Support sampling depth and stencil of combined d/s formats

This CL adds sampling of depth-only and stencil-only texture
views on all backends. However, Metal on macOS <= 10.11 will
need a workaround to use separate depth/stencil textures for
each aspect since it is impossible to sample the stencil
aspect of a combined depth/stencil texture.

Also fixes sampling of depth24plus on D3D12 which had an
incomplete check for determining if a TYPELESS format is
necessary.

Bug: dawn:439, dawn:553
Change-Id: Id4991c565f822add200054296714e2dcd330119a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/30725
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>

src/common/Math.h

@@ -90,4 +90,12 @@ bool IsFloat16NaN(uint16_t fp16);
 
 float SRGBToLinear(float srgb);
 
+template <typename T1,
+          typename T2,
+          typename Enable = typename std::enable_if<sizeof(T1) == sizeof(T2)>::type>
+constexpr bool IsSubset(T1 subset, T2 set) {
+    T2 bitsAlsoInSet = subset & set;
+    return bitsAlsoInSet == subset;
+}
+
 #endif  // COMMON_MATH_H_

src/dawn_native/Format.cpp

@@ -150,7 +150,7 @@ namespace dawn_native {
         };
 
         auto AddDepthStencilFormat = [&AddFormat](wgpu::TextureFormat format, Aspect aspects,
-                                                  uint32_t byteSize, bool isDepthSampleable) {
+                                                  uint32_t byteSize) {
             Format internalFormat;
             internalFormat.format = format;
             internalFormat.isRenderable = true;
@@ -162,12 +162,8 @@ namespace dawn_native {
             internalFormat.firstAspect.block.width = 1;
             internalFormat.firstAspect.block.height = 1;
             internalFormat.firstAspect.baseType = wgpu::TextureComponentType::Float;
-            if (isDepthSampleable) {
+            internalFormat.firstAspect.supportedComponentTypes =
-                internalFormat.firstAspect.supportedComponentTypes =
+                ComponentTypeBit::Float | ComponentTypeBit::DepthComparison;
-                    ComponentTypeBit::Float | ComponentTypeBit::DepthComparison;
-            } else {
-                internalFormat.firstAspect.supportedComponentTypes = ComponentTypeBit::None;
-            }
             AddFormat(internalFormat);
         };
 
@@ -238,12 +234,12 @@ namespace dawn_native {
         AddColorFormat(wgpu::TextureFormat::RGBA32Float, true, true, 16, Type::Float);
 
         // Depth-stencil formats
-        AddDepthStencilFormat(wgpu::TextureFormat::Depth32Float, Aspect::Depth, 4, true);
+        AddDepthStencilFormat(wgpu::TextureFormat::Depth32Float, Aspect::Depth, 4);
-        AddDepthStencilFormat(wgpu::TextureFormat::Depth24Plus, Aspect::Depth, 4, false);
+        AddDepthStencilFormat(wgpu::TextureFormat::Depth24Plus, Aspect::Depth, 4);
         // TODO(cwallez@chromium.org): It isn't clear if this format should be copyable
         // because its size isn't well defined, is it 4, 5 or 8?
         AddDepthStencilFormat(wgpu::TextureFormat::Depth24PlusStencil8,
-                              Aspect::Depth | Aspect::Stencil, 4, false);
+                              Aspect::Depth | Aspect::Stencil, 4);
 
         // BC compressed formats
         bool isBCFormatSupported = device->IsExtensionEnabled(Extension::TextureCompressionBC);

src/dawn_native/d3d12/TextureD3D12.cpp

@@ -171,7 +171,7 @@ namespace dawn_native { namespace d3d12 {
                     return DXGI_FORMAT_R32_TYPELESS;
 
                 case wgpu::TextureFormat::Depth24PlusStencil8:
-                    return DXGI_FORMAT_X32_TYPELESS_G8X24_UINT;
+                    return DXGI_FORMAT_R32G8X24_TYPELESS;
 
                 case wgpu::TextureFormat::BC1RGBAUnorm:
                 case wgpu::TextureFormat::BC1RGBAUnormSrgb:
@@ -451,8 +451,8 @@ namespace dawn_native { namespace d3d12 {
 
         // This will need to be much more nuanced when WebGPU has
         // texture view compatibility rules.
-        bool needsTypelessFormat = GetFormat().format == wgpu::TextureFormat::Depth32Float &&
+        const bool needsTypelessFormat =
-                                   (GetUsage() & wgpu::TextureUsage::Sampled) != 0;
+            GetFormat().HasDepthOrStencil() && (GetUsage() & wgpu::TextureUsage::Sampled) != 0;
 
         DXGI_FORMAT dxgiFormat = needsTypelessFormat
                                      ? D3D12TypelessTextureFormat(GetFormat().format)
@@ -1027,13 +1027,50 @@ namespace dawn_native { namespace d3d12 {
     TextureView::TextureView(TextureBase* texture, const TextureViewDescriptor* descriptor)
         : TextureViewBase(texture, descriptor) {
         mSrvDesc.Format = D3D12TextureFormat(descriptor->format);
-        if (descriptor->format == wgpu::TextureFormat::Depth32Float) {
-            // TODO(enga): This will need to be much more nuanced when WebGPU has
-            // texture view compatibility rules.
-            mSrvDesc.Format = DXGI_FORMAT_R32_FLOAT;
-        }
         mSrvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
 
+        // TODO(enga): This will need to be much more nuanced when WebGPU has
+        // texture view compatibility rules.
+        UINT planeSlice = 0;
+        if (GetFormat().HasDepthOrStencil()) {
+            // Configure the SRV descriptor to reinterpret the texture allocated as
+            // TYPELESS as a single-plane shader-accessible view.
+            switch (descriptor->format) {
+                case wgpu::TextureFormat::Depth32Float:
+                case wgpu::TextureFormat::Depth24Plus:
+                    mSrvDesc.Format = DXGI_FORMAT_R32_FLOAT;
+                    break;
+                case wgpu::TextureFormat::Depth24PlusStencil8:
+                    switch (descriptor->aspect) {
+                        case wgpu::TextureAspect::DepthOnly:
+                            planeSlice = 0;
+                            mSrvDesc.Format = DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS;
+                            break;
+                        case wgpu::TextureAspect::StencilOnly:
+                            planeSlice = 1;
+                            mSrvDesc.Format = DXGI_FORMAT_X32_TYPELESS_G8X24_UINT;
+                            // Stencil is accessed using the .g component in the shader.
+                            // Map it to the zeroth component to match other APIs.
+                            mSrvDesc.Shader4ComponentMapping =
+                                D3D12_ENCODE_SHADER_4_COMPONENT_MAPPING(
+                                    D3D12_SHADER_COMPONENT_MAPPING_FROM_MEMORY_COMPONENT_1,
+                                    D3D12_SHADER_COMPONENT_MAPPING_FORCE_VALUE_0,
+                                    D3D12_SHADER_COMPONENT_MAPPING_FORCE_VALUE_0,
+                                    D3D12_SHADER_COMPONENT_MAPPING_FORCE_VALUE_1);
+                            break;
+                        case wgpu::TextureAspect::All:
+                            // A single aspect is not selected. The texture view must not be
+                            // sampled.
+                            mSrvDesc.Format = DXGI_FORMAT_UNKNOWN;
+                            break;
+                    }
+                    break;
+                default:
+                    UNREACHABLE();
+                    break;
+            }
+        }
+
         // Currently we always use D3D12_TEX2D_ARRAY_SRV because we cannot specify base array layer
         // and layer count in D3D12_TEX2D_SRV. For 2D texture views, we treat them as 1-layer 2D
         // array textures.
@@ -1065,7 +1102,7 @@ namespace dawn_native { namespace d3d12 {
                     mSrvDesc.Texture2DArray.FirstArraySlice = descriptor->baseArrayLayer;
                     mSrvDesc.Texture2DArray.MipLevels = descriptor->mipLevelCount;
                     mSrvDesc.Texture2DArray.MostDetailedMip = descriptor->baseMipLevel;
-                    mSrvDesc.Texture2DArray.PlaneSlice = 0;
+                    mSrvDesc.Texture2DArray.PlaneSlice = planeSlice;
                     mSrvDesc.Texture2DArray.ResourceMinLODClamp = 0;
                     break;
                 case wgpu::TextureViewDimension::Cube:
@@ -1093,6 +1130,7 @@ namespace dawn_native { namespace d3d12 {
     }
 
