// Copyright 2017 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "dawn_native/d3d12/CommandBufferD3D12.h"

#include "common/Assert.h"
#include "dawn_native/BindGroupAndStorageBarrierTracker.h"
#include "dawn_native/CommandEncoder.h"
#include "dawn_native/Commands.h"
#include "dawn_native/RenderBundle.h"
#include "dawn_native/d3d12/BindGroupD3D12.h"
#include "dawn_native/d3d12/BindGroupLayoutD3D12.h"
#include "dawn_native/d3d12/BufferD3D12.h"
#include "dawn_native/d3d12/CommandRecordingContext.h"
#include "dawn_native/d3d12/ComputePipelineD3D12.h"
#include "dawn_native/d3d12/DescriptorHeapAllocator.h"
#include "dawn_native/d3d12/DeviceD3D12.h"
#include "dawn_native/d3d12/PipelineLayoutD3D12.h"
#include "dawn_native/d3d12/PlatformFunctions.h"
#include "dawn_native/d3d12/RenderPassBuilderD3D12.h"
#include "dawn_native/d3d12/RenderPipelineD3D12.h"
#include "dawn_native/d3d12/SamplerD3D12.h"
#include "dawn_native/d3d12/TextureCopySplitter.h"
#include "dawn_native/d3d12/TextureD3D12.h"
#include "dawn_native/d3d12/UtilsD3D12.h"

#include <deque>

namespace dawn_native { namespace d3d12 {

    namespace {

        DXGI_FORMAT DXGIIndexFormat(wgpu::IndexFormat format) {
            switch (format) {
                case wgpu::IndexFormat::Uint16:
                    return DXGI_FORMAT_R16_UINT;
                case wgpu::IndexFormat::Uint32:
                    return DXGI_FORMAT_R32_UINT;
                default:
                    UNREACHABLE();
            }
        }

        bool CanUseCopyResource(const uint32_t sourceNumMipLevels,
                                const Extent3D& srcSize,
                                const Extent3D& dstSize,
                                const Extent3D& copySize) {
            if (sourceNumMipLevels == 1 && srcSize.width == dstSize.width &&
                srcSize.height == dstSize.height && srcSize.depth == dstSize.depth &&
                srcSize.width == copySize.width && srcSize.height == copySize.height &&
                srcSize.depth == copySize.depth) {
                return true;
            }

            return false;
        }

    }  // anonymous namespace

    class BindGroupStateTracker : public BindGroupAndStorageBarrierTrackerBase<false, uint64_t> {
      public:
        BindGroupStateTracker(Device* device)
            : BindGroupAndStorageBarrierTrackerBase(), mDevice(device) {
        }

        void SetInComputePass(bool inCompute_) {
            mInCompute = inCompute_;
        }

        MaybeError AllocateDescriptorHeaps(Device* device) {
            // This function should only be called once.
            ASSERT(mCbvSrvUavGPUDescriptorHeap.Get() == nullptr &&
                   mSamplerGPUDescriptorHeap.Get() == nullptr);

            DescriptorHeapAllocator* descriptorHeapAllocator = device->GetDescriptorHeapAllocator();

            if (mCbvSrvUavDescriptorHeapSize > 0) {
                DAWN_TRY_ASSIGN(
                    mCbvSrvUavGPUDescriptorHeap,
                    descriptorHeapAllocator->AllocateGPUHeap(D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV,
                                                             mCbvSrvUavDescriptorHeapSize));
            }

            if (mSamplerDescriptorHeapSize > 0) {
                DAWN_TRY_ASSIGN(mSamplerGPUDescriptorHeap, descriptorHeapAllocator->AllocateGPUHeap(
                                                               D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER,
                                                               mSamplerDescriptorHeapSize));
            }

            uint32_t cbvSrvUavDescriptorIndex = 0;
            uint32_t samplerDescriptorIndex = 0;
            for (BindGroup* group : mBindGroupsToAllocate) {
                ASSERT(group);
                ASSERT(cbvSrvUavDescriptorIndex +
                           ToBackend(group->GetLayout())->GetCbvUavSrvDescriptorCount() <=
                       mCbvSrvUavDescriptorHeapSize);
                ASSERT(samplerDescriptorIndex +
                           ToBackend(group->GetLayout())->GetSamplerDescriptorCount() <=
                       mSamplerDescriptorHeapSize);
                group->AllocateDescriptors(mCbvSrvUavGPUDescriptorHeap, &cbvSrvUavDescriptorIndex,
                                           mSamplerGPUDescriptorHeap, &samplerDescriptorIndex);
            }

            ASSERT(cbvSrvUavDescriptorIndex == mCbvSrvUavDescriptorHeapSize);
            ASSERT(samplerDescriptorIndex == mSamplerDescriptorHeapSize);

            return {};
        }

        // This function must only be called before calling AllocateDescriptorHeaps().
        void TrackSetBindGroup(BindGroup* group, uint32_t index, uint32_t indexInSubmit) {
            if (mBindGroups[index] != group) {
                mBindGroups[index] = group;
                if (!group->TestAndSetCounted(mDevice->GetPendingCommandSerial(), indexInSubmit)) {
                    const BindGroupLayout* layout = ToBackend(group->GetLayout());

                    mCbvSrvUavDescriptorHeapSize += layout->GetCbvUavSrvDescriptorCount();
                    mSamplerDescriptorHeapSize += layout->GetSamplerDescriptorCount();
                    mBindGroupsToAllocate.push_back(group);
                }
            }
        }

        void Apply(CommandRecordingContext* commandContext) {
            ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

            for (uint32_t index : IterateBitSet(mDirtyBindGroupsObjectChangedOrIsDynamic)) {
                ApplyBindGroup(commandList, ToBackend(mPipelineLayout), index,
                               ToBackend(mBindGroups[index]), mDynamicOffsetCounts[index],
                               mDynamicOffsets[index].data());
            }

            if (mInCompute) {
                for (uint32_t index : IterateBitSet(mBindGroupLayoutsMask)) {
                    for (uint32_t binding : IterateBitSet(mBuffersNeedingBarrier[index])) {
                        wgpu::BindingType bindingType = mBindingTypes[index][binding];
                        switch (bindingType) {
                            case wgpu::BindingType::StorageBuffer:
                                ToBackend(mBuffers[index][binding])
                                    ->TransitionUsageNow(commandContext,
                                                         wgpu::BufferUsage::Storage);
                                break;

                            case wgpu::BindingType::StorageTexture:
                                // Not implemented.

                            case wgpu::BindingType::UniformBuffer:
                            case wgpu::BindingType::ReadonlyStorageBuffer:
                            case wgpu::BindingType::Sampler:
                            case wgpu::BindingType::SampledTexture:
                                // Don't require barriers.

