the
    <<fundamentals-validusage-flags, Valid Usage for Flags>> section (public
    issue 442).
  * *Important*: run `gem update --pre asciidoctor-pdf` before trying to
    build this version of the spec - 1.5.0.alpha15 is required for this
    change. Removes the monkey patch currently used to draw valid usage
    blocks across multiple pages which had numerous issues. A fixed version
    was incorporated into Asciidoctor-PDF for the latest release, so the
    monkey patch or any variant thereof is no longer required (public issue
    465).

Internal Issues:

  * Add ename:VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR_EXT
    to `VK_EXT_debug_report` extension
  * Fix ptext:pNext member of
    slink:VkPhysicalDeviceDiscardRectanglePropertiesEXT to be a non-const
    pointer. Properties structures return values, so the chain should be
    non-const.
  * Explicitly remove gl_NumSamples from the `GL_KHR_vulkan_glsl` extension,
    against 1.0 (internal issue 612).
  * Add Valid Usage statements requiring that each structure type valid in a
    ptext:pNext chain must: not appear more than once in a chain (internal
    issue 752).
  * Use ename:VK_USE_PLATFORM_WIN32_KHX in the
    `VK_KHX_external_memory_win32` extension, rather than etext:_KHR
    (internal issue 754).

New Extensions:

  * `VK_KHR_incremental_present`

-----------------------------------------------------

Change log for March 24, 2017 Vulkan 1.0.45 spec update:

  * Bump API patch number and header version number to 45 for this update.

Github Issues:

  * Defined the lifetime of the memory pointed to by
    slink:VkDisplayPropertiesKHR::pname:displayName to be equal to that of
    its associated display handle (public issue 460).
  * Correct several cases where the sparse memory feature name
    pname:residencyNonResidentStrict was written as
    pname:sparseResidencyNonResidentStrict (public issue 475).

Internal Issues:

  * Fix ptext:pNext member of slink:VkPhysicalDeviceGroupPropertiesKHX to be
    a non-const pointer. Properties structures return values, so the chain
    should be non-const.
  * Clarify definition of memory aliasing to consistently use the terms
    "linear" and "non-linear" when referring to resources, and define what
    those terms mean.
  * Modified XML schema and implicit validity scripts to generate language
    for all ptext:pNext values in a ptext:pNext chain instead of just the
    top level struct, and made `noautovalidity` functional for ptext:sType
    and ptext:pNext (internal issue 535).
  * Add more detail for BT2020 and scRGB color spaces in
    `VK_EXT_swapchain_colorspace` extension (internal issue 632).
  * Add naming rules for Extension Structure Names (structures added to the
    ptext:pNext chain of a base structure) to the style guide (internal
    issue 706).
  * Define the glossary term "ptext:pNext chain", and use it consistently in
    the spec (internal issue 744).

-----------------------------------------------------

Change log for March 17, 2017 Vulkan 1.0.44 spec update:

  * Bump API patch number and header version number to 44 for this update.

Github Issues:

  * Fix description of <<features-extentperimagetype, Allowed Extent Values
    Based On Image Type>> (public issue 290).
  * Better specify VK_DEVICE_LOST behavior around flink:vkQueueSubmit,
    flink:vkWaitForFences, and flink:vkGetFenceStatus (public issue 423).
  * Clarify definition of flink:vkGetQueryPoolResults::pname:queryCount
    (public issue 441).
  * Simplify and clean up normative language. Remove shall and replace
    recommend and variants with should wherever possible (public issue 448).
  * Fix all dangling internal cross-references in the 1.0-extensions
    specification, and add scripts/checkXrefs to find these in the future
    (public issue 456).
  * Reverse order of ChangeLog.txt entries so the most recent version is
    documented first (public issue 463)
  * Removes "become invalid" which clashes with invalid state for command
    buffers. (public issue 467)
  * Disallowed pending state in spec text for vkResetCommandBuffer, matching
    valid usage (public issue 468)
  * Removes sentence describing invalid state "like initial state". (public
    issue 469)
  * Disallows begin command buffer from resetting command buffers in the
    "recording" state. (public issue 470)
  * Removes mention of state from description of
    VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT (public issue 471)
  * Removed extra valid usage statement in VkSubmitInfo (public issue 472)

Internal Issues:

  * Clarify description of the pname:imageLayout member of
    sname:VkDescriptorImageInfo.
  * Fix typos where etext:VK_VIEW_TYPE* was used instead of
    etext:VK_IMAGE_VIEW_TYPE.
  * Removed the <<VK_KHR_display>> and <<VK_KHR_display_swapchain>> example
    code from the specification and noted it has been moved to the Vulkan
    SDK cube demo (internal issue 179).
  * Reorder VkExternalMemoryHandleTypeFlagBitsNV description (internal issue
    480).
  * Clarify than an implementation is
    <<fundamentals-validusage-flags,permitted to return 'undefined' bit
    flags>> in a bitfield (internal issue 640).
  * Break Valid Usage statements describing unrelated parameters into
    separate statements, and add a style guide entry to follow this approach
    (internal issue 685).
  * Move valid usage statement for slink:VkImageCreateInfo from spec body to
    the explicit valid usage block (internal issue 693).
  * Fix typos in the descriptions of slink:VkDisplaySurfaceCreateInfoKHR,
    flink:vkCreateDisplayModeKHR, and
    flink:vkGetDisplayPlaneSupportedDisplaysKHR in the <<display,Presenting
    Directly to Display Devices>> section (internal issue 698, 704, 716).
  * Clarified that mandatory depth/stencil formats are only a requirement
    for 2D images (internal issue 719).
  * Clarify that variables decorated with DeviceIndex/ViewIndex must be in
    the Input storage class (internal issue 733).
  * Work around generator script problem with removal of Unicode literals
    from Python 3.0-3.2 using `future` package (internal issue 737).
  * Remove nonexistent structure type enums from vk.xml (internal issue
    738).
  * Fix validextensionstructs attributes for structures in the pname:pNext
    chain for VkPresentInfoKHR, fixing implicit valid usage statements for
    those structures (internal issue 740).

-----------------------------------------------------

Change log for March 10, 2017 Vulkan 1.0.43 spec update:

  * Bump API patch number and header version number to 43 for this update.

Github Issues:

  * Make clearer that color write mask is applied regardless of whether
    blending is enabled, by referring to the
    <<framebuffer-color-write-mask,Color Write Mask>> section (public issue
    241).
  * Fix public issue 414:
  ** Added two new command buffer states (invalid, pending), and an explicit
     "command buffer lifecycle" section to explain them.
  ** Replaced "pending execution" with "in the pending state".
  ** Replaced a bunch of "this will invalidate the command buffer" language
     with "this will move the command buffer to the invalid state", and added
     validation language for what state those command buffers should be in.
  ** Added additional validation language about what state a command buffer
     should be in for various commands that affect it.
  ** Added invalidation language to destroy commands in the lifetimes section
     of fundamentals.
  ** Added command buffers to list of objects which must not be deleted
     whilst a (primary) command buffer is in the recording or pending state.
  * Update `GL_KHR_vulkan_glsl` extension to allow anonymous push constant
    blocks (public issue 428).

Internal Issues:

  * Document rules about extension interactions in the style guide (internal
    issue 579).
  * Require ename:VK_PRESENT_MODE_MAILBOX_KHR support in queries of surfaces
    created with flink:vkCreateWaylandSurfaceKHR using the
    VK_KHR_wayland_surface extension (internal issue 666).
  * Remove Valid Usage constraints for flink:vkAllocateDescriptorSets when
    the `VK_KHR_maintainance1` extension is present (internal issue 686).
  * Remove undocumented KHX-variants of vkGetPhysicalDeviceProperties2KHR
    and vkGetPhysicalDeviceImageFormatProperties2KHR from the
    <<VK_KHX_external_memory_capabilities>> and
    <<VK_KHX_external_semaphore_capabilities>> extensions.

New Extensions:

  * `VK_EXT_hdr_metadata`
  * `VK_GOOGLE_display_timing`

-----------------------------------------------------

Change log for February 27, 2017 Vulkan 1.0.42 spec update:

  * Bump API patch number and header version number to 42 for this update
    (the first anniversary edition).

Github Issues:

  * Changed asciidoctor macros so cross-page links in the standalone
    reference pages function properly (public issue 462).

Internal Issues:

  * Clarified host visibility discussion for slink:VkMemoryType,
    flink:vkInvalidateMappedMemoryRanges, elink:VkAccessFlagBits, and the
    <<synchronization-framebuffer-regions,Framebuffer Region Dependencies>>
    section, removing duplicated information and adding a central definition
    in the access types section (internal issue 552).
  * Change description of
    slink:vkGetPhysicalDeviceSurfacePresentModesKHR::pname:pPresentModes to
    return an array of values, not structures (internal issue 699).

New Extensions:

  * Add a NOTE to the <<extensions,Layers & Extensions>> chapter describing
    the experimental status of `KHX` extensions.
  * Add new Khronos, Khronos Experimental, and vendor Vulkan extensions for
    release at GDC:
  ** VK_KHR_descriptor_update_template
  ** VK_KHR_push_descriptor
  ** VK_KHX_device_group
  ** VK_KHX_device_group_creation
  ** VK_KHX_external_memory
  ** VK_KHX_external_memory_capabilities
  ** VK_KHX_external_memory_fd
  ** VK_KHX_external_memory_win32
  ** VK_KHX_external_semaphore
  ** VK_KHX_external_semaphore_capabilities
  ** VK_KHX_external_semaphore_fd
  ** VK_KHX_external_semaphore_win32
  ** VK_KHX_multiview
  ** VK_KHX_win32_keyed_mutex
  ** VK_EXT_discard_rectangles
  ** VK_MVK_ios_surface
  ** VK_MVK_macos_surface
  ** VK_NVX_multiview_per_view_attributes
  ** VK_NV_clip_space_w_scaling
  ** VK_NV_geometry_shader_passthrough
  ** VK_NV_sample_mask_override_coverage
  ** VK_NV_viewport_array2
  ** VK_NV_viewport_swizzle
  * Add new GLSL vendor extensions to support new builtin variables:
  ** GL_EXT_device_group
  ** GL_EXT_multiview

-----------------------------------------------------

Change log for February 17, 2017 Vulkan 1.0.41 spec update:

  * Bump API patch number and header version number to 41 for this update.

Github Issues:

  * Made all uses of `NULL` vs. code:VK_NULL_HANDLE consistent (public issue
    276).
  * Clarify render pass compatibility in different usage scenarios (public
    issues 403 and 404).
  * Add valid usage statements to slink:VkFramebufferCreateInfo requiring
    that the width, height, and number of layers of the framebuffer all be
    nonzero (public issue 432).
  * Allow `offset` and `align` in any GLSL version for the
    `GL_KHR_vulkan_glsl` extension (public issue 435).
  * Specify lifetime of string objects passed to the
    tlink:PFN_vkDebugReportCallbackEXT user callback in the
    +VK_EXT_debug_report+ extension (public issue 446).
  * Fix inter-page links in multi-file reference pages (public issue 454).

Internal Issues:

  * Update valid usage language for slink:VkImageCreateInfo to disallow
    creating images that have ename:VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT
    set without other attachment usage bits
    (ename:VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT,
    ename:VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT, or
    ename:VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT) (internal issue 540).
  * Disable `VK_EXT_swapchain_colorspace` extension until internal issues
    640 and 661 are mutually resolved.
  * Allow alternative mipmap level selection when [eq]#lambda == 0.5# during
    texture <<textures-image-level-selection,Image Level(s) Selection>>
    (internal issue 680).

Other Issues:

  * Add a clarification to the style guide that the extension revision
    number is treated as a patch number, so that changes to published
    extensions should only include bug fixes and spec clarifications.