     const D3D12_SHADER_RESOURCE_VIEW_DESC& TextureView::GetSRVDescriptor() const {
+        ASSERT(mSrvDesc.Format != DXGI_FORMAT_UNKNOWN);
         return mSrvDesc;
     }
 

src/dawn_native/metal/TextureMTL.mm

@@ -34,7 +34,7 @@ namespace dawn_native { namespace metal {
             return usage & kUsageNeedsTextureView;
         }
 
-        MTLTextureUsage MetalTextureUsage(wgpu::TextureUsage usage) {
+        MTLTextureUsage MetalTextureUsage(const Format& format, wgpu::TextureUsage usage) {
             MTLTextureUsage result = MTLTextureUsageUnknown;  // This is 0
 
             if (usage & (wgpu::TextureUsage::Storage)) {
@@ -43,6 +43,14 @@ namespace dawn_native { namespace metal {
 
             if (usage & (wgpu::TextureUsage::Sampled)) {
                 result |= MTLTextureUsageShaderRead;
+
+                // For sampling stencil aspect of combined depth/stencil. See TextureView
+                // constructor.
+                if (@available(macOS 10.12, iOS 10.0, *)) {
+                    if (IsSubset(Aspect::Depth | Aspect::Stencil, format.aspects)) {
+                        result |= MTLTextureUsagePixelFormatView;
+                    }
+                }
             }
 
             if (usage & (wgpu::TextureUsage::RenderAttachment)) {
@@ -85,6 +93,11 @@ namespace dawn_native { namespace metal {
                 return true;
             }
 
+            if (IsSubset(Aspect::Depth | Aspect::Stencil, texture->GetFormat().aspects) &&
+                textureViewDescriptor->aspect == wgpu::TextureAspect::StencilOnly) {
+                return true;
+            }
+
             switch (textureViewDescriptor->dimension) {
                 case wgpu::TextureViewDimension::Cube:
                 case wgpu::TextureViewDimension::CubeArray:
@@ -285,7 +298,8 @@ namespace dawn_native { namespace metal {
         return {};
     }
 
-    MTLTextureDescriptor* CreateMetalTextureDescriptor(const TextureDescriptor* descriptor) {
+    MTLTextureDescriptor* CreateMetalTextureDescriptor(DeviceBase* device,
+                                                       const TextureDescriptor* descriptor) {
         MTLTextureDescriptor* mtlDesc = [MTLTextureDescriptor new];
 
         mtlDesc.width = descriptor->size.width;
@@ -293,7 +307,8 @@ namespace dawn_native { namespace metal {
         mtlDesc.sampleCount = descriptor->sampleCount;
         // TODO: add MTLTextureUsagePixelFormatView when needed when we support format
         // reinterpretation.
-        mtlDesc.usage = MetalTextureUsage(descriptor->usage);
+        mtlDesc.usage = MetalTextureUsage(device->GetValidInternalFormat(descriptor->format),
+                                          descriptor->usage);
         mtlDesc.pixelFormat = MetalPixelFormat(descriptor->format);
         mtlDesc.mipmapLevelCount = descriptor->mipLevelCount;
         mtlDesc.storageMode = MTLStorageModePrivate;
@@ -328,7 +343,7 @@ namespace dawn_native { namespace metal {
 
     Texture::Texture(Device* device, const TextureDescriptor* descriptor)
         : TextureBase(device, descriptor, TextureState::OwnedInternal) {
-        MTLTextureDescriptor* mtlDesc = CreateMetalTextureDescriptor(descriptor);
+        MTLTextureDescriptor* mtlDesc = CreateMetalTextureDescriptor(device, descriptor);
         mMtlTexture = [device->GetMTLDevice() newTextureWithDescriptor:mtlDesc];
         [mtlDesc release];
 
@@ -351,7 +366,7 @@ namespace dawn_native { namespace metal {
                       reinterpret_cast<const TextureDescriptor*>(descriptor->cTextureDescriptor),
                       TextureState::OwnedInternal) {
         MTLTextureDescriptor* mtlDesc = CreateMetalTextureDescriptor(
-            reinterpret_cast<const TextureDescriptor*>(descriptor->cTextureDescriptor));
+            device, reinterpret_cast<const TextureDescriptor*>(descriptor->cTextureDescriptor));
         mtlDesc.storageMode = kIOSurfaceStorageMode;
         mMtlTexture = [device->GetMTLDevice() newTextureWithDescriptor:mtlDesc
                                                              iosurface:ioSurface
@@ -581,6 +596,20 @@ namespace dawn_native { namespace metal {
             mMtlTextureView = [mtlTexture retain];
         } else {
             MTLPixelFormat format = MetalPixelFormat(descriptor->format);
+            if (descriptor->aspect == wgpu::TextureAspect::StencilOnly) {
+                if (@available(macOS 10.12, iOS 10.0, *)) {
+                    ASSERT(format == MTLPixelFormatDepth32Float_Stencil8);
+                    format = MTLPixelFormatX32_Stencil8;
+                } else {
+                    // TODO(enga): Add a workaround to back combined depth/stencil textures
+                    // with Sampled usage using two separate textures.
+                    // Or, consider always using the workaround for D32S8.
+                    GetDevice()->ConsumedError(
+                        DAWN_DEVICE_LOST_ERROR("Cannot create stencil-only texture view of "
+                                               "combined depth/stencil format."));
+                }
+            }
+
             MTLTextureType textureViewType =
                 MetalTextureViewType(descriptor->dimension, texture->GetSampleCount());
             auto mipLevelRange = NSMakeRange(descriptor->baseMipLevel, descriptor->mipLevelCount);

