// 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/TextureD3D12.h"

#include "common/Constants.h"
#include "common/Math.h"
#include "dawn_native/DynamicUploader.h"
#include "dawn_native/Error.h"
#include "dawn_native/d3d12/BufferD3D12.h"
#include "dawn_native/d3d12/CommandRecordingContext.h"
#include "dawn_native/d3d12/D3D12Error.h"
#include "dawn_native/d3d12/DeviceD3D12.h"
#include "dawn_native/d3d12/HeapD3D12.h"
#include "dawn_native/d3d12/ResourceAllocatorManagerD3D12.h"
#include "dawn_native/d3d12/StagingBufferD3D12.h"
#include "dawn_native/d3d12/StagingDescriptorAllocatorD3D12.h"
#include "dawn_native/d3d12/TextureCopySplitter.h"
#include "dawn_native/d3d12/UtilsD3D12.h"

namespace dawn_native { namespace d3d12 {

    namespace {
        D3D12_RESOURCE_STATES D3D12TextureUsage(wgpu::TextureUsage usage, const Format& format) {
            D3D12_RESOURCE_STATES resourceState = D3D12_RESOURCE_STATE_COMMON;

            // Present is an exclusive flag.
            if (usage & wgpu::TextureUsage::Present) {
                return D3D12_RESOURCE_STATE_PRESENT;
            }

            if (usage & wgpu::TextureUsage::CopySrc) {
                resourceState |= D3D12_RESOURCE_STATE_COPY_SOURCE;
            }
            if (usage & wgpu::TextureUsage::CopyDst) {
                resourceState |= D3D12_RESOURCE_STATE_COPY_DEST;
            }
            if (usage & wgpu::TextureUsage::Sampled) {
                resourceState |= (D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE |
                                  D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE);
            }
            if (usage & wgpu::TextureUsage::Storage) {
                resourceState |= D3D12_RESOURCE_STATE_UNORDERED_ACCESS;
            }
            if (usage & wgpu::TextureUsage::OutputAttachment) {
                if (format.HasDepthOrStencil()) {
                    resourceState |= D3D12_RESOURCE_STATE_DEPTH_WRITE;
                } else {
                    resourceState |= D3D12_RESOURCE_STATE_RENDER_TARGET;
                }
            }

            return resourceState;
        }

        D3D12_RESOURCE_FLAGS D3D12ResourceFlags(wgpu::TextureUsage usage,
                                                const Format& format,
                                                bool isMultisampledTexture) {
            D3D12_RESOURCE_FLAGS flags = D3D12_RESOURCE_FLAG_NONE;

            if (usage & wgpu::TextureUsage::Storage) {
                flags |= D3D12_RESOURCE_FLAG_ALLOW_UNORDERED_ACCESS;
            }

            // A multisampled resource must have either D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET or
            // D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL set in D3D12_RESOURCE_DESC::Flags.
            // https://docs.microsoft.com/en-us/windows/desktop/api/d3d12/ns-d3d12-d3d12_resource_desc
            // Currently all textures are zero-initialized via the render-target path so always add
            // the render target flag, except for compressed textures for which the render-target
            // flag is invalid.
            // TODO(natlee@microsoft.com, jiawei.shao@intel.com): do not require render target for
            // lazy clearing.
            if ((usage & wgpu::TextureUsage::OutputAttachment) || isMultisampledTexture ||
                !format.isCompressed) {
                if (format.HasDepthOrStencil()) {
                    flags |= D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL;
                } else {
                    flags |= D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET;
                }
            }

            ASSERT(!(flags & D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL) ||
                   flags == D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL);
            return flags;
        }

        D3D12_RESOURCE_DIMENSION D3D12TextureDimension(wgpu::TextureDimension dimension) {
            switch (dimension) {
                case wgpu::TextureDimension::e2D:
                    return D3D12_RESOURCE_DIMENSION_TEXTURE2D;
                default:
                    UNREACHABLE();
            }
        }
    }  // namespace

    DXGI_FORMAT D3D12TextureFormat(wgpu::TextureFormat format) {
        switch (format) {
            case wgpu::TextureFormat::R8Unorm:
                return DXGI_FORMAT_R8_UNORM;
            case wgpu::TextureFormat::R8Snorm:
                return DXGI_FORMAT_R8_SNORM;
            case wgpu::TextureFormat::R8Uint:
                return DXGI_FORMAT_R8_UINT;
            case wgpu::TextureFormat::R8Sint:
                return DXGI_FORMAT_R8_SINT;

            case wgpu::TextureFormat::R16Uint:
                return DXGI_FORMAT_R16_UINT;
            case wgpu::TextureFormat::R16Sint:
                return DXGI_FORMAT_R16_SINT;
            case wgpu::TextureFormat::R16Float:
                return DXGI_FORMAT_R16_FLOAT;
            case wgpu::TextureFormat::RG8Unorm:
                return DXGI_FORMAT_R8G8_UNORM;
            case wgpu::TextureFormat::RG8Snorm:
                return DXGI_FORMAT_R8G8_SNORM;
            case wgpu::TextureFormat::RG8Uint:
                return DXGI_FORMAT_R8G8_UINT;
            case wgpu::TextureFormat::RG8Sint:
                return DXGI_FORMAT_R8G8_SINT;

