src/dawn/native/BlitColorToColorWithDraw.cpp - dawn - Git at Google


            
            // Copyright 2023 The Dawn & Tint Authors

            
            //

            
            // Redistribution and use in source and binary forms, with or without

            
            // modification, are permitted provided that the following conditions are met:

            
            //

            
            // 1. Redistributions of source code must retain the above copyright notice, this

            
            //    list of conditions and the following disclaimer.

            
            //

            
            // 2. Redistributions in binary form must reproduce the above copyright notice,

            
            //    this list of conditions and the following disclaimer in the documentation

            
            //    and/or other materials provided with the distribution.

            
            //

            
            // 3. Neither the name of the copyright holder nor the names of its

            
            //    contributors may be used to endorse or promote products derived from

            
            //    this software without specific prior written permission.

            
            //

            
            // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

            
            // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

            
            // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

            
            // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

            
            // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

            
            // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

            
            // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

            
            // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

            
            // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

            
            // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


            #include "src/dawn/native/BlitColorToColorWithDraw.h"


            #include <limits>

            
            #include <sstream>

            
            #include <string>

            
            #include <utility>


            #include "absl/container/inlined_vector.h"

            
            #include "src/dawn/common/Enumerator.h"

            
            #include "src/dawn/common/HashUtils.h"

            
            #include "src/dawn/common/Strings.h"

            
            #include "src/dawn/native/BindGroup.h"

            
            #include "src/dawn/native/ChainUtils.h"

            
            #include "src/dawn/native/CommandEncoder.h"

            
            #include "src/dawn/native/Device.h"

            
            #include "src/dawn/native/InternalPipelineStore.h"

            
            #include "src/dawn/native/RenderPassEncoder.h"

            
            #include "src/dawn/native/RenderPipeline.h"

            
            #include "src/dawn/native/utils/WGPUHelpers.h"

            
            #include "src/dawn/native/webgpu_absl_format.h"

            
            #include "src/utils/assert.h"

            
            #include "src/utils/compiler.h"


            namespace dawn::native {


            namespace {


            constexpr std::string_view kVertexOutputsStruct = DAWN_MULTILINE(

            
                struct VertexOutputs {

            
                    @builtin(position) position : vec4<f32>,

            
                    @location(0) @interpolate(flat, either) offsets : vec2i,

            
                };

            
            );


            std::string GenerateBlitToColorVS() {

            
                constexpr std::string_view kBlitToColorVS = DAWN_MULTILINE(

            
                    // Unpack a u32 into two i32 values, each was originally two 16-bit signed

            
                    // integer.

            
                    fn unpack_offsets(offsets : u32) -> vec2<i32> {

            
                        // First extract the high and low 16-bit values, then convert to u32 for

            
                        // zero-extension.

            
                        var offsets_bits = vec2u(offsets & 0xFFFFu, (offsets >> 16) & 0xFFFFu);

            
                        // For each 16-bit value, if the sign bit is set (0x8000), perform sign

            
                        // extension by setting the upper 16 bits to 1s (0xFFFF0000).

            
                        offsets_bits = select(

            
                            offsets_bits,

            
                            offsets_bits | vec2u(0xFFFF0000u),

            
                            // Check if negative.

            
                            (offsets_bits & vec2u(0x8000u)) != vec2u(0u),

            
                        );

            
                        // Reinterpret the final 32-bit values as signed integers.

            
                        return bitcast<vec2i>(offsets_bits);

            
                    }


                    @vertex fn vert_fullscreen_quad(

            
                        @builtin(vertex_index) vertex_index : u32,

            
                        @builtin(instance_index) instance_index : u32

            
                    ) -> VertexOutputs {

            
                        var output : VertexOutputs;

            
                        const pos = array(

            
                            vec2f(-1.0, -1.0),

            
                            vec2f(3.0, -1.0),

            
                            vec2f(-1.0, 3.0));

            
                        output.position = vec4f(pos[vertex_index], 0.0, 1.0);

            
                        output.offsets = unpack_offsets(instance_index);

            
                        return output;

            
                    }

            
                );

            
                return std::string(kVertexOutputsStruct) + std::string(kBlitToColorVS);

            
            }


            std::string GenerateExpandFS(const BlitColorToColorWithDrawPipelineKey& pipelineKey) {

            
                std::ostringstream outputStructStream;

            
                std::ostringstream assignOutputsStream;

            
                std::ostringstream finalStream;

            
                for (auto i : pipelineKey.attachmentsToExpandResolve) {

            
                    finalStream << absl::StrFormat("@group(0) @binding(%u) var srcTex%u : texture_2d<f32>;", i,

            
                                                   i);


                    outputStructStream << absl::StrFormat("@location(%u) output%u : vec4f,", i, i);


                    assignOutputsStream << absl::StrFormat(

            
                        "\toutputColor.output%u = textureLoad(srcTex%u, vec2i(input.position.xy) + "

            
                        "input.offsets, 0);",

            
                        i, i);

            
                }


                finalStream << kVertexOutputsStruct << "struct OutputColor {" << outputStructStream.str()

            
                            << "}";

            
                finalStream << DAWN_MULTILINE(

            
                    @fragment fn expand_multisample(input: VertexOutputs) -> OutputColor {

            
                        var outputColor : OutputColor;

            
                );

            
                finalStream << assignOutputsStream.str();

            
                finalStream << DAWN_MULTILINE(

            
                        return outputColor;

            
                    }

            
                );


                return finalStream.str();

            
            }


            // Generate the fragment shader to average multiple samples into one.