                            default:
                                UNREACHABLE();
                                break;
                        }
                    }
                }
            }
            DidApply();
        }

        void Reset() {
            for (uint32_t i = 0; i < kMaxBindGroups; ++i) {
                mBindGroups[i] = nullptr;
            }
        }

        void SetID3D12DescriptorHeaps(ComPtr<ID3D12GraphicsCommandList> commandList) {
            ASSERT(commandList != nullptr);
            ID3D12DescriptorHeap* descriptorHeaps[2] = {mCbvSrvUavGPUDescriptorHeap.Get(),
                                                        mSamplerGPUDescriptorHeap.Get()};
            if (descriptorHeaps[0] && descriptorHeaps[1]) {
                commandList->SetDescriptorHeaps(2, descriptorHeaps);
            } else if (descriptorHeaps[0]) {
                commandList->SetDescriptorHeaps(1, descriptorHeaps);
            } else if (descriptorHeaps[1]) {
                commandList->SetDescriptorHeaps(1, &descriptorHeaps[1]);
            }
        }

      private:
        void ApplyBindGroup(ID3D12GraphicsCommandList* commandList,
                            PipelineLayout* pipelineLayout,
                            uint32_t index,
                            BindGroup* group,
                            uint32_t dynamicOffsetCount,
                            uint64_t* dynamicOffsets) {
            // Usually, the application won't set the same offsets many times,
            // so always try to apply dynamic offsets even if the offsets stay the same
            if (dynamicOffsetCount) {
                // Update dynamic offsets
                const BindGroupLayout::LayoutBindingInfo& layout =
                    group->GetLayout()->GetBindingInfo();
                uint32_t currentDynamicBufferIndex = 0;

                for (uint32_t bindingIndex : IterateBitSet(layout.hasDynamicOffset)) {
                    ASSERT(dynamicOffsetCount > 0);
                    uint32_t parameterIndex =
                        pipelineLayout->GetDynamicRootParameterIndex(index, bindingIndex);
                    BufferBinding binding = group->GetBindingAsBufferBinding(bindingIndex);

                    // Calculate buffer locations that root descriptors links to. The location
                    // is (base buffer location + initial offset + dynamic offset)
                    uint64_t dynamicOffset = dynamicOffsets[currentDynamicBufferIndex];
                    uint64_t offset = binding.offset + dynamicOffset;
                    D3D12_GPU_VIRTUAL_ADDRESS bufferLocation =
                        ToBackend(binding.buffer)->GetVA() + offset;

                    switch (layout.types[bindingIndex]) {
                        case wgpu::BindingType::UniformBuffer:
                            if (mInCompute) {
                                commandList->SetComputeRootConstantBufferView(parameterIndex,
                                                                              bufferLocation);
                            } else {
                                commandList->SetGraphicsRootConstantBufferView(parameterIndex,
                                                                               bufferLocation);
                            }
                            break;
                        case wgpu::BindingType::StorageBuffer:
                            if (mInCompute) {
                                commandList->SetComputeRootUnorderedAccessView(parameterIndex,
                                                                               bufferLocation);
                            } else {
                                commandList->SetGraphicsRootUnorderedAccessView(parameterIndex,
                                                                                bufferLocation);
                            }
                            break;
                        case wgpu::BindingType::ReadonlyStorageBuffer:
                            if (mInCompute) {
                                commandList->SetComputeRootShaderResourceView(parameterIndex,
                                                                              bufferLocation);
                            } else {
                                commandList->SetGraphicsRootShaderResourceView(parameterIndex,
                                                                               bufferLocation);
                            }
                            break;
                        case wgpu::BindingType::SampledTexture:
                        case wgpu::BindingType::Sampler:
                        case wgpu::BindingType::StorageTexture:
                            UNREACHABLE();
                            break;
                    }

                    ++currentDynamicBufferIndex;
                }
            }

            // It's not necessary to update descriptor tables if only the dynamic offset changed.
            if (!mDirtyBindGroups[index]) {
                return;
            }

            uint32_t cbvUavSrvCount = ToBackend(group->GetLayout())->GetCbvUavSrvDescriptorCount();
            uint32_t samplerCount = ToBackend(group->GetLayout())->GetSamplerDescriptorCount();

            if (cbvUavSrvCount > 0) {
                uint32_t parameterIndex = pipelineLayout->GetCbvUavSrvRootParameterIndex(index);

                if (mInCompute) {
                    commandList->SetComputeRootDescriptorTable(
                        parameterIndex,
                        mCbvSrvUavGPUDescriptorHeap.GetGPUHandle(group->GetCbvUavSrvHeapOffset()));
                } else {
                    commandList->SetGraphicsRootDescriptorTable(
                        parameterIndex,
                        mCbvSrvUavGPUDescriptorHeap.GetGPUHandle(group->GetCbvUavSrvHeapOffset()));
                }
            }

            if (samplerCount > 0) {
                uint32_t parameterIndex = pipelineLayout->GetSamplerRootParameterIndex(index);

                if (mInCompute) {
                    commandList->SetComputeRootDescriptorTable(
                        parameterIndex,
                        mSamplerGPUDescriptorHeap.GetGPUHandle(group->GetSamplerHeapOffset()));
                } else {
                    commandList->SetGraphicsRootDescriptorTable(
                        parameterIndex,
                        mSamplerGPUDescriptorHeap.GetGPUHandle(group->GetSamplerHeapOffset()));
                }
            }
        }

        uint32_t mCbvSrvUavDescriptorHeapSize = 0;
        uint32_t mSamplerDescriptorHeapSize = 0;
        std::deque<BindGroup*> mBindGroupsToAllocate = {};
        bool mInCompute = false;

        DescriptorHeapHandle mCbvSrvUavGPUDescriptorHeap = {};
        DescriptorHeapHandle mSamplerGPUDescriptorHeap = {};

        Device* mDevice;
    };

    class RenderPassDescriptorHeapTracker {
      public:
        RenderPassDescriptorHeapTracker(Device* device) : mDevice(device) {
        }

        // This function must only be called before calling AllocateRTVAndDSVHeaps().
        void TrackRenderPass(const BeginRenderPassCmd* renderPass) {
            DAWN_ASSERT(mRTVHeap.Get() == nullptr && mDSVHeap.Get() == nullptr);

            mNumRTVs += static_cast<uint32_t>(
                renderPass->attachmentState->GetColorAttachmentsMask().count());
            if (renderPass->attachmentState->HasDepthStencilAttachment()) {
                ++mNumDSVs;
            }
        }

        MaybeError AllocateRTVAndDSVHeaps() {
            // This function should only be called once.
            DAWN_ASSERT(mRTVHeap.Get() == nullptr && mDSVHeap.Get() == nullptr);
            DescriptorHeapAllocator* allocator = mDevice->GetDescriptorHeapAllocator();
            if (mNumRTVs > 0) {
                DAWN_TRY_ASSIGN(
                    mRTVHeap, allocator->AllocateCPUHeap(D3D12_DESCRIPTOR_HEAP_TYPE_RTV, mNumRTVs));
            }
            if (mNumDSVs > 0) {
                DAWN_TRY_ASSIGN(
                    mDSVHeap, allocator->AllocateCPUHeap(D3D12_DESCRIPTOR_HEAP_TYPE_DSV, mNumDSVs));
            }
            return {};
        }