            case wgpu::TextureFormat::R32Uint:
                return DXGI_FORMAT_R32_UINT;
            case wgpu::TextureFormat::R32Sint:
                return DXGI_FORMAT_R32_SINT;
            case wgpu::TextureFormat::R32Float:
                return DXGI_FORMAT_R32_FLOAT;
            case wgpu::TextureFormat::RG16Uint:
                return DXGI_FORMAT_R16G16_UINT;
            case wgpu::TextureFormat::RG16Sint:
                return DXGI_FORMAT_R16G16_SINT;
            case wgpu::TextureFormat::RG16Float:
                return DXGI_FORMAT_R16G16_FLOAT;
            case wgpu::TextureFormat::RGBA8Unorm:
                return DXGI_FORMAT_R8G8B8A8_UNORM;
            case wgpu::TextureFormat::RGBA8UnormSrgb:
                return DXGI_FORMAT_R8G8B8A8_UNORM_SRGB;
            case wgpu::TextureFormat::RGBA8Snorm:
                return DXGI_FORMAT_R8G8B8A8_SNORM;
            case wgpu::TextureFormat::RGBA8Uint:
                return DXGI_FORMAT_R8G8B8A8_UINT;
            case wgpu::TextureFormat::RGBA8Sint:
                return DXGI_FORMAT_R8G8B8A8_SINT;
            case wgpu::TextureFormat::BGRA8Unorm:
                return DXGI_FORMAT_B8G8R8A8_UNORM;
            case wgpu::TextureFormat::BGRA8UnormSrgb:
                return DXGI_FORMAT_B8G8R8A8_UNORM_SRGB;
            case wgpu::TextureFormat::RGB10A2Unorm:
                return DXGI_FORMAT_R10G10B10A2_UNORM;
            case wgpu::TextureFormat::RG11B10Float:
                return DXGI_FORMAT_R11G11B10_FLOAT;

            case wgpu::TextureFormat::RG32Uint:
                return DXGI_FORMAT_R32G32_UINT;
            case wgpu::TextureFormat::RG32Sint:
                return DXGI_FORMAT_R32G32_SINT;
            case wgpu::TextureFormat::RG32Float:
                return DXGI_FORMAT_R32G32_FLOAT;
            case wgpu::TextureFormat::RGBA16Uint:
                return DXGI_FORMAT_R16G16B16A16_UINT;
            case wgpu::TextureFormat::RGBA16Sint:
                return DXGI_FORMAT_R16G16B16A16_SINT;
            case wgpu::TextureFormat::RGBA16Float:
                return DXGI_FORMAT_R16G16B16A16_FLOAT;

            case wgpu::TextureFormat::RGBA32Uint:
                return DXGI_FORMAT_R32G32B32A32_UINT;
            case wgpu::TextureFormat::RGBA32Sint:
                return DXGI_FORMAT_R32G32B32A32_SINT;
            case wgpu::TextureFormat::RGBA32Float:
                return DXGI_FORMAT_R32G32B32A32_FLOAT;

            case wgpu::TextureFormat::Depth32Float:
                return DXGI_FORMAT_D32_FLOAT;
            case wgpu::TextureFormat::Depth24Plus:
                return DXGI_FORMAT_D32_FLOAT;
            case wgpu::TextureFormat::Depth24PlusStencil8:
                return DXGI_FORMAT_D32_FLOAT_S8X24_UINT;

            case wgpu::TextureFormat::BC1RGBAUnorm:
                return DXGI_FORMAT_BC1_UNORM;
            case wgpu::TextureFormat::BC1RGBAUnormSrgb:
                return DXGI_FORMAT_BC1_UNORM_SRGB;
            case wgpu::TextureFormat::BC2RGBAUnorm:
                return DXGI_FORMAT_BC2_UNORM;
            case wgpu::TextureFormat::BC2RGBAUnormSrgb:
                return DXGI_FORMAT_BC2_UNORM_SRGB;
            case wgpu::TextureFormat::BC3RGBAUnorm:
                return DXGI_FORMAT_BC3_UNORM;
            case wgpu::TextureFormat::BC3RGBAUnormSrgb:
                return DXGI_FORMAT_BC3_UNORM_SRGB;
            case wgpu::TextureFormat::BC4RSnorm:
                return DXGI_FORMAT_BC4_SNORM;
            case wgpu::TextureFormat::BC4RUnorm:
                return DXGI_FORMAT_BC4_UNORM;
            case wgpu::TextureFormat::BC5RGSnorm:
                return DXGI_FORMAT_BC5_SNORM;
            case wgpu::TextureFormat::BC5RGUnorm:
                return DXGI_FORMAT_BC5_UNORM;
            case wgpu::TextureFormat::BC6HRGBSfloat:
                return DXGI_FORMAT_BC6H_SF16;
            case wgpu::TextureFormat::BC6HRGBUfloat:
                return DXGI_FORMAT_BC6H_UF16;
            case wgpu::TextureFormat::BC7RGBAUnorm:
                return DXGI_FORMAT_BC7_UNORM;
            case wgpu::TextureFormat::BC7RGBAUnormSrgb:
                return DXGI_FORMAT_BC7_UNORM_SRGB;