-----------------------------------------------------

Change log for February 10, 2017 Vulkan 1.0.40 spec update:

  * Bump API patch number and header version number to 40 for this update.
  * There is a major build change in this release. We are now using the
    Ruby-based ``asciidoctor'' implementation, rather than the Python-based
    ``asciidoc'' implementation, to process the specification. While the
    actual specification markup changes were minimal, this requires a new
    set of build tools and a very different installation process, especially
    because we now use an experimental direct-to-PDF backend for Asciidoctor
    instead of Docbook->dblatex->PDF. It is no longer possible to build the
    Specification using asciidoc. See doc/specs/vulkan/README.adoc
    for some guidance on installing the new toolchain components.
  * There are some minor rendering issues in the PDF output due to teething
    problems with the asciidoctor toolchain, especially with mathematical
    equations. We are aware of these and working on them.

Github Issues:

  * Updated sample code for the <<sparsememory-examples-basic,sparse
    resource binding example>> (public issue 97).
  * Modify line and point clipping behavior in the
    <<vertexpostproc-clipping, Primitive Clipping>> section to allow for
    pop-free behavior. The ability to check for which behavior is
    implemented may be added a future feature or extension (public issue
    113).
  * Unify the discussions of implicit ordering throughout the spec, in
    particular in the new sections <<drawing-primitive-order, Primitive
    Order>>, <<primrast-order, Rasterization Order>>, and
    <<synchronization-implicit, Implicit Synchronization Guarantees>>; the
    discussion of <<synchronization-submission-order, submission order>>;
    and references elsewhere to these sections (public issue 133).
  * Clarify \<\<descriptorsets-compatibility,Pipeline Layout Compatibility>>
    language and introduce the term ``identically defined'' (public issue
    164).
  * Add a dependency to the +VK_EXT_debug_marker+ extension that's needed to
    reuse the object type enum from +VK_EXT_debug_report+, and moves the
    definition of that enum into +VK_EXT_debug_report+ where it should be
    (public issue 409).
  * Remove redundant valid usage statement from slink:VkImageBlit (public
    issue 421).
  * Update GL_KHR_vulkan_glsl to allow the ternary operator to result in a
    specialization constant (public issue 424).
  * Fix valid usage for flink:VkPipelineShaderStageCreateInfo (public issue
    426).
  * Correct typo in New Objects list for <<VK_EXT_debug_report>> (public
    issue 447).

Internal Issues:

  * Moved to asciidoctor for spec builds (internal issue 121).
  * Update style guide to describe where to put new extensions-specific
    asciidoc files, and what to name them (internal issue 626).
  * Add src/spec/indexExt.py to autogenerate registry index entries linking
    into the 1.0-extensions specification, instead of maintaining the index
    manually. (internal issue 642).
  * Autogenerate extension dependencies and lists of all extensions and all
    KHR extensions from the "supported" attributes in +vk.xml+. Execute
    +make config/extDependency.sh+ from +doc/specs/vulkan+ when a supported
    extension is added to vk.xml, to regenerate the dependency script. The
    consequence is that specifying a single extension to the +makeExt+
    script will automatically enable all extensions it depends on as well,
    and that the +makeAllExts+ and +makeKHR+ scripts do not need to be
    updated when a new extension is supported (internal issue 648).
  * Put extension appendices all at the same asciidoc section level, so KHR
    WSI extensions show up in the HTML index (internal issue 648).

Other Issues:

  * Imbed images in the generated HTML specs instead of loading them from
    the images/ directory.
  * Fix missing EXT in extension name
    (ename:VK_EXT_SWAPCHAIN_COLOR_SPACE_EXTENSION_NAME).
  * Add new +VK_EXT_SMPTE_2086_metadata+ extension.
  * In the <<platformCreateSurface_xlib,Xlib Surface>> section of the
    `VK_KHR_xlib_surface` specification, add language warning users that
    they always need to call code:XinitThreads.
  * Use the term "presentable image" (rather than "swapchain image")
    consistently in `VK_KHR_swapchain` and related extensions, and add a
    glossary term defining it.
  * Relocate the valid usage for samples of
    flink:vkGetPhysicalDeviceSparseImageFormatProperties2KHR::pname:pFormatInfo
    to be below the flink:VkPhysicalDeviceSparseImageFormatInfo2KHR
    structure.

-----------------------------------------------------

Change log for January 23, 2017 Vulkan 1.0.39 spec update:

  * Bump API patch number and header version number to 39 for this update.

Github Issues:

  * Clarified that only accesses via the specified buffer/image subresource
    ranges are included in the access scopes (public issue 306).
  * Add missing valid usage statements for flink:vkCreateComputePipelines
    and flink:vkCreateGraphicsPipelines (public issue 427).

Internal Issues:

  * Add a Note to the <<invariance,Invariance>> appendix about a difference
    between OpenGL and Vulkan with regards to how primitives derived from
    offsets are handled (internal issue 355).
  * Add the +<<VK_KHR_get_physical_device_properties2>>+,
    +<<VK_KHR_maintenance1>>+, and +<<VK_KHR_shader_draw_parameters>>+
    extensions (internal issue 448).
  * Add the +<<VK_EXT_shader_subgroup_vote>>+ and
    +<<VK_EXT_shader_subgroup_ballot>>+ extensions (internal issue 449).
  * Update the texture level-of-detail equation in the
    <<textures-scale-factor,Scale Factor Operation>> section to better
    approximate the ellipse major and minor axes (internal issue 547).
  * Forbid non-explicitly allowed uses of interface decorations in the
    introduction to the <<interfaces,Shader Interfaces>> chapter (internal
    issue 607).
  * Replace use of MathJax with KaTeX, for improved load-time performance as
    well as avoiding the scrolling-and-scrolling behavior due to MathJax
    asynchronous rendering when loading at an anchor inside the spec. This
    change also requires moving to HTML5 output for the spec instead of
    XHTML, and there is a visible difference in that the chapter navigation
    index is now in a scrollable sidebar instead of at the top of the
    document. We may or may not retain the nav sidebar based on feedback
    (internal issue 613).
  * Improve consistency of markup and formatting in extension appendices
    (internal issue 631).

Other Issues:

  * Add explicit valid usage statements to slink:VkImageCopy requiring that
    the source and destination layer ranges be contained in their respective
    source and destination images.
  * Add valid usage language for swapchain of flink:vkAcquireNextImage. If
    the swapchain has been replaced, then it should not be passed to
    flink:vkAcquireNextImage.
  * Add a valid usage statement to flink:vkCreateImageView, that the image
    must have been created with an appropriate usage bit set.
  * Noted that slink:VkDisplayPresentInfoKHR is a valid extension of
    slink:VkPresentInfoKHR in the <<wsi_swapchain,WSI Swapchain>> section.
  * Update valid usage for flink:vkCmdSetViewport and flink:vkCmdSetScissor
    to account for the multiple viewport feature. If the feature is not
    enabled, the parameters for these functions have required values that
    are defined in the <<features-features-multiViewport,multiple
    viewports>> section of the spec but were not reflected in the valid
    usage text for these functions.
  * Add the +<<VK_EXT_swapchain_colorspace>>+ extension defining common
    color spaces.

-----------------------------------------------------

Change log for December 16, 2016 Vulkan 1.0.38 spec update:

  * Bump API patch number and header version number to 38 for this update.

Github Issues:

  * Make ename:VK_PIPELINE_STAGE_HOST_BIT invalid for all stage masks,
    except for flink:vkCmdWaitEvents (public issue 261).

Internal Issues:

  * Added validation language for flink:vkQueueBindSparse,
    slink:VkPresentInfoKHR, and slink:VkSubmitInfo, and a note to the
    <<synchronization-semaphores-waiting,Semaphore Waiting and Unsignaling>>
    section to clarify that semaphores must be signaled and waited on in a
    1:1 fashion (internal issue 546).
  * Modify valid usage for slink:VkBufferImageCopy to only require
    pname:bufferOffset to be a multiple of the image format's element size
    when the format is not depth/stencil (internal issue 594).

Other Issues:

  * Vulkan(R) is now a registered trademark symbol, and this is reflected in
    documents and copyright statements.

-----------------------------------------------------

Change log for December 10, 2016 Vulkan 1.0.37 spec update:

  * Bump API patch number and header version number to 37 for this update.

Github Issues:

  * Add usability guarantees on the values returned by
    flink:vkGetPhysicalDeviceSurfaceCapabilitiesKHR in the
    slink:VkSurfaceCapabilitiesKHR structure and by
    flink:vkGetPhysicalDeviceSurfaceFormatsKHR in the
    pname:pSurfaceFormatCount parameter (public issue 385).
  * Add elink:VkDebugReportObjectTypeEXT enumerants for new object types
    introduced by new extensions (public issue 408).
  * Add +VK_NVX_device_generated_commands+ etext:ACCESS bits and define how
    they are used (public issue 415).
  * Fix indentation for slink:VkDebugReportCallbackCreateInfoEXT member
    descriptions (public issue 419).

Internal Issues:

  * Expand requirements memory binding of non-sparse images and buffers from
    the <<resources-association,Resource Memory Association>> section into
    valid usage statements for all of the applicable API calls (internal
    issue 508).
  * Explicitly state that valid usage of flink:vkCreateImage requires that
    flink:vkGetPhysicalDeviceImageFormatProperties would return
    ename:VK_SUCCESS for the requested image configuration (internal issue
    598).

-----------------------------------------------------

Change log for December 1, 2016 Vulkan 1.0.36 spec update:

  * Bump API patch number and header version number to 36 for this update.

Github Issues:

  * Fix "recorded with" terminology in the valid usage language for the
    flink:vkCmdExecuteCommands::pname:pCommandBuffers parameter (public
    issue 390).
  * Modify +genvk.py+ to support specifying extensions to remove from output
    generators, allowing the extension loader +vulkan_ext.c+ to be created
    without WSI extensions which are statically exported by the Vulkan
    loader (public issue 412).
  * Added validation language for slink:VkSubpassDependency and in the
    <<synchronization-access-types-supported,supported access types>>
    section to catch access masks that include bits which are not supported
    by pipeline stages in the stage masks (partially addresses
    github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers/issues/1006 ).

Internal Issues:

  * Added validation language for flink:vkCmdWaitEvents,
    flink:vkQueueSubmit, flink:VkRenderPassCreateInfo, and in the
    <<synchronization-pipeline-stages-supported>> section to prevent
    recording stage dependencies that aren't supported on the queue
    (internal issue 516).
  * Make a few changes that generalize spec language for use with possible
    future extensions by adding glossary terms and generalizing ``feature''
    to ``feature or extension'' where relevant (internal issues 448, 590).
  * Added "pipeline type" attribute to +vk.xml+ for relevant commands and
    utilize it in automatic generation of the Command Properties table
    (internal issue 517).
  * Specify that WSI implementations must provide both UNORM and sRGB
    formats in the description of slink:VkColorSpaceKHR (internal issue
    529).
  * Remove nesting of explicit valid usage statements where it is not
    meaningful (internal issue 583).

Other Issues:

  * Add validity language requiring that
    slink:VkPushConstantRange::pname:offset be a multiple of 4, as stated in
    the spec language.

-----------------------------------------------------

Change log for November 25, 2016 Vulkan 1.0.35 spec update:

  * Bump API patch number and header version number to 35 for this update.