src/dawn_native/opengl/CommandBufferGL.cpp

@@ -306,6 +306,24 @@ namespace dawn_native { namespace opengl {
                             for (auto unit : mPipeline->GetTextureUnitsForTextureView(viewIndex)) {
                                 gl.ActiveTexture(GL_TEXTURE0 + unit);
                                 gl.BindTexture(target, handle);
+                                if (ToBackend(view->GetTexture())->GetGLFormat().format ==
+                                    GL_DEPTH_STENCIL) {
+                                    Aspect aspect = view->GetAspects();
+                                    ASSERT(HasOneBit(aspect));
+                                    switch (aspect) {
+                                        case Aspect::None:
+                                        case Aspect::Color:
+                                            UNREACHABLE();
+                                        case Aspect::Depth:
+                                            gl.TexParameteri(target, GL_DEPTH_STENCIL_TEXTURE_MODE,
+                                                             GL_DEPTH_COMPONENT);
+                                            break;
+                                        case Aspect::Stencil:
+                                            gl.TexParameteri(target, GL_DEPTH_STENCIL_TEXTURE_MODE,
+                                                             GL_STENCIL_INDEX);
+                                            break;
+                                    }
+                                }
                             }
                             break;
                         }

src/dawn_native/opengl/TextureGL.cpp

@@ -96,6 +96,16 @@ namespace dawn_native { namespace opengl {
                 return true;
             }
 
+            if (ToBackend(texture)->GetGLFormat().format == GL_DEPTH_STENCIL &&
+                (texture->GetUsage() & wgpu::TextureUsage::Sampled) != 0 &&
+                textureViewDescriptor->aspect == wgpu::TextureAspect::StencilOnly) {
+                // We need a separate view for one of the depth or stencil planes
+                // because each glTextureView needs it's own handle to set
+                // GL_DEPTH_STENCIL_TEXTURE_MODE. Choose the stencil aspect for the
+                // extra handle since it is likely sampled less often.
+                return true;
+            }
+
             switch (textureViewDescriptor->dimension) {
                 case wgpu::TextureViewDimension::Cube:
                 case wgpu::TextureViewDimension::CubeArray:

src/tests/end2end/DepthSamplingTests.cpp

@@ -19,6 +19,16 @@
 
 namespace {
 
+    constexpr wgpu::TextureFormat kDepthFormats[] = {
+        wgpu::TextureFormat::Depth32Float,
+        wgpu::TextureFormat::Depth24Plus,
+        wgpu::TextureFormat::Depth24PlusStencil8,
+    };
+
+    constexpr wgpu::TextureFormat kStencilFormats[] = {
+        wgpu::TextureFormat::Depth24PlusStencil8,
+    };
+
     constexpr wgpu::CompareFunction kCompareFunctions[] = {
         wgpu::CompareFunction::Never,        wgpu::CompareFunction::Less,
         wgpu::CompareFunction::LessEqual,    wgpu::CompareFunction::Greater,
@@ -32,10 +42,19 @@ namespace {
     // Test 0, below the ref, equal to, above the ref, and 1.
     const std::vector<float> kNormalizedTextureValues = {0.0, 0.3, 0.4, 0.5, 1.0};
 
+    // Test the limits, and some values in between.
+    const std::vector<uint8_t> kStencilValues = {uint8_t(0), uint8_t(1), uint8_t(38), uint8_t(255),
+                                                 uint8_t(256)};
+
 }  // anonymous namespace
 
-class DepthSamplingTest : public DawnTest {
+class DepthStencilSamplingTest : public DawnTest {
   protected:
+    enum class TestAspect {
+        Depth,
+        Stencil,
+    };
+
     void SetUp() override {
         DawnTest::SetUp();
 
@@ -43,32 +62,10 @@ class DepthSamplingTest : public DawnTest {
         uniformBufferDesc.usage = wgpu::BufferUsage::Uniform | wgpu::BufferUsage::CopyDst;
         uniformBufferDesc.size = sizeof(float);
         mUniformBuffer = device.CreateBuffer(&uniformBufferDesc);
-
-        wgpu::BufferDescriptor textureUploadDesc;
-        textureUploadDesc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::CopyDst;
-        textureUploadDesc.size = sizeof(float);
-        mTextureUploadBuffer = device.CreateBuffer(&textureUploadDesc);
-
-        wgpu::TextureDescriptor inputTextureDesc;
-        inputTextureDesc.usage = wgpu::TextureUsage::Sampled | wgpu::TextureUsage::RenderAttachment;
-        inputTextureDesc.size = {1, 1, 1};
-        inputTextureDesc.format = wgpu::TextureFormat::Depth32Float;
-        mInputTexture = device.CreateTexture(&inputTextureDesc);
-
-        wgpu::TextureDescriptor outputTextureDesc;
-        outputTextureDesc.usage =
-            wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::CopySrc;
-        outputTextureDesc.size = {1, 1, 1};
-        outputTextureDesc.format = wgpu::TextureFormat::R32Float;
-        mOutputTexture = device.CreateTexture(&outputTextureDesc);
-
-        wgpu::BufferDescriptor outputBufferDesc;
-        outputBufferDesc.usage = wgpu::BufferUsage::Storage | wgpu::BufferUsage::CopySrc;
-        outputBufferDesc.size = sizeof(float);
-        mOutputBuffer = device.CreateBuffer(&outputBufferDesc);
     }
 
-    wgpu::RenderPipeline CreateSamplingRenderPipeline() {
+    wgpu::RenderPipeline CreateSamplingRenderPipeline(std::vector<TestAspect> aspects,
+                                                      uint32_t componentIndex) {
         wgpu::ShaderModule vsModule =
             utils::CreateShaderModule(device, utils::SingleShaderStage::Vertex, R"(
                 #version 450
@@ -78,42 +75,102 @@ class DepthSamplingTest : public DawnTest {
                 }
             )");
 