            default:
                UNREACHABLE();
        }
    }

    MaybeError ValidateTextureDescriptorCanBeWrapped(const TextureDescriptor* descriptor) {
        if (descriptor->dimension != wgpu::TextureDimension::e2D) {
            return DAWN_VALIDATION_ERROR("Texture must be 2D");
        }

        if (descriptor->mipLevelCount != 1) {
            return DAWN_VALIDATION_ERROR("Mip level count must be 1");
        }

        if (descriptor->arrayLayerCount != 1) {
            return DAWN_VALIDATION_ERROR("Array layer count must be 1");
        }

        if (descriptor->sampleCount != 1) {
            return DAWN_VALIDATION_ERROR("Sample count must be 1");
        }

        return {};
    }

    MaybeError ValidateD3D12TextureCanBeWrapped(ID3D12Resource* d3d12Resource,
                                                const TextureDescriptor* dawnDescriptor) {
        const D3D12_RESOURCE_DESC d3dDescriptor = d3d12Resource->GetDesc();
        if ((dawnDescriptor->size.width != d3dDescriptor.Width) ||
            (dawnDescriptor->size.height != d3dDescriptor.Height) ||
            (dawnDescriptor->size.depth != 1)) {
            return DAWN_VALIDATION_ERROR("D3D12 texture size doesn't match descriptor");
        }

        const DXGI_FORMAT dxgiFormatFromDescriptor = D3D12TextureFormat(dawnDescriptor->format);
        if (dxgiFormatFromDescriptor != d3dDescriptor.Format) {
            return DAWN_VALIDATION_ERROR(
                "D3D12 texture format must be compatible with descriptor format.");
        }

        if (d3dDescriptor.MipLevels != 1) {
            return DAWN_VALIDATION_ERROR("D3D12 texture number of miplevels must be 1.");
        }

        if (d3dDescriptor.DepthOrArraySize != 1) {
            return DAWN_VALIDATION_ERROR("D3D12 texture array size must be 1.");
        }

        // Shared textures cannot be multi-sample so no need to check those.
        ASSERT(d3dDescriptor.SampleDesc.Count == 1);
        ASSERT(d3dDescriptor.SampleDesc.Quality == 0);

        return {};
    }

    ResultOrError<TextureBase*> Texture::Create(Device* device,
                                                const TextureDescriptor* descriptor) {
        Ref<Texture> dawnTexture =
            AcquireRef(new Texture(device, descriptor, TextureState::OwnedInternal));
        DAWN_TRY(dawnTexture->InitializeAsInternalTexture());
        return dawnTexture.Detach();
    }

    ResultOrError<TextureBase*> Texture::Create(Device* device,
                                                const ExternalImageDescriptor* descriptor,
                                                HANDLE sharedHandle,
                                                uint64_t acquireMutexKey,
                                                bool isSwapChainTexture) {
        const TextureDescriptor* textureDescriptor =
            reinterpret_cast<const TextureDescriptor*>(descriptor->cTextureDescriptor);

        Ref<Texture> dawnTexture =
            AcquireRef(new Texture(device, textureDescriptor, TextureState::OwnedExternal));
        DAWN_TRY(dawnTexture->InitializeAsExternalTexture(textureDescriptor, sharedHandle,
                                                          acquireMutexKey, isSwapChainTexture));

        dawnTexture->SetIsSubresourceContentInitialized(descriptor->isCleared, 0,
                                                        textureDescriptor->mipLevelCount, 0,
                                                        textureDescriptor->arrayLayerCount);
        return dawnTexture.Detach();
    }

    MaybeError Texture::InitializeAsExternalTexture(const TextureDescriptor* descriptor,
                                                    HANDLE sharedHandle,
                                                    uint64_t acquireMutexKey,
                                                    bool isSwapChainTexture) {
        Device* dawnDevice = ToBackend(GetDevice());
        DAWN_TRY(ValidateTextureDescriptor(dawnDevice, descriptor));
        DAWN_TRY(ValidateTextureDescriptorCanBeWrapped(descriptor));

        ComPtr<ID3D12Resource> d3d12Resource;
        DAWN_TRY(CheckHRESULT(dawnDevice->GetD3D12Device()->OpenSharedHandle(
                                  sharedHandle, IID_PPV_ARGS(&d3d12Resource)),
                              "D3D12 opening shared handle"));

        DAWN_TRY(ValidateD3D12TextureCanBeWrapped(d3d12Resource.Get(), descriptor));

        ComPtr<IDXGIKeyedMutex> dxgiKeyedMutex;
        DAWN_TRY_ASSIGN(dxgiKeyedMutex,
                        dawnDevice->CreateKeyedMutexForTexture(d3d12Resource.Get()));

