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+SP #005: Write-Only Textures
+=================
+
+Add Write-Only texture types to Slang's core module.
+
+
+Status
+------
+
+Status: Design Review.
+
+Implemtation: N/A
+
+Author: Yong He
+
+Reviewer: 
+
+Background
+----------
+
+Slang inherits HLSL's RWTexture types to represent UAV/storage texture resources, this works well for HLSL, GLSL, CUDA and SPIRV targets.
+However Metal has the notion of write only textures, and WebGPU has limited support of read-write textures. In WebGPU, a read-write texture can only have
+uncompressed single-channel 32bit texel format, which means a `RWTexture2D` cannot be used to write to a `rgba8unorm` texture.
+
+To provide better mapping to write-only textures on Metal and WebGPU, we propose to add write-only textures to Slang to allow writing portable code
+without relying on backend workarounds.
+
+Proposed Approach
+-----------------
+
+Slang's core module already defines all texture types as a single generic `_Texture<T, ..., access, ...>` type, where `access` is a value parameter
+representing the allowed access of the texture. The valid values of access are:
+
+```
+kCoreModule_ResourceAccessReadOnly
+kCoreModule_ResourceAccessReadWrite
+kCoreModule_ResourceAccessRasterizerOrdered
+kCoreModule_ResourceAccessFeedback
+```
+
+We propose to add another case:
+
+```
+kCoreModule_ResourceAccessWriteOnly
+```
+
+to represent write-only textures.
+
+
+Also add the typealiases prefixed with "W" for all write only textures:
+```
+WTexture1D, WTexture2D, ...
+```
+
+These types will be reported in the reflection API with `access=SLANG_RESOURCE_ACCESS_WRITE`.
+
+Write-only textures support `GetDimension` and `Store(coord, value)` methods. `Load` or `subscript` is not defined for write-only texture types,
+so the user cannot write code that reads from a write-only texture.
+
+Write only textures are supported on all targets. For traditional HLSL, GLSL, SPIRV and CUDA targets, they are translated
+exactly the same as `RW` textures. For Metal, they map to `access::write`, and for WGSL, they map to `texture_storage_X<format, write>`.