            
            std::string GenerateResolveFS(uint32_t sampleCount) {

            
                std::ostringstream ss;

            
                ss << kVertexOutputsStruct;

            
                ss << DAWN_MULTILINE(

            
                    @group(0) @binding(0) var srcTex : texture_multisampled_2d<f32>;


                    @fragment

            
                    fn resolve_multisample(input: VertexOutputs) -> @location(0) vec4f {

            
                        var sum = vec4f(0.0, 0.0, 0.0, 0.0);

            
                        var offsetPos = vec2i(input.position.xy) - input.offsets;

            
                );

            
                for (uint32_t sample = 0; sample < sampleCount; ++sample) {

            
                    ss << absl::StrFormat("sum += textureLoad(srcTex, offsetPos, %u);", sample);

            
                }

            
                ss << absl::StrFormat("return sum / %u;", sampleCount);

            
                ss << DAWN_MULTILINE(

            
                    }

            
                );


                return ss.str();

            
            }


            ResultOrError<Ref<RenderPipelineBase>> GetOrCreateExpandMultisamplePipeline(

            
                DeviceBase* device,

            
                const BlitColorToColorWithDrawPipelineKey& pipelineKey) {

            
                InternalPipelineStore* store = device->GetInternalPipelineStore();

            
                {

            
                    auto it = store->expandResolveTexturePipelines.find(pipelineKey);

            
                    if (it != store->expandResolveTexturePipelines.end()) {

            
                        return it->second;

            
                    }

            
                }


                // vertex shader's source.

            
                ShaderSourceWGSL wgslDesc = {};

            
                ShaderModuleDescriptor shaderModuleDesc = {};

            
                shaderModuleDesc.nextInChain = &wgslDesc;

            
                const std::string vsCode = GenerateBlitToColorVS();

            
                wgslDesc.code = vsCode.c_str();


                Ref<ShaderModuleBase> vshaderModule;

            
                DAWN_TRY_ASSIGN(vshaderModule, device->CreateShaderModule(&shaderModuleDesc));


                // fragment shader's source will depend on pipeline key.

            
                std::string fsCode = GenerateExpandFS(pipelineKey);

            
                wgslDesc.code = fsCode.c_str();

            
                Ref<ShaderModuleBase> fshaderModule;

            
                DAWN_TRY_ASSIGN(fshaderModule, device->CreateShaderModule(&shaderModuleDesc));


                // Color target states.

            
                PerColorAttachment<ColorTargetState> colorTargets = {};

            
                PerColorAttachment<wgpu::ColorTargetStateExpandResolveTextureDawn> msaaExpandResolveStates;


                for (auto [i, target] : Enumerate(colorTargets)) {

            
                    target.format = pipelineKey.colorTargetFormats[i];

            
                    // We shouldn't change the color targets that are not involved in.

            
                    if (pipelineKey.resolveTargetsMask[i]) {

            
                        target.nextInChain = &msaaExpandResolveStates[i];

            
                        msaaExpandResolveStates[i].enabled = pipelineKey.attachmentsToExpandResolve[i];

            
                        if (msaaExpandResolveStates[i].enabled) {

            
                            target.writeMask = wgpu::ColorWriteMask::All;

            
                        } else {

            
                            target.writeMask = wgpu::ColorWriteMask::None;

            
                        }

            
                    } else {

            
                        target.writeMask = wgpu::ColorWriteMask::None;

            
                    }

            
                }


                FragmentState fragmentState = {};

            
                fragmentState.module = fshaderModule.Get();

            
                fragmentState.entryPoint = "expand_multisample";

            
                fragmentState.targets = colorTargets;


                RenderPipelineDescriptor renderPipelineDesc = {};

            
                renderPipelineDesc.label = "expand_multisample";

            
                renderPipelineDesc.vertex.module = vshaderModule.Get();

            
                renderPipelineDesc.vertex.entryPoint = "vert_fullscreen_quad";

            
                renderPipelineDesc.fragment = &fragmentState;


                // Depth stencil state.

            
                DepthStencilState depthStencilState = {};

            
                if (pipelineKey.depthStencilFormat != wgpu::TextureFormat::Undefined) {

            
                    depthStencilState.format = pipelineKey.depthStencilFormat;

            
                    depthStencilState.depthWriteEnabled = wgpu::OptionalBool::False;

            
                    depthStencilState.depthCompare = wgpu::CompareFunction::Always;


                    renderPipelineDesc.depthStencil = &depthStencilState;

            
                }


                // Multisample state.

            
                DAWN_CHECK(pipelineKey.sampleCount > 1);

            
                renderPipelineDesc.multisample.count = pipelineKey.sampleCount;


                // Bind group layout.

            
                absl::InlinedVector<BindGroupLayoutEntry, kMaxColorAttachments> bglEntries;

            
                for (auto colorIdx : pipelineKey.attachmentsToExpandResolve) {

            
                    bglEntries.push_back({});

            
                    auto& bglEntry = bglEntries.back();

            
                    bglEntry.binding = static_cast<uint8_t>(colorIdx);

            
                    bglEntry.visibility = wgpu::ShaderStage::Fragment;

            
                    bglEntry.texture.sampleType = kInternalResolveAttachmentSampleType;

            
                    bglEntry.texture.viewDimension = wgpu::TextureViewDimension::e2D;

            
                }

            
                BindGroupLayoutDescriptor bglDesc = {};

            
                bglDesc.entries = bglEntries;


                Ref<BindGroupLayoutBase> bindGroupLayout;

            
                DAWN_TRY_ASSIGN(bindGroupLayout,

            
                                device->CreateBindGroupLayout(&bglDesc, /* allowInternalBinding */ true));


                Ref<PipelineLayoutBase> pipelineLayout;

            
                DAWN_TRY_ASSIGN(pipelineLayout, utils::MakeBasicPipelineLayout(device, bindGroupLayout));


                renderPipelineDesc.layout = pipelineLayout.Get();


                Ref<RenderPipelineBase> pipeline;

            
                DAWN_TRY_ASSIGN(pipeline, device->CreateRenderPipeline(&renderPipelineDesc));


                store->expandResolveTexturePipelines.emplace(pipelineKey, pipeline);

            
                return pipeline;

            
            }


            ResultOrError<Ref<RenderPipelineBase>> GetOrCreateResolveMultisamplePipeline(

            
                DeviceBase* device,

            
                const ResolveMultisampleWithDrawPipelineKey& pipelineKey) {

            
                // Try finding the pipeline from the cache.