        DAWN_TRY(CheckHRESULT(dxgiKeyedMutex->AcquireSync(acquireMutexKey, INFINITE),
                              "D3D12 acquiring shared mutex"));

        mAcquireMutexKey = acquireMutexKey;
        mDxgiKeyedMutex = std::move(dxgiKeyedMutex);
        mSwapChainTexture = isSwapChainTexture;

        AllocationInfo info;
        info.mMethod = AllocationMethod::kExternal;
        // When creating the ResourceHeapAllocation, the resource heap is set to nullptr because the
        // texture is owned externally. The texture's owning entity must remain responsible for
        // memory management.
        mResourceAllocation = {info, 0, std::move(d3d12Resource), nullptr};

        return {};
    }

    MaybeError Texture::InitializeAsInternalTexture() {
        D3D12_RESOURCE_DESC resourceDescriptor;
        resourceDescriptor.Dimension = D3D12TextureDimension(GetDimension());
        resourceDescriptor.Alignment = 0;

        const Extent3D& size = GetSize();
        resourceDescriptor.Width = size.width;
        resourceDescriptor.Height = size.height;

        resourceDescriptor.DepthOrArraySize = GetDepthOrArraySize();
        resourceDescriptor.MipLevels = static_cast<UINT16>(GetNumMipLevels());
        resourceDescriptor.Format = D3D12TextureFormat(GetFormat().format);
        resourceDescriptor.SampleDesc.Count = GetSampleCount();
        // TODO(bryan.bernhart@intel.com): investigate how to specify standard MSAA sample pattern.
        resourceDescriptor.SampleDesc.Quality = 0;
        resourceDescriptor.Layout = D3D12_TEXTURE_LAYOUT_UNKNOWN;
        resourceDescriptor.Flags =
            D3D12ResourceFlags(GetUsage(), GetFormat(), IsMultisampledTexture());

        DAWN_TRY_ASSIGN(mResourceAllocation,
                        ToBackend(GetDevice())
                            ->AllocateMemory(D3D12_HEAP_TYPE_DEFAULT, resourceDescriptor,
                                             D3D12_RESOURCE_STATE_COMMON));

        Device* device = ToBackend(GetDevice());

        if (device->IsToggleEnabled(Toggle::NonzeroClearResourcesOnCreationForTesting)) {
            CommandRecordingContext* commandContext;
            DAWN_TRY_ASSIGN(commandContext, device->GetPendingCommandContext());

            DAWN_TRY(ClearTexture(commandContext, 0, GetNumMipLevels(), 0, GetArrayLayers(),
                                  TextureBase::ClearValue::NonZero));
        }

        return {};
    }

    Texture::Texture(Device* device,
                     const TextureDescriptor* descriptor,
                     ComPtr<ID3D12Resource> nativeTexture)
        : TextureBase(device, descriptor, TextureState::OwnedExternal) {
        AllocationInfo info;
        info.mMethod = AllocationMethod::kExternal;
        // When creating the ResourceHeapAllocation, the resource heap is set to nullptr because the
        // texture is owned externally. The texture's owning entity must remain responsible for
        // memory management.
        mResourceAllocation = {info, 0, std::move(nativeTexture), nullptr};

        SetIsSubresourceContentInitialized(true, 0, descriptor->mipLevelCount, 0,
                                           descriptor->arrayLayerCount);
    }

    Texture::~Texture() {
        DestroyInternal();
    }

    void Texture::DestroyImpl() {
        Device* device = ToBackend(GetDevice());

        // In PIX's D3D12-only mode, there is no way to determine frame boundaries
        // for WebGPU since Dawn does not manage DXGI swap chains. Without assistance,
        // PIX will wait forever for a present that never happens.
        // If we know we're dealing with a swapbuffer texture, inform PIX we've
        // "presented" the texture so it can determine frame boundaries and use its
        // contents for the UI.
        if (mSwapChainTexture) {
            ID3D12SharingContract* d3dSharingContract = device->GetSharingContract();
            if (d3dSharingContract != nullptr) {
                d3dSharingContract->Present(mResourceAllocation.GetD3D12Resource().Get(), 0, 0);
            }
        }

        device->DeallocateMemory(mResourceAllocation);

        if (mDxgiKeyedMutex != nullptr) {
            mDxgiKeyedMutex->ReleaseSync(mAcquireMutexKey + 1);
            device->ReleaseKeyedMutexForTexture(std::move(mDxgiKeyedMutex));
        }
    }

    DXGI_FORMAT Texture::GetD3D12Format() const {
        return D3D12TextureFormat(GetFormat().format);
    }

    ID3D12Resource* Texture::GetD3D12Resource() const {
        return mResourceAllocation.GetD3D12Resource().Get();
    }

    UINT16 Texture::GetDepthOrArraySize() {
        switch (GetDimension()) {
            case wgpu::TextureDimension::e2D:
                return static_cast<UINT16>(GetArrayLayers());
            default:
                UNREACHABLE();
        }
    }

