RenderCompositorANGLE.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "RenderCompositorANGLE.h"

#include "GLContext.h"
#include "GLContextEGL.h"
#include "GLContextProvider.h"
#include "mozilla/gfx/DeviceManagerDx.h"
#include "mozilla/gfx/gfxVars.h"
#include "mozilla/gfx/Logging.h"
#include "mozilla/gfx/StackArray.h"
#include "mozilla/layers/HelpersD3D11.h"
#include "mozilla/layers/SyncObject.h"
#include "mozilla/StaticPrefs_gfx.h"
#include "mozilla/webrender/DCLayerTree.h"
#include "mozilla/webrender/RenderThread.h"
#include "mozilla/widget/CompositorWidget.h"
#include "mozilla/widget/WinCompositorWidget.h"
#include "mozilla/WindowsVersion.h"
#include "mozilla/Telemetry.h"
#include "FxROutputHandler.h"

#undef NTDDI_VERSION
#define NTDDI_VERSION NTDDI_WIN8

#include <d3d11.h>
#include <dcomp.h>
#include <dxgi1_2.h>

// Flag for PrintWindow() that is defined in Winuser.h. It is defined since
// Windows 8.1. This allows PrintWindow to capture window content that is
// rendered with DirectComposition.
#undef PW_RENDERFULLCONTENT
#define PW_RENDERFULLCONTENT 0x00000002

namespace mozilla {
namespace wr {

/* static */
UniquePtr<RenderCompositor> RenderCompositorANGLE::Create(
    RefPtr<widget::CompositorWidget>&& aWidget) {
  const auto& gl = RenderThread::Get()->SharedGL();
  if (!gl) {
    gfxCriticalNote << "Failed to get shared GL context";
    return nullptr;
  }

  UniquePtr<RenderCompositorANGLE> compositor =
      MakeUnique<RenderCompositorANGLE>(std::move(aWidget));
  if (!compositor->Initialize()) {
    return nullptr;
  }
  return compositor;
}

RenderCompositorANGLE::RenderCompositorANGLE(
    RefPtr<widget::CompositorWidget>&& aWidget)
    : RenderCompositor(std::move(aWidget)),
      mEGLConfig(nullptr),
      mEGLSurface(nullptr),
      mUseTripleBuffering(false),
      mUseAlpha(false),
      mUseNativeCompositor(true),
      mUsePartialPresent(false),
      mFullRender(false),
      mDisablingNativeCompositor(false) {}

RenderCompositorANGLE::~RenderCompositorANGLE() {
  DestroyEGLSurface();
  MOZ_ASSERT(!mEGLSurface);
}

ID3D11Device* RenderCompositorANGLE::GetDeviceOfEGLDisplay() {
  auto* egl = gl::GLLibraryEGL::Get();
  MOZ_ASSERT(egl);
  if (!egl || !egl->IsExtensionSupported(gl::GLLibraryEGL::EXT_device_query)) {
    return nullptr;
  }

  // Fetch the D3D11 device.
  EGLDeviceEXT eglDevice = nullptr;
  egl->fQueryDisplayAttribEXT(egl->Display(), LOCAL_EGL_DEVICE_EXT,
                              (EGLAttrib*)&eglDevice);
  MOZ_ASSERT(eglDevice);
  ID3D11Device* device = nullptr;
  egl->fQueryDeviceAttribEXT(eglDevice, LOCAL_EGL_D3D11_DEVICE_ANGLE,
                             (EGLAttrib*)&device);
  if (!device) {
    gfxCriticalNote << "Failed to get D3D11Device from EGLDisplay";
    return nullptr;
  }
  return device;
}

bool RenderCompositorANGLE::SutdownEGLLibraryIfNecessary() {
  const RefPtr<gl::GLLibraryEGL> egl = gl::GLLibraryEGL::Get();
  if (!egl) {
    // egl is not initialized yet;
    return true;
  }

  RefPtr<ID3D11Device> device =
      gfx::DeviceManagerDx::Get()->GetCompositorDevice();
  // When DeviceReset is handled by GPUProcessManager/GPUParent,
  // CompositorDevice is updated to a new device. EGLDisplay also needs to be
  // updated, since EGLDisplay uses DeviceManagerDx::mCompositorDevice on ANGLE
  // WebRender use case. EGLDisplay could be updated when Renderer count becomes
  // 0. It is ensured by GPUProcessManager during handling DeviceReset.
  // GPUChild::RecvNotifyDeviceReset() destroys all CompositorSessions before
  // re-creating them.
  if (device.get() != GetDeviceOfEGLDisplay() &&
      RenderThread::Get()->RendererCount() == 0) {
    // Shutdown GLLibraryEGL for updating EGLDisplay.
    RenderThread::Get()->ClearSharedGL();
    egl->Shutdown();
  }
  return true;
}

bool RenderCompositorANGLE::Initialize() {
  if (RenderThread::Get()->IsHandlingDeviceReset()) {
    gfxCriticalNote << "Waiting for handling device reset";
    return false;
  }