            
                InternalPipelineStore* store = device->GetInternalPipelineStore();

            
                {

            
                    auto it = store->resolveMultisamplePipelines.find(pipelineKey);

            
                    if (it != store->resolveMultisamplePipelines.end()) {

            
                        return it->second;

            
                    }

            
                }


                // vertex shader's source.

            
                ShaderSourceWGSL wgslDesc = {};

            
                ShaderModuleDescriptor shaderModuleDesc = {};

            
                shaderModuleDesc.nextInChain = &wgslDesc;

            
                const std::string vsCode = GenerateBlitToColorVS();

            
                wgslDesc.code = vsCode.c_str();


                Ref<ShaderModuleBase> vshaderModule;

            
                DAWN_TRY_ASSIGN(vshaderModule, device->CreateShaderModule(&shaderModuleDesc));


                // fragment shader's source will depend on sample count.

            
                std::string fsCode = GenerateResolveFS(pipelineKey.sampleCount);

            
                wgslDesc.code = fsCode.c_str();

            
                Ref<ShaderModuleBase> fshaderModule;

            
                DAWN_TRY_ASSIGN(fshaderModule, device->CreateShaderModule(&shaderModuleDesc));


                // Color target states.

            
                ColorTargetState colorTarget = {};

            
                colorTarget.format = pipelineKey.colorTargetFormat;


                FragmentState fragmentState = {};

            
                fragmentState.module = fshaderModule.Get();

            
                fragmentState.entryPoint = "resolve_multisample";

            
                fragmentState.targets = SpanFromRef<ColorAttachmentIndex>(colorTarget);


                RenderPipelineDescriptor renderPipelineDesc = {};

            
                renderPipelineDesc.label = "resolve_multisample";

            
                renderPipelineDesc.vertex.module = vshaderModule.Get();

            
                renderPipelineDesc.vertex.entryPoint = "vert_fullscreen_quad";

            
                renderPipelineDesc.fragment = &fragmentState;


                Ref<RenderPipelineBase> pipeline;

            
                DAWN_TRY_ASSIGN(pipeline, device->CreateRenderPipeline(&renderPipelineDesc));


                store->resolveMultisamplePipelines.emplace(pipelineKey, pipeline);

            
                return pipeline;

            
            }


            }  // namespace


            // Since texture dimensions never exceed 16 bits, we can safely store offsets in 16 bits. This

            
            // allows packing two signed 16-bit offsets (each within −32,768 ~ +32,767) into a single 32-bit

            
            // unsigned integer for efficient storage and retrieval.

            
            uint32_t PackOffsets(const RenderPassDescriptorResolveRect& expandResolveRect) {

            
                const auto offsetX = static_cast<int32_t>(expandResolveRect.resolveOffsetX) -

            
                                     static_cast<int32_t>(expandResolveRect.colorOffsetX);

            
                const auto offsetY = static_cast<int32_t>(expandResolveRect.resolveOffsetY) -

            
                                     static_cast<int32_t>(expandResolveRect.colorOffsetY);

            
                DAWN_CHECK(std::abs(offsetX) < std::numeric_limits<int16_t>::max());

            
                DAWN_CHECK(std::abs(offsetY) < std::numeric_limits<int16_t>::max());

            
                return static_cast<uint32_t>(offsetX & 0xffff) | static_cast<uint32_t>(offsetY << 16);

            
            }


            MaybeError ExpandResolveTextureWithDraw(

            
                DeviceBase* device,

            
                RenderPassEncoder* renderEncoder,

            
                const UnpackedPtr<RenderPassDescriptor>& renderPassDescriptor) {

            
                DAWN_ASSERT(device->IsLockedByCurrentThreadIfNeeded());

            
                DAWN_CHECK(device->CanTextureLoadResolveTargetInTheSameRenderpass());


                BlitColorToColorWithDrawPipelineKey pipelineKey;

            
                uint32_t colorAttachmentWidth = 0;

            
                uint32_t colorAttachmentHeight = 0;

            
                for (auto [colorIdx, colorAttachment] : Enumerate(renderPassDescriptor->colorAttachments)) {

            
                    TextureViewBase* view = colorAttachment.view;

            
                    if (!view) {

            
                        continue;

            
                    }

            
                    if (colorAttachmentWidth == 0) {

            
                        Extent3D renderSize = view->GetSingleSubresourceVirtualSize();

            
                        colorAttachmentWidth = renderSize.width;

            
                        colorAttachmentHeight = renderSize.height;

            
                    }

            
                    const Format& format = view->GetFormat();

            
                    TextureComponentType baseType = format.GetAspectInfo(Aspect::Color).baseType;

            
                    // TODO(dawn:1710): blitting integer textures are not currently supported.

            
                    DAWN_CHECK(baseType == TextureComponentType::Float);


                    if (colorAttachment.loadOp == wgpu::LoadOp::ExpandResolveTexture) {

            
                        DAWN_CHECK(colorAttachment.resolveTarget->GetLayerCount() == 1u);

            
                        DAWN_CHECK(colorAttachment.resolveTarget->GetDimension() ==

            
                                   wgpu::TextureViewDimension::e2D);

            
                        pipelineKey.attachmentsToExpandResolve.set(colorIdx);

            
                    }

            
                    pipelineKey.resolveTargetsMask.set(colorIdx, colorAttachment.resolveTarget != nullptr);


                    pipelineKey.colorTargetFormats[colorIdx] = format.format;

            
                    pipelineKey.sampleCount = view->GetTexture()->GetSampleCount();

            
                }


                if (!pipelineKey.attachmentsToExpandResolve.any()) {

            
                    return {};

            
                }


                pipelineKey.depthStencilFormat = wgpu::TextureFormat::Undefined;

            
                if (renderPassDescriptor->depthStencilAttachment != nullptr) {

            
                    pipelineKey.depthStencilFormat =

            
                        renderPassDescriptor->depthStencilAttachment->view->GetFormat().format;

            
                }


                Ref<RenderPipelineBase> pipeline;

            
                DAWN_TRY_ASSIGN(pipeline, GetOrCreateExpandMultisamplePipeline(device, pipelineKey));