    // When true is returned, a D3D12_RESOURCE_BARRIER has been created and must be used in a
    // ResourceBarrier call. Failing to do so will cause the tracked state to become invalid and can
    // cause subsequent errors.
    bool Texture::TrackUsageAndGetResourceBarrier(CommandRecordingContext* commandContext,
                                                  D3D12_RESOURCE_BARRIER* barrier,
                                                  wgpu::TextureUsage newUsage) {
        return TrackUsageAndGetResourceBarrier(commandContext, barrier,
                                               D3D12TextureUsage(newUsage, GetFormat()));
    }

    // When true is returned, a D3D12_RESOURCE_BARRIER has been created and must be used in a
    // ResourceBarrier call. Failing to do so will cause the tracked state to become invalid and can
    // cause subsequent errors.
    bool Texture::TrackUsageAndGetResourceBarrier(CommandRecordingContext* commandContext,
                                                  D3D12_RESOURCE_BARRIER* barrier,
                                                  D3D12_RESOURCE_STATES newState) {
        if (mResourceAllocation.GetInfo().mMethod != AllocationMethod::kExternal) {
            // Track the underlying heap to ensure residency.
            Heap* heap = ToBackend(mResourceAllocation.GetResourceHeap());
            commandContext->TrackHeapUsage(heap, GetDevice()->GetPendingCommandSerial());
        }

        // Return the resource barrier.
        return TransitionUsageAndGetResourceBarrier(commandContext, barrier, newState);
    }

    void Texture::TrackUsageAndTransitionNow(CommandRecordingContext* commandContext,
                                             wgpu::TextureUsage usage) {
        D3D12_RESOURCE_BARRIER barrier;

        if (TrackUsageAndGetResourceBarrier(commandContext, &barrier, usage)) {
            commandContext->GetCommandList()->ResourceBarrier(1, &barrier);
        }
    }

    void Texture::TrackUsageAndTransitionNow(CommandRecordingContext* commandContext,
                                             D3D12_RESOURCE_STATES newState) {
        D3D12_RESOURCE_BARRIER barrier;

        if (TrackUsageAndGetResourceBarrier(commandContext, &barrier, newState)) {
            commandContext->GetCommandList()->ResourceBarrier(1, &barrier);
        }
    }

    // When true is returned, a D3D12_RESOURCE_BARRIER has been created and must be used in a
    // ResourceBarrier call. Failing to do so will cause the tracked state to become invalid and can
    // cause subsequent errors.
    bool Texture::TransitionUsageAndGetResourceBarrier(CommandRecordingContext* commandContext,
                                                       D3D12_RESOURCE_BARRIER* barrier,
                                                       D3D12_RESOURCE_STATES newState) {
        // Textures with keyed mutexes can be written from other graphics queues. Hence, they
        // must be acquired before command list submission to ensure work from the other queues
        // has finished. See Device::ExecuteCommandContext.
        if (mDxgiKeyedMutex != nullptr) {
            commandContext->AddToSharedTextureList(this);
        }

        // Avoid transitioning the texture when it isn't needed.
        // TODO(cwallez@chromium.org): Need some form of UAV barriers at some point.
        if (mLastState == newState) {
            return false;
        }

        D3D12_RESOURCE_STATES lastState = mLastState;

        // The COMMON state represents a state where no write operations can be pending, and where
        // all pixels are uncompressed. This makes it possible to transition to and from some states
        // without synchronization (i.e. without an explicit ResourceBarrier call). Textures can be
        // implicitly promoted to 1) a single write state, or 2) multiple read states. Textures will
        // implicitly decay to the COMMON state when all of the following are true: 1) the texture
        // is accessed on a command list, 2) the ExecuteCommandLists call that uses that command
        // list has ended, and 3) the texture was promoted implicitly to a read-only state and is
        // still in that state.
        // https://docs.microsoft.com/en-us/windows/desktop/direct3d12/using-resource-barriers-to-synchronize-resource-states-in-direct3d-12#implicit-state-transitions

        // To track implicit decays, we must record the pending serial on which that transition will
        // occur. When that texture is used again, the previously recorded serial must be compared
        // to the last completed serial to determine if the texture has implicity decayed to the
        // common state.
        const Serial pendingCommandSerial = ToBackend(GetDevice())->GetPendingCommandSerial();
        if (mValidToDecay && pendingCommandSerial > mLastUsedSerial) {
            lastState = D3D12_RESOURCE_STATE_COMMON;
        }

        // Update the tracked state.
        mLastState = newState;