        // TODO(jiawei.shao@intel.com): use hash map <RenderPass, OMSetRenderTargetArgs> as
        // cache to avoid redundant RTV and DSV memory allocations.
        OMSetRenderTargetArgs GetSubpassOMSetRenderTargetArgs(BeginRenderPassCmd* renderPass) {
            OMSetRenderTargetArgs args = {};

            unsigned int rtvIndex = 0;
            uint32_t rtvCount = static_cast<uint32_t>(
                renderPass->attachmentState->GetColorAttachmentsMask().count());
            DAWN_ASSERT(mAllocatedRTVs + rtvCount <= mNumRTVs);
            for (uint32_t i :
                 IterateBitSet(renderPass->attachmentState->GetColorAttachmentsMask())) {
                TextureView* view = ToBackend(renderPass->colorAttachments[i].view).Get();
                D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = mRTVHeap.GetCPUHandle(mAllocatedRTVs);
                D3D12_RENDER_TARGET_VIEW_DESC rtvDesc = view->GetRTVDescriptor();
                mDevice->GetD3D12Device()->CreateRenderTargetView(
                    ToBackend(view->GetTexture())->GetD3D12Resource(), &rtvDesc, rtvHandle);
                args.RTVs[i] = rtvHandle;

                ++rtvIndex;
                ++mAllocatedRTVs;
            }
            args.numRTVs = rtvIndex;

            if (renderPass->attachmentState->HasDepthStencilAttachment()) {
                DAWN_ASSERT(mAllocatedDSVs < mNumDSVs);
                TextureView* view = ToBackend(renderPass->depthStencilAttachment.view).Get();
                D3D12_CPU_DESCRIPTOR_HANDLE dsvHandle = mDSVHeap.GetCPUHandle(mAllocatedDSVs);
                D3D12_DEPTH_STENCIL_VIEW_DESC dsvDesc = view->GetDSVDescriptor();
                mDevice->GetD3D12Device()->CreateDepthStencilView(
                    ToBackend(view->GetTexture())->GetD3D12Resource(), &dsvDesc, dsvHandle);
                args.dsv = dsvHandle;

                ++mAllocatedDSVs;
            }

            return args;
        }

        bool IsHeapAllocationCompleted() const {
            return mNumRTVs == mAllocatedRTVs && mNumDSVs == mAllocatedDSVs;
        }

      private:
        Device* mDevice;
        DescriptorHeapHandle mRTVHeap = {};
        DescriptorHeapHandle mDSVHeap = {};
        uint32_t mNumRTVs = 0;
        uint32_t mNumDSVs = 0;

        uint32_t mAllocatedRTVs = 0;
        uint32_t mAllocatedDSVs = 0;
    };

    namespace {

        class VertexBufferTracker {
          public:
            void OnSetVertexBuffer(uint32_t slot, Buffer* buffer, uint64_t offset) {
                mStartSlot = std::min(mStartSlot, slot);
                mEndSlot = std::max(mEndSlot, slot + 1);

                auto* d3d12BufferView = &mD3D12BufferViews[slot];
                d3d12BufferView->BufferLocation = buffer->GetVA() + offset;
                d3d12BufferView->SizeInBytes = buffer->GetSize() - offset;
                // The bufferView stride is set based on the vertex state before a draw.
            }

            void Apply(ID3D12GraphicsCommandList* commandList,
                       const RenderPipeline* renderPipeline) {
                ASSERT(renderPipeline != nullptr);

                std::bitset<kMaxVertexBuffers> vertexBufferSlotsUsed =
                    renderPipeline->GetVertexBufferSlotsUsed();

                uint32_t startSlot = mStartSlot;
                uint32_t endSlot = mEndSlot;

                // If the vertex state has changed, we need to update the StrideInBytes
                // for the D3D12 buffer views. We also need to extend the dirty range to
                // touch all these slots because the stride may have changed.
                if (mLastAppliedRenderPipeline != renderPipeline) {
                    mLastAppliedRenderPipeline = renderPipeline;

                    for (uint32_t slot : IterateBitSet(vertexBufferSlotsUsed)) {
                        startSlot = std::min(startSlot, slot);
                        endSlot = std::max(endSlot, slot + 1);
                        mD3D12BufferViews[slot].StrideInBytes =
                            renderPipeline->GetVertexBuffer(slot).arrayStride;
                    }
                }

                if (endSlot <= startSlot) {
                    return;
                }

                // mD3D12BufferViews is kept up to date with the most recent data passed
                // to SetVertexBuffer. This makes it correct to only track the start
                // and end of the dirty range. When Apply is called,
                // we will at worst set non-dirty vertex buffers in duplicate.
                uint32_t count = endSlot - startSlot;
                commandList->IASetVertexBuffers(startSlot, count, &mD3D12BufferViews[startSlot]);

                mStartSlot = kMaxVertexBuffers;
                mEndSlot = 0;
            }

          private:
            // startSlot and endSlot indicate the range of dirty vertex buffers.
            // If there are multiple calls to SetVertexBuffer, the start and end
            // represent the union of the dirty ranges (the union may have non-dirty
            // data in the middle of the range).
            const RenderPipeline* mLastAppliedRenderPipeline = nullptr;
            uint32_t mStartSlot = kMaxVertexBuffers;
            uint32_t mEndSlot = 0;
            std::array<D3D12_VERTEX_BUFFER_VIEW, kMaxVertexBuffers> mD3D12BufferViews = {};
        };

        class IndexBufferTracker {
          public:
            void OnSetIndexBuffer(Buffer* buffer, uint64_t offset) {
                mD3D12BufferView.BufferLocation = buffer->GetVA() + offset;
                mD3D12BufferView.SizeInBytes = buffer->GetSize() - offset;

                // We don't need to dirty the state unless BufferLocation or SizeInBytes
                // change, but most of the time this will always be the case.
                mLastAppliedIndexFormat = DXGI_FORMAT_UNKNOWN;
            }

            void OnSetPipeline(const RenderPipelineBase* pipeline) {
                mD3D12BufferView.Format =
                    DXGIIndexFormat(pipeline->GetVertexStateDescriptor()->indexFormat);
            }

            void Apply(ID3D12GraphicsCommandList* commandList) {
                if (mD3D12BufferView.Format == mLastAppliedIndexFormat) {
                    return;
                }

                commandList->IASetIndexBuffer(&mD3D12BufferView);
                mLastAppliedIndexFormat = mD3D12BufferView.Format;
            }

          private:
            DXGI_FORMAT mLastAppliedIndexFormat = DXGI_FORMAT_UNKNOWN;
            D3D12_INDEX_BUFFER_VIEW mD3D12BufferView = {};
        };

        MaybeError AllocateAndSetDescriptorHeaps(Device* device,
                                                 BindGroupStateTracker* bindingTracker,
                                                 RenderPassDescriptorHeapTracker* renderPassTracker,
                                                 CommandIterator* commands,
                                                 uint32_t indexInSubmit) {
            {
                Command type;

                auto HandleCommand = [&](CommandIterator* commands, Command type) {
                    switch (type) {
                        case Command::SetBindGroup: {
                            SetBindGroupCmd* cmd = commands->NextCommand<SetBindGroupCmd>();
                            BindGroup* group = ToBackend(cmd->group.Get());
                            if (cmd->dynamicOffsetCount) {
                                commands->NextData<uint32_t>(cmd->dynamicOffsetCount);
                            }
                            bindingTracker->TrackSetBindGroup(group, cmd->index, indexInSubmit);
                        } break;
                        case Command::BeginRenderPass: {
                            BeginRenderPassCmd* cmd = commands->NextCommand<BeginRenderPassCmd>();
                            renderPassTracker->TrackRenderPass(cmd);
                        } break;
                        default:
                            SkipCommand(commands, type);
                    }
                };

                while (commands->NextCommandId(&type)) {
                    switch (type) {
                        case Command::ExecuteBundles: {
                            ExecuteBundlesCmd* cmd = commands->NextCommand<ExecuteBundlesCmd>();
                            auto bundles = commands->NextData<Ref<RenderBundleBase>>(cmd->count);