  // Update device if necessary.
  if (!SutdownEGLLibraryIfNecessary()) {
    return false;
  }
  const auto gl = RenderThread::Get()->SharedGL();
  if (!gl) {
    gfxCriticalNote << "[WR] failed to get shared GL context.";
    return false;
  }

  // Force enable alpha channel to make sure ANGLE use correct framebuffer
  // formart
  const auto& gle = gl::GLContextEGL::Cast(gl);
  const auto& egl = gle->mEgl;
  if (!gl::CreateConfig(egl, &mEGLConfig, /* bpp */ 32,
                        /* enableDepthBuffer */ true)) {
    gfxCriticalNote << "Failed to create EGLConfig for WebRender";
  }
  MOZ_ASSERT(mEGLConfig);

  mDevice = GetDeviceOfEGLDisplay();

  if (!mDevice) {
    gfxCriticalNote << "[WR] failed to get compositor device.";
    return false;
  }

  mDevice->GetImmediateContext(getter_AddRefs(mCtx));
  if (!mCtx) {
    gfxCriticalNote << "[WR] failed to get immediate context.";
    return false;
  }

  // Create DCLayerTree when DirectComposition is used.
  if (gfx::gfxVars::UseWebRenderDCompWin()) {
    HWND compositorHwnd = mWidget->AsWindows()->GetCompositorHwnd();
    if (compositorHwnd) {
      mDCLayerTree =
          DCLayerTree::Create(gl, mEGLConfig, mDevice, compositorHwnd);
    } else {
      gfxCriticalNote << "Compositor window was not created";
    }
  }

  // Create SwapChain when compositor is not used
  if (!UseCompositor()) {
    if (!CreateSwapChain()) {
      // SwapChain creation failed.
      return false;
    }
  }

  mSyncObject = layers::SyncObjectHost::CreateSyncObjectHost(mDevice);
  if (!mSyncObject->Init()) {
    // Some errors occur. Clear the mSyncObject here.
    // Then, there will be no texture synchronization.
    return false;
  }

  InitializeUsePartialPresent();

  return true;
}

bool RenderCompositorANGLE::CreateSwapChain() {
  MOZ_ASSERT(!UseCompositor());

  HWND hwnd = mWidget->AsWindows()->GetHwnd();

  RefPtr<IDXGIDevice> dxgiDevice;
  mDevice->QueryInterface((IDXGIDevice**)getter_AddRefs(dxgiDevice));

  RefPtr<IDXGIFactory> dxgiFactory;
  {
    RefPtr<IDXGIAdapter> adapter;
    dxgiDevice->GetAdapter(getter_AddRefs(adapter));

    adapter->GetParent(
        IID_PPV_ARGS((IDXGIFactory**)getter_AddRefs(dxgiFactory)));
  }

  RefPtr<IDXGIFactory2> dxgiFactory2;
  HRESULT hr = dxgiFactory->QueryInterface(
      (IDXGIFactory2**)getter_AddRefs(dxgiFactory2));
  if (FAILED(hr)) {
    dxgiFactory2 = nullptr;
  }

  CreateSwapChainForDCompIfPossible(dxgiFactory2);

  if (!mSwapChain && dxgiFactory2 && IsWin8OrLater()) {
    RefPtr<IDXGISwapChain1> swapChain1;
    bool useTripleBuffering = false;

    DXGI_SWAP_CHAIN_DESC1 desc{};
    desc.Width = 0;
    desc.Height = 0;
    desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    desc.SampleDesc.Count = 1;
    desc.SampleDesc.Quality = 0;
    desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;

    if (gfx::gfxVars::UseWebRenderFlipSequentialWin()) {
      useTripleBuffering = gfx::gfxVars::UseWebRenderTripleBufferingWin();
      if (useTripleBuffering) {
        desc.BufferCount = 3;
      } else {
        desc.BufferCount = 2;
      }
      desc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
    } else {
      desc.BufferCount = 1;
      desc.SwapEffect = DXGI_SWAP_EFFECT_SEQUENTIAL;
    }
    desc.Scaling = DXGI_SCALING_NONE;
    desc.Flags = 0;

