* 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`
* 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`