Github Issues:

  * Document in the <<memory-device-hostaccess,Host Access>> section that
    mapping and unmapping does not invalidate or flush the mapped memory
    (public issues 27, 126).
  * Redefine the entire <<synchronization>> chapter in terms of consistent
    and well defined terminology, that's called out at the start of the
    chapter. This terminology is applied equally to all synchronization
    types, including subpass dependencies, submissions, and much of the
    implicit ordering stuff dotted around the spec. Key terms are laid out
    in the <<synchronization-dependencies,Execution and Memory
    Dependencies>> section at the top of the rewritten chapter (public
    issues 128, 131, 132, 217, 299, 300, 302, 306, 322, 346, 347, 371, 407).
  * Specify order of submission for batches in the
    <<vkQueueSubmit,vkQueueSubmit>> and
    <<vkQueueBindSparse,vkQueueBindSparse>> commands (public issue 371).
  * Add valid usage statements to each of the WSI extension sections
    indicating that the WSI-specific structure parameters must be valid, and
    remove automatically generated valid usage statements now covered by the
    manual sections (public issue 383).
  * Clarify render pass compatibility for flink:vkCmdExecuteCommands (public
    issue 390).

Internal Issues:

  * Update +vk.xml+ to make previously explicit valid usage statements for
    <<vkDebugReportMessageEXT,vkDebugReportMessageEXT>> implicit instead
    (internal issue 553).
  * Add valid usage statement for slink:VkCreateImageInfo preventing
    creation of 1D sparse images (internal issue 573).
  * Fix Python scripts to always read/write files in utf-8 encoding, and a
    logic error in reflib.py which could cause a fatal error for
    malstructured asciidoc (internal issues 578, 586).

-----------------------------------------------------

Change log for November 18, 2016 Vulkan 1.0.34 spec update:

  * Bump API patch number and header version number to 34 for this update.

Github Issues:

  * Allow vkUpdateDescriptorSets overflow to skip empty bindings. Clarify
    that unused bindings have a descriptorCount of zero. Improve some valid
    usage for vkUpdateDescriptorSets (public issue 256).
  * Require that slink:VkImageSubresourceRange always define a non-empty
    range of the resource (public issue 303).
  * Added valid usage for slink:VkPresentInfoKHR on the layout of presented
    images (public issue 397).

Internal Issues:

  * Add dependency in src/spec/Makefile so specversion.txt is regenerated
    when needed (internal issue 462).
  * Shorten the table of contents in the single-page ref page HTML output.
    Still working on the PDF (internal issue 536).

-----------------------------------------------------

Change log for November 11, 2016 Vulkan 1.0.33 spec update:

  * Bump API patch number and header version number to 33 for this update.

Github Issues:

  * Added implicit external synchronization parameters to
    vkBegin/EndCommandBuffer, and fixed missing command pool host
    synchronization from per-command lists (public issue 398).
  * Started using git tags including the spec release number, such as
    'v1.0.32-core', instead of tags including the date of release, such as
    'v1.0-core-20161025' (public issue 405).

Internal Issues:

  * Add validity constraint for
    slink:VkImportMemoryWin32HandleInfoNV::pname:handle (internal issue
    #480).
  * Add scripts to compare two Vulkan HTML specifications, derived from W3
    htmldiff service (internal issue 525).
  * Relax requirement that memoryTypeBits can't depend on format, to allow
    it to differ only for depth/stencil formats (internal issue 544).
  * Add a new generator script to create a simple extension loader for
    Vulkan based on +vk.xml+ (internal issue 558).
  * Add the overlooked requirement that buffer and image memory
    alignment requirements must be a power of two in the
    <<resources-association,Resource Memory Association>> section
    (internal issue 569).

Other Issues:

  * Add a naming rule to the style guide for members of extension structures
    defining array lengths which are the same as array lengths of the core
    structure they are chained from.
  * Add a new generator to create a simple extension loader in
    +src/ext_loader/vulkan_ext.[ch]+ from +vk.xml+. This code can be
    included in your project, and is expected to be packaged in the Vulkan
    SDK provided by LunarG in the future.

-----------------------------------------------------

Change log for October 25, 2016 Vulkan 1.0.32 spec update:

  * Bump API patch number and header version number to 32 for this update.

Github Issues:

  * Add automatic visibility operations to the presentation engineE when
    doing a queue present in flink:vkAcquireNextImageKHR. Removed all
    references to MEMORY_READ that referenced WSI - they no longer make
    sense (some aspects of public issues 128, 131, 132, 261, and 298).
  * Document valid non-boolean +externsync+ attribute values for <param>
    tags in +vk.xml+ (public issue 265).
  * Add valid usage to slink:VkImageCreateInfo requiring that
    pname:arrayLayers be 1 for images of type ename:VK_IMAGE_TYPE_3D
    (public issue 319).
  * Add missing captions to figures in the <<textures,Image Operations>>
    chapter (public issue 334).
  * Clarify WSI interaction with exclusive sharing mode (public issue
    344).
  * Added explicit language clarifying the allowed queue usage of
    resources created with ename:VK_SHARING_MODE_CONCURRENT (public
    issue 386).
  * Require that the
    slink:VkDescriptorSetLayoutCreateInfo::pname:binding members of the
    pname:pBindings array passed to
    flink:vkDescriptorSetLayoutCreateInfo all be distinct (public issue
    391).

Internal Issues:

  * Remove empty validity blocks from +vk.xml+ and suppressed broken
    validity statements and added missing statements to explicit
    validity. Doesn't affect output, other than some statements
    appearing in another block now (internal issue 513).

-----------------------------------------------------

Change log for October 14, 2016 Vulkan 1.0.31 spec update:

  * Bump API patch number and header version number to 31 for this update.

Github Issues:

  * Clarifying wording of slink:VkGraphicsPipelineCreateInfo parameters and
    adding Valid Usage statements on render pass compatibility to the
    <<drawing,drawing commands>> (public issue 375).
  * Replace 'texel size' with 'element size', and add a definition to the
    glossary (public issue 382).
  * Clarify the description of ename:VK_ERROR_NATIVE_WINDOW_IN_USE_KHR to
    make it accurate, but still generic (non-exhaustive). Remove two Valid
    Usage statements describing error situations that will return
    ename:VK_ERROR_NATIVE_WINDOW_IN_USE_KHR (public issue 387).
  * Fix refBegin tag for elink:VkDebugReportFlagBitsEXT (public issue 392).
  * The <<interfaces-builtin-variables,built-in variable>> code:PrimitiveId
    in a fragment shader needs the code:Input storage class (public issue
    393).

Internal Issues:

  * Unused ({y,z} and {height,depth} for 1D, z and depth for 2D) offsets
    must be 0 and unused extents must be 1. Added basic offset and extent
    valid usage for slink:VkImageResolve to match that of slink:VkImageCopy
    (internal issue 413).
  * Describe what flink:vkGetPhysicalDeviceImageFormatProperties returns for
    pname:sampleCounts when for pname:usage only includes transfer-related
    flags (internal issue 478).
  * Remove mention of
    slink:VkPhysicalDeviceLimits::pname:maxImageArrayLayers from the valid
    usage for slink:VkImageCreateInfo::pname:arrayLayers (internal issue
    520).
  * Tag usages of ``dynamically uniform'' as glossary terms and add a
    glossary entry pointing to the SPIR-V Specification's definition of the
    term (internal issue 531).

-----------------------------------------------------

Change log for October 7, 2016 Vulkan 1.0.30 spec update:

  * Bump API patch number and header version number to 30 for this update.

Github Issues:

  * Document missing pname:sType and pname:pNext parameters for
    slink:VkCommandBufferInheritanceInfo (public issue 224).
  * As promised, we are removing the example code, from the appendix, for
    the VK_KHR_surface and VK_KHR_swapchain extensions. The cube demo
    (shipped in the official Khronos SDK) has been updated, and is the
    example code that we want people to look at for how to use these two
    extensions (public issues 279, 308, and 311).
  * Clarify the formats for which the slink:VkClearColorValue pname:float32
    member is used. Also clean up related language for flink:vkCmdBlitImage
    (public issue 369).
  * Reword the <<invariance, Invariance>> appendix chapter to better match
    Vulkan terminology (public issue 372).

Internal Issues:

  * Update slink:VkMemoryRequirements to not require a host_visible memory
    type exists that can be bound to sparse buffers (internal issue 494).
  * Modify the <<features-supported-sample-counts,Supported Sample Counts>>
    language to allow multisampled depth-stencil images (internal issue
    521).

-----------------------------------------------------

Change log for September 30, 2016 Vulkan 1.0.29 spec update:

  * Bump API patch number and header version number to 29 for this update.

Github Issues:

  * Remove redundant constraint on
    slink:VkCommandBufferInheritanceInfo::pname:queryFlags (public issue
    224).
  * Fix typo and remove link in Note in the
    <<extended-functionality-instance-extensions-and-devices, Instance
    Extensions and Device Extensions>> section (public issue 359).
  * Fix erroneous validation statement for the pname:layout member of
    slink:VkComputePipelineCreateInfo (public issue 362).

Internal Issues:

  * Restore long figure captions using asciidoc sidebar blocks, due to
    restrictions of asciidoc syntax (internal issue 101).
  * Replace most latexmath equations with comparable markup in straight
    asciidoc, which significantly improves time required to fully load and
    process the HTML forms of the Specification. There are known minor font
    and alignment inconsistencies with MathJax and PDF rendering of
    latexmath equations. Please do not file github issues about these. We
    are aware of the inconsistencies and will make refinements over time,
    while the performance improvements are compelling in at least some major
    browsers (internal issue 313).
  * Move handcoded validity statements from +vk.xml+ into the Specification
    body, easing work in the single-branch model. Specify the distinction
    between these explicit statements, and the implicit validity statements
    inferred from vk.xml. Validity statements now appear in two blocks for
    each command and structure - handcoded "Valid Usage" and the implicit
    "Valid Usage (Implicit)" (internal issue 392).
  * Add the +returnedonly="false"+ attribute to WSI output structures,
    removing incorrectly generated implicit validity statements for
    slink:VkDisplayPropertiesKHR, slink:VkDisplayPlanePropertiesKHR,
    slink:VkDisplayModePropertiesKHR, slink:VkDisplayPlaneCapabilitiesKHR,
    slink:VkSurfaceCapabilitiesKHR, and slink:VkSurfaceFormatKHR structures
    (internal issue 486).
  * Update slink:VkImageLayout to require the
    ename:VK_IMAGE_USAGE_SAMPLED_BIT be set for sampled depth/stencil images
    (internal issue 487).
  * Use an explicit format specifier string for the date command invocation
    in the +Makefile+ instead of the shorthand -R option, which doesn't work
    on BSD and MaxOS X date commands (internal issue 500).

Other Issues:

  * Use the terms ``allocation scope'' and ``extension scope'' instead of
    just ``scope'', and add them to the glossary.

-----------------------------------------------------

Change log for September 23, 2016 Vulkan 1.0.28 spec update:

  * Bump API patch number and header version number to 28 for this update.

Github Issues:

  * Minor spelling and typography cleanup, add definitions of
    ename:VK_FALSE and ename:VK_TRUE as just what their names say
    (public issues 220, 318, 325, 365; internal issues 451, 496)
  * Clarify that the pname:maxDescriptorSet limits in the
    <<features-limits-required,Required Limits>> table are n *
    maxPerStage limit (where n=number of supported stages) (public issue
    254).
  * Minor cleanup to <<boilerplate-platform-macros,Platform-Specific
    Macro Definitions>> appendix (public issue 314).
  * Add valid usage statement to slink:VkPipelineLayoutCreateInfo
    disallowing multiple push constant ranges for the same shader stage
    (public issue 340).
  * Clarify the elink:VkSharingMode description of what executing the
    "same" barriers means in case of ownership transfer (public issue
    347).
  * Rename copyright.txt and add COPYING.md to try and reduce confusion
    about applicable copyrights (public issue 350).
  * Extend the table in the <<boilerplate-wsi-header, Window System-Specific
    Header Control>> section to describe the external headers included when
    each etext:VK_USE_PLATFORM_* macro is defined (public issue 376).