    hr = dxgiFactory2->CreateSwapChainForHwnd(
        mDevice, hwnd, &desc, nullptr, nullptr, getter_AddRefs(swapChain1));
    if (SUCCEEDED(hr) && swapChain1) {
      DXGI_RGBA color = {1.0f, 1.0f, 1.0f, 1.0f};
      swapChain1->SetBackgroundColor(&color);
      mSwapChain = swapChain1;
      mSwapChain1 = swapChain1;
      mUseTripleBuffering = useTripleBuffering;
    }
  }

  if (!mSwapChain) {
    DXGI_SWAP_CHAIN_DESC swapDesc{};
    swapDesc.BufferDesc.Width = 0;
    swapDesc.BufferDesc.Height = 0;
    swapDesc.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    swapDesc.BufferDesc.RefreshRate.Numerator = 60;
    swapDesc.BufferDesc.RefreshRate.Denominator = 1;
    swapDesc.SampleDesc.Count = 1;
    swapDesc.SampleDesc.Quality = 0;
    swapDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapDesc.BufferCount = 1;
    swapDesc.OutputWindow = hwnd;
    swapDesc.Windowed = TRUE;
    swapDesc.Flags = 0;
    swapDesc.SwapEffect = DXGI_SWAP_EFFECT_SEQUENTIAL;

    HRESULT hr = dxgiFactory->CreateSwapChain(dxgiDevice, &swapDesc,
                                              getter_AddRefs(mSwapChain));
    if (FAILED(hr)) {
      gfxCriticalNote << "Could not create swap chain: " << gfx::hexa(hr);
      return false;
    }

    RefPtr<IDXGISwapChain1> swapChain1;
    hr = mSwapChain->QueryInterface(
        (IDXGISwapChain1**)getter_AddRefs(swapChain1));
    if (SUCCEEDED(hr)) {
      mSwapChain1 = swapChain1;
    }
  }

  // We need this because we don't want DXGI to respond to Alt+Enter.
  dxgiFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_WINDOW_CHANGES);

  if (!ResizeBufferIfNeeded()) {
    return false;
  }

  return true;
}

void RenderCompositorANGLE::CreateSwapChainForDCompIfPossible(
    IDXGIFactory2* aDXGIFactory2) {
  if (!aDXGIFactory2 || !mDCLayerTree) {
    return;
  }

  HWND hwnd = mWidget->AsWindows()->GetCompositorHwnd();
  if (!hwnd) {
    // When DirectComposition or DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL is used,
    // compositor window needs to exist.
    if (gfx::gfxVars::UseWebRenderDCompWin() ||
        gfx::gfxVars::UseWebRenderFlipSequentialWin()) {
      gfxCriticalNote << "Compositor window was not created";
    }
    return;
  }

  MOZ_ASSERT(XRE_IsGPUProcess());

  // When compositor is enabled, CompositionSurface is used for rendering.
  // It does not support triple buffering.
  bool useTripleBuffering =
      gfx::gfxVars::UseWebRenderTripleBufferingWin() && !UseCompositor();
  // Non Glass window is common since Windows 10.
  bool useAlpha = false;
  RefPtr<IDXGISwapChain1> swapChain1 =
      CreateSwapChainForDComp(useTripleBuffering, useAlpha);
  if (swapChain1) {
    mSwapChain = swapChain1;
    mSwapChain1 = swapChain1;
    mUseTripleBuffering = useTripleBuffering;
    mUseAlpha = useAlpha;
    mDCLayerTree->SetDefaultSwapChain(swapChain1);
  } else {
    // Clear CLayerTree on falire
    mDCLayerTree = nullptr;
  }
}

RefPtr<IDXGISwapChain1> RenderCompositorANGLE::CreateSwapChainForDComp(
    bool aUseTripleBuffering, bool aUseAlpha) {
  HRESULT hr;
  RefPtr<IDXGIDevice> dxgiDevice;
  mDevice->QueryInterface((IDXGIDevice**)getter_AddRefs(dxgiDevice));

  RefPtr<IDXGIFactory> dxgiFactory;
  {
    RefPtr<IDXGIAdapter> adapter;
    dxgiDevice->GetAdapter(getter_AddRefs(adapter));

    adapter->GetParent(
        IID_PPV_ARGS((IDXGIFactory**)getter_AddRefs(dxgiFactory)));
  }

  RefPtr<IDXGIFactory2> dxgiFactory2;
  hr = dxgiFactory->QueryInterface(
      (IDXGIFactory2**)getter_AddRefs(dxgiFactory2));
  if (FAILED(hr)) {
    return nullptr;
  }

