* 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.