-        wgpu::ShaderModule fsModule =
-            utils::CreateShaderModule(device, utils::SingleShaderStage::Fragment, R"(
-                #version 450
-                layout(set = 0, binding = 0) uniform sampler samp;
-                layout(set = 0, binding = 1) uniform texture2D tex;
-
-                layout(location = 0) out float samplerResult;
-
-                void main() {
-                    samplerResult = texture(sampler2D(tex, samp), vec2(0.5, 0.5)).r;
-                }
-            )");
-
         utils::ComboRenderPipelineDescriptor pipelineDescriptor(device);
+
+        std::ostringstream shaderSource;
+        std::ostringstream shaderBody;
+        shaderSource << R"(
+            #version 450
+            layout(set = 0, binding = 0) uniform sampler samp;
+        )";
+
+        uint32_t index = 0;
+        for (TestAspect aspect : aspects) {
+            switch (aspect) {
+                case TestAspect::Depth:
+                    shaderSource << "layout(set = 0, binding = " << 1 + index
+                                 << ") uniform texture2D tex" << index << ";\n";
+
+                    shaderSource << "layout(location = " << index << ") out float result" << index
+                                 << ";\n";
+
+                    shaderBody << "result" << index << " = texture(sampler2D(tex" << index
+                               << ", samp), vec2(0.5, 0.5))[" << componentIndex << "];\n";
+                    pipelineDescriptor.cColorStates[index].format = wgpu::TextureFormat::R32Float;
+                    break;
+                case TestAspect::Stencil:
+                    shaderSource << "layout(set = 0, binding = " << 1 + index
+                                 << ") uniform utexture2D tex" << index << ";\n";
+
+                    shaderSource << "layout(location = " << index << ") out uint result" << index
+                                 << ";\n";
+
+                    shaderBody << "result" << index << " = texelFetch(usampler2D(tex" << index
+                               << ", samp), ivec2(0, 0), 0)[" << componentIndex << "];\n";
+                    pipelineDescriptor.cColorStates[index].format = wgpu::TextureFormat::R8Uint;
+                    break;
+            }
+
+            index++;
+        }
+
+        shaderSource << "void main() { " << shaderBody.str() << " }";
+
+        wgpu::ShaderModule fsModule = utils::CreateShaderModule(
+            device, utils::SingleShaderStage::Fragment, shaderSource.str().c_str());
         pipelineDescriptor.vertexStage.module = vsModule;
         pipelineDescriptor.cFragmentStage.module = fsModule;
         pipelineDescriptor.primitiveTopology = wgpu::PrimitiveTopology::PointList;
-        pipelineDescriptor.cColorStates[0].format = wgpu::TextureFormat::R32Float;
+        pipelineDescriptor.colorStateCount = static_cast<uint32_t>(aspects.size());
 
         return device.CreateRenderPipeline(&pipelineDescriptor);
     }
 
-    wgpu::ComputePipeline CreateSamplingComputePipeline() {
+    wgpu::ComputePipeline CreateSamplingComputePipeline(std::vector<TestAspect> aspects,
-        wgpu::ShaderModule csModule =
+                                                        uint32_t componentIndex) {
-            utils::CreateShaderModule(device, utils::SingleShaderStage::Compute, R"(
+        std::ostringstream shaderSource;
-                #version 450
+        std::ostringstream shaderBody;
-                layout(set = 0, binding = 0) uniform sampler samp;
+        shaderSource << R"(
-                layout(set = 0, binding = 1) uniform texture2D tex;
+            #version 450
-                layout(set = 0, binding = 2) writeonly buffer SamplerResult {
+            layout(set = 0, binding = 0) uniform sampler samp;
-                    float samplerResult;
+        )";
-                };
 
-                void main() {
+        uint32_t index = 0;
-                    samplerResult = texture(sampler2D(tex, samp), vec2(0.5, 0.5)).r;
+        for (TestAspect aspect : aspects) {
-                }
+            switch (aspect) {
-            )");
+                case TestAspect::Depth:
+                    shaderSource << "layout(set = 0, binding = " << 1 + 2 * index
+                                 << ") uniform texture2D tex" << index << ";\n";
+
+                    shaderSource << "layout(set = 0, binding = " << 1 + 2 * index + 1
+                                 << ") writeonly buffer Result" << index << " {\n"
+                                 << "    float result" << index << ";\n"
+                                 << "};\n";
+
+                    shaderBody << "result" << index << " = texture(sampler2D(tex" << index
+                               << ", samp), vec2(0.5, 0.5))[" << componentIndex << "];\n";
+                    break;
+                case TestAspect::Stencil:
+                    shaderSource << "layout(set = 0, binding = " << 1 + 2 * index
+                                 << ") uniform utexture2D tex" << index << ";\n";
+
+                    shaderSource << "layout(set = 0, binding = " << 1 + 2 * index + 1
+                                 << ") writeonly buffer Result" << index << " {\n"
+                                 << "    uint result" << index << ";\n"
+                                 << "};\n";
+
+                    shaderBody << "result" << index << " = texelFetch(usampler2D(tex" << index
+                               << ", samp), ivec2(0, 0), 0)[" << componentIndex << "];\n";
+                    break;
+            }
+
+            index++;
+        }
+
+        shaderSource << "void main() { " << shaderBody.str() << " }";
+
+        wgpu::ShaderModule csModule = utils::CreateShaderModule(
+            device, utils::SingleShaderStage::Compute, shaderSource.str().c_str());
 
         wgpu::ComputePipelineDescriptor pipelineDescriptor;
         pipelineDescriptor.computeStage.module = csModule;
@@ -202,32 +259,97 @@ class DepthSamplingTest : public DawnTest {
         return device.CreateComputePipeline(&pipelineDescriptor);
     }
 
-    void UpdateInputTexture(wgpu::CommandEncoder commandEncoder, float textureValue) {
+    wgpu::Texture CreateInputTexture(wgpu::TextureFormat format) {
-        utils::ComboRenderPassDescriptor passDescriptor({}, mInputTexture.CreateView());
+        wgpu::TextureDescriptor inputTextureDesc;
-        passDescriptor.cDepthStencilAttachmentInfo.clearDepth = textureValue;
+        inputTextureDesc.usage = wgpu::TextureUsage::Sampled | wgpu::TextureUsage::OutputAttachment;
+        inputTextureDesc.size = {1, 1, 1};
+        inputTextureDesc.format = format;
+        return device.CreateTexture(&inputTextureDesc);
+    }
+
+    wgpu::Texture CreateOutputTexture(wgpu::TextureFormat format) {
+        wgpu::TextureDescriptor outputTextureDesc;
+        outputTextureDesc.usage =
+            wgpu::TextureUsage::OutputAttachment | wgpu::TextureUsage::CopySrc;
+        outputTextureDesc.size = {1, 1, 1};
+        outputTextureDesc.format = format;
+        return device.CreateTexture(&outputTextureDesc);
+    }
+
+    wgpu::Buffer CreateOutputBuffer() {
+        wgpu::BufferDescriptor outputBufferDesc;
+        outputBufferDesc.usage = wgpu::BufferUsage::Storage | wgpu::BufferUsage::CopySrc;
+        outputBufferDesc.size = sizeof(float);  // Large enough for both float and uint8_t
+        return device.CreateBuffer(&outputBufferDesc);
+    }
+
+    void UpdateInputDepth(wgpu::CommandEncoder commandEncoder,
+                          wgpu::Texture texture,
+                          float depthValue) {
+        utils::ComboRenderPassDescriptor passDescriptor({}, texture.CreateView());
+        passDescriptor.cDepthStencilAttachmentInfo.clearDepth = depthValue;
 
         wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
         pass.EndPass();
     }
 