                            for (uint32_t i = 0; i < cmd->count; ++i) {
                                CommandIterator* commands = bundles[i]->GetCommands();
                                commands->Reset();
                                while (commands->NextCommandId(&type)) {
                                    HandleCommand(commands, type);
                                }
                            }
                        } break;
                        default:
                            HandleCommand(commands, type);
                            break;
                    }
                }

                commands->Reset();
            }

            DAWN_TRY(renderPassTracker->AllocateRTVAndDSVHeaps());
            DAWN_TRY(bindingTracker->AllocateDescriptorHeaps(device));
            return {};
        }

        void ResolveMultisampledRenderPass(CommandRecordingContext* commandContext,
                                           BeginRenderPassCmd* renderPass) {
            ASSERT(renderPass != nullptr);

            for (uint32_t i :
                 IterateBitSet(renderPass->attachmentState->GetColorAttachmentsMask())) {
                TextureViewBase* resolveTarget =
                    renderPass->colorAttachments[i].resolveTarget.Get();
                if (resolveTarget == nullptr) {
                    continue;
                }

                Texture* colorTexture =
                    ToBackend(renderPass->colorAttachments[i].view->GetTexture());
                Texture* resolveTexture = ToBackend(resolveTarget->GetTexture());

                // Transition the usages of the color attachment and resolve target.
                colorTexture->TransitionUsageNow(commandContext,
                                                 D3D12_RESOURCE_STATE_RESOLVE_SOURCE);
                resolveTexture->TransitionUsageNow(commandContext,
                                                   D3D12_RESOURCE_STATE_RESOLVE_DEST);

                // Do MSAA resolve with ResolveSubResource().
                ID3D12Resource* colorTextureHandle = colorTexture->GetD3D12Resource();
                ID3D12Resource* resolveTextureHandle = resolveTexture->GetD3D12Resource();
                const uint32_t resolveTextureSubresourceIndex = resolveTexture->GetSubresourceIndex(
                    resolveTarget->GetBaseMipLevel(), resolveTarget->GetBaseArrayLayer());
                constexpr uint32_t kColorTextureSubresourceIndex = 0;
                commandContext->GetCommandList()->ResolveSubresource(
                    resolveTextureHandle, resolveTextureSubresourceIndex, colorTextureHandle,
                    kColorTextureSubresourceIndex, colorTexture->GetD3D12Format());
            }
        }

    }  // anonymous namespace

    CommandBuffer::CommandBuffer(CommandEncoder* encoder, const CommandBufferDescriptor* descriptor)
        : CommandBufferBase(encoder, descriptor), mCommands(encoder->AcquireCommands()) {
    }

    CommandBuffer::~CommandBuffer() {
        FreeCommands(&mCommands);
    }

    MaybeError CommandBuffer::RecordCommands(CommandRecordingContext* commandContext,
                                             uint32_t indexInSubmit) {
        Device* device = ToBackend(GetDevice());
        BindGroupStateTracker bindingTracker(device);
        RenderPassDescriptorHeapTracker renderPassTracker(device);

        ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

        // Precompute the allocation of bindgroups in descriptor heaps
        // TODO(cwallez@chromium.org): Iterating over all the commands here is inefficient. We
        // should have a system where commands and descriptors are recorded in parallel then the
        // heaps set using a small CommandList inserted just before the main CommandList.
        {
            DAWN_TRY(AllocateAndSetDescriptorHeaps(device, &bindingTracker, &renderPassTracker,
                                                   &mCommands, indexInSubmit));
            bindingTracker.Reset();
            bindingTracker.SetID3D12DescriptorHeaps(commandList);
        }

        // Records the necessary barriers for the resource usage pre-computed by the frontend
        auto TransitionForPass = [](CommandRecordingContext* commandContext,
                                    const PassResourceUsage& usages) -> bool {
            std::vector<D3D12_RESOURCE_BARRIER> barriers;

            ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

            wgpu::BufferUsage bufferUsages = wgpu::BufferUsage::None;

            for (size_t i = 0; i < usages.buffers.size(); ++i) {
                D3D12_RESOURCE_BARRIER barrier;
                if (ToBackend(usages.buffers[i])
                        ->TransitionUsageAndGetResourceBarrier(commandContext, &barrier,
                                                               usages.bufferUsages[i])) {
                    barriers.push_back(barrier);
                }
                bufferUsages |= usages.bufferUsages[i];
            }

            for (size_t i = 0; i < usages.textures.size(); ++i) {
                Texture* texture = ToBackend(usages.textures[i]);
                // Clear textures that are not output attachments. Output attachments will be
                // cleared during record render pass if the texture subresource has not been
                // initialized before the render pass.
                if (!(usages.textureUsages[i] & wgpu::TextureUsage::OutputAttachment)) {
                    texture->EnsureSubresourceContentInitialized(commandContext, 0,
                                                                 texture->GetNumMipLevels(), 0,
                                                                 texture->GetArrayLayers());
                }
            }

            wgpu::TextureUsage textureUsages = wgpu::TextureUsage::None;

            for (size_t i = 0; i < usages.textures.size(); ++i) {
                D3D12_RESOURCE_BARRIER barrier;
                if (ToBackend(usages.textures[i])
                        ->TransitionUsageAndGetResourceBarrier(commandContext, &barrier,
                                                               usages.textureUsages[i])) {
                    barriers.push_back(barrier);
                }
                textureUsages |= usages.textureUsages[i];
            }

            if (barriers.size()) {
                commandList->ResourceBarrier(barriers.size(), barriers.data());
            }

            return (bufferUsages & wgpu::BufferUsage::Storage ||
                    textureUsages & wgpu::TextureUsage::Storage);
        };

        const std::vector<PassResourceUsage>& passResourceUsages = GetResourceUsages().perPass;
        uint32_t nextPassNumber = 0;

        Command type;
        while (mCommands.NextCommandId(&type)) {
            switch (type) {
                case Command::BeginComputePass: {
                    mCommands.NextCommand<BeginComputePassCmd>();