        // Destination states that qualify for an implicit promotion for a non-simultaneous-access
        // texture: NON_PIXEL_SHADER_RESOURCE, PIXEL_SHADER_RESOURCE, COPY_SRC, COPY_DEST.
        {
            static constexpr D3D12_RESOURCE_STATES kD3D12TextureReadOnlyStates =
                D3D12_RESOURCE_STATE_COPY_SOURCE | D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE |
                D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE;

            if (lastState == D3D12_RESOURCE_STATE_COMMON) {
                if (newState == (newState & kD3D12TextureReadOnlyStates)) {
                    // Implicit texture state decays can only occur when the texture was implicitly
                    // transitioned to a read-only state. mValidToDecay is needed to differentiate
                    // between resources that were implictly or explicitly transitioned to a
                    // read-only state.
                    mValidToDecay = true;
                    mLastUsedSerial = pendingCommandSerial;
                    return false;
                } else if (newState == D3D12_RESOURCE_STATE_COPY_DEST) {
                    mValidToDecay = false;
                    return false;
                }
            }
        }

        barrier->Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
        barrier->Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
        barrier->Transition.pResource = GetD3D12Resource();
        barrier->Transition.StateBefore = lastState;
        barrier->Transition.StateAfter = newState;
        barrier->Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;

        mValidToDecay = false;

        return true;
    }

    D3D12_RENDER_TARGET_VIEW_DESC Texture::GetRTVDescriptor(uint32_t mipLevel,
                                                            uint32_t baseArrayLayer,
                                                            uint32_t layerCount) const {
        ASSERT(GetDimension() == wgpu::TextureDimension::e2D);
        D3D12_RENDER_TARGET_VIEW_DESC rtvDesc;
        rtvDesc.Format = GetD3D12Format();
        if (IsMultisampledTexture()) {
            ASSERT(GetNumMipLevels() == 1);
            ASSERT(layerCount == 1);
            ASSERT(baseArrayLayer == 0);
            ASSERT(mipLevel == 0);
            rtvDesc.ViewDimension = D3D12_RTV_DIMENSION_TEXTURE2DMS;
        } else {
            // Currently we always use D3D12_TEX2D_ARRAY_RTV because we cannot specify base array
            // layer and layer count in D3D12_TEX2D_RTV. For 2D texture views, we treat them as
            // 1-layer 2D array textures. (Just like how we treat SRVs)
            // https://docs.microsoft.com/en-us/windows/desktop/api/d3d12/ns-d3d12-d3d12_tex2d_rtv
            // https://docs.microsoft.com/en-us/windows/desktop/api/d3d12/ns-d3d12-d3d12_tex2d_array
            // _rtv
            rtvDesc.ViewDimension = D3D12_RTV_DIMENSION_TEXTURE2DARRAY;
            rtvDesc.Texture2DArray.FirstArraySlice = baseArrayLayer;
            rtvDesc.Texture2DArray.ArraySize = layerCount;
            rtvDesc.Texture2DArray.MipSlice = mipLevel;
            rtvDesc.Texture2DArray.PlaneSlice = 0;
        }
        return rtvDesc;
    }

    D3D12_DEPTH_STENCIL_VIEW_DESC Texture::GetDSVDescriptor(uint32_t mipLevel,
                                                            uint32_t baseArrayLayer,
                                                            uint32_t layerCount) const {
        D3D12_DEPTH_STENCIL_VIEW_DESC dsvDesc;
        dsvDesc.Format = GetD3D12Format();
        dsvDesc.Flags = D3D12_DSV_FLAG_NONE;

        if (IsMultisampledTexture()) {
            ASSERT(GetNumMipLevels() == 1);
            ASSERT(layerCount == 1);
            ASSERT(baseArrayLayer == 0);
            ASSERT(mipLevel == 0);
            dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2DMS;
        } else {
            dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2DARRAY;
            dsvDesc.Texture2DArray.FirstArraySlice = baseArrayLayer;
            dsvDesc.Texture2DArray.ArraySize = layerCount;
            dsvDesc.Texture2DArray.MipSlice = mipLevel;
        }

        return dsvDesc;
    }

    MaybeError Texture::ClearTexture(CommandRecordingContext* commandContext,
                                     uint32_t baseMipLevel,
                                     uint32_t levelCount,
                                     uint32_t baseArrayLayer,
                                     uint32_t layerCount,
                                     TextureBase::ClearValue clearValue) {
        // TODO(jiawei.shao@intel.com): initialize the textures in compressed formats with copies.
        if (GetFormat().isCompressed) {
            SetIsSubresourceContentInitialized(true, baseMipLevel, levelCount, baseArrayLayer,
                                               layerCount);
            return {};
        }

        ID3D12GraphicsCommandList* commandList = commandContext->GetCommandList();

        Device* device = ToBackend(GetDevice());

        uint8_t clearColor = (clearValue == TextureBase::ClearValue::Zero) ? 0 : 1;
        float fClearColor = (clearValue == TextureBase::ClearValue::Zero) ? 0.f : 1.f;

        if (GetFormat().isRenderable) {
            if (GetFormat().HasDepthOrStencil()) {
                TrackUsageAndTransitionNow(commandContext, D3D12_RESOURCE_STATE_DEPTH_WRITE);

                D3D12_CLEAR_FLAGS clearFlags = {};

                for (uint32_t level = baseMipLevel; level < baseMipLevel + levelCount; ++level) {
                    for (uint32_t layer = baseArrayLayer; layer < baseArrayLayer + layerCount;
                         ++layer) {
                        if (clearValue == TextureBase::ClearValue::Zero &&
                            IsSubresourceContentInitialized(level, 1, layer, 1)) {
                            // Skip lazy clears if already initialized.
                            continue;
                        }