-    void DoSamplingTest(wgpu::RenderPipeline pipeline, std::vector<float> textureValues) {
+    void UpdateInputStencil(wgpu::CommandEncoder commandEncoder,
+                            wgpu::Texture texture,
+                            uint8_t stencilValue) {
+        utils::ComboRenderPassDescriptor passDescriptor({}, texture.CreateView());
+        passDescriptor.cDepthStencilAttachmentInfo.clearStencil = stencilValue;
+
+        wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
+        pass.EndPass();
+    }
+
+    template <typename T>
+    void DoSamplingTest(TestAspect aspect,
+                        wgpu::RenderPipeline pipeline,
+                        wgpu::TextureFormat format,
+                        std::vector<T> textureValues,
+                        std::vector<T> expectedValues) {
+        ASSERT(textureValues.size() == expectedValues.size());
+
         wgpu::SamplerDescriptor samplerDesc;
         wgpu::Sampler sampler = device.CreateSampler(&samplerDesc);
 
-        wgpu::BindGroup bindGroup = utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+        wgpu::Texture outputTexture;
-                                                         {
+        wgpu::Texture inputTexture = CreateInputTexture(format);
-                                                             {0, sampler},
+        wgpu::TextureViewDescriptor inputViewDesc = {};
-                                                             {1, mInputTexture.CreateView()},
+        switch (aspect) {
-                                                         });
+            case TestAspect::Depth:
+                inputViewDesc.aspect = wgpu::TextureAspect::DepthOnly;
+                outputTexture = CreateOutputTexture(wgpu::TextureFormat::R32Float);
+                break;
+            case TestAspect::Stencil:
+                inputViewDesc.aspect = wgpu::TextureAspect::StencilOnly;
+                outputTexture = CreateOutputTexture(wgpu::TextureFormat::R8Uint);
+                break;
+        }
 
-        for (float textureValue : textureValues) {
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+                                 {
+                                     {0, sampler},
+                                     {1, inputTexture.CreateView(&inputViewDesc)},
+                                 });
+
+        for (size_t i = 0; i < textureValues.size(); ++i) {
             // Set the input depth texture to the provided texture value
             wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
-            UpdateInputTexture(commandEncoder, textureValue);
+            switch (aspect) {
+                case TestAspect::Depth:
+                    UpdateInputDepth(commandEncoder, inputTexture, textureValues[i]);
+                    break;
+                case TestAspect::Stencil:
+                    UpdateInputStencil(commandEncoder, inputTexture, textureValues[i]);
+                    break;
+            }
 
             // Render into the output texture
             {
-                utils::ComboRenderPassDescriptor passDescriptor({mOutputTexture.CreateView()});
+                utils::ComboRenderPassDescriptor passDescriptor({outputTexture.CreateView()});
                 wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
                 pass.SetPipeline(pipeline);
                 pass.SetBindGroup(0, bindGroup);
@@ -238,22 +360,49 @@ class DepthSamplingTest : public DawnTest {
             wgpu::CommandBuffer commands = commandEncoder.Finish();
             queue.Submit(1, &commands);
 
-            EXPECT_PIXEL_FLOAT_EQ(textureValue, mOutputTexture, 0, 0);
+            EXPECT_TEXTURE_EQ(expectedValues[i], outputTexture, 0, 0);
         }
     }
 
-    void DoSamplingTest(wgpu::ComputePipeline pipeline, std::vector<float> textureValues) {
+    template <typename T>
+    void DoSamplingTest(TestAspect aspect,
+                        wgpu::ComputePipeline pipeline,
+                        wgpu::TextureFormat format,
+                        std::vector<T> textureValues,
+                        std::vector<T> expectedValues) {
+        ASSERT(textureValues.size() == expectedValues.size());
+
         wgpu::SamplerDescriptor samplerDesc;
         wgpu::Sampler sampler = device.CreateSampler(&samplerDesc);
 
+        wgpu::Texture inputTexture = CreateInputTexture(format);
+        wgpu::TextureViewDescriptor inputViewDesc = {};
+        switch (aspect) {
+            case TestAspect::Depth:
+                inputViewDesc.aspect = wgpu::TextureAspect::DepthOnly;
+                break;
+            case TestAspect::Stencil:
+                inputViewDesc.aspect = wgpu::TextureAspect::StencilOnly;
+                break;
+        }
+
+        wgpu::Buffer outputBuffer = CreateOutputBuffer();
+
         wgpu::BindGroup bindGroup = utils::MakeBindGroup(
             device, pipeline.GetBindGroupLayout(0),
-            {{0, sampler}, {1, mInputTexture.CreateView()}, {2, mOutputBuffer}});
+            {{0, sampler}, {1, inputTexture.CreateView(&inputViewDesc)}, {2, outputBuffer}});
 
-        for (float textureValue : textureValues) {
+        for (size_t i = 0; i < textureValues.size(); ++i) {
             // Set the input depth texture to the provided texture value
             wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
-            UpdateInputTexture(commandEncoder, textureValue);
+            switch (aspect) {
+                case TestAspect::Depth:
+                    UpdateInputDepth(commandEncoder, inputTexture, textureValues[i]);
+                    break;
+                case TestAspect::Stencil:
+                    UpdateInputStencil(commandEncoder, inputTexture, textureValues[i]);
+                    break;
+            }
 
             // Sample into the output buffer
             {
@@ -267,10 +416,28 @@ class DepthSamplingTest : public DawnTest {
             wgpu::CommandBuffer commands = commandEncoder.Finish();
             queue.Submit(1, &commands);
 
-            EXPECT_BUFFER_U32_EQ(*reinterpret_cast<uint32_t*>(&textureValue), mOutputBuffer, 0);
+            uint32_t expectedValueU32 = 0;
+            memcpy(&expectedValueU32, &expectedValues[i], std::min(sizeof(T), sizeof(uint32_t)));
+            EXPECT_BUFFER_U32_EQ(expectedValueU32, outputBuffer, 0);
         }
     }
 
+    template <typename T>
+    void DoSamplingTest(TestAspect aspect,
+                        wgpu::RenderPipeline pipeline,
+                        wgpu::TextureFormat format,
+                        std::vector<T> textureValues) {
+        DoSamplingTest(aspect, pipeline, format, textureValues, textureValues);
+    }
+
+    template <typename T>
+    void DoSamplingTest(TestAspect aspect,
+                        wgpu::ComputePipeline pipeline,
+                        wgpu::TextureFormat format,
+                        std::vector<T> textureValues) {
+        DoSamplingTest(aspect, pipeline, format, textureValues, textureValues);
+    }
+
     static bool CompareFunctionPasses(float compareRef,
                                       wgpu::CompareFunction compare,
                                       float textureValue) {
@@ -296,31 +463,38 @@ class DepthSamplingTest : public DawnTest {
         }
     }
 
-    void DoCompareRefTest(wgpu::RenderPipeline pipeline,
+    void DoDepthCompareRefTest(wgpu::RenderPipeline pipeline,
-                          float compareRef,
+                               wgpu::TextureFormat format,
-                          wgpu::CompareFunction compare,
+                               float compareRef,
-                          std::vector<float> textureValues) {
+                               wgpu::CompareFunction compare,
+                               std::vector<float> textureValues) {
         queue.WriteBuffer(mUniformBuffer, 0, &compareRef, sizeof(float));
 
         wgpu::SamplerDescriptor samplerDesc;
         samplerDesc.compare = compare;
         wgpu::Sampler sampler = device.CreateSampler(&samplerDesc);
 