                    TransitionForPass(commandContext, passResourceUsages[nextPassNumber]);
                    bindingTracker.SetInComputePass(true);
                    RecordComputePass(commandContext, &bindingTracker);

                    nextPassNumber++;
                } break;

                case Command::BeginRenderPass: {
                    BeginRenderPassCmd* beginRenderPassCmd =
                        mCommands.NextCommand<BeginRenderPassCmd>();

                    const bool passHasUAV =
                        TransitionForPass(commandContext, passResourceUsages[nextPassNumber]);
                    bindingTracker.SetInComputePass(false);
                    RecordRenderPass(commandContext, &bindingTracker, &renderPassTracker,
                                     beginRenderPassCmd, passHasUAV);

                    nextPassNumber++;
                } break;

                case Command::CopyBufferToBuffer: {
                    CopyBufferToBufferCmd* copy = mCommands.NextCommand<CopyBufferToBufferCmd>();
                    Buffer* srcBuffer = ToBackend(copy->source.Get());
                    Buffer* dstBuffer = ToBackend(copy->destination.Get());

                    srcBuffer->TransitionUsageNow(commandContext, wgpu::BufferUsage::CopySrc);
                    dstBuffer->TransitionUsageNow(commandContext, wgpu::BufferUsage::CopyDst);

                    commandList->CopyBufferRegion(
                        dstBuffer->GetD3D12Resource().Get(), copy->destinationOffset,
                        srcBuffer->GetD3D12Resource().Get(), copy->sourceOffset, copy->size);
                } break;

                case Command::CopyBufferToTexture: {
                    CopyBufferToTextureCmd* copy = mCommands.NextCommand<CopyBufferToTextureCmd>();
                    Buffer* buffer = ToBackend(copy->source.buffer.Get());
                    Texture* texture = ToBackend(copy->destination.texture.Get());

                    if (IsCompleteSubresourceCopiedTo(texture, copy->copySize,
                                                      copy->destination.mipLevel)) {
                        texture->SetIsSubresourceContentInitialized(
                            true, copy->destination.mipLevel, 1, copy->destination.arrayLayer, 1);
                    } else {
                        texture->EnsureSubresourceContentInitialized(
                            commandContext, copy->destination.mipLevel, 1,
                            copy->destination.arrayLayer, 1);
                    }

                    buffer->TransitionUsageNow(commandContext, wgpu::BufferUsage::CopySrc);
                    texture->TransitionUsageNow(commandContext, wgpu::TextureUsage::CopyDst);

                    auto copySplit = ComputeTextureCopySplit(
                        copy->destination.origin, copy->copySize, texture->GetFormat(),
                        copy->source.offset, copy->source.rowPitch, copy->source.imageHeight);

                    D3D12_TEXTURE_COPY_LOCATION textureLocation =
                        ComputeTextureCopyLocationForTexture(texture, copy->destination.mipLevel,
                                                             copy->destination.arrayLayer);

                    for (uint32_t i = 0; i < copySplit.count; ++i) {
                        TextureCopySplit::CopyInfo& info = copySplit.copies[i];

                        D3D12_TEXTURE_COPY_LOCATION bufferLocation =
                            ComputeBufferLocationForCopyTextureRegion(
                                texture, buffer->GetD3D12Resource().Get(), info.bufferSize,
                                copySplit.offset, copy->source.rowPitch);
                        D3D12_BOX sourceRegion =
                            ComputeD3D12BoxFromOffsetAndSize(info.bufferOffset, info.copySize);

                        commandList->CopyTextureRegion(&textureLocation, info.textureOffset.x,
                                                       info.textureOffset.y, info.textureOffset.z,
                                                       &bufferLocation, &sourceRegion);
                    }
                } break;

                case Command::CopyTextureToBuffer: {
                    CopyTextureToBufferCmd* copy = mCommands.NextCommand<CopyTextureToBufferCmd>();
                    Texture* texture = ToBackend(copy->source.texture.Get());
                    Buffer* buffer = ToBackend(copy->destination.buffer.Get());

                    texture->EnsureSubresourceContentInitialized(
                        commandContext, copy->source.mipLevel, 1, copy->source.arrayLayer, 1);

                    texture->TransitionUsageNow(commandContext, wgpu::TextureUsage::CopySrc);
                    buffer->TransitionUsageNow(commandContext, wgpu::BufferUsage::CopyDst);

                    TextureCopySplit copySplit = ComputeTextureCopySplit(
                        copy->source.origin, copy->copySize, texture->GetFormat(),
                        copy->destination.offset, copy->destination.rowPitch,
                        copy->destination.imageHeight);

                    D3D12_TEXTURE_COPY_LOCATION textureLocation =
                        ComputeTextureCopyLocationForTexture(texture, copy->source.mipLevel,
                                                             copy->source.arrayLayer);

                    for (uint32_t i = 0; i < copySplit.count; ++i) {
                        TextureCopySplit::CopyInfo& info = copySplit.copies[i];

                        D3D12_TEXTURE_COPY_LOCATION bufferLocation =
                            ComputeBufferLocationForCopyTextureRegion(
                                texture, buffer->GetD3D12Resource().Get(), info.bufferSize,
                                copySplit.offset, copy->destination.rowPitch);

                        D3D12_BOX sourceRegion =
                            ComputeD3D12BoxFromOffsetAndSize(info.textureOffset, info.copySize);

                        commandList->CopyTextureRegion(&bufferLocation, info.bufferOffset.x,
                                                       info.bufferOffset.y, info.bufferOffset.z,
                                                       &textureLocation, &sourceRegion);
                    }
                } break;

                case Command::CopyTextureToTexture: {
                    CopyTextureToTextureCmd* copy =
                        mCommands.NextCommand<CopyTextureToTextureCmd>();

                    Texture* source = ToBackend(copy->source.texture.Get());
                    Texture* destination = ToBackend(copy->destination.texture.Get());

                    source->EnsureSubresourceContentInitialized(
                        commandContext, copy->source.mipLevel, 1, copy->source.arrayLayer, 1);
                    if (IsCompleteSubresourceCopiedTo(destination, copy->copySize,
                                                      copy->destination.mipLevel)) {
                        destination->SetIsSubresourceContentInitialized(
                            true, copy->destination.mipLevel, 1, copy->destination.arrayLayer, 1);
                    } else {
                        destination->EnsureSubresourceContentInitialized(
                            commandContext, copy->destination.mipLevel, 1,
                            copy->destination.arrayLayer, 1);
                    }
                    source->TransitionUsageNow(commandContext, wgpu::TextureUsage::CopySrc);
                    destination->TransitionUsageNow(commandContext, wgpu::TextureUsage::CopyDst);

                    if (CanUseCopyResource(source->GetNumMipLevels(), source->GetSize(),
                                           destination->GetSize(), copy->copySize)) {
                        commandList->CopyResource(destination->GetD3D12Resource(),
                                                  source->GetD3D12Resource());
                    } else {
                        D3D12_TEXTURE_COPY_LOCATION srcLocation =
                            ComputeTextureCopyLocationForTexture(source, copy->source.mipLevel,
                                                                 copy->source.arrayLayer);

                        D3D12_TEXTURE_COPY_LOCATION dstLocation =
                            ComputeTextureCopyLocationForTexture(destination,
                                                                 copy->destination.mipLevel,
                                                                 copy->destination.arrayLayer);

                        D3D12_BOX sourceRegion =
                            ComputeD3D12BoxFromOffsetAndSize(copy->source.origin, copy->copySize);

                        commandList->CopyTextureRegion(
                            &dstLocation, copy->destination.origin.x, copy->destination.origin.y,
                            copy->destination.origin.z, &srcLocation, &sourceRegion);
                    }
                } break;

                default: { UNREACHABLE(); } break;
            }
        }

        DAWN_ASSERT(renderPassTracker.IsHeapAllocationCompleted());
        return {};
    }

    void CommandBuffer::RecordComputePass(CommandRecordingContext* commandContext,
                                          BindGroupStateTracker* bindingTracker) {
        PipelineLayout* lastLayout = nullptr;
        ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