                Ref<BindGroupLayoutBase> bgl;

            
                DAWN_TRY_ASSIGN(bgl, pipeline->GetBindGroupLayout(0));


                Ref<BindGroupBase> bindGroup;

            
                {

            
                    absl::InlinedVector<BindGroupEntry, kMaxColorAttachments> bgEntries = {};


                    for (auto colorIdx : pipelineKey.attachmentsToExpandResolve) {

            
                        const auto& colorAttachment = renderPassDescriptor->colorAttachments[colorIdx];

            
                        bgEntries.push_back({});

            
                        auto& bgEntry = bgEntries.back();

            
                        bgEntry.binding = uint8_t{colorIdx};

            
                        bgEntry.textureView = colorAttachment.resolveTarget;

            
                    }


                    BindGroupDescriptor bgDesc = {};

            
                    bgDesc.layout = bgl.Get();

            
                    bgDesc.entries = bgEntries;

            
                    DAWN_TRY_ASSIGN(bindGroup, device->CreateBindGroup(&bgDesc, UsageValidationMode::Internal));

            
                }

            
                renderEncoder->APISetBindGroup(0, bindGroup.Get());


                renderEncoder->APISetPipeline(pipeline.Get());


                const auto* expandResolveRect = renderPassDescriptor.Get<RenderPassDescriptorResolveRect>();

            
                if (expandResolveRect) {

            
                    // TODO(chromium:344814092): Prevent the scissor to be reset to outside of this region by

            
                    // passing the scissor bound to the render pass creation.

            
                    renderEncoder->APISetScissorRect(expandResolveRect->colorOffsetX,

            
                                                     expandResolveRect->colorOffsetY, expandResolveRect->width,

            
                                                     expandResolveRect->height);

            
                }

            
                // The texture size never exceeds 16 bits. We pack two values {offsetX, offsetY} into a 32-bit

            
                // firstInstance value, which avoids creating a uniform buffer.

            
                const auto offsets = expandResolveRect ? PackOffsets(*expandResolveRect) : 0;

            
                // Draw to perform the blit.

            
                renderEncoder->APIDraw(/*vertexCount=*/3,

            
                                       /*instanceCount=*/1,

            
                                       /*firstVertex=*/0,

            
                                       /*firstInstance=*/offsets);


                // After expanding the resolve texture, we reset the scissor rect to the full size of the color

            
                // attachment to prevent the previous scissor rect from affecting all subsequent user draws.

            
                if (expandResolveRect) {

            
                    renderEncoder->APISetScissorRect(0, 0, colorAttachmentWidth, colorAttachmentHeight);

            
                }


                return {};

            
            }


            size_t BlitColorToColorWithDrawPipelineKey::HashFunc::operator()(

            
                const BlitColorToColorWithDrawPipelineKey& key) const {

            
                size_t hash = 0;


                HashCombine(&hash, key.attachmentsToExpandResolve);

            
                HashCombine(&hash, key.resolveTargetsMask);


                for (auto format : key.colorTargetFormats) {

            
                    HashCombine(&hash, format);

            
                }


                HashCombine(&hash, key.depthStencilFormat);

            
                HashCombine(&hash, key.sampleCount);


                return hash;

            
            }


            bool BlitColorToColorWithDrawPipelineKey::EqualityFunc::operator()(

            
                const BlitColorToColorWithDrawPipelineKey& a,

            
                const BlitColorToColorWithDrawPipelineKey& b) const {

            
                if (a.attachmentsToExpandResolve != b.attachmentsToExpandResolve) {

            
                    return false;

            
                }

            
                if (a.resolveTargetsMask != b.resolveTargetsMask) {

            
                    return false;

            
                }


                for (auto [i, format] : Enumerate(a.colorTargetFormats)) {

            
                    if (format != b.colorTargetFormats[i]) {

            
                        return false;

            
                    }

            
                }


                return a.depthStencilFormat == b.depthStencilFormat && a.sampleCount == b.sampleCount;

            
            }


            MaybeError ResolveMultisampleWithDraw(DeviceBase* device,

            
                                                  CommandEncoder* encoder,

            
                                                  const RenderPassDescriptorResolveRect& rect,

            
                                                  TextureViewBase* src,

            
                                                  TextureViewBase* dst) {

            
                DAWN_ASSERT(device->IsLockedByCurrentThreadIfNeeded());


                ResolveMultisampleWithDrawPipelineKey pipelineKey{dst->GetFormat().format,

            
                                                                  src->GetTexture()->GetSampleCount()};

            
                Ref<RenderPipelineBase> pipeline;

            
                DAWN_TRY_ASSIGN(pipeline, GetOrCreateResolveMultisamplePipeline(device, pipelineKey));


                Ref<BindGroupLayoutBase> bindGroupLayout;

            
                DAWN_TRY_ASSIGN(bindGroupLayout, pipeline->GetBindGroupLayout(0));


                Ref<BindGroupBase> bindGroup;

            
                DAWN_TRY_ASSIGN(bindGroup, utils::MakeBindGroup(device, bindGroupLayout, {{0, src}},

            
                                                                UsageValidationMode::Internal));

            
                // Color attachment descriptor.

            
                RenderPassColorAttachment colorAttachmentDesc;

            
                colorAttachmentDesc.view = dst;

            
                colorAttachmentDesc.loadOp = wgpu::LoadOp::Load;

            
                colorAttachmentDesc.storeOp = wgpu::StoreOp::Store;


                // Create render pass.

            
                RenderPassDescriptor renderPassDesc;

            
                renderPassDesc.colorAttachments = SpanFromRef<ColorAttachmentIndex>(colorAttachmentDesc);

            
                Ref<RenderPassEncoder> renderEncoder = encoder->BeginRenderPass(&renderPassDesc);


                // Draw to perform the resolve.