Internal Issues:

  * Add "Revision History" to the PDF outputs following the table of
    contents, to match HTML outputs (internal issue 43).
  * Clarified that flink:vkMapMemory may fail due to virtual address
    space limitations (internal issue 346).
  * Add +refBody+ comment markup for ref page autoextraction when required
    (internal issue 400).
  * Document proper use of "mipmap" and "mip" in the style guide API
    naming rules, matching the spelling rules (internal issue 471).
  * Tweak the <<extensions,Layers and Extensions>> appendix to note that
    the Specification may be built with arbitrary combinations of
    extensions (internal issue 483).
  * Remove incorrect statement allowing
    slink:VkClearAttachment::pname:colorAttachment to be >=
    slink:VkSubpassDescription::pname:colorAttachmentCount (internal
    issue 488).
  * The <<features-limits-viewportboundsrange,viewportBoundsRange>> is
    expressed in terms of the pname:maxViewportDimensions but this is
    actually two values. Clarify that it's based on the larger of the two
    (if they differ) (internal issue 499).

Other Issues:

  * Reflowed text of the entire spec using the 'reflow' Makefile target, to
    (hopefully) reduce future internal git churn as edits are made and
    extensions added in return for one-time pain. This has no perceptible
    effect on the spec outputs, but considerable changes on the asciidoc
    source (internal issue 367).

-----------------------------------------------------

Change log for September 16, 2016 Vulkan 1.0.27 spec update:

  * Bump API patch number and header version number to 27 for this update.

Github Issues:

  * Weaken flink:vkGetPipelineCacheData invariance conditions; previous
    conditions were stronger than agreed and can't be guaranteed (public
    issue 280).
  * Add link to "Vulkan Loader Specification and Architecture Overview"
    document to Normative References section (public issue 359).

Internal Issues:

  * Be more clear in the <<interfaces-resources-layout-std140, uniform
    buffer layout>> section that block offsets can be out of order
    (internal issue 396).
  * Document that extension authors should add support for their extensions
    to the validation layers (internal issue 398).
  * Clarify that the valid range of depth clear values should be limited
    to the 0..1 range and that copies to depth aspect must also be in this
    range (internal issue 412).
  * Specify ``a'' vs. ``an'' use in the style guide (internal issue 432).
  * Increase the maximum pname:nonCoherentAtomSize value in the
    <<features-limits-required,Required Limits>> section from 128 to 256
    (internal issue 435).
  * Fix vk_platform.h for compiler errors on some Android platforms
    (internal issue 441).
  * Clarify that slink:VkPhysicalDeviceFeatures::pname:pEnabledFeatures ==
    `NULL` disables all features, including the "required" feature
    pname:robustBufferAccess (internal issue 479).

Other Issues:

  * Expand style guide and make it more self-consistent.
  * Use ISO 8601 date format everywhere.
  * Emphasise the correct way of using
    slink:VkSurfaceCapabilitiesKHR::pname:maxImageCount.
  * Added +VK_EXT_validation_flags+ extension for validation flag mechanism.
  * Fix an <<credits,author credit>> to include their current employer.

-----------------------------------------------------

Change log for September 6, 2016 Vulkan 1.0.26 spec update:

  * Bump API patch number and header version number to 26 for this update.

Github Issues:

  * Bring sample code in the `VK_KHR_surface` and `VK_KHR_swapchain`
    extension summary appendices up to date, and note they will be replaced
    with pointers to the LunarG SDK examples in the future (public issue
    279).
  * Add a new <<fundamentals-commandsyntax-results-lifetime,Lifetime of
    Retrieved Results>> section specifying that ftext:vkGet* and
    ftext:VkEnumerate* results are invariant unless otherwise specified, and
    specify behavior for individual commands which are not invariant (public
    issue 280).
  * Remove conflicting definition of
    slink:VkDisplayPlaneCapabilitiesKHR::pname:maxSrcPosition and clean up
    language of the remaining definition (public issue 351).
  * Fix many minor spelling errors and add rules to the style guide to
    prevent recurrences (public issue 352).

Internal Issues:

  * Remove redundant descriptions of the etext:VK_USE_PLATFORM_* macros from
    the <<wsi,Window System Integration>> chapter in favor of the
    description in the <<boilerplate-wsi-header,Window System-Specific
    Header Control>> appendix (internal issue 6).
  * Replace misleading 'can: be destroyed when not X' with more correct
    'must: not be destroyed while X' in the
    <<fundamentals-objectmodel-lifetime,Object Lifetime>> section. Disallow
    destroying a pipeline layout while a command buffer using it is
    recording (internal issue 241).
  * Clarify that ename:VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT is valid for
    all images used as attachments in elink:VkImageUsageFlagBits and the
    slink:VkImageLayout validity language (internal issue 320).
  * Note that <<extended-functionality-layers,Layers>> may wrap object
    handles, but that this is a generally discouraged. A link to additional
    information in the documentation for layer authors is provided (issue
    398)
  * Replace the mustnot: and shouldnot: macros with equivalent must: not and
    should: not to get rid of non-English words while still highlighting
    normative language (internal issue 407).
  * Disallow creating multisampled images with
    ename:VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT in the slink:VkImageLayout
    validity language and the <<features-supported-sample-counts,Supported
    Sample Counts>> section (internal issue 445).
  * Fix typo so that flink:vkCmdDrawIndexedIndirect is defined in terms of
    flink:vkCmdDrawIndexed rather than flink:vkCmdDrawIndirect (internal
    issue 446).
  * Reorganize the per-extension information sections to all be in the
    <<extensions,Layers & Extensions>> appendix. Also fix a typo in
    +VK_IMG_filter_cubic+ which incorrectly identified it as a +KHR+
    extension (internal issue 461).

Other Issues:

  * Use asciidoc markup instead of latexmath to simplify diagrams in the
    <<features-formats-non-packed,byte mapping tables>> for color formats.
  * Fix a markup problem with the wildcarded enumerant names in a NOTE in
    the <<textures-texel-replacement,Texel Replacement>> section.
  * Fix missing attributes in the XML interface for
    elink:VkExternalMemoryHandleTypeFlagBitsNV and
    elink:VkExternalMemoryFeatureFlagBitsNV (KhronosGroup/Vulkan-Hpp issue
    25)
  * Cleanup reference page builds so only core pages are built for releases.

-----------------------------------------------------

Change log for August 26, 2016 Vulkan 1.0.25 spec update:

  * Bump API patch number and header version number to 25 for this update.
  * Structurally change the specification so that multiple extensions are
    included in the +1.0+ git branch, and specifications will include or not
    include those extensions at build time based on options passed to the
    Makefile. See +doc/specs/vulkan/README.html+ and the ``Layers and
    Extensions'' section of the ``Vulkan Documentation and Extensions''
    document for more information on this change.
  * Register and publish new extensions in the single-branch form:
  ** +VK_NV_external_memory_capabilities+
  ** +VK_NV_external_memory+
  ** +VK_NV_external_memory_win32+
  ** +VK_NV_win32_keyed_mutex+

Github Issues:

  * Clarify description of GetInstanceProcAddr and GetDeviceProcAddr (public
    issue 212).
  * Add SPIR-V <<textures-operation-validation, instruction validation>> for
    single-sampled images (public issue 316).
  * Fix spelling of ``tesselation'' in a few places and note it as an
    exception to the American spelling rules convention (public issue
    327).
  * Fix Makefile to create output directory for ``styleguide''
    target (public issue 329).
  * Fix numerous minor issues with incorrectly tags on enumerant names and
    table titles (public issue 330).
  * Generate specversion.txt date in UTC time and RFC 2822 format
    (public issue 335).
  * Convert link to the SPIR-V Specification for
    flink:VkShaderModuleCreateInfo into an internal link to the normative
    reference (public issue 336).
  * Add ename:VK_ERROR_OUT_OF_MEMORY error code to
    flink:vkCreateDebugReportCallbackEXT (public issue 337).

Internal Issues:

  * Update style guide regarding use of code:NULL and dname:VK_NULL_HANDLE
    (internal issue 393).
  * Change the definition of latexmath:[$q$] in the
    <<textures-image-level-selection,texture image level selection>> section
    to be the index of the maximum defined level for the view, not the
    number of levels in the view (internal issue 406).
  * Allow developers to override dname:VK_DEFINE_NON_DISPATCHABLE_HANDLE
    with their own binary-compatible definition (internal issue 439).
  * Fix +vk_platform.h+ conditional logic causing compile failure with some
    Android compilers (internal issue 441).
  * Implement the single-branch model as described above (internal issue
    461).

-----------------------------------------------------

Change log for August 12, 2016 Vulkan 1.0.24 spec update:

  * Bump API patch number and header version number to 24 for this update.

Github Issues:

  * Fix type mismatch in swapchain image equivalency table (public issue
    289).
  * Fix a copy-and-paste error in the description of
    flink:vkGetSwapchainImagesKHR::pname:pSwapchainImages, that said it
    was an array of ``sname:VkSwapchainImageKHR structures'' instead of
    an array of ``sname:VkImage handles'' (public issue 292).
  * Specify that ename:VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT is only valid
    for ename:VK_IMAGE_TYPE_2D images (public issue 293).
  * Add a valid usage statement to flink:vkCmdExecuteCommands saying
    that when called outside a render pass instance, the secondary
    command buffers must not have been created with the
    ename:VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT (public issue
    297).
  * Fix description of +VK_NO_STDINT_H+ in the
    <<boilerplate-platform-macros,platform macros>> section (public
    issue 314).

Internal Issues:

  * Normalize the language for the remaining built-in variables in the
    <<interfaces-builtin-variables,Built-In Variables>> section. Fix
    code:FrontFacing and code:HelperInvocation, as they should be of
    code:boolean type rather than code:integer (internal issue 323).
  * Clarify that when ename:VK_WHOLE_SIZE is used for a buffer
    descriptor range, the effective range must still be within the max
    buffer range (internal issue 426).
  * Clarify that command buffers and descriptor sets are allocated
    rather than created. Also clarify when the recording state of a
    command buffer is relevant (internal issue 434).

-----------------------------------------------------

Change log for August 5, 2016 Vulkan 1.0.23 spec update:

  * Bump API patch number and header version number to 23 for this update.

Github Issues:

  * Add explicit valid value attributes to pname:sType members in vk.xml
    (public issue 34).
  * Clarify usage of flink:vkGetInstanceProcAddr and
    flink:vkGetDeviceProcAddr (public issue 225).
  * Fix a copy-and-paste error in the description of
    pname:pSwapchainImageCount saying that it was the count of ``format
    pairs'' instead of ``swapchain images'' (public issue 292).
  * flink:vkCmdExecuteCommandBuffers requires all command buffers to be
    allocated from command pools created for the same queue family (public
    issue 296).
  * Remove bogus +optional+ attribute for
    flink:vkEnumerateDeviceLayerProperties::pname:physicalDevice from vk.xml
    (public issue 301).
  * Clean up the <<resources-image-views-compatibility,image and image view
    compatibility table>> reference and contents. Use full enumerant names.
    Refer to pname:layerCount in the ``view parameters'' column instead of
    pname:arrayLayers. Require N >= 1 for the cube array subview row, not
    just arrayLayers >= 6 N (public issue 304).
  * Modify description of <<resources-memory-aliasing,memory aliasing>> to
    be consistent with the description of
    <<resources-bufferimagegranularity,buffer image granularity>> (public
    issue 307).

Internal Issues:

  * Describe remaining +vk_platform.h+ macros in the <<boilerplate,API
    Boilerplate>> appendix (internal issue 6).
  * Clarify
    <<features-features-robustBufferAccess,pname:robustBufferAccess>>
    feature behavior; what memory can be accessed, how bounds checking is
    performed, and allowing for vectorization (internal issue 332).
  * Document markup for automatic extraction of reference pages from the
    spec sources in the style guide (internal issue 395).
  * Allow flink:vkCreateDisplayModeKHR to return
    ename:VK_ERROR_INITIALIZAION_FAILED_KHR if the user requests mode
    parameters that the specified display does not support (internal issue
    411).
  * Remove atomic counters (atomic_uint style) from KHR_vulkan_glsl, and
    more clearly remove the subroutine keyword alongside it (internal issue
    421).
  * Clarify behavior of flink:vkCmdBindDescriptorSets for descriptor sets
    not contained in the layout (internal issue 427).