        Command type;
        while (mCommands.NextCommandId(&type)) {
            switch (type) {
                case Command::Dispatch: {
                    DispatchCmd* dispatch = mCommands.NextCommand<DispatchCmd>();

                    bindingTracker->Apply(commandContext);
                    commandList->Dispatch(dispatch->x, dispatch->y, dispatch->z);
                } break;

                case Command::DispatchIndirect: {
                    DispatchIndirectCmd* dispatch = mCommands.NextCommand<DispatchIndirectCmd>();

                    bindingTracker->Apply(commandContext);
                    Buffer* buffer = ToBackend(dispatch->indirectBuffer.Get());
                    ComPtr<ID3D12CommandSignature> signature =
                        ToBackend(GetDevice())->GetDispatchIndirectSignature();
                    commandList->ExecuteIndirect(signature.Get(), 1,
                                                 buffer->GetD3D12Resource().Get(),
                                                 dispatch->indirectOffset, nullptr, 0);
                } break;

                case Command::EndComputePass: {
                    mCommands.NextCommand<EndComputePassCmd>();
                    return;
                } break;

                case Command::SetComputePipeline: {
                    SetComputePipelineCmd* cmd = mCommands.NextCommand<SetComputePipelineCmd>();
                    ComputePipeline* pipeline = ToBackend(cmd->pipeline).Get();
                    PipelineLayout* layout = ToBackend(pipeline->GetLayout());

                    commandList->SetComputeRootSignature(layout->GetRootSignature().Get());
                    commandList->SetPipelineState(pipeline->GetPipelineState().Get());

                    bindingTracker->OnSetPipeline(pipeline);

                    lastLayout = layout;
                } break;

                case Command::SetBindGroup: {
                    SetBindGroupCmd* cmd = mCommands.NextCommand<SetBindGroupCmd>();
                    BindGroup* group = ToBackend(cmd->group.Get());
                    uint32_t* dynamicOffsets = nullptr;

                    if (cmd->dynamicOffsetCount > 0) {
                        dynamicOffsets = mCommands.NextData<uint32_t>(cmd->dynamicOffsetCount);
                    }

                    bindingTracker->OnSetBindGroup(cmd->index, group, cmd->dynamicOffsetCount,
                                                   dynamicOffsets);
                } break;

                case Command::InsertDebugMarker: {
                    InsertDebugMarkerCmd* cmd = mCommands.NextCommand<InsertDebugMarkerCmd>();
                    const char* label = mCommands.NextData<char>(cmd->length + 1);

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        // PIX color is 1 byte per channel in ARGB format
                        constexpr uint64_t kPIXBlackColor = 0xff000000;
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixSetMarkerOnCommandList(commandList, kPIXBlackColor, label);
                    }
                } break;

                case Command::PopDebugGroup: {
                    mCommands.NextCommand<PopDebugGroupCmd>();

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixEndEventOnCommandList(commandList);
                    }
                } break;

                case Command::PushDebugGroup: {
                    PushDebugGroupCmd* cmd = mCommands.NextCommand<PushDebugGroupCmd>();
                    const char* label = mCommands.NextData<char>(cmd->length + 1);

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        // PIX color is 1 byte per channel in ARGB format
                        constexpr uint64_t kPIXBlackColor = 0xff000000;
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixBeginEventOnCommandList(commandList, kPIXBlackColor, label);
                    }
                } break;

                default: { UNREACHABLE(); } break;
            }
        }
    }

    void CommandBuffer::SetupRenderPass(CommandRecordingContext* commandContext,
                                        BeginRenderPassCmd* renderPass,
                                        RenderPassBuilder* renderPassBuilder) {
        for (uint32_t i : IterateBitSet(renderPass->attachmentState->GetColorAttachmentsMask())) {
            RenderPassColorAttachmentInfo& attachmentInfo = renderPass->colorAttachments[i];
            TextureView* view = ToBackend(attachmentInfo.view.Get());
            Texture* texture = ToBackend(view->GetTexture());

            // Load operation is changed to clear when the texture is uninitialized.
            if (!texture->IsSubresourceContentInitialized(view->GetBaseMipLevel(), 1,
                                                          view->GetBaseArrayLayer(), 1) &&
                attachmentInfo.loadOp == wgpu::LoadOp::Load) {
                attachmentInfo.loadOp = wgpu::LoadOp::Clear;
                attachmentInfo.clearColor = {0.0f, 0.0f, 0.0f, 0.0f};
            }

            // Set color load operation.
            renderPassBuilder->SetRenderTargetBeginningAccess(
                i, attachmentInfo.loadOp, attachmentInfo.clearColor, view->GetD3D12Format());

            // Set color store operation.
            if (attachmentInfo.resolveTarget.Get() != nullptr) {
                TextureView* resolveDestinationView = ToBackend(attachmentInfo.resolveTarget.Get());
                Texture* resolveDestinationTexture =
                    ToBackend(resolveDestinationView->GetTexture());

                resolveDestinationTexture->TransitionUsageNow(commandContext,
                                                              D3D12_RESOURCE_STATE_RESOLVE_DEST);

                // Mark resolve target as initialized to prevent clearing later.
                resolveDestinationTexture->SetIsSubresourceContentInitialized(
                    true, resolveDestinationView->GetBaseMipLevel(), 1,
                    resolveDestinationView->GetBaseArrayLayer(), 1);

                renderPassBuilder->SetRenderTargetEndingAccessResolve(i, attachmentInfo.storeOp,
                                                                      view, resolveDestinationView);
            } else {
                renderPassBuilder->SetRenderTargetEndingAccess(i, attachmentInfo.storeOp);
            }

            // Set whether or not the texture requires initialization after the pass.
            bool isInitialized = attachmentInfo.storeOp == wgpu::StoreOp::Store;
            texture->SetIsSubresourceContentInitialized(isInitialized, view->GetBaseMipLevel(), 1,
                                                        view->GetBaseArrayLayer(), 1);
        }

        if (renderPass->attachmentState->HasDepthStencilAttachment()) {
            RenderPassDepthStencilAttachmentInfo& attachmentInfo =
                renderPass->depthStencilAttachment;
            TextureView* view = ToBackend(renderPass->depthStencilAttachment.view.Get());
            Texture* texture = ToBackend(view->GetTexture());

            const bool hasDepth = view->GetTexture()->GetFormat().HasDepth();
            const bool hasStencil = view->GetTexture()->GetFormat().HasStencil();

            // Load operations are changed to clear when the texture is uninitialized.
            if (!view->GetTexture()->IsSubresourceContentInitialized(
                    view->GetBaseMipLevel(), view->GetLevelCount(), view->GetBaseArrayLayer(),
                    view->GetLayerCount())) {
                if (hasDepth && attachmentInfo.depthLoadOp == wgpu::LoadOp::Load) {
                    attachmentInfo.clearDepth = 0.0f;
                    attachmentInfo.depthLoadOp = wgpu::LoadOp::Clear;
                }
                if (hasStencil && attachmentInfo.stencilLoadOp == wgpu::LoadOp::Load) {
                    attachmentInfo.clearStencil = 0u;
                    attachmentInfo.stencilLoadOp = wgpu::LoadOp::Clear;
                }
            }