            
                renderEncoder->APISetBindGroup(0, bindGroup.Get());

            
                renderEncoder->APISetPipeline(pipeline.Get());

            
                renderEncoder->APISetScissorRect(rect.resolveOffsetX, rect.resolveOffsetY, rect.width,

            
                                                 rect.height);

            
                // The texture size never exceeds 16 bits. We pack two values {offsetX, offsetY} into a 32-bit

            
                // firstInstance value, which avoids creating a uniform buffer.

            
                const auto offsets = PackOffsets(rect);

            
                renderEncoder->APIDraw(/*vertexCount=*/3,

            
                                       /*instanceCount=*/1,

            
                                       /*firstVertex=*/0,

            
                                       /*firstInstance=*/offsets);

            
                renderEncoder->End();


                return {};

            
            }


            size_t ResolveMultisampleWithDrawPipelineKey::HashFunc::operator()(

            
                const ResolveMultisampleWithDrawPipelineKey& key) const {

            
                size_t hash = 0;


                HashCombine(&hash, key.colorTargetFormat);

            
                HashCombine(&hash, key.sampleCount);


                return hash;

            
            }


            bool ResolveMultisampleWithDrawPipelineKey::EqualityFunc::operator()(

            
                const ResolveMultisampleWithDrawPipelineKey& a,

            
                const ResolveMultisampleWithDrawPipelineKey& b) const {

            
                return a.colorTargetFormat == b.colorTargetFormat && a.sampleCount == b.sampleCount;

            
            }


            }  // namespace dawn::native
	// Copyright 2023 The Dawn & Tint Authors
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are met:
	//
	// 1. Redistributions of source code must retain the above copyright notice, this
	// list of conditions and the following disclaimer.
	//
	// 2. Redistributions in binary form must reproduce the above copyright notice,
	// this list of conditions and the following disclaimer in the documentation
	// and/or other materials provided with the distribution.
	//
	// 3. Neither the name of the copyright holder nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
	// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	#include "src/dawn/native/BlitColorToColorWithDraw.h"

	#include <limits>
	#include <sstream>
	#include <string>
	#include <utility>

	#include "absl/container/inlined_vector.h"
	#include "src/dawn/common/Enumerator.h"
	#include "src/dawn/common/HashUtils.h"
	#include "src/dawn/common/Strings.h"
	#include "src/dawn/native/BindGroup.h"
	#include "src/dawn/native/ChainUtils.h"
	#include "src/dawn/native/CommandEncoder.h"
	#include "src/dawn/native/Device.h"
	#include "src/dawn/native/InternalPipelineStore.h"
	#include "src/dawn/native/RenderPassEncoder.h"
	#include "src/dawn/native/RenderPipeline.h"
	#include "src/dawn/native/utils/WGPUHelpers.h"
	#include "src/dawn/native/webgpu_absl_format.h"
	#include "src/utils/assert.h"
	#include "src/utils/compiler.h"

	namespace dawn::native {

	namespace {

	constexpr std::string_view kVertexOutputsStruct = DAWN_MULTILINE(
	struct VertexOutputs {
	@builtin(position) position : vec4<f32>,
	@location(0) @interpolate(flat, either) offsets : vec2i,
	};
	);

	std::string GenerateBlitToColorVS() {
	constexpr std::string_view kBlitToColorVS = DAWN_MULTILINE(
	// Unpack a u32 into two i32 values, each was originally two 16-bit signed
	// integer.
	fn unpack_offsets(offsets : u32) -> vec2<i32> {
	// First extract the high and low 16-bit values, then convert to u32 for
	// zero-extension.
	var offsets_bits = vec2u(offsets & 0xFFFFu, (offsets >> 16) & 0xFFFFu);
	// For each 16-bit value, if the sign bit is set (0x8000), perform sign
	// extension by setting the upper 16 bits to 1s (0xFFFF0000).
	offsets_bits = select(
	offsets_bits,
	offsets_bits \| vec2u(0xFFFF0000u),
	// Check if negative.
	(offsets_bits & vec2u(0x8000u)) != vec2u(0u),
	);
	// Reinterpret the final 32-bit values as signed integers.
	return bitcast<vec2i>(offsets_bits);
	}

	@vertex fn vert_fullscreen_quad(
	@builtin(vertex_index) vertex_index : u32,
	@builtin(instance_index) instance_index : u32
	) -> VertexOutputs {
	var output : VertexOutputs;
	const pos = array(
	vec2f(-1.0, -1.0),
	vec2f(3.0, -1.0),
	vec2f(-1.0, 3.0));
	output.position = vec4f(pos[vertex_index], 0.0, 1.0);
	output.offsets = unpack_offsets(instance_index);
	return output;
	}
	);
	return std::string(kVertexOutputsStruct) + std::string(kBlitToColorVS);
	}

	std::string GenerateExpandFS(const BlitColorToColorWithDrawPipelineKey& pipelineKey) {
	std::ostringstream outputStructStream;
	std::ostringstream assignOutputsStream;
	std::ostringstream finalStream;
	for (auto i : pipelineKey.attachmentsToExpandResolve) {
	finalStream << absl::StrFormat("@group(0) @binding(%u) var srcTex%u : texture_2d<f32>;", i,
	i);

	outputStructStream << absl::StrFormat("@location(%u) output%u : vec4f,", i, i);

	assignOutputsStream << absl::StrFormat(
	"\toutputColor.output%u = textureLoad(srcTex%u, vec2i(input.position.xy) + "
	"input.offsets, 0);",
	i, i);
	}

	finalStream << kVertexOutputsStruct << "struct OutputColor {" << outputStructStream.str()
	<< "}";
	finalStream << DAWN_MULTILINE(
	@fragment fn expand_multisample(input: VertexOutputs) -> OutputColor {
	var outputColor : OutputColor;
	);
	finalStream << assignOutputsStream.str();
	finalStream << DAWN_MULTILINE(
	return outputColor;
	}
	);

	return finalStream.str();
	}

	// Generate the fragment shader to average multiple samples into one.
	std::string GenerateResolveFS(uint32_t sampleCount) {
	std::ostringstream ss;
	ss << kVertexOutputsStruct;
	ss << DAWN_MULTILINE(
	@group(0) @binding(0) var srcTex : texture_multisampled_2d<f32>;

