WebGPU: set usage in texture view descriptor

Author: TheMostDiligent

Graphics/GraphicsEngineWebGPU/src/TextureWebGPUImpl.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2023-2024 Diligent Graphics LLC
+ *  Copyright 2023-2025 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -138,6 +138,36 @@ WGPUTextureDescriptor TextureDescToWGPUTextureDescriptor(const TextureDesc&
     return wgpuTextureDesc;
 }
 
+#if !PLATFORM_EMSCRIPTEN
+static WGPUTextureUsage TextureViewTypeToWGPUTextureUsage(TEXTURE_VIEW_TYPE ViewType)
+{
+    static_assert(TEXTURE_VIEW_NUM_VIEWS == 7, "Please update the switch below to handle the new view type");
+    switch (ViewType)
+    {
+        case TEXTURE_VIEW_SHADER_RESOURCE:
+            return WGPUTextureUsage_TextureBinding;
+
+        case TEXTURE_VIEW_RENDER_TARGET:
+        case TEXTURE_VIEW_DEPTH_STENCIL:
+            return WGPUTextureUsage_RenderAttachment;
+
+        case TEXTURE_VIEW_READ_ONLY_DEPTH_STENCIL:
+            return WGPUTextureUsage_TextureBinding;
+
+        case TEXTURE_VIEW_UNORDERED_ACCESS:
+            return WGPUTextureUsage_StorageBinding;
+
+        case TEXTURE_VIEW_SHADING_RATE:
+            UNEXPECTED("Shading rate texture views are not supported in WebGPU");
+            return WGPUTextureUsage_None;
+
+        default:
+            UNEXPECTED("Unexpected view type");
+            return WGPUTextureUsage_None;
+    }
+}
+#endif
+
 WGPUTextureViewDescriptor TextureViewDescToWGPUTextureViewDescriptor(const TextureDesc&            TexDesc,
                                                                      TextureViewDesc&              ViewDesc,
                                                                      const RenderDeviceWebGPUImpl* pRenderDevice) noexcept
@@ -199,6 +229,15 @@ WGPUTextureViewDescriptor TextureViewDescToWGPUTextureViewDescriptor(const Textu
             wgpuTextureViewDesc.aspect = WGPUTextureAspect_All;
     }
 
+    // TODO: enable this as soon as Emscripten adds the usage member to WGPUTextureViewDescriptor
+    // https://github.com/emscripten-core/emscripten/issues/23945
+#if !PLATFORM_EMSCRIPTEN
+    if (ViewDesc.Format != TexDesc.Format)
+    {
+        wgpuTextureViewDesc.usage = TextureViewTypeToWGPUTextureUsage(ViewDesc.ViewType);
+    }
+#endif
+
     return wgpuTextureViewDesc;
 }