            // Set depth/stencil load operations.
            if (hasDepth) {
                renderPassBuilder->SetDepthAccess(
                    attachmentInfo.depthLoadOp, attachmentInfo.depthStoreOp,
                    attachmentInfo.clearDepth, view->GetD3D12Format());
            } else {
                renderPassBuilder->SetDepthNoAccess();
            }

            if (hasStencil) {
                renderPassBuilder->SetStencilAccess(
                    attachmentInfo.stencilLoadOp, attachmentInfo.stencilStoreOp,
                    attachmentInfo.clearStencil, view->GetD3D12Format());
            } else {
                renderPassBuilder->SetStencilNoAccess();
            }

            // Set whether or not the texture requires initialization.
            ASSERT(!hasDepth || !hasStencil ||
                   attachmentInfo.depthStoreOp == attachmentInfo.stencilStoreOp);
            bool isInitialized = attachmentInfo.depthStoreOp == wgpu::StoreOp::Store;
            texture->SetIsSubresourceContentInitialized(isInitialized, view->GetBaseMipLevel(), 1,
                                                        view->GetBaseArrayLayer(), 1);
        } else {
            renderPassBuilder->SetDepthStencilNoAccess();
        }
    }

    void CommandBuffer::EmulateBeginRenderPass(CommandRecordingContext* commandContext,
                                               const RenderPassBuilder* renderPassBuilder) const {
        ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

        // Clear framebuffer attachments as needed.
        {
            for (uint32_t i = 0; i < renderPassBuilder->GetColorAttachmentCount(); i++) {
                // Load op - color
                if (renderPassBuilder->GetRenderPassRenderTargetDescriptors()[i]
                        .BeginningAccess.Type == D3D12_RENDER_PASS_BEGINNING_ACCESS_TYPE_CLEAR) {
                    commandList->ClearRenderTargetView(
                        renderPassBuilder->GetRenderPassRenderTargetDescriptors()[i].cpuDescriptor,
                        renderPassBuilder->GetRenderPassRenderTargetDescriptors()[i]
                            .BeginningAccess.Clear.ClearValue.Color,
                        0, nullptr);
                }
            }

            if (renderPassBuilder->HasDepth()) {
                D3D12_CLEAR_FLAGS clearFlags = {};
                float depthClear = 0.0f;
                uint8_t stencilClear = 0u;

                if (renderPassBuilder->GetRenderPassDepthStencilDescriptor()
                        ->DepthBeginningAccess.Type ==
                    D3D12_RENDER_PASS_BEGINNING_ACCESS_TYPE_CLEAR) {
                    clearFlags |= D3D12_CLEAR_FLAG_DEPTH;
                    depthClear = renderPassBuilder->GetRenderPassDepthStencilDescriptor()
                                     ->DepthBeginningAccess.Clear.ClearValue.DepthStencil.Depth;
                }
                if (renderPassBuilder->GetRenderPassDepthStencilDescriptor()
                        ->StencilBeginningAccess.Type ==
                    D3D12_RENDER_PASS_BEGINNING_ACCESS_TYPE_CLEAR) {
                    clearFlags |= D3D12_CLEAR_FLAG_STENCIL;
                    stencilClear =
                        renderPassBuilder->GetRenderPassDepthStencilDescriptor()
                            ->StencilBeginningAccess.Clear.ClearValue.DepthStencil.Stencil;
                }

                // TODO(kainino@chromium.org): investigate: should the Dawn clear
                // stencil type be uint8_t?
                if (clearFlags) {
                    commandList->ClearDepthStencilView(
                        renderPassBuilder->GetRenderPassDepthStencilDescriptor()->cpuDescriptor,
                        clearFlags, depthClear, stencilClear, 0, nullptr);
                }
            }
        }

        commandList->OMSetRenderTargets(
            renderPassBuilder->GetColorAttachmentCount(), renderPassBuilder->GetRenderTargetViews(),
            FALSE,
            renderPassBuilder->HasDepth()
                ? &renderPassBuilder->GetRenderPassDepthStencilDescriptor()->cpuDescriptor
                : nullptr);
    }

    void CommandBuffer::RecordRenderPass(
        CommandRecordingContext* commandContext,
        BindGroupStateTracker* bindingTracker,
        RenderPassDescriptorHeapTracker* renderPassDescriptorHeapTracker,
        BeginRenderPassCmd* renderPass,
        const bool passHasUAV) {
        OMSetRenderTargetArgs args =
            renderPassDescriptorHeapTracker->GetSubpassOMSetRenderTargetArgs(renderPass);

        const bool useRenderPass = GetDevice()->IsToggleEnabled(Toggle::UseD3D12RenderPass);

        // renderPassBuilder must be scoped to RecordRenderPass because any underlying
        // D3D12_RENDER_PASS_ENDING_ACCESS_RESOLVE_SUBRESOURCE_PARAMETERS structs must remain
        // valid until after EndRenderPass() has been called.
        RenderPassBuilder renderPassBuilder(args, passHasUAV);

        SetupRenderPass(commandContext, renderPass, &renderPassBuilder);

        // Use D3D12's native render pass API if it's available, otherwise emulate the
        // beginning and ending access operations.
        if (useRenderPass) {
            commandContext->GetCommandList4()->BeginRenderPass(
                renderPassBuilder.GetColorAttachmentCount(),
                renderPassBuilder.GetRenderPassRenderTargetDescriptors(),
                renderPassBuilder.HasDepth()
                    ? renderPassBuilder.GetRenderPassDepthStencilDescriptor()
                    : nullptr,
                renderPassBuilder.GetRenderPassFlags());
        } else {
            EmulateBeginRenderPass(commandContext, &renderPassBuilder);
        }

        ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

        // Set up default dynamic state
        {
            uint32_t width = renderPass->width;
            uint32_t height = renderPass->height;
            D3D12_VIEWPORT viewport = {
                0.f, 0.f, static_cast<float>(width), static_cast<float>(height), 0.f, 1.f};
            D3D12_RECT scissorRect = {0, 0, static_cast<long>(width), static_cast<long>(height)};
            commandList->RSSetViewports(1, &viewport);
            commandList->RSSetScissorRects(1, &scissorRect);

            static constexpr std::array<float, 4> defaultBlendFactor = {0, 0, 0, 0};
            commandList->OMSetBlendFactor(&defaultBlendFactor[0]);
        }

        RenderPipeline* lastPipeline = nullptr;
        PipelineLayout* lastLayout = nullptr;
        VertexBufferTracker vertexBufferTracker = {};
        IndexBufferTracker indexBufferTracker = {};

        auto EncodeRenderBundleCommand = [&](CommandIterator* iter, Command type) {
            switch (type) {
                case Command::Draw: {
                    DrawCmd* draw = iter->NextCommand<DrawCmd>();

                    bindingTracker->Apply(commandContext);
                    vertexBufferTracker.Apply(commandList, lastPipeline);
                    commandList->DrawInstanced(draw->vertexCount, draw->instanceCount,
                                               draw->firstVertex, draw->firstInstance);
                } break;

                case Command::DrawIndexed: {
                    DrawIndexedCmd* draw = iter->NextCommand<DrawIndexedCmd>();

                    bindingTracker->Apply(commandContext);
                    indexBufferTracker.Apply(commandList);
                    vertexBufferTracker.Apply(commandList, lastPipeline);
                    commandList->DrawIndexedInstanced(draw->indexCount, draw->instanceCount,
                                                      draw->firstIndex, draw->baseVertex,
                                                      draw->firstInstance);
                } break;

