[scenario] Core Texture and Sampler Support

[inbelic]

This workstream is complete when all core texture/sampler types are defined and basic texture sampling, load/store, and operator methods are supported on both SPIR-V/DirectX.

At the time of issue creation, support for Texture2D when targeting SPIR-V has progressed substantially. The approach taken is vertical to define the Texture2D and [Comparison]Sampler types and to then implement all the methods on Texture2D. It should then allow us to add support for the other types by adjusting methods for the new type. We will plan to use a similar approach.

Proposal Updates

• [0037] Describe the Store method and .sample operator #407
• [0037] Describe semantic validations of texture methods #408

Texture Methods

Note: The frontend for Texture2D/Sampler types are defined and all of the methods (except Store and .sample) currently output a placeholder call to the corresponding dx intrinsic, the work will be to correct the intrinsic call and provide the DXIL lowering.

• Load method ([DirectX] Implement lowering of llvm.dx.resource.load.level to the TextureLoad DXIL Op llvm-project#192546)
• Store method
• operator[] ([DirectX] Implement lowering of operator[] on texture types to the TextureLoad DXIL Op llvm-project#192558)
• .mips[level][pos] operator ([DirectX] Implement lowering of llvm.dx.resource.load.level to the TextureLoad DXIL Op llvm-project#192546)
• .sample[index][pos] operator
• Sample method ([DirectX] Implement lowering of llvm.dx.resource.sample to the Sample DXIL Op llvm-project#192547)
• SampleBias method ([DirectX] Implement lowering of llvm.dx.resource.samplebias to the SampleBias DXIL Op llvm-project#192548)
• SampleGrad method ([DirectX] Implement lowering of llvm.dx.resource.samplegrad to the SampleGrad DXIL Op llvm-project#192549)
• SampleLevel method ([DirectX] Implement lowering of llvm.dx.resource.samplelevel to the SampleLevel DXIL Op llvm-project#192550)

Shader Flags

• [DirectX] Implement Shader Flag Analysis for AdvancedTextureOps llvm-project#116137
• [DirectX] Implement Shader Flag Analysis for SampleCmpGradientOrBias llvm-project#116138
• [DirectX] Implement Shader Flags Analysis for WriteableMSAATextures llvm-project#116203
• [DirectX] Implement Shader Flag Analysis for ResourceDescriptorHeapIndexing llvm-project#116134
• [DirectX] Implement Shader Flag Analysis for SamplerDescriptorHeapIndexing llvm-project#116135

Texture Types

• Texture1D
• Texture3D
• TextureCube
• Texture1DArray
• Texture2DArray
• TextureCubeArray
• Texture2DMS
• Texture2DMSArray
• RWTexture1D
• RWTexture2D
• RWTexture3D
• RWTexture1DArray
• RWTexture2DArray

todo: update with issue links