                        CPUDescriptorHeapAllocation dsvHandle;
                        DAWN_TRY_ASSIGN(dsvHandle, device->GetDepthStencilViewAllocator()
                                                       ->AllocateTransientCPUDescriptors());
                        const D3D12_CPU_DESCRIPTOR_HANDLE baseDescriptor =
                            dsvHandle.GetBaseDescriptor();
                        D3D12_DEPTH_STENCIL_VIEW_DESC dsvDesc = GetDSVDescriptor(level, layer, 1);
                        device->GetD3D12Device()->CreateDepthStencilView(GetD3D12Resource(),
                                                                         &dsvDesc, baseDescriptor);

                        if (GetFormat().HasDepth()) {
                            clearFlags |= D3D12_CLEAR_FLAG_DEPTH;
                        }
                        if (GetFormat().HasStencil()) {
                            clearFlags |= D3D12_CLEAR_FLAG_STENCIL;
                        }

                        commandList->ClearDepthStencilView(baseDescriptor, clearFlags, fClearColor,
                                                           clearColor, 0, nullptr);
                    }
                }
            } else {
                TrackUsageAndTransitionNow(commandContext, D3D12_RESOURCE_STATE_RENDER_TARGET);

                const float clearColorRGBA[4] = {fClearColor, fClearColor, fClearColor,
                                                 fClearColor};

                for (uint32_t level = baseMipLevel; level < baseMipLevel + levelCount; ++level) {
                    for (uint32_t layer = baseArrayLayer; layer < baseArrayLayer + layerCount;
                         ++layer) {
                        if (clearValue == TextureBase::ClearValue::Zero &&
                            IsSubresourceContentInitialized(level, 1, layer, 1)) {
                            // Skip lazy clears if already initialized.
                            continue;
                        }

                        CPUDescriptorHeapAllocation rtvHeap;
                        DAWN_TRY_ASSIGN(rtvHeap, device->GetRenderTargetViewAllocator()
                                                     ->AllocateTransientCPUDescriptors());
                        const D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = rtvHeap.GetBaseDescriptor();

                        D3D12_RENDER_TARGET_VIEW_DESC rtvDesc = GetRTVDescriptor(level, layer, 1);
                        device->GetD3D12Device()->CreateRenderTargetView(GetD3D12Resource(),
                                                                         &rtvDesc, rtvHandle);
                        commandList->ClearRenderTargetView(rtvHandle, clearColorRGBA, 0, nullptr);
                    }
                }
            }
        } else {
            // TODO(natlee@microsoft.com): test compressed textures are cleared
            // create temp buffer with clear color to copy to the texture image
            uint32_t rowPitch =
                Align((GetSize().width / GetFormat().blockWidth) * GetFormat().blockByteSize,
                      kTextureRowPitchAlignment);
            uint64_t bufferSize64 = rowPitch * (GetSize().height / GetFormat().blockHeight);
            if (bufferSize64 > std::numeric_limits<uint32_t>::max()) {
                return DAWN_OUT_OF_MEMORY_ERROR("Unable to allocate buffer.");
            }
            uint32_t bufferSize = static_cast<uint32_t>(bufferSize64);
            DynamicUploader* uploader = device->GetDynamicUploader();
            UploadHandle uploadHandle;
            DAWN_TRY_ASSIGN(uploadHandle,
                            uploader->Allocate(bufferSize, device->GetPendingCommandSerial()));
            memset(uploadHandle.mappedBuffer, clearColor, bufferSize);

            TrackUsageAndTransitionNow(commandContext, D3D12_RESOURCE_STATE_COPY_DEST);

            for (uint32_t level = baseMipLevel; level < baseMipLevel + levelCount; ++level) {
                // compute d3d12 texture copy locations for texture and buffer
                Extent3D copySize = GetMipLevelVirtualSize(level);
                TextureCopySplit copySplit = ComputeTextureCopySplit(
                    {0, 0, 0}, copySize, GetFormat(), uploadHandle.startOffset, rowPitch, 0);

                for (uint32_t layer = baseArrayLayer; layer < baseArrayLayer + layerCount;
                     ++layer) {
                    if (clearValue == TextureBase::ClearValue::Zero &&
                        IsSubresourceContentInitialized(level, 1, layer, 1)) {
                        // Skip lazy clears if already initialized.
                        continue;
                    }

                    D3D12_TEXTURE_COPY_LOCATION textureLocation =
                        ComputeTextureCopyLocationForTexture(this, level, layer);
                    for (uint32_t i = 0; i < copySplit.count; ++i) {
                        TextureCopySplit::CopyInfo& info = copySplit.copies[i];

                        D3D12_TEXTURE_COPY_LOCATION bufferLocation =
                            ComputeBufferLocationForCopyTextureRegion(
                                this, ToBackend(uploadHandle.stagingBuffer)->GetResource(),
                                info.bufferSize, copySplit.offset, rowPitch);
                        D3D12_BOX sourceRegion =
                            ComputeD3D12BoxFromOffsetAndSize(info.bufferOffset, info.copySize);