Other Commits:

  * Change the order in which members of sname:VkAttachmentDescription and
    sname:VkPipelineInputAssemblyStateCreateInfo are described to match
    their order in the structures.

-----------------------------------------------------

Change log for July 22, 2016 Vulkan 1.0.22 spec update:

  * Bump API patch number and header version number to 22 for this update.

Github Issues:

  * Translate the subpass self-dependency language into concrete
    validity statements, and added a validity statement about the
    restrictions on layout parameters (public issue 267).
  * Add validity requirement that
    slink:VkAttachmentDescription::pname:finalLayout and
    slink:VkAttachmentReference::pname:layout must not be
    ename:VK_IMAGE_LAYOUT_UNDEFINED or
    ename:VK_IMAGE_LAYOUT_PREINITIALIZED (public issue 268).
  * Clarify that slink:VkSubpassDescription::pname:pResolveAttachments
    layouts are used. Make language consistent with other attachment
    arrays (public issue 270).
  * Changed 64-bit definition for
    dname:VK_DEFINE_NON_DISPATCHABLE_HANDLE to work for x32 platform in
    +vk.xml+ and the resulting +vulkan.h+ (public issue 282).
  * Add missing error return code for
    flink:vkEnumerateInstanceExtensionProperties and
    flink:vkEnumerateDeviceExtensionProperties (public issue 285)
  * Fix several cases of stext::VkStructName.memberName markup to
    stext::VkStructName::pname:memberName, to match other usage in the
    spec, and describe this markup in the style guide (public issue
    286).
  * Modified validity language generation script to avoid redundant
    common ancestor language if covered by generic parent language, and
    used `Both' instead of `Each' when appropriate (public issue 288).

Internal Issues:

  * Add language about behavior of flink:vkAllocateDescriptorSets when
    allocation fails due to fragmentation, a new error
    ename:VK_ERROR_FRAGMENTED_POOL, and a Note explaining the situation
    (internal issue 309).
  * For the features of code:PointSize, code:ClipDistance, and
    code:CullDistance, the SPIR-V capability is required to be declared
    on use (read or write) rather than on decoration (internal issue
    359).
  * Have desktop versions of GLSL respect precision qualification
    (code:mediump and code:lowp) when compiling for Vulkan. These will
    get translated to SPIR-V's code:RelaxedPrecision decoration as they
    do with OpenGL ES versions of GLSL (ESSL). The default precision of
    all types is code:highp when using a desktop version (internal issue
    360).
  * Add validity statement for slink:VkImageCreateInfo specifying that
    multisampled images must be two-dimensional, optimally tiled, and
    with a single mipmap level (internal issue 369).
  * Add validity statements to slink:VkImageViewCreateInfo disallowing
    creation of images or image views with no supported features. Made
    some slink:VkImageViewCreateInfo validity statements more precise
    and consistent. Added a Note to the <<features,features>> chapter
    about formats with no features (internal issue 371).
  * Remove +manpages+ from default build targets. Nroff outputs
    containing imbedded latexmath will not render properly. Fixing this
    is a lot of work for limited use cases (internal issue 401).

Other Commits:

  * Fix flink:vkRenderPassBeginInfo::pname:clearValueCount validity
    statement to be based on attachment indices rather than the number
    of cleared attachments
    (Vulkan-LoaderAndValidationLayers/issues/601).
  * Convert registry documentation from LaTeX to asciidoc source and
    rename from +src/spec/readme.tex+ to +src/spec/registry.txt+.
  * Fix lack of Oxford commas in validity language.
  * Lots of cleanup of generator scripts and Makefiles to move extension
    list for generator into the script arguments instead of the body of
    genvk.py, and express better dependencies between XML, scripts, and
    generated files.

-----------------------------------------------------

Change log for July 15, 2016 Vulkan 1.0.21 spec update:

  * Bump API patch number and header version number to 21 for this update.

Github Issues:

  * Clarify how <<features-supported-sample-counts,sample count queries>>
    relate to the limits in slink:VkPhysicalDeviceLimits. (public issue
    185).
  * Clarify in the <<interfaces-iointerfaces,Shader Input and Output
    Interfaces>> section that shader output variables have undefined values
    until the shader writes to them (public issue 240).
  * Specify the implicit value of image parameters that cannot be set in
    slink:VkSwapchainCreateInfo::pname:flags, pname:imageType,
    pname:mipLevels, pname:samples, pname:tiling, and pname:initialLayout
    (public issue 243).
  * Make use of code:NULL and code:VK_NULL_HANDLE consistent in the
    VK_KHR_swapchain extension (public issue 276).

Internal Issues:

  * Clarify that presenting an image to a display surface swapchain applies
    the display surface's mode, and that destroying a display surface
    swapchain may reset the display's mode, in the VK_KHR_display_swapchain
    extension (internal issue 247).
  * Better describe what a slink:VkSurfaceKHR is, and that creating one does
    not set a mode, in the VK_KHR_display extension. This is a round-about
    way of pointing out that mode setting is not covered by the extension,
    but rather is performed as a side effect of presentation (internal issue
    247).
  * Add more valid usage statements to flink:vkQueuePresentKHR command when
    the VK_KHR_display_swapchain extension is present (internal issue
    247).
  * Add more includes to the VK_KHR_swapchain extension to better document
    interactions with VK_KHR_display_swapchain (internal issue 247).
  * Clarify restrictions on location aliasing in the
    <<fxvertex,Fixed-Function Vertex Processing>> section (internal issue
    370).
  * Add mathematical description of blitting to flink:vkCmdBlitImage, and
    link it to the <<textures,Image Operations>> chapter. Use mathematical
    notation for ranges of texel coordinates in the <<textures,Image
    Operations>> chapter. Fixed miscellaneous validity statements for
    flink:vkCmdBlit and slink:VkImageBlit (internal issue 382).

Other Commits:

  * Added a valid usage rule to flink:VkGraphicsPipelineCreateInfo that the
    ename:VK_PRIMITIVE_TOPOLOGY_PATCH_LIST topology must only be used when
    tessellation shaders are used.
  * Expand the style guide into a formal "Procedures and Conventions"
    document. Add a API Naming Conventions section, move most of the API
    Specification Appendix C (Layers and Extensions) content into the new
    document, and define the resulting procedures as mandatory (where
    relevant). This more clearly separates use vs. specification of Vulkan
    APIs.
  * Update vk_platform.h to handle 32-bit ARMv8 binaries.
  * Various minor cleanups to the Makefile and build process.

-----------------------------------------------------

Change log for July 8, 2016 Vulkan 1.0.20 spec update:

  * Bump API patch number and header version number to 20 for this
    update.

Github Issues:

  * Replaced existing reference pages by text automatically extracted from
    the specification source, or generated from vk.xml in some cases. This
    is not a complete solution for the reference pages, but puts them in a
    much better state. The ref pages (only) are now placed under a CC BY
    open source license, which is more current than the obsolete license
    previously used. Various minor tweaks to the Specification sources were
    made to enable this, and a new ``API Boilerplate'' chapter added to
    include definitions of all the entities in the API and +vulkan.h+ which
    were not already described in some form in the document.

    Further improvements to the pages should not edit them directly, but
    instead concentrate on the specification source from which the ref pages
    are being extracted (public issues 44, 55, 160; internal issue 389).

-----------------------------------------------------

Change log for July 1, 2016 Vulkan 1.0.19 spec update:

  * Bump API patch number and header version number to 19 for this
    update.

Github Issues:

  * Clarified how flink:vkGetImageSubresourceLayout interacts with image
    layouts (public issue 247).
  * Remove ename:VK_IMAGE_LAYOUT_PREINITIALIZED from valid usage rule for
    slink:VkImageMemoryBarrier::pname:oldLayout. It is only valid if it is
    the current layout (public issue 248).
  * Modify valid usage for flink:vkBindBufferMemory so implementations are
    free to require a different backing memory size than the buffer size
    (public issue 251).
  * Clarify that filtering rules for flink:vkCmdBlitImage always apply, and
    are usually no-ops if the formats are the same (public issue 253).
  * Remove 'non-sparse' from description of
    flink:vkGetBufferMemoryRequirements and
    flink:vkGetImageMemoryRequirements (public issue 257).
  * Remove ename:VK_ERROR_LAYER_NOT_PRESENT error code from
    flink:vkCreateDevice (public issue 259).
  * Change "must: not" to "should: not" in constraint on when
    flink:vkAcquireNextImageKHR is called in the VK_KHR_swapchain branch
    (public issue 262).
  * Change type of flink:vkCmdUpdateBuffer::pname:pData from
    basetype:uint32_t* to basetype:void* (public issue 263).
  * Change should: to must: in description of where additional segments are
    placed in the <<[tessellation-tessellator-spacing,Tessellator Spacing>>
    section (public issue 264).

Internal Issues:

  * Normalize the language of all the compute shader built-ins in the
    <<interfaces-builtin-variables,Built-in Variables>> section (internal
    issue 323).
  * Remove definition of presentation engine internal queue lengths
    associated with ename:VK_PRESENT_MODE_FIFO_KHR and
    ename:VK_PRESENT_MODE_FIFO_RELAXED_KHR in the <<Window System
    Integration,wsi>> chapter (internal issue 374).
  * The language of a Note was too broad, and implied that loaders for a
    given OS would statically export functions for WSI extensions that
    were not relevant to (or supported on) the OS. Also, removed
    "Khronos-provided" since the Android loader is not (internal issue 380)

Other Commits:

  * Add ename:VK_INCOMPLETE to list of return values for
    flink:vkGetPipelineCacheData. Spec says this value is returnable, but it
    was not listed in the error codes.
  * Fix "correponds" typo in member definitions for
    slink:VkSubpassDescription.

-----------------------------------------------------

Change log for June 24, 2016 Vulkan 1.0.18 spec update:

  * Bump API patch number and header version number to 18 for this
    update.

Github Issues:

  * Added "queue operation" terminology, and modified spec to actually
    use this terminology (public issue 155). The act of submitting a
    piece of work to a queue now generates "operations" for the queue to
    execute, including operations to wait on/signal semaphores and
    fences. Synchronization waits on these operations, making execution
    dependency chains more obvious for semaphores and fences (though
    additional work is still needed here). These changes include:
  ** Overview of "queue submission" commands in chapter
     <<devsandqueues-submission>>.
  ** Updated descriptions for fence and semaphore waits and signals in
     the synchronization chapter <<synchronization-semaphores-waiting>>,
     <<synchronization-semaphores-signaling>> and
     <<synchronization-fences-waiting>>.
  ** Clarifications to semaphore and fence operation within queue
     submission functions.
  ** New glossary terms.
  ** Moved device idle and queue wait idle to synchronization chapter in
     order to describe them in terms of other synchronization
     primitives.
  ** Clarifications to semaphore and fence operation allowed removal of
     the "implicit ordering guarantees" section, as this information is
     now wholly covered where these primitives are described.
  *** The "host writes" section of this is still there for now - in its
      own section. This could probably be merged into other sections
      later.
  *** Modified fundamentals chapter on queue ordering to make sense in
      context of the new changes, and avoid duplication.
      <<fundamentals-queueoperation>>
  * Added "aspect" and "component" definitions to the glossary, and made
    sure these terms are referenced correctly (public issue 163).
  * Update valid usage for ftext:vkGet*ProcAddr to only include
    conditions that must be met to get a valid result. In particular,
    it is okay to call flink:vkGetDeviceProcAddr with any string and will
    get a code:NULL if that string is not a core Vulkan function or an
    enabled extension function (addresses but does not fully close
    public issue 214).
  * Change the WSI extension dependencies to refer to version 1.0 of the
    Vulkan API, instead of the pre-1.0-release internal revisions
    numbers (public issue 238).
  * Specified that <<interfaces-fragmentoutput,undeclared fragment
    shader outputs>> result in undefined values input to the blending
    unit or color attachment (public issue 240).
  * Fix latexmath:[$\leq$] operators turning into Unicode left arrow symbols
    (public issue 245).