	@fragment
	fn resolve_multisample(input: VertexOutputs) -> @location(0) vec4f {
	var sum = vec4f(0.0, 0.0, 0.0, 0.0);
	var offsetPos = vec2i(input.position.xy) - input.offsets;
	);
	for (uint32_t sample = 0; sample < sampleCount; ++sample) {
	ss << absl::StrFormat("sum += textureLoad(srcTex, offsetPos, %u);", sample);
	}
	ss << absl::StrFormat("return sum / %u;", sampleCount);
	ss << DAWN_MULTILINE(
	}
	);

	return ss.str();
	}

	ResultOrError<Ref<RenderPipelineBase>> GetOrCreateExpandMultisamplePipeline(
	DeviceBase* device,
	const BlitColorToColorWithDrawPipelineKey& pipelineKey) {
	InternalPipelineStore* store = device->GetInternalPipelineStore();
	{
	auto it = store->expandResolveTexturePipelines.find(pipelineKey);
	if (it != store->expandResolveTexturePipelines.end()) {
	return it->second;
	}
	}

	// vertex shader's source.
	ShaderSourceWGSL wgslDesc = {};
	ShaderModuleDescriptor shaderModuleDesc = {};
	shaderModuleDesc.nextInChain = &wgslDesc;
	const std::string vsCode = GenerateBlitToColorVS();
	wgslDesc.code = vsCode.c_str();

	Ref<ShaderModuleBase> vshaderModule;
	DAWN_TRY_ASSIGN(vshaderModule, device->CreateShaderModule(&shaderModuleDesc));

	// fragment shader's source will depend on pipeline key.
	std::string fsCode = GenerateExpandFS(pipelineKey);
	wgslDesc.code = fsCode.c_str();
	Ref<ShaderModuleBase> fshaderModule;
	DAWN_TRY_ASSIGN(fshaderModule, device->CreateShaderModule(&shaderModuleDesc));

	// Color target states.
	PerColorAttachment<ColorTargetState> colorTargets = {};
	PerColorAttachment<wgpu::ColorTargetStateExpandResolveTextureDawn> msaaExpandResolveStates;

	for (auto [i, target] : Enumerate(colorTargets)) {
	target.format = pipelineKey.colorTargetFormats[i];
	// We shouldn't change the color targets that are not involved in.
	if (pipelineKey.resolveTargetsMask[i]) {
	target.nextInChain = &msaaExpandResolveStates[i];
	msaaExpandResolveStates[i].enabled = pipelineKey.attachmentsToExpandResolve[i];
	if (msaaExpandResolveStates[i].enabled) {
	target.writeMask = wgpu::ColorWriteMask::All;
	} else {
	target.writeMask = wgpu::ColorWriteMask::None;
	}
	} else {
	target.writeMask = wgpu::ColorWriteMask::None;
	}
	}

	FragmentState fragmentState = {};
	fragmentState.module = fshaderModule.Get();
	fragmentState.entryPoint = "expand_multisample";
	fragmentState.targets = colorTargets;

	RenderPipelineDescriptor renderPipelineDesc = {};
	renderPipelineDesc.label = "expand_multisample";
	renderPipelineDesc.vertex.module = vshaderModule.Get();
	renderPipelineDesc.vertex.entryPoint = "vert_fullscreen_quad";
	renderPipelineDesc.fragment = &fragmentState;

	// Depth stencil state.
	DepthStencilState depthStencilState = {};
	if (pipelineKey.depthStencilFormat != wgpu::TextureFormat::Undefined) {
	depthStencilState.format = pipelineKey.depthStencilFormat;
	depthStencilState.depthWriteEnabled = wgpu::OptionalBool::False;
	depthStencilState.depthCompare = wgpu::CompareFunction::Always;

	renderPipelineDesc.depthStencil = &depthStencilState;
	}

	// Multisample state.
	DAWN_CHECK(pipelineKey.sampleCount > 1);
	renderPipelineDesc.multisample.count = pipelineKey.sampleCount;

	// Bind group layout.
	absl::InlinedVector<BindGroupLayoutEntry, kMaxColorAttachments> bglEntries;
	for (auto colorIdx : pipelineKey.attachmentsToExpandResolve) {
	bglEntries.push_back({});
	auto& bglEntry = bglEntries.back();
	bglEntry.binding = static_cast<uint8_t>(colorIdx);
	bglEntry.visibility = wgpu::ShaderStage::Fragment;
	bglEntry.texture.sampleType = kInternalResolveAttachmentSampleType;
	bglEntry.texture.viewDimension = wgpu::TextureViewDimension::e2D;
	}
	BindGroupLayoutDescriptor bglDesc = {};
	bglDesc.entries = bglEntries;

	Ref<BindGroupLayoutBase> bindGroupLayout;
	DAWN_TRY_ASSIGN(bindGroupLayout,
	device->CreateBindGroupLayout(&bglDesc, /* allowInternalBinding */ true));

	Ref<PipelineLayoutBase> pipelineLayout;
	DAWN_TRY_ASSIGN(pipelineLayout, utils::MakeBasicPipelineLayout(device, bindGroupLayout));

	renderPipelineDesc.layout = pipelineLayout.Get();

	Ref<RenderPipelineBase> pipeline;
	DAWN_TRY_ASSIGN(pipeline, device->CreateRenderPipeline(&renderPipelineDesc));

	store->expandResolveTexturePipelines.emplace(pipelineKey, pipeline);
	return pipeline;
	}

	ResultOrError<Ref<RenderPipelineBase>> GetOrCreateResolveMultisamplePipeline(
	DeviceBase* device,
	const ResolveMultisampleWithDrawPipelineKey& pipelineKey) {
	// Try finding the pipeline from the cache.
	InternalPipelineStore* store = device->GetInternalPipelineStore();
	{
	auto it = store->resolveMultisamplePipelines.find(pipelineKey);
	if (it != store->resolveMultisamplePipelines.end()) {
	return it->second;
	}
	}