                        // copy the buffer filled with clear color to the texture
                        commandList->CopyTextureRegion(&textureLocation, info.textureOffset.x,
                                                       info.textureOffset.y, info.textureOffset.z,
                                                       &bufferLocation, &sourceRegion);
                    }
                }
            }
        }
        if (clearValue == TextureBase::ClearValue::Zero) {
            SetIsSubresourceContentInitialized(true, baseMipLevel, levelCount, baseArrayLayer,
                                               layerCount);
            GetDevice()->IncrementLazyClearCountForTesting();
        }
        return {};
    }

    void Texture::EnsureSubresourceContentInitialized(CommandRecordingContext* commandContext,
                                                      uint32_t baseMipLevel,
                                                      uint32_t levelCount,
                                                      uint32_t baseArrayLayer,
                                                      uint32_t layerCount) {
        if (!ToBackend(GetDevice())->IsToggleEnabled(Toggle::LazyClearResourceOnFirstUse)) {
            return;
        }
        if (!IsSubresourceContentInitialized(baseMipLevel, levelCount, baseArrayLayer,
                                             layerCount)) {
            // If subresource has not been initialized, clear it to black as it could contain
            // dirty bits from recycled memory
            GetDevice()->ConsumedError(ClearTexture(commandContext, baseMipLevel, levelCount,
                                                    baseArrayLayer, layerCount,
                                                    TextureBase::ClearValue::Zero));
        }
    }

    TextureView::TextureView(TextureBase* texture, const TextureViewDescriptor* descriptor)
        : TextureViewBase(texture, descriptor) {
        mSrvDesc.Format = D3D12TextureFormat(descriptor->format);
        mSrvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;

        // Currently we always use D3D12_TEX2D_ARRAY_SRV because we cannot specify base array layer
        // and layer count in D3D12_TEX2D_SRV. For 2D texture views, we treat them as 1-layer 2D
        // array textures.
        // https://docs.microsoft.com/en-us/windows/desktop/api/d3d12/ns-d3d12-d3d12_tex2d_srv
        // https://docs.microsoft.com/en-us/windows/desktop/api/d3d12/ns-d3d12-d3d12_tex2d_array_srv
        // TODO(jiawei.shao@intel.com): support more texture view dimensions.
        // TODO(jiawei.shao@intel.com): support creating SRV on multisampled textures.
        switch (descriptor->dimension) {
            case wgpu::TextureViewDimension::e2D:
            case wgpu::TextureViewDimension::e2DArray:
                ASSERT(texture->GetDimension() == wgpu::TextureDimension::e2D);
                mSrvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2DARRAY;
                mSrvDesc.Texture2DArray.ArraySize = descriptor->arrayLayerCount;
                mSrvDesc.Texture2DArray.FirstArraySlice = descriptor->baseArrayLayer;
                mSrvDesc.Texture2DArray.MipLevels = descriptor->mipLevelCount;
                mSrvDesc.Texture2DArray.MostDetailedMip = descriptor->baseMipLevel;
                mSrvDesc.Texture2DArray.PlaneSlice = 0;
                mSrvDesc.Texture2DArray.ResourceMinLODClamp = 0;
                break;
            case wgpu::TextureViewDimension::Cube:
            case wgpu::TextureViewDimension::CubeArray:
                ASSERT(texture->GetDimension() == wgpu::TextureDimension::e2D);
                ASSERT(descriptor->arrayLayerCount % 6 == 0);
                mSrvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURECUBEARRAY;
                mSrvDesc.TextureCubeArray.First2DArrayFace = descriptor->baseArrayLayer;
                mSrvDesc.TextureCubeArray.NumCubes = descriptor->arrayLayerCount / 6;
                mSrvDesc.TextureCubeArray.MostDetailedMip = descriptor->baseMipLevel;
                mSrvDesc.TextureCubeArray.MipLevels = descriptor->mipLevelCount;
                mSrvDesc.TextureCubeArray.ResourceMinLODClamp = 0;
                break;
            default:
                UNREACHABLE();
        }
    }

    DXGI_FORMAT TextureView::GetD3D12Format() const {
        return D3D12TextureFormat(GetFormat().format);
    }

    const D3D12_SHADER_RESOURCE_VIEW_DESC& TextureView::GetSRVDescriptor() const {
        return mSrvDesc;
    }

    D3D12_RENDER_TARGET_VIEW_DESC TextureView::GetRTVDescriptor() const {
        return ToBackend(GetTexture())
            ->GetRTVDescriptor(GetBaseMipLevel(), GetBaseArrayLayer(), GetLayerCount());
    }

    D3D12_DEPTH_STENCIL_VIEW_DESC TextureView::GetDSVDescriptor() const {
        // TODO(jiawei.shao@intel.com): support rendering into a layer of a texture.
        ASSERT(GetLevelCount() == 1);
        uint32_t mipLevel = GetBaseMipLevel();
        return ToBackend(GetTexture())
            ->GetDSVDescriptor(mipLevel, GetBaseArrayLayer(), GetLayerCount());
    }

}}  // namespace dawn_native::d3d12