-        wgpu::BindGroup bindGroup = utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+        wgpu::Texture inputTexture = CreateInputTexture(format);
-                                                         {
+        wgpu::TextureViewDescriptor inputViewDesc = {};
-                                                             {0, sampler},
+        inputViewDesc.aspect = wgpu::TextureAspect::DepthOnly;
-                                                             {1, mInputTexture.CreateView()},
-                                                             {2, mUniformBuffer},
-                                                         });
 
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+                                 {
+                                     {0, sampler},
+                                     {1, inputTexture.CreateView(&inputViewDesc)},
+                                     {2, mUniformBuffer},
+                                 });
+
+        wgpu::Texture outputTexture = CreateOutputTexture(wgpu::TextureFormat::R32Float);
         for (float textureValue : textureValues) {
             // Set the input depth texture to the provided texture value
             wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
-            UpdateInputTexture(commandEncoder, textureValue);
+            UpdateInputDepth(commandEncoder, inputTexture, textureValue);
 
             // Render into the output texture
             {
-                utils::ComboRenderPassDescriptor passDescriptor({mOutputTexture.CreateView()});
+                utils::ComboRenderPassDescriptor passDescriptor({outputTexture.CreateView()});
                 wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
                 pass.SetPipeline(pipeline);
                 pass.SetBindGroup(0, bindGroup);
@@ -331,32 +505,39 @@ class DepthSamplingTest : public DawnTest {
             wgpu::CommandBuffer commands = commandEncoder.Finish();
             queue.Submit(1, &commands);
 
-            EXPECT_PIXEL_FLOAT_EQ(
+            EXPECT_TEXTURE_EQ(CompareFunctionPasses(compareRef, compare, textureValue) ? 1.f : 0.f,
-                CompareFunctionPasses(compareRef, compare, textureValue) ? 1.f : 0.f,
+                              outputTexture, 0, 0);
-                mOutputTexture, 0, 0);
         }
     }
 
-    void DoCompareRefTest(wgpu::ComputePipeline pipeline,
+    void DoDepthCompareRefTest(wgpu::ComputePipeline pipeline,
-                          float compareRef,
+                               wgpu::TextureFormat format,
-                          wgpu::CompareFunction compare,
+                               float compareRef,
-                          std::vector<float> textureValues) {
+                               wgpu::CompareFunction compare,
+                               std::vector<float> textureValues) {
         queue.WriteBuffer(mUniformBuffer, 0, &compareRef, sizeof(float));
 
         wgpu::SamplerDescriptor samplerDesc;
         samplerDesc.compare = compare;
         wgpu::Sampler sampler = device.CreateSampler(&samplerDesc);
 
-        wgpu::BindGroup bindGroup = utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+        wgpu::Texture inputTexture = CreateInputTexture(format);
-                                                         {{0, sampler},
+        wgpu::TextureViewDescriptor inputViewDesc = {};
-                                                          {1, mInputTexture.CreateView()},
+        inputViewDesc.aspect = wgpu::TextureAspect::DepthOnly;
-                                                          {2, mUniformBuffer},
+
-                                                          {3, mOutputBuffer}});
+        wgpu::Buffer outputBuffer = CreateOutputBuffer();
+
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+                                 {{0, sampler},
+                                  {1, inputTexture.CreateView(&inputViewDesc)},
+                                  {2, mUniformBuffer},
+                                  {3, outputBuffer}});
 
         for (float textureValue : textureValues) {
             // Set the input depth texture to the provided texture value
             wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
-            UpdateInputTexture(commandEncoder, textureValue);
+            UpdateInputDepth(commandEncoder, inputTexture, textureValue);
 
             // Sample into the output buffer
             {
@@ -375,63 +556,212 @@ class DepthSamplingTest : public DawnTest {
             float* expected =
                 CompareFunctionPasses(compareRef, compare, textureValue) ? &float1 : &float0;
 
-            EXPECT_BUFFER_U32_EQ(*reinterpret_cast<uint32_t*>(expected), mOutputBuffer, 0);
+            EXPECT_BUFFER_U32_EQ(*reinterpret_cast<uint32_t*>(expected), outputBuffer, 0);
         }
     }
 
   private:
     wgpu::Buffer mUniformBuffer;
-    wgpu::Buffer mTextureUploadBuffer;
-    wgpu::Texture mInputTexture;
-    wgpu::Texture mOutputTexture;
-    wgpu::Buffer mOutputBuffer;
 };
 
-// Test that sampling a depth texture with a render pipeline works
+// Test that sampling a depth texture with a render/compute pipeline works
-TEST_P(DepthSamplingTest, SampleRender) {
+TEST_P(DepthStencilSamplingTest, SampleDepth) {
-    // Test 0, between [0, 1], and 1.
+    for (wgpu::TextureFormat format : kDepthFormats) {
-    DoSamplingTest(CreateSamplingRenderPipeline(), kNormalizedTextureValues);
+        // Test 0, between [0, 1], and 1.
+        DoSamplingTest(TestAspect::Depth, CreateSamplingRenderPipeline({TestAspect::Depth}, 0),
+                       format, kNormalizedTextureValues);
+
+        DoSamplingTest(TestAspect::Depth, CreateSamplingComputePipeline({TestAspect::Depth}, 0),
+                       format, kNormalizedTextureValues);
+    }
 }
 
