* 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 The `1.0` branch is out of
date and will not be maintained, since we will be generating both 1.1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`
* 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`
* 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.
* 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`
* 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`
* 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`
-----------------------------------------------------
Note: the 1.0.52 spec wasn't published on github, so the 1.0.53 release
combines both change sets.
-----------------------------------------------------
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`
* 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.
New Extensions:
* 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`
* 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`
* 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`
* 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).
New Extensions:
* 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).
New Extensions:
* 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 303 and 304).
* 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.
* 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.
* 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.
* 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).
* 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).
* 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).
* 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).
* 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.
* 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 gater,
to (hopefully) reduce future internal git churn as edits are made
and extensions added in return for one-time pain. This has no
perceptible change on the spec outputs but considerable changes on
the asciidoc source (internal issue 367).
Jon Leech