	// vertex shader's source.
	ShaderSourceWGSL wgslDesc = {};
	ShaderModuleDescriptor shaderModuleDesc = {};
	shaderModuleDesc.nextInChain = &wgslDesc;
	const std::string vsCode = GenerateBlitToColorVS();
	wgslDesc.code = vsCode.c_str();

	Ref<ShaderModuleBase> vshaderModule;
	DAWN_TRY_ASSIGN(vshaderModule, device->CreateShaderModule(&shaderModuleDesc));

	// fragment shader's source will depend on sample count.
	std::string fsCode = GenerateResolveFS(pipelineKey.sampleCount);
	wgslDesc.code = fsCode.c_str();
	Ref<ShaderModuleBase> fshaderModule;
	DAWN_TRY_ASSIGN(fshaderModule, device->CreateShaderModule(&shaderModuleDesc));

	// Color target states.
	ColorTargetState colorTarget = {};
	colorTarget.format = pipelineKey.colorTargetFormat;

	FragmentState fragmentState = {};
	fragmentState.module = fshaderModule.Get();
	fragmentState.entryPoint = "resolve_multisample";
	fragmentState.targets = SpanFromRef<ColorAttachmentIndex>(colorTarget);

	RenderPipelineDescriptor renderPipelineDesc = {};
	renderPipelineDesc.label = "resolve_multisample";
	renderPipelineDesc.vertex.module = vshaderModule.Get();
	renderPipelineDesc.vertex.entryPoint = "vert_fullscreen_quad";
	renderPipelineDesc.fragment = &fragmentState;

	Ref<RenderPipelineBase> pipeline;
	DAWN_TRY_ASSIGN(pipeline, device->CreateRenderPipeline(&renderPipelineDesc));

	store->resolveMultisamplePipelines.emplace(pipelineKey, pipeline);
	return pipeline;
	}

	} // namespace

	// Since texture dimensions never exceed 16 bits, we can safely store offsets in 16 bits. This
	// allows packing two signed 16-bit offsets (each within −32,768 ~ +32,767) into a single 32-bit
	// unsigned integer for efficient storage and retrieval.
	uint32_t PackOffsets(const RenderPassDescriptorResolveRect& expandResolveRect) {
	const auto offsetX = static_cast<int32_t>(expandResolveRect.resolveOffsetX) -
	static_cast<int32_t>(expandResolveRect.colorOffsetX);
	const auto offsetY = static_cast<int32_t>(expandResolveRect.resolveOffsetY) -
	static_cast<int32_t>(expandResolveRect.colorOffsetY);
	DAWN_CHECK(std::abs(offsetX) < std::numeric_limits<int16_t>::max());
	DAWN_CHECK(std::abs(offsetY) < std::numeric_limits<int16_t>::max());
	return static_cast<uint32_t>(offsetX & 0xffff) \| static_cast<uint32_t>(offsetY << 16);
	}

	MaybeError ExpandResolveTextureWithDraw(
	DeviceBase* device,
	RenderPassEncoder* renderEncoder,
	const UnpackedPtr<RenderPassDescriptor>& renderPassDescriptor) {
	DAWN_ASSERT(device->IsLockedByCurrentThreadIfNeeded());
	DAWN_CHECK(device->CanTextureLoadResolveTargetInTheSameRenderpass());

	BlitColorToColorWithDrawPipelineKey pipelineKey;
	uint32_t colorAttachmentWidth = 0;
	uint32_t colorAttachmentHeight = 0;
	for (auto [colorIdx, colorAttachment] : Enumerate(renderPassDescriptor->colorAttachments)) {
	TextureViewBase* view = colorAttachment.view;
	if (!view) {
	continue;
	}
	if (colorAttachmentWidth == 0) {
	Extent3D renderSize = view->GetSingleSubresourceVirtualSize();
	colorAttachmentWidth = renderSize.width;
	colorAttachmentHeight = renderSize.height;
	}
	const Format& format = view->GetFormat();
	TextureComponentType baseType = format.GetAspectInfo(Aspect::Color).baseType;
	// TODO(dawn:1710): blitting integer textures are not currently supported.
	DAWN_CHECK(baseType == TextureComponentType::Float);

	if (colorAttachment.loadOp == wgpu::LoadOp::ExpandResolveTexture) {
	DAWN_CHECK(colorAttachment.resolveTarget->GetLayerCount() == 1u);
	DAWN_CHECK(colorAttachment.resolveTarget->GetDimension() ==
	wgpu::TextureViewDimension::e2D);
	pipelineKey.attachmentsToExpandResolve.set(colorIdx);
	}
	pipelineKey.resolveTargetsMask.set(colorIdx, colorAttachment.resolveTarget != nullptr);

	pipelineKey.colorTargetFormats[colorIdx] = format.format;
	pipelineKey.sampleCount = view->GetTexture()->GetSampleCount();
	}

	if (!pipelineKey.attachmentsToExpandResolve.any()) {
	return {};
	}

	pipelineKey.depthStencilFormat = wgpu::TextureFormat::Undefined;
	if (renderPassDescriptor->depthStencilAttachment != nullptr) {
	pipelineKey.depthStencilFormat =
	renderPassDescriptor->depthStencilAttachment->view->GetFormat().format;
	}

	Ref<RenderPipelineBase> pipeline;
	DAWN_TRY_ASSIGN(pipeline, GetOrCreateExpandMultisamplePipeline(device, pipelineKey));

	Ref<BindGroupLayoutBase> bgl;
	DAWN_TRY_ASSIGN(bgl, pipeline->GetBindGroupLayout(0));

	Ref<BindGroupBase> bindGroup;
	{
	absl::InlinedVector<BindGroupEntry, kMaxColorAttachments> bgEntries = {};

	for (auto colorIdx : pipelineKey.attachmentsToExpandResolve) {
	const auto& colorAttachment = renderPassDescriptor->colorAttachments[colorIdx];
	bgEntries.push_back({});
	auto& bgEntry = bgEntries.back();
	bgEntry.binding = uint8_t{colorIdx};
	bgEntry.textureView = colorAttachment.resolveTarget;
	}