-// Test that sampling a depth texture with a compute pipeline works
+// Test that sampling a stencil texture with a render/compute pipeline works
-TEST_P(DepthSamplingTest, SampleCompute) {
+TEST_P(DepthStencilSamplingTest, SampleStencil) {
-    // Test 0, between [0, 1], and 1.
+    for (wgpu::TextureFormat format : kStencilFormats) {
-    DoSamplingTest(CreateSamplingComputePipeline(), kNormalizedTextureValues);
+        DoSamplingTest(TestAspect::Stencil, CreateSamplingRenderPipeline({TestAspect::Stencil}, 0),
+                       format, kStencilValues);
+
+        DoSamplingTest(TestAspect::Stencil, CreateSamplingComputePipeline({TestAspect::Stencil}, 0),
+                       format, kStencilValues);
+    }
+}
+
+// Test that sampling a depth/stencil texture at components 1, 2, and 3 yield 0, 0, and 1
+// respectively
+TEST_P(DepthStencilSamplingTest, SampleExtraComponents) {
+    // TODO(enga): In Metal, color textures' unspecified default components values
+    // are (0, 0, 0, 1). Depth/stencil textures are undefined! Figure out what
+    // to do here.
+    // See Section 6.10 of the Metal Shading Language Specification
+    DAWN_SKIP_TEST_IF(IsMetal());
+
+    float expectedDepth[4] = {0, 0, 0, 1};
+    uint8_t expectedStencil[4] = {0, 0, 0, 1};
+
+    for (uint32_t component : {1, 2, 3}) {
+        DoSamplingTest<float>(
+            TestAspect::Depth, CreateSamplingRenderPipeline({TestAspect::Depth}, component),
+            wgpu::TextureFormat::Depth24PlusStencil8, {0.2f}, {expectedDepth[component]});
+
+        DoSamplingTest<float>(
+            TestAspect::Depth, CreateSamplingComputePipeline({TestAspect::Depth}, component),
+            wgpu::TextureFormat::Depth24PlusStencil8, {0.2f}, {expectedDepth[component]});
+
+        DoSamplingTest<uint8_t>(
+            TestAspect::Stencil, CreateSamplingRenderPipeline({TestAspect::Stencil}, component),
+            wgpu::TextureFormat::Depth24PlusStencil8, {uint8_t(37)}, {expectedStencil[component]});
+
+        DoSamplingTest<uint8_t>(
+            TestAspect::Stencil, CreateSamplingComputePipeline({TestAspect::Stencil}, component),
+            wgpu::TextureFormat::Depth24PlusStencil8, {uint8_t(37)}, {expectedStencil[component]});
+    }
+}
+
+// Test sampling both depth and stencil with a render/compute pipeline works.
+TEST_P(DepthStencilSamplingTest, SampleDepthAndStencilRender) {
+    wgpu::SamplerDescriptor samplerDesc;
+    wgpu::Sampler sampler = device.CreateSampler(&samplerDesc);
+
+    wgpu::Texture inputTexture = CreateInputTexture(wgpu::TextureFormat::Depth24PlusStencil8);
+
+    wgpu::TextureViewDescriptor depthViewDesc = {};
+    depthViewDesc.aspect = wgpu::TextureAspect::DepthOnly;
+
+    wgpu::TextureViewDescriptor stencilViewDesc = {};
+    stencilViewDesc.aspect = wgpu::TextureAspect::StencilOnly;
+
+    // With render pipeline
+    {
+        wgpu::RenderPipeline pipeline =
+            CreateSamplingRenderPipeline({TestAspect::Depth, TestAspect::Stencil}, 0);
+
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+                                 {
+                                     {0, sampler},
+                                     {1, inputTexture.CreateView(&depthViewDesc)},
+                                     {2, inputTexture.CreateView(&stencilViewDesc)},
+                                 });
+
+        wgpu::Texture depthOutput = CreateOutputTexture(wgpu::TextureFormat::R32Float);
+        wgpu::Texture stencilOutput = CreateOutputTexture(wgpu::TextureFormat::R8Uint);
+
+        wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
+
+        // Initialize both depth and stencil aspects.
+        utils::ComboRenderPassDescriptor passDescriptor({}, inputTexture.CreateView());
+        passDescriptor.cDepthStencilAttachmentInfo.clearDepth = 0.43f;
+        passDescriptor.cDepthStencilAttachmentInfo.clearStencil = 31;
+
+        wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
+        pass.EndPass();
+
+        // Render into the output textures
+        {
+            utils::ComboRenderPassDescriptor passDescriptor(
+                {depthOutput.CreateView(), stencilOutput.CreateView()});
+            wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
+            pass.SetPipeline(pipeline);
+            pass.SetBindGroup(0, bindGroup);
+            pass.Draw(1);
+            pass.EndPass();
+        }
+
+        wgpu::CommandBuffer commands = commandEncoder.Finish();
+        queue.Submit(1, &commands);
+
+        EXPECT_TEXTURE_EQ(passDescriptor.cDepthStencilAttachmentInfo.clearDepth, depthOutput, 0, 0);
+        EXPECT_TEXTURE_EQ(uint8_t(passDescriptor.cDepthStencilAttachmentInfo.clearStencil),
+                          stencilOutput, 0, 0);
+    }
+
+    // With compute pipeline
+    {
+        wgpu::ComputePipeline pipeline =
+            CreateSamplingComputePipeline({TestAspect::Depth, TestAspect::Stencil}, 0);
+
+        wgpu::Buffer depthOutput = CreateOutputBuffer();
+        wgpu::Buffer stencilOutput = CreateOutputBuffer();
+
+        wgpu::BindGroup bindGroup =
+            utils::MakeBindGroup(device, pipeline.GetBindGroupLayout(0),
+                                 {{0, sampler},
+                                  {1, inputTexture.CreateView(&depthViewDesc)},
+                                  {2, depthOutput},
+                                  {3, inputTexture.CreateView(&stencilViewDesc)},
+                                  {4, stencilOutput}});
+
+        wgpu::CommandEncoder commandEncoder = device.CreateCommandEncoder();
+        // Initialize both depth and stencil aspects.
+        utils::ComboRenderPassDescriptor passDescriptor({}, inputTexture.CreateView());
+        passDescriptor.cDepthStencilAttachmentInfo.clearDepth = 0.43f;
+        passDescriptor.cDepthStencilAttachmentInfo.clearStencil = 31;
+
+        wgpu::RenderPassEncoder pass = commandEncoder.BeginRenderPass(&passDescriptor);
+        pass.EndPass();
+
+        // Sample into the output buffers
+        {
+            wgpu::ComputePassEncoder pass = commandEncoder.BeginComputePass();
+            pass.SetPipeline(pipeline);
+            pass.SetBindGroup(0, bindGroup);
+            pass.Dispatch(1);
+            pass.EndPass();
+        }
+
+        wgpu::CommandBuffer commands = commandEncoder.Finish();
+        queue.Submit(1, &commands);
+
+        uint32_t expectedValueU32 = 0;
+        memcpy(&expectedValueU32, &passDescriptor.cDepthStencilAttachmentInfo.clearDepth,
+               sizeof(float));
+        EXPECT_BUFFER_U32_EQ(expectedValueU32, depthOutput, 0);
+
+        expectedValueU32 = 0;
+        memcpy(&expectedValueU32, &passDescriptor.cDepthStencilAttachmentInfo.clearStencil,
+               sizeof(uint8_t));
+        EXPECT_BUFFER_U32_EQ(expectedValueU32, stencilOutput, 0);
+    }
 }
 
 // Test that sampling in a render pipeline with all of the compare functions works.
-TEST_P(DepthSamplingTest, CompareFunctionsRender) {
+TEST_P(DepthStencilSamplingTest, CompareFunctionsRender) {
     // Initialization via renderPass loadOp doesn't work on Mac Intel.
     DAWN_SKIP_TEST_IF(IsMetal() && IsIntel());
 
     wgpu::RenderPipeline pipeline = CreateComparisonRenderPipeline();
 
-    // Test a "normal" ref value between 0 and 1; as well as negative and > 1 refs.
+    for (wgpu::TextureFormat format : kDepthFormats) {
-    for (float compareRef : kCompareRefs) {
+        // Test a "normal" ref value between 0 and 1; as well as negative and > 1 refs.
-        // Test 0, below the ref, equal to, above the ref, and 1.
+        for (float compareRef : kCompareRefs) {
-        for (wgpu::CompareFunction f : kCompareFunctions) {
+            // Test 0, below the ref, equal to, above the ref, and 1.
-            DoCompareRefTest(pipeline, compareRef, f, kNormalizedTextureValues);
+            for (wgpu::CompareFunction f : kCompareFunctions) {
+                DoDepthCompareRefTest(pipeline, format, compareRef, f, kNormalizedTextureValues);
+            }
         }
     }
 }
 