Internal Issues:

  * Better documented that the registry XML "optional" tag for values
    only applies when that value is the size of an array (internal issue
    335).
  * Add a stronger definition for the valid usages of
    VkSpecializationMapEntry.size in the
    <<pipelines-specialization-constants,Specialization Constants>>
    section (internal issue 345).
  * Change code:OpName to code:OpDecorate (along with appropriate
    syntax) for vertex shader built-ins (internal issue 368).
  * Add missing ref pages (those which are not currently stubs) to
    apispec.txt for the single-page version of the ref pages (internal
    issue 378).

Other Commits:

  * Fix example in the <<descriptorsets,Descriptor Sets>> section to use
    M, N, and I, describing set, binding, and index, consistently
    throughout the example code.

-----------------------------------------------------

Change log for June 17, 2016 Vulkan 1.0.17 spec update:

  * Bump API patch number and header version number to 17 for this
    update.

Github Issues:

  * Update description of vertex shader reuse in
    <<shaders-vertex-execution>> (public issue 106).
  * Simplify validity language around pname:ppEnabledExtensionNames and
    pname:ppEnabledLayerNames (in the <<initialization-instances>> and
    <<devsandqueues-device-creation>> sections) (public issue 214).
  * Add missing validity rule to flink:vkCmdBeginRenderPass requiring
    compatibility between slink:VkAttachmentDescription pname:initalLayout
    members and the corresponding attached framebuffer images (public issue
    233).
  * Fix Unicode arrows appearing in output instead of relational operators
    (public issue 239).
  * Correctly describe the required number of elements for
    code:TessLevelInner and code:TessLevelOuter arrays in the
    <<interfaces-builtin-variables,Built-In Variables>> section as two and
    four, respectively, instead of the other way around, and refer to this
    section from the <<tessellation,Tessellation>> chapter (public issue
    246).

Internal Issues:

  * Document deprecation of ename:VK_COLORSPACE_SRGB_NONLINEAR_KHR in the
    VK_KHR_surface extension, and of
    ename:VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT in the
    VK_EXT_debug_report extension (internal issue 328).
  * Added language to define what a valid usage statement is and should be,
    with a note about some apparent weirdnesses this might entail (internal
    issue 357).

Other Commits:

  * Added missing ename:VK_ERROR_DEVICE_LOST error to
    flink:vkQueueBindSparse.

-----------------------------------------------------

Change log for June 10, 2016 Vulkan 1.0.16 spec update:

  * Bump API patch number and header version number to 16 for this
    update.

Github Issues:

  * Clarify that integer border values are meant to be 0/1, and that
    integer texture lookups are sign-extended in the
    <<textures-format-conversion,Format Conversion>> and
    <<textures-texel-replacement,Texel Replacement>> sections (public
    issue 52).
  * Add logic to generate spec boilerplate without using the 'git'
    command-line client, needed when building from a tarball or another
    source of the Vulkan tree rather than a cloned git repo. Remove
    boilerplate as part of 'clean' target (public issue 195).
  * Document that color writes and clears to unused attachments have no
    effect for slink:VkClearAttachment and
    elink:VkColorComponentFlagBits (public issue 198).
  * Fixed flink:vkCmdExecuteCommands validity statement for
    sname:VkCommandBufferInheritanceInfo::pname:framebuffer. If used, it
    must match the framebuffer in the current renderpass instance
    (public issue 226).
  * Added valid usage language to require for all functions that set
    dynamic state that the currently bound graphics pipeline has the
    corresponding dynamic state enabled (public issue 235).

Internal Issues:

  * Clarify for flink:vkEnumerateInstanceExtensionProperties, in the
    <<extended-functionality-instance-extensions-and-devices, Instance
    Extensions and Device Extensions>> section, and in the
    <<glossary,Glossary>> section when functionality should be exposed
    as an instance extension, as a device extension, or as both
    (internal issue 109).
  * Place WorkgroupSize in alphabetical order in the
    <<interfaces-builtin-variables,Built-in Variables>> section
    (internal issue 323).
  * Corrects valid usage in vkEndRenderPass to only affect primary
    render passes, as secondaries may be entirely within a render pass,
    and should be able to be ended (previous language disallowed that)
    (internal issue 338).
  * Fix relational operator from <= to >= in the
    <<features-extentperimagetype,Allowed Extent Values>> section
    (internal issue 343).
  * Disallow recursion under SPIR-V entry points in the
    <<spirvenv-module-validation,Validation Rules within a Module>>
    section (internal SPIR-V issue 37).

Other Commits:

  * Use standard Python ElementTree package instead of lxml.etree in
    header / validation layer / include autogeneration from XML,
    reducing platform dependencies.

-----------------------------------------------------

Change log for May 27, 2016 Vulkan 1.0.15 spec update:

  * Bump API patch number and header version number to 15 for this
    update.

Github Issues:

  * Fixed the <<glossary,Glossary>> entry for Fragment Input Attachment
    Interface to specify code:UniformConstant storage class (public issue
    156).
  * Disallow lazily allocated memory for buffers in the description of
    slink:VkMemoryRequirements::pname:memoryTypeBits (public issue 196).
  * Add numbered figure captions (public issue 219).
  * Fix output variable names in the <<fundamentals-fpfixedconv,Conversion
    from Floating-Point to Normalized Fixed-Point>> section and related
    minor normative language and markup cleanup (public issue 220).

Internal Issues:

  * Fix reference to nonexistent etext:VK_IMAGE_LAYOUT_TRANSFER_{SRC,DST}BIT
    to the actual etext:VK_IMAGE_LAYOUT{SRC,DST}_OPTIMAL (internal issue
    296).
  * Update the <<sparsememory-sparse-memory-aliasing,Sparse Resource
    Implementation Guidelines>> to refer to the correct feature names
    (internal issue 305).

-----------------------------------------------------

Change log for May 20, 2016 Vulkan 1.0.14 spec update:

  * Bump API patch number and header version number to 14 for this
    update.

Github Issues:

  * Fix validity language for sname:VkCommandBufferAllocateInfo to
    impose range limits on pname:commandBufferCount (public issue 178).
  * Fix validity language for flink:vkCmdExecuteCommands to refer to the
    correct structure names (public issue 179).
  * Fix two copy-and-paste errors in the WSI queries, where the wrong
    term was used for what was being returned (public issue 206).
  * Add a note in the documentation of
    flink:vkGetPhysicalDeviceSurfaceFormatsKHR, about what it means if
    ename:VK_FORMAT_UNDEFINED is returned (public issue 207).

Internal Issues:

  * Clarify the usage and correct the name for the bitmask referenced in
    <<queries-pipestats,Pipeline Statistics Queries>> (internal issue
    334).

Other Commits:

  * Fix the names of decorations listed in the
    <<interfaces-builtin-variables,Built-in Variables>> section such
    that they match the SPIR-V specification.

-----------------------------------------------------

Change log for May 13, 2016 Vulkan 1.0.13 spec update:

  * Bump API patch number and header version number to 13 for this
    update.

Github Issues:

  * Improve the description of ename:VK_PRESENT_MODE_FIFO_RELAXED_KHR in the
    VK_KHR_surface extension (public issue 174).
  * Clarify use of etext:*_SIMULTANEOUS_USE_BIT for secondary command
    buffers (public issue 182).
  * Fix typos in VK_KHR_wayland_surface extension where code:wl_device was
    used instead of code:wl_display (public issue 193).
  * Replaced {apiname} with ``Vulkan'' in XML validity statements (public
    issue 199).
  * Fix dead links for WSI handle types (public issue 200).
  * Use "signaled" instead of "signalled" spelling everywhere (public issue
    201).
  * Move readme.pdf target directory for XML schema documentation into the
    target generation directory, instead of leaving it checked into the spec
    source tree (public issue 203).
  * Fix duplicate 'which which' typo in description of
    elink:VkCommandPoolResetFlagBits (public issue 204).
  * Move the <<Programmable Primitive Shading>> section up one level, out of
    the <<drawing-primitive-topologies,Primitive Topologies>> section
    (public issue 209).

Internal Issues:

  * Clarify in the <<pipelines-cache,Pipeline Cache>> section that
    implementations should not manage the size of pipeline cache (internal
    issue 192).
  * Deprecate the concept of device layers and associated commands (internal
    issue 255).
  * Remove ename:VK_INCOMPLETE from the list of possible result codes of
    flink:vkGetPhysicalDeviceSurfaceCapabilitiesKHR (internal issue 314).
  * Add missing std140/std430 rule: the base alignment of a member following
    a structure is a multiple of the structure's base alignment (internal
    issue 321).
  * Fixes naming of the single elink:VkColorSpaceKHR enum from
    ename:VK_COLORSPACE_SRGB_NONLINEAR_KHR to
    ename:VK_COLOR_SPACE_SRGB_NONLINEAR_KHR in XML/header and the
    VK_KHR_swapchain and VK_KHR_surface extensions to match the style of the
    typename (space and color are two words, not one) (internal issue 322).
  * Make it clear that code:LocalInvocationID should only be applied to an
    input variable and normalize the language describing
    code:LocalInvocationID to the language for other compute shader
    variables in the <<interfaces-builtin-variables,Built-in Variables>>
    section, and add normative language (internal issue 323).
  * Clarify in the <<fundamentals-returncodes,Return Codes>> section that
    the result pointer may be modified for specific commands, even if a
    runtime error is returned (internal issue 324).

-----------------------------------------------------

Change log for April 29, 2016 Vulkan 1.0.12 spec update:

  * Bump API patch number and header version number to 12 for this
    update.

Github Issues:

  * Change valid usage statements intended to be "sub-points" to
    be actual sub-points (public issue 66).
  * Replace double negation in description of
    slink:VkRenderPassBeginInfo::pname:pClearValues (based on public
    merge 142).
  * Cleanup minor typos in spec, ref pages and XML, including those
    proposed in public pull requests 144, 150, 151, 167, 168, 181, and
    186.
  * Use *strict subset* in describing the partial order of memory
    property types for slink:VkMemoryType, and update the style guide
    accordingly (public issue 190).
  * Fix various "a image" -> "an image" typos (public issue 191).
  * Note in the <<fundamentals-validusage,Valid Usage>> and
    <<extensions-interactions,Extension Interactions>> sections that
    structures defined by extensions which may be passed in structure
    chains using the ptext:pNext member must include initial
    ptext:sType and ptext:pNext members (public issue 192).

Internal Issues:

  * Remove duplicate language from the description of the pname:fence
    parameter to flink:vkQueueSubmit and improve validity language
    (internal issue 91).
  * Added documentation for "optional" attribute to XML readme.tex/pdf
    (internal issue 149).
  * Clarify the host-side data validity rules and behavior of
    flink:vkFlushMappedMemoryRanges and
    flink:vkInvalidateMappedMemoryRanges (internal issue 266).

Other Commits:

  * Added clarification to flink:vkCmdFillBuffer regarding the use of
    ename:VK_WHOLE_SIZE.
  * Fixed and documented implementation of "validextensionstructs"
    attribute. in XML processing scripts and readme.tex/pdf.
  * Add missing validity statements to flink:vkResetEvent and
    flink:vkCmdResetEvent.
  * Fix validity for the
    ename:VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT flag.
    Correct all the draw/dispatch commands to mention optimally tiled
    images as well as linear tiled images, and say image VIEWS instead
    of images. Add validity statement to flink:vkCmdBlitImage
  * Replace the {apiname} macro with hardcoded "Vulkan", now that we have
    committed to that name.
  * Add the VK_AMD_rasterization_order extension to vk.xml.