	BindGroupDescriptor bgDesc = {};
	bgDesc.layout = bgl.Get();
	bgDesc.entries = bgEntries;
	DAWN_TRY_ASSIGN(bindGroup, device->CreateBindGroup(&bgDesc, UsageValidationMode::Internal));
	}
	renderEncoder->APISetBindGroup(0, bindGroup.Get());

	renderEncoder->APISetPipeline(pipeline.Get());

	const auto* expandResolveRect = renderPassDescriptor.Get<RenderPassDescriptorResolveRect>();
	if (expandResolveRect) {
	// TODO(chromium:344814092): Prevent the scissor to be reset to outside of this region by
	// passing the scissor bound to the render pass creation.
	renderEncoder->APISetScissorRect(expandResolveRect->colorOffsetX,
	expandResolveRect->colorOffsetY, expandResolveRect->width,
	expandResolveRect->height);
	}
	// The texture size never exceeds 16 bits. We pack two values {offsetX, offsetY} into a 32-bit
	// firstInstance value, which avoids creating a uniform buffer.
	const auto offsets = expandResolveRect ? PackOffsets(*expandResolveRect) : 0;
	// Draw to perform the blit.
	renderEncoder->APIDraw(/vertexCount=/3,
	/instanceCount=/1,
	/firstVertex=/0,
	/firstInstance=/offsets);

	// After expanding the resolve texture, we reset the scissor rect to the full size of the color
	// attachment to prevent the previous scissor rect from affecting all subsequent user draws.
	if (expandResolveRect) {
	renderEncoder->APISetScissorRect(0, 0, colorAttachmentWidth, colorAttachmentHeight);
	}

	return {};
	}

	size_t BlitColorToColorWithDrawPipelineKey::HashFunc::operator()(
	const BlitColorToColorWithDrawPipelineKey& key) const {
	size_t hash = 0;

	HashCombine(&hash, key.attachmentsToExpandResolve);
	HashCombine(&hash, key.resolveTargetsMask);

	for (auto format : key.colorTargetFormats) {
	HashCombine(&hash, format);
	}

	HashCombine(&hash, key.depthStencilFormat);
	HashCombine(&hash, key.sampleCount);

	return hash;
	}

	bool BlitColorToColorWithDrawPipelineKey::EqualityFunc::operator()(
	const BlitColorToColorWithDrawPipelineKey& a,
	const BlitColorToColorWithDrawPipelineKey& b) const {
	if (a.attachmentsToExpandResolve != b.attachmentsToExpandResolve) {
	return false;
	}
	if (a.resolveTargetsMask != b.resolveTargetsMask) {
	return false;
	}

	for (auto [i, format] : Enumerate(a.colorTargetFormats)) {
	if (format != b.colorTargetFormats[i]) {
	return false;
	}
	}

	return a.depthStencilFormat == b.depthStencilFormat && a.sampleCount == b.sampleCount;
	}

	MaybeError ResolveMultisampleWithDraw(DeviceBase* device,
	CommandEncoder* encoder,
	const RenderPassDescriptorResolveRect& rect,
	TextureViewBase* src,
	TextureViewBase* dst) {
	DAWN_ASSERT(device->IsLockedByCurrentThreadIfNeeded());

	ResolveMultisampleWithDrawPipelineKey pipelineKey{dst->GetFormat().format,
	src->GetTexture()->GetSampleCount()};
	Ref<RenderPipelineBase> pipeline;
	DAWN_TRY_ASSIGN(pipeline, GetOrCreateResolveMultisamplePipeline(device, pipelineKey));

	Ref<BindGroupLayoutBase> bindGroupLayout;
	DAWN_TRY_ASSIGN(bindGroupLayout, pipeline->GetBindGroupLayout(0));

	Ref<BindGroupBase> bindGroup;
	DAWN_TRY_ASSIGN(bindGroup, utils::MakeBindGroup(device, bindGroupLayout, {{0, src}},
	UsageValidationMode::Internal));
	// Color attachment descriptor.
	RenderPassColorAttachment colorAttachmentDesc;
	colorAttachmentDesc.view = dst;
	colorAttachmentDesc.loadOp = wgpu::LoadOp::Load;
	colorAttachmentDesc.storeOp = wgpu::StoreOp::Store;

	// Create render pass.
	RenderPassDescriptor renderPassDesc;
	renderPassDesc.colorAttachments = SpanFromRef<ColorAttachmentIndex>(colorAttachmentDesc);
	Ref<RenderPassEncoder> renderEncoder = encoder->BeginRenderPass(&renderPassDesc);

	// Draw to perform the resolve.
	renderEncoder->APISetBindGroup(0, bindGroup.Get());
	renderEncoder->APISetPipeline(pipeline.Get());
	renderEncoder->APISetScissorRect(rect.resolveOffsetX, rect.resolveOffsetY, rect.width,
	rect.height);
	// The texture size never exceeds 16 bits. We pack two values {offsetX, offsetY} into a 32-bit
	// firstInstance value, which avoids creating a uniform buffer.
	const auto offsets = PackOffsets(rect);
	renderEncoder->APIDraw(/vertexCount=/3,
	/instanceCount=/1,
	/firstVertex=/0,
	/firstInstance=/offsets);
	renderEncoder->End();

	return {};
	}

	size_t ResolveMultisampleWithDrawPipelineKey::HashFunc::operator()(
	const ResolveMultisampleWithDrawPipelineKey& key) const {
	size_t hash = 0;

	HashCombine(&hash, key.colorTargetFormat);
	HashCombine(&hash, key.sampleCount);

	return hash;
	}

	bool ResolveMultisampleWithDrawPipelineKey::EqualityFunc::operator()(
	const ResolveMultisampleWithDrawPipelineKey& a,
	const ResolveMultisampleWithDrawPipelineKey& b) const {
	return a.colorTargetFormat == b.colorTargetFormat && a.sampleCount == b.sampleCount;
	}

	} // namespace dawn::native