 // Test that sampling in a render pipeline with all of the compare functions works.
-TEST_P(DepthSamplingTest, CompareFunctionsCompute) {
+TEST_P(DepthStencilSamplingTest, CompareFunctionsCompute) {
     // Initialization via renderPass loadOp doesn't work on Mac Intel.
     DAWN_SKIP_TEST_IF(IsMetal() && IsIntel());
 
     wgpu::ComputePipeline pipeline = CreateComparisonComputePipeline();
 
-    // Test a "normal" ref value between 0 and 1; as well as negative and > 1 refs.
+    for (wgpu::TextureFormat format : kDepthFormats) {
-    for (float compareRef : kCompareRefs) {
+        // Test a "normal" ref value between 0 and 1; as well as negative and > 1 refs.
-        // Test 0, below the ref, equal to, above the ref, and 1.
+        for (float compareRef : kCompareRefs) {
-        for (wgpu::CompareFunction f : kCompareFunctions) {
+            // Test 0, below the ref, equal to, above the ref, and 1.
-            DoCompareRefTest(pipeline, compareRef, f, kNormalizedTextureValues);
+            for (wgpu::CompareFunction f : kCompareFunctions) {
+                DoDepthCompareRefTest(pipeline, format, compareRef, f, kNormalizedTextureValues);
+            }
         }
     }
 }
 
-DAWN_INSTANTIATE_TEST(DepthSamplingTest,
+DAWN_INSTANTIATE_TEST(DepthStencilSamplingTest,
                       D3D12Backend(),
                       MetalBackend(),
                       OpenGLBackend(),

src/tests/unittests/MathTests.cpp

@@ -15,9 +15,23 @@
 #include <gtest/gtest.h>
 
 #include "common/Math.h"
+#include "dawn/EnumClassBitmasks.h"
 
 #include <cmath>
 
+namespace wgpu {
+    enum class TestEnum {
+        A = 0x1,
+        B = 0x2,
+        C = 0x4,
+    };
+}  // namespace wgpu
+
+template <>
+struct wgpu::IsDawnBitmask<wgpu::TestEnum> {
+    static constexpr bool enable = true;
+};
+
 // Tests for ScanForward
 TEST(Math, ScanForward) {
     // Test extrema
@@ -260,3 +274,32 @@ TEST(Math, RoundUp) {
     ASSERT_EQ(RoundUp(0x7FFFFFFFFFFFFFFFull, 0x8000000000000000ull), 0x8000000000000000ull);
     ASSERT_EQ(RoundUp(1, 1), 1u);
 }
+
+// Tests for IsSubset
+TEST(Math, IsSubset) {
+    // single value is a subset
+    ASSERT_TRUE(IsSubset(0b100, 0b101));
+    ASSERT_FALSE(IsSubset(0b010, 0b101));
+    ASSERT_TRUE(IsSubset(0b001, 0b101));
+
+    // empty set is a subset
+    ASSERT_TRUE(IsSubset(0b000, 0b101));
+
+    // equal-to is a subset
+    ASSERT_TRUE(IsSubset(0b101, 0b101));
+
+    // superset is not a subset
+    ASSERT_FALSE(IsSubset(0b111, 0b101));
+
+    // only empty is a subset of empty
+    ASSERT_FALSE(IsSubset(0b100, 0b000));
+    ASSERT_FALSE(IsSubset(0b010, 0b000));
+    ASSERT_FALSE(IsSubset(0b001, 0b000));
+    ASSERT_TRUE(IsSubset(0b000, 0b000));
+
+    // Test with enums
+    ASSERT_TRUE(IsSubset(wgpu::TestEnum::A, wgpu::TestEnum::A));
+    ASSERT_TRUE(IsSubset(wgpu::TestEnum::A, wgpu::TestEnum::A | wgpu::TestEnum::B));
+    ASSERT_FALSE(IsSubset(wgpu::TestEnum::C, wgpu::TestEnum::A | wgpu::TestEnum::B));
+    ASSERT_FALSE(IsSubset(wgpu::TestEnum::A | wgpu::TestEnum::C, wgpu::TestEnum::A));
+}

src/tests/unittests/validation/BindGroupValidationTests.cpp

@@ -311,10 +311,8 @@ TEST_F(BindGroupValidationTest, TextureComponentType) {
     ASSERT_DEVICE_ERROR(utils::MakeBindGroup(device, layout, {{0, uintTextureView}}));
 }
 
-// Test which depth-stencil formats are allowed to be sampled.
+// Test which depth-stencil formats are allowed to be sampled (all).
-// This is a regression test for a change in dawn_native mistakenly allowing the depth24plus formats
+TEST_F(BindGroupValidationTest, SamplingDepthStencilTexture) {
-// to be sampled without proper backend support.
-TEST_F(BindGroupValidationTest, SamplingDepthTexture) {
     wgpu::BindGroupLayout layout = utils::MakeBindGroupLayout(
         device, {{0, wgpu::ShaderStage::Fragment, wgpu::BindingType::SampledTexture}});
 
@@ -330,20 +328,30 @@ TEST_F(BindGroupValidationTest, SamplingDepthTexture) {
         utils::MakeBindGroup(device, layout, {{0, texture.CreateView()}});
     }
 
-    // Depth24Plus is not allowed to be sampled.
+    // Depth24Plus is allowed to be sampled.
     {
         desc.format = wgpu::TextureFormat::Depth24Plus;
         wgpu::Texture texture = device.CreateTexture(&desc);
 
-        ASSERT_DEVICE_ERROR(utils::MakeBindGroup(device, layout, {{0, texture.CreateView()}}));
+        utils::MakeBindGroup(device, layout, {{0, texture.CreateView()}});
     }
 
-    // Depth24PlusStencil8 is not allowed to be sampled.
+    // Depth24PlusStencil8 is allowed to be sampled, if the depth or stencil aspect is selected.
     {
         desc.format = wgpu::TextureFormat::Depth24PlusStencil8;
         wgpu::Texture texture = device.CreateTexture(&desc);
+        wgpu::TextureViewDescriptor viewDesc = {};
 
-        ASSERT_DEVICE_ERROR(utils::MakeBindGroup(device, layout, {{0, texture.CreateView()}}));
+        viewDesc.aspect = wgpu::TextureAspect::DepthOnly;
+        utils::MakeBindGroup(device, layout, {{0, texture.CreateView(&viewDesc)}});
+
+        wgpu::BindGroupLayoutEntry entry = {0, wgpu::ShaderStage::Fragment,
+                                            wgpu::BindingType::SampledTexture};
+        entry.textureComponentType = wgpu::TextureComponentType::Uint;
+        layout = utils::MakeBindGroupLayout(device, {entry});
+
+        viewDesc.aspect = wgpu::TextureAspect::StencilOnly;
+        utils::MakeBindGroup(device, layout, {{0, texture.CreateView(&viewDesc)}});
     }
 }