-----------------------------------------------------

Change log for April 22, 2016 Vulkan 1.0.11 spec update:

  * Bump API patch number and header version number to 11 for this
    update.

Github Issues:

  * Clarify the WSI extension language by switching from the fuzzier
    "ownership" language to more-consistent "acquire" language (public
    issue 117).
  * Clarify that memory barriers apply to all commands in the dependency
    chains in the flink:vkGetRenderAreaGranularity command and the
    <<synchronization-execution-and-memory-dependencies,Execution And
    Memory Dependencies>> section (public issue 132).
  * Clarify that a queue family is a set of queues in the
    <<fundamentals-execmodel,Execution Model>> section (public issue
    166).
  * Removed requirement from valid usage language that
    VkPresentInfoKHR::waitSemaphoreCount must be greater than 0 (public
    issue 171).
  * Fix broken internal links, describe structures consistently, use
    consistent style for SPIR-V codewords, and tag normative terms that
    were missing asciidoc tags (public issue 183 and ancillary
    markup/normative language fixes).
  * Fix typos for slink:VkPhysicalDeviceLimits member names in
    slink:VkImageCreateInfo validity language (public issue 184).

Internal Issues:

  * Document that the requested patch version number specified as part
    of slink:VkApplicationInfo::pname:apiVersion is ignored when
    creating an instance (internal issue 176).
  * Clarify handling of extension structs in the
    <<fundamentals-validusageValid Usage>> section (internal issue 254).
  * Update required slink:VkImageFormatProperties::pname:maxMipLevels to
    be limited to the maximum allowed mipmap pyramid size corresponding
    to the actual maximum supported size for the format (internal issue
    256).
  * Modify the <<features-extentperimagetype,Allowed Extent Values Based
    On Image Type>> section so the allowed maximum extent is the maximum
    image dimension supported for each dimension of the type of texture
    being queried (internal issue 257).
  * Clarify in the <<spirvenv-module-validation,Validation Rules within
    a Module>> section that at least one of the code:LocalSize execution
    mode or code:WorkgroupSize decoration is required for each compute
    shader entry point in a shader module (internal issue 279).
  * Add validity rules for formats in flink:vkCmdClearColorImage and
    flink:vkCmdClearDepthStencilImage (internal issue 283).
  * Clarify that slink:VkImageFormatProperties::pname:maxResourceSize is
    an upper bound, and that it may not be possible to create an image
    anywhere near that size (internal issue 284).

Other Commits:

  * Fix various minor markup errors reported by validation scripts.
  * Change copyright from Khronos Free Use License to Apache 2.0 license
    on relevant script/XML/header files. This does not affect the
    specification source copyright.

-----------------------------------------------------

Change log for April 15, 2016 Vulkan 1.0.10 spec update:

  * Bump API patch number and header version number to 10 for this
    update.

Github Issues:

  * Slightly tweak the <<memory-allocation,Host Memory>> allocator language
    so that an application wrapping the standard C alloc/free/realloc
    functions is still correct - the previous language was too strong with
    regards to freeing memory. Also made certain scenarios clearer - an
    implementation may now continue without error if an allocation failed
    and it is able to continue correctly (public issue 21).
  * Require that etext:VK_*_CREATE_SPARSE_BINDING_BIT is set when the
    corresponding etext:VK_*_CREATE_SPARSE_RESIDENCY_BIT is used, in the
    <<sparsememory-miptail,Mip Tail Regions>> section and related commands
    flink:vkCreateBuffer and flink:vkCreateImage (public issue 84).
  * Update the <<features,Features, Limits, and Formats>> chapter to clarify
    interactions between optional features and dynamic state for the
    pname:depthBiasClamp and pname:wideLines features (public issue 89).
  * Describe the code:WorkgroupSize builtin in the
    <<interfaces-builtin-variables,Built-In Variables>> section, and update
    the <<compute-shaders,Compute Shaders>> section to further clarify how
    to set the number of workgroups to execute in a compute shader (public
    issue 145).
  * Use the term *image subresource* everywhere instead of *subresource*,
    except for the special case of *host-accessible subresource*, which may
    be either an image subresource or buffer range (public issue 120)
  * Add a note to the <<features,Features, Limits, and Formats>> section
    about extensibility of structures (Public issue 165).
  * Fix return code flink:vkAcquireNextImageKHR when the timeout parameter
    is 0 to ename:VK_NOT_READY instead of ename:VK_TIMEOUT (public issue
    170).
  * Fix typo in slink:VkLayerProperties::pname:apiVersion field (public
    issue 172).

Internal Issues:

  * Fix a few minor internally-detected typos.
  * Minor formatting tweaks to pseudocode in the <<resources,Resource
    Creation>> chapter (internal issue 179).
  * Fix typo in the definition of point sampling for
    elink:VkCullModeFlagBits (internal issue 268).

-----------------------------------------------------

Change log for April 8, 2016 Vulkan 1.0.9 spec update:

  * Bump API patch number and header version number to 9 for this
    update.

Github Issues:

  * Fix memory type preorder definition and clarify example list and source
    code for slink:VkMemoryRequirements and slink:VkMemoryHeap (public issue
    26).
  * Ensure slink:VkAllocationCallbacks are properly defined (public issue
    73).
  * Clarify the WSI extension language by switching from the fuzzier
    "ownership" language to more-consistent "acquire" language (public issue
    117).
  * Add language allowing allocation and freeing of memory scoped to the
    duration of any API command in the <<memory-allocation,Memory
    Allocation>> section (public issue 136).
  * Clarify the explicit location assignment always overrides the inherited
    location in the <<interfaces-iointerfaces-locations,Location
    Assignment>> section, even for the first member of a block (public issue
    141).
  * Fixed references to
    slink:VkCommandBufferInheritanceInfo::pname:pipelineStatistics (public
    issue 158).
  * Fix name of slink:VkBufferCopy::pname:size field in validity language
    for flink:vkCmdCopyBuffer (public issue 162).

Internal Issues:

  * Update GL_KHR_vulkan_glsl specification to clarify disallowance of
    spec-const arrays in initializers (internal issue 248).
  * Clarify <<interfaces-iointerfaces-matching,Interface Matching>> section
    to state that user-defined variable interface must match too (internal
    issue 250).

-----------------------------------------------------

Change log for April 1, 2016 Vulkan 1.0.8 spec update:

  * Bump API patch number and header version number to 8 for this
    update.

Github Issues:

  * Specify in the validity language for flink:vkBeginCommandBuffer that
    pname:commandBuffer must not currently be pending execution (public
    issue 96).
  * Describe depth comparison using the correct temporary variable names
    in the <<textures-depth-compare-operation,Depth Compare Operation>>
    section (public issue 100).
  * Clarify the order of descriptor update operations in the
    flink:vkUpdateDescriptorSets command (public issue 115).
  * Specify in the VK_KHR_swapchain extension that
    flink:vkAcquireNextImageKHR's pname:semaphore and pname:fence
    parameters cannot both be sname:VK_NULL_HANDLE (partly addresses,
    but does not fully close, public issue 117 / internal issue 246).
  * Change reference to the "lifetime" of a Vulkan command to
    "duration", and define the "duration" term (public issue 135).
  * Added valid usage language for slink:VkImageLayout to require both
    pname:height and pname:depth to be 1 for 1D images and pname:depth
    to be 1 for 2D images (public issue 137).
  * Fix SPIR-V example code in the
    <<descriptorsets-inputattachment,Input Attachment>> section to
    properly decorate the code:InputAttachmentIndex (public issue 139).
  * Fix reference to nonexistent pname:imageInfo in the description of
    flink:VkWriteDescriptorSet to refer to pname:pImageInfo (public
    issue 140).

Internal Issues:

  * Link to the fixed-function vertex chapter from the drawing chapter
    (internal issue 110)
  * Fix typo in slink:VkImageCreateInfo validity language:
    ptext:maxExtent.sampleCounts -> pname:sampleCounts (internal issue
    249).
  * Explain why the non-core token etext:VK_IMAGE_LAYOUT_PRESENT_SRC_KHR
    is used in the example in the
    <<synchronization-semaphores,Semaphores>> section (internal issue
    251).
  * Attempt to clarify in the VK_KHR_android_surface extension's
    <<platformQuerySupport_android,Android Platform Support>> section
    that there is no Android-specific WSI query, and why (internal issue
    252).

Other Commits:

  * Add missing language about ename:VK_INCOMPLETE being returned from
    array queries when the passed array is too short, in the
    VK_KHR_display, VK_KHR_swapchain, and VK_KHR_surface extensions.

-----------------------------------------------------

Change log for March 25, 2016 Vulkan 1.0.7 spec update:

  * Bump API patch number and header version number to 7 for this
    update.

Github Issues:

  * Fix slink:VkSpecializationMapEntry example to avoid C/C++ strict
    aliasing issues (public issue 14).
  * Clarify the meaning of "matching" in flink:vkCmdBindDescriptorSets
    validity language (public issue 33).
  * Add stub reference pages so xrefs to not-yet-written pages do not
    generate 404 errors. However, the actual content of these pages
    still needs to be filled in as time allows (public issue 44, but
    does not close that issue out).
  * Remove incorrect validity statement for
    flink:vkGetImageSparseMemoryRequirements (public issue 85).
  * Reword the
    <<features-limits-bufferImageGranularity,bufferImageGranularity>>
    feature in terms of "aliasing", and clarify that it applies to
    bindings in the same memory object (public issue 90).
  * Clarify the relationship of the slink:VkPhysicalDeviceLimits
    pname:maxViewportDimensions and pname:viewportBoundsRange limits
    (public issue 92).
  * Specify sparse unbound texture replacement in the
    <<textures-texel-replacement,Texel Replacement>> section
    independently of robust buffer access language (public issue 100).
  * Add the <<fundamentals-architecture-model,Architecture Model>>
    section to explain architecture constraints Vulkan has chosen to
    accept in order to enable portable and performant code (public issue
    122).
  * State that an object must not be destroyed until *all* (not *any*)
    uses of that object have completed (public issue 123).
  * Minor editorial cleanup (public issues 129, 134, 146, 148).
  * Add validity language for layer and extension names to
    slink:VkDeviceCreateInfo matching that used for
    slink:VkInstanceCreateInfo (public issue 130).
  * Clean up terminology for the case when the bits set in one bitmask
    are a subset of the bits set in another bitmask (public issue 138).
  * Document that input attachments are UniformConstant not Input, in
    the <<interfaces-inputattachment,Fragment Input Attachment
    Interface>> section (public glslang bug 169).

Internal Issues:

  * Add max enum values to "flag bits" enums (internal issue 136).
  * Clarify language around the various uses of the term "block" in the
    <<appendix-compressedtex-bc,Block Compressed Image Formats>> section
    (internal issue 202).
  * Removed "expand" dependency from <enums> groups in vk.xml and added
    auto-generation code in the scripts to infer it instead, to ensure
    consistency. This caused renaming of sname:VkColorSpaceKHR and
    sname:VkPresentModeKHR etext:BEGIN_RANGE (etc.) tokens, but those
    tokens are metadata, not part of the API, and the Vulkan WG is OK
    with this change. This change adds ranges to two additional enums
    that were missing them due to not defining the "expand" attribute
    (internal issue 217).
  * Tweak makefile to generate ref page nroff (.3) files in the right
    output directory, working around an a2x limitation (internal issue
    223).

Other Commits:

  * Add validity requirements for flink:vkCmdCopyQueryPoolResults
    pname:dstBuffer parameter.
  * Fix ref page build to generate .3 targets in the right output
    directory.

