Metal does not support resolving all formats that support MSAA, whereas Vulkan
assumes any MSAA format can be resolved. We fix that by running an optional
post-renderpass compute shader that resolves such textures by simply taking the
first sample as the resolved sample. This works to fix all failing CTS tests,
because such formats are all integer formats, and Vulkan allows an arbitrary
single sample value to be selected.
If we need to resolve, but the Metal format doesn't support it,
cause the Metal renderpass to store the MSAA attachment results.
MVKRenderSubpass don't establish Metal resolve attachment textures if format
is not natively resolvable, and encode Metal renderpass store actions accordingly.
MVKCommandEncodingPool add MTLComputePipelineStates to run simple resolve
compute shaders on attachments that cannot be resolved in Metal renderpass.
Add MVKRenderSubpass::resolveUnresolvableAttachments() and call from
MVKCommandEncoder::endMetalRenderEncoding(), before subpass index is updated.
Rename MVKCommandEncodingPool::getClearStateIndex() to
getRenderpassLoadStoreStateIndex() and remove MVK_MACOS restriction on
clearing shaders to allow compatibility with resolve shader handling.
MVKRenderPassAttachment remove validation of whether a format can be resolved.
MVKPixelFormats::getMTLTextureUsage() add read and write usage as appropriate
to allow compute shader to run to resolve formats not natively resolvable.
MVKPixelFormats remove obsolete unit test code.
MVKImageView clean up access functions and obsolete constructor
use of MVKConfiguration.