                case Command::DrawIndirect: {
                    DrawIndirectCmd* draw = iter->NextCommand<DrawIndirectCmd>();

                    bindingTracker->Apply(commandContext);
                    vertexBufferTracker.Apply(commandList, lastPipeline);
                    Buffer* buffer = ToBackend(draw->indirectBuffer.Get());
                    ComPtr<ID3D12CommandSignature> signature =
                        ToBackend(GetDevice())->GetDrawIndirectSignature();
                    commandList->ExecuteIndirect(signature.Get(), 1,
                                                 buffer->GetD3D12Resource().Get(),
                                                 draw->indirectOffset, nullptr, 0);
                } break;

                case Command::DrawIndexedIndirect: {
                    DrawIndexedIndirectCmd* draw = iter->NextCommand<DrawIndexedIndirectCmd>();

                    bindingTracker->Apply(commandContext);
                    indexBufferTracker.Apply(commandList);
                    vertexBufferTracker.Apply(commandList, lastPipeline);
                    Buffer* buffer = ToBackend(draw->indirectBuffer.Get());
                    ComPtr<ID3D12CommandSignature> signature =
                        ToBackend(GetDevice())->GetDrawIndexedIndirectSignature();
                    commandList->ExecuteIndirect(signature.Get(), 1,
                                                 buffer->GetD3D12Resource().Get(),
                                                 draw->indirectOffset, nullptr, 0);
                } break;

                case Command::InsertDebugMarker: {
                    InsertDebugMarkerCmd* cmd = iter->NextCommand<InsertDebugMarkerCmd>();
                    const char* label = iter->NextData<char>(cmd->length + 1);

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        // PIX color is 1 byte per channel in ARGB format
                        constexpr uint64_t kPIXBlackColor = 0xff000000;
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixSetMarkerOnCommandList(commandList, kPIXBlackColor, label);
                    }
                } break;

                case Command::PopDebugGroup: {
                    iter->NextCommand<PopDebugGroupCmd>();

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixEndEventOnCommandList(commandList);
                    }
                } break;

                case Command::PushDebugGroup: {
                    PushDebugGroupCmd* cmd = iter->NextCommand<PushDebugGroupCmd>();
                    const char* label = iter->NextData<char>(cmd->length + 1);

                    if (ToBackend(GetDevice())->GetFunctions()->IsPIXEventRuntimeLoaded()) {
                        // PIX color is 1 byte per channel in ARGB format
                        constexpr uint64_t kPIXBlackColor = 0xff000000;
                        ToBackend(GetDevice())
                            ->GetFunctions()
                            ->pixBeginEventOnCommandList(commandList, kPIXBlackColor, label);
                    }
                } break;

                case Command::SetRenderPipeline: {
                    SetRenderPipelineCmd* cmd = iter->NextCommand<SetRenderPipelineCmd>();
                    RenderPipeline* pipeline = ToBackend(cmd->pipeline).Get();
                    PipelineLayout* layout = ToBackend(pipeline->GetLayout());

                    commandList->SetGraphicsRootSignature(layout->GetRootSignature().Get());
                    commandList->SetPipelineState(pipeline->GetPipelineState().Get());
                    commandList->IASetPrimitiveTopology(pipeline->GetD3D12PrimitiveTopology());

                    bindingTracker->OnSetPipeline(pipeline);
                    indexBufferTracker.OnSetPipeline(pipeline);

                    lastPipeline = pipeline;
                    lastLayout = layout;
                } break;

                case Command::SetBindGroup: {
                    SetBindGroupCmd* cmd = iter->NextCommand<SetBindGroupCmd>();
                    BindGroup* group = ToBackend(cmd->group.Get());
                    uint32_t* dynamicOffsets = nullptr;

                    if (cmd->dynamicOffsetCount > 0) {
                        dynamicOffsets = iter->NextData<uint32_t>(cmd->dynamicOffsetCount);
                    }

                    bindingTracker->OnSetBindGroup(cmd->index, group, cmd->dynamicOffsetCount,
                                                   dynamicOffsets);
                } break;

                case Command::SetIndexBuffer: {
                    SetIndexBufferCmd* cmd = iter->NextCommand<SetIndexBufferCmd>();

                    indexBufferTracker.OnSetIndexBuffer(ToBackend(cmd->buffer.Get()), cmd->offset);
                } break;

                case Command::SetVertexBuffer: {
                    SetVertexBufferCmd* cmd = iter->NextCommand<SetVertexBufferCmd>();

                    vertexBufferTracker.OnSetVertexBuffer(cmd->slot, ToBackend(cmd->buffer.Get()),
                                                          cmd->offset);
                } break;

                default:
                    UNREACHABLE();
                    break;
            }
        };

        Command type;
        while (mCommands.NextCommandId(&type)) {
            switch (type) {
                case Command::EndRenderPass: {
                    mCommands.NextCommand<EndRenderPassCmd>();
                    if (useRenderPass) {
                        commandContext->GetCommandList4()->EndRenderPass();
                    } else if (renderPass->attachmentState->GetSampleCount() > 1) {
                        ResolveMultisampledRenderPass(commandContext, renderPass);
                    }
                    return;
                } break;

                case Command::SetStencilReference: {
                    SetStencilReferenceCmd* cmd = mCommands.NextCommand<SetStencilReferenceCmd>();

                    commandList->OMSetStencilRef(cmd->reference);
                } break;

                case Command::SetViewport: {
                    SetViewportCmd* cmd = mCommands.NextCommand<SetViewportCmd>();
                    D3D12_VIEWPORT viewport;
                    viewport.TopLeftX = cmd->x;
                    viewport.TopLeftY = cmd->y;
                    viewport.Width = cmd->width;
                    viewport.Height = cmd->height;
                    viewport.MinDepth = cmd->minDepth;
                    viewport.MaxDepth = cmd->maxDepth;

                    commandList->RSSetViewports(1, &viewport);
                } break;

                case Command::SetScissorRect: {
                    SetScissorRectCmd* cmd = mCommands.NextCommand<SetScissorRectCmd>();
                    D3D12_RECT rect;
                    rect.left = cmd->x;
                    rect.top = cmd->y;
                    rect.right = cmd->x + cmd->width;
                    rect.bottom = cmd->y + cmd->height;

                    commandList->RSSetScissorRects(1, &rect);
                } break;

                case Command::SetBlendColor: {
                    SetBlendColorCmd* cmd = mCommands.NextCommand<SetBlendColorCmd>();
                    commandList->OMSetBlendFactor(static_cast<const FLOAT*>(&cmd->color.r));
                } break;

                case Command::ExecuteBundles: {
                    ExecuteBundlesCmd* cmd = mCommands.NextCommand<ExecuteBundlesCmd>();
                    auto bundles = mCommands.NextData<Ref<RenderBundleBase>>(cmd->count);

                    for (uint32_t i = 0; i < cmd->count; ++i) {
                        CommandIterator* iter = bundles[i]->GetCommands();
                        iter->Reset();
                        while (iter->NextCommandId(&type)) {
                            EncodeRenderBundleCommand(iter, type);
                        }
                    }
                } break;

                default: { EncodeRenderBundleCommand(&mCommands, type); } break;
            }
        }
    }

}}  // namespace dawn_native::d3d12