-----------------------------------------------------

Change log for March 10, 2016 Vulkan 1.0.6 spec update:

  * Bump API patch number and header version number to 6 for this
    update.

Github Issues:

  * Define 'invocation group' for compute and graphics shaders. Cleanup
    definition and use of 'workgroup', and add glossary entries (public
    issue 1).
  * Various minor editorial fixes (public issue 33).
  * Clarify locations for block members in the
    <<interfaces-iointerfaces-locations,Location Assignment>>
    section (public issue 45).
  * Editorial fixes for <<commandbuffer-allocation,Command Buffer
    Allocation>> section (public issues 54, 59).
  * Clarify behavior of depth test in the <<fragops-depth,Depth Test>>
    section (public issues 80, 81).
  * Remove discussion of return codes from
    flink:vkGetPhysicalDeviceSparseImageFormatProperties and
    flink:vkGetImageSparseMemoryRequirements, which do not return values
    (public issue 82).
  * Allow flink:vkCmdDrawIndirect and flink:vkCmdDrawIndexedIndirect
    pname:drawCount of 0, as well as 1, when the multiDrawIndirect
    feature is not supported (public issue 88).
  * Remove confusing wording in the <<features-limits,Limits>>
    section describing the slink:VkPhysicalDeviceLimits
    pname:minTexelBufferOffsetAlignment,
    pname:minUniformBufferOffsetAlignment, and
    pname:minStorageBufferOffsetAlignment members as both minimums and
    maximums (public issue 91).
  * Clarified that only the RGB components should be affected in places
    where sRGB is referred to in the spec, such as ASTC formats. Minor
    re-wording to avoid "color space" when actively incorrect, now that
    we refer to the Data Format Spec which actually makes a distinction
    between color space and transfer function (public issue 94).
  * Treat pname:pPropertyCount == 0 consistently in
    flink:vkEnumerateInstanceLayerProperties and
    flink:vkEnumerateDeviceLayerProperties (public issue 99)
  * Cleanup minor editorial issues in chapters 14-17 (public issue 100).
  * Clarify definition of flink:vkEnumerateInstanceExtensionProperties
    and flink:vkEnumerateDeviceExtensionProperties (public issue 101).
  * Define the flink:vkEnumerateInstanceExtensionProperties and
    flink:vkEnumerateDeviceExtensionProperties pname:pLayerName
    parameter to be a pointer to a null-terminated UTF-8 string (public
    issue 101).
  * Rearrange "Missing information" references in mandatory format
    tables (public issue 101).
  * Clarify that the enumerated extensions returned by
    flink:vkEnumerateInstanceExtensionProperties and
    flink:vkEnumerateDeviceExtensionProperties will only include
    extensions provided by the platform or extensions implemented in
    implicitly enabled layers (public issue 101).
  * Miscellaneous editorial fixes. Include the Vulkan spec patch number
    in the PDF title. Fix label on <<fig-non-strict-lines,Non
    strict lines>> diagram. Use more easily distinguished symbols in
    tables in the <<features-required-format-support,Required
    Format Support>> section. Do not require FQDNs used as layer names be
    encoded in lower case if not possible, in the
    <<extensions-naming-conventions, Extension and Layer Naming
    Conventions>> section (public issues 101, 119, 121).

Internal Issues:

  * Fixed excessive spacing in tables in XHTML (internal issue 18).
  * Clarify that ename:VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT
    applies to secondary command buffers. Previously spec only referred
    to the members of pname:pCommandBuffers being affected by this bit.
    Added a separate slink:VkSubmitInfo Valid Usage restriction
    specifying that ename:VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT
    also applies to any secondary command buffers that are recorded into
    the primary command buffers in pname:pCommandBuffers (internal issue
    106).
  * Clarify that slink:VkDeviceCreateInfo::pname:pEnabledFeatures can be
    NULL (internal issue 117).
  * Remove "the value of" where it is redundant (e.g. speaking of an API
    parameter, struct member, or SPIR-V variable, but not when speaking
    of color components) (internal issue 175).
  * Forced patch version to always be 0 in the header. Add a
    "VK_API_VERSION_<major>_<minor>" macro for people to use to do the
    right thing. Add a VK_HEADER_VERSION which captures the header
    release number independent of the spec patch number (internal issue
    176).
  * Correct description of
    slink:VkPipelineShaderStageCreateInfo::pname:pName to "a pointer to
    a null-terminated UTF-8 string" (internal issue 197).

Other Commits:

  * Updated DataFormat spec reference to the new date for revision 5 of
    that spec.
  * Fixed KEEP option (to retain LaTeX intermediate files) in the
    Makefile to be included when edited there, as well as set on the
    command line.
  * Reserve and add "VK_IMG_filter_cubic" to the registry, and implement
    script functionality to add and remove validity from existing
    functions. Includes schema and readme changes.
  * Update GL_KHR_vulkan_glsl so push_constants do not have descriptor
    sets.

-----------------------------------------------------

Change log for March 4, 2016 Vulkan 1.0.5 spec update:

  * Bump API patch number to 5 for this update.

Github Issues:

  * Correctly describe slink:VkPhysicalDeviceProperties pname:deviceName
    member as a string, not a pointer to a string. Also one typo fix for
    "hetereogeneous" (public issue 4).
  * Replace maynot: macro with may: not, and "may: or maynot:" with
    "may:" (public issue 4).
  * Clarify that redundantly setting the state of a fence or event has
    no effect (public issue 4).
  * Minor fixes to ref pages to track descriptions of memory bits that
    changed in the core spec. Fix name of a member in the description of
    sname:sname:VkPipelineMultisampleStateCreateInfo (public issues 8,
    13).
  * Remove redundant validity statement for
    sname:VkGraphicsPipelineCreateInfo::pname:stageCount (public issue
    14).
  * Fix typos in chapters 7-9 (public issue 14).
  * Clarify the example demonstrating the behavior of
    code:OpMemoryBarrier in the
    <<shaders-execution-memory-ordering,shader memory acces
    ordering>> section (public issue 16).
  * Specify that freeing mapped memory implicitly unmaps the memory in
    the description of flink:vkFreeMemory (public issue 17).
  * Forbid allocation callbacks from calling into the API in the
    <<memory-allocation,memory allocation>> section (public issue
    20).
  * Add missing validity rules about size being greater than 0 and
    offset being less than size of object. Fix
    flink:VkMappedMemoryRange's misinterpretation of offset (public
    issues 27, 31).
  * Add validity rule disallowing overlapping source/destination
    descriptors in flink:VkCopyDescriptorSet (public issue 32).
  * Clarify that array and matrix stride has to be a multiple of the
    base alignment of the array or matrix in the
    <<interfaces-resources-layout,Offset and Stride Assignment>>
    section (public issue 38).
  * Correct parenthesis floor nesting error in equation for
    <<textures-RGB-sexp,RGB to shared exponent conversion>>.
    Clarify case of when exp' is forced to 0, avoiding log2(0) undefined
    problem (public issue 40).
  * Remove redundant statement from the code:FragDepth description in
    the <<interfaces-builtin-variables,Built-In Variables>>
    section (public issue 47).
  * Define the clamping of the
    <<textures-level-of-detail-operation,bias added to the scale
    factor>> by linking to the slink:VkPhysicalDevice feature
    pname:maxSamplerLodBias (public issue 64).
  * Fix typo "optimal linear resources" and clarify the set of resources
    <<features-limits-bufferImageGranularity,the
    pname:bufferImageGranularity resource>> applies to (public issue
    67).
  * Replace 'descriptor accessed by a pipeline' language for
    sname:VkDescriptorSetAllocateInfo with more precise phrasing about
    binding a descriptor set before a command that invokes work using
    that set (public issue 69).
  * tstripadj.svg contained an Inkscape tag which caused Firefox and IE
    11 to fail to render it, and was illegal SVG. Generating Plain SVG
    from the Inkscape SVG source fixes this (public issue 70).
  * Fix validity for sname:VkVertexInputBindingDescription and
    sname:VkVertexInputAttributeDescription numbers (public issue 72).

Internal Issues:

  * Clarify the meaning of
    ename:VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT in
    elink:VkFormatFeatureFlagBits with respect to depth compare
    (internal issue 107).
  * Added a note explaining that ename:VK_QUEUE_TRANSFER_BIT may or may
    not be reported for a queue family that already supports
    ename:VK_QUEUE_GRAPHICS_BIT or ename:VK_QUEUE_COMPUTE_BIT as the
    former is a strict subset of the latter ones (internal issue 116).
  * Add validity language for sname:VkDescriptorSetAllocateInfo about
    exceeding the descriptor pool capacity (internal issue 140).
  * Add ename:VK_INCOMPLETE success code for
    flink:vkEnumeratePhysicalDevices query (internal issue 163).

Other Commits:

  * Add the VK_NV_glsl_shader extension definitions to the API.
  * Update GL_KHR_vulkan_glsl with 1) origin_upper_left as default 2)
    specialization array constant semantics.
  * Corrected/updated Data Format Specification date.

-----------------------------------------------------

Change log for February 25, 2015 Vulkan 1.0.4 spec update:

  * Bump API patch number from 3 to 4 for the first public update to the
    spec. Add patch number to the spec title (this will be done
    automatically from XML, later).
  * Fixes for numerous editorial issues. Regularize descriptions of
    variable-length array queries. Properly tag enumerants so they come
    out in the right font (many were mislabeled in usage tags in vk.xml,
    or not tagged). Spelling and markup corrections (public issue 4).
  * Fix typos and clearly separate description of different types of
    memory areas (public issue 5).
  * Use standards-compliant preprocessor guard symbols on headers
    (public issue 7).
  * Note that Github users cannot currently set labels on issues, and
    recommend a fallback approach (public issue 15).
  * Use latexmath prefix on len= attributes (public issue 29).
  * Make flink:vkCmdUpdateBuffer pname:dataSize limit consistent (public
    issue 65).
  * Add VK_KHR_mirror_clamp_to_edge extension to core API branch, as an
    optional feature not introducing new commands or enums (internal
    issue 104).
  * Cleanup invariance language inherited from the GL specification to
    not refer to nonexistent (GL-specific) state (internal issue 111).
  * Modify the flink:vkCmdDrawIndexed pname:vertexOffset definition to
    not be the "base offset within the index buffer" but rather the
    "value added to the vertex index before indexing into the vertex
    buffer" (internal issue 118).
  * Fix drawing chapter in the "Programmable Primitive Shading" section
    where it described categories of drawing commands. It referenced
    flink:vkCmdDrawIndexed twice. Replace the second reference with
    flink:vkCmdDrawIndexedIndirect (internal issue 119).
  * Typo fixed in <<sparsememory-examples-advanced,Advanced Sparse
    Resources>> sparse memory example (internal issue 122).
  * Add flink:VkDisplayPlaneAlphaFlagsKHR to <require> section of
    VK_KHR_display extension (internal issue 125)
  * Add missing optional="false,true" to
    flink:vkGetImageSparseMemoryRequirements
    pname:pSparseMemoryRequirementCount parameter (internal issue 132)
  * Rename ename:VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT to
    ename:VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT
    (internal issue 133)
  * Fix a handful of broken cross-references in the
    <<samplers,Samplers>> chapter (internal issue 134).
  * Fix "Input Attachement" GLSL example to use correct syntax (internal
    issue 135).
  * Update XML schema and documentation to accomodate recently added
    attributes for validity. Add some introductory material describing
    design choices and pointing to the public repository to file issues.
  * Put include of validity in the core spec extensions chapter on its
    own line, so that asciidoc is happy.
  * Fix vertexOffset language to specify that it is the value added to
    the vertex index before indexing into the vertex buffer, not the
    base offset within the index buffer.
  * Fix error in the description of flink:vkCmdNextSubpass.

-----------------------------------------------------

February 16, 2016 - Vulkan 1.0 initial public release