  RefPtr<IDXGISwapChain1> swapChain1;
  DXGI_SWAP_CHAIN_DESC1 desc{};
  // DXGI does not like 0x0 swapchains. Swap chain creation failed when 0x0 was
  // set.
  desc.Width = 1;
  desc.Height = 1;
  desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
  desc.SampleDesc.Count = 1;
  desc.SampleDesc.Quality = 0;
  desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
  if (aUseTripleBuffering) {
    desc.BufferCount = 3;
  } else {
    desc.BufferCount = 2;
  }
  // DXGI_SCALING_NONE caused swap chain creation failure.
  desc.Scaling = DXGI_SCALING_STRETCH;
  desc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
  if (aUseAlpha) {
    // This could degrade performance. Use it only when it is necessary.
    desc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;
  } else {
    desc.AlphaMode = DXGI_ALPHA_MODE_IGNORE;
  }
  desc.Flags = 0;

  hr = dxgiFactory2->CreateSwapChainForComposition(mDevice, &desc, nullptr,
                                                   getter_AddRefs(swapChain1));
  if (SUCCEEDED(hr) && swapChain1) {
    DXGI_RGBA color = {1.0f, 1.0f, 1.0f, 1.0f};
    swapChain1->SetBackgroundColor(&color);
    return swapChain1;
  }

  return nullptr;
}

bool RenderCompositorANGLE::BeginFrame() {
  mWidget->AsWindows()->UpdateCompositorWndSizeIfNecessary();

  if (!UseCompositor()) {
    if (mDCLayerTree) {
      bool useAlpha = mWidget->AsWindows()->HasGlass();
      // When Alpha usage is changed, SwapChain needs to be recreatd.
      if (useAlpha != mUseAlpha) {
        DestroyEGLSurface();
        mBufferSize.reset();

        RefPtr<IDXGISwapChain1> swapChain1 =
            CreateSwapChainForDComp(mUseTripleBuffering, useAlpha);
        if (swapChain1) {
          mSwapChain = swapChain1;
          mUseAlpha = useAlpha;
          mDCLayerTree->SetDefaultSwapChain(swapChain1);
          // When alpha is used, we want to disable partial present.
          // See Bug 1595027.
          if (useAlpha) {
            mFullRender = true;
          }
        } else {
          gfxCriticalNote << "Failed to re-create SwapChain";
          RenderThread::Get()->HandleWebRenderError(
              WebRenderError::NEW_SURFACE);
          return false;
        }
      }
    }

    if (!ResizeBufferIfNeeded()) {
      return false;
    }
  }

  if (!MakeCurrent()) {
    gfxCriticalNote << "Failed to make render context current, can't draw.";
    return false;
  }

  if (mSyncObject) {
    if (!mSyncObject->Synchronize(/* aFallible */ true)) {
      // It's timeout or other error. Handle the device-reset here.
      RenderThread::Get()->HandleDeviceReset("SyncObject", /* aNotify */ true);
      return false;
    }
  }
  return true;
}

RenderedFrameId RenderCompositorANGLE::EndFrame(
    const nsTArray<DeviceIntRect>& aDirtyRects) {
  RenderedFrameId frameId = GetNextRenderFrameId();
  InsertGraphicsCommandsFinishedWaitQuery(frameId);

  if (!UseCompositor()) {
    auto start = TimeStamp::Now();
    if (mWidget->AsWindows()->HasFxrOutputHandler()) {
      // There is a Firefox Reality handler for this swapchain. Update this
      // window's contents to the VR window.
      FxROutputHandler* fxrHandler =
          mWidget->AsWindows()->GetFxrOutputHandler();
      if (fxrHandler->TryInitialize(mSwapChain, mDevice)) {
        fxrHandler->UpdateOutput(mCtx);
      }
    }

    const LayoutDeviceIntSize& bufferSize = mBufferSize.ref();

    // During high contrast mode, alpha is used. In this case,
    // IDXGISwapChain1::Present1 shows nothing with compositor window.
    // In this case, we want to disable partial present by full render.
    // See Bug 1595027
    MOZ_ASSERT_IF(mUsePartialPresent && mUseAlpha, mFullRender);

    if (mUsePartialPresent && !mUseAlpha) {
      // Clear full render flag.
      mFullRender = false;
      // If there is no diry rect, we skip SwapChain present.
      if (!aDirtyRects.IsEmpty()) {
        StackArray<RECT, 1> rects(aDirtyRects.Length());
        for (size_t i = 0; i < aDirtyRects.Length(); ++i) {
          const DeviceIntRect& rect = aDirtyRects[i];
          // Clip rect to bufferSize
          rects[i].left =
              std::max(0, std::min(rect.origin.x, bufferSize.width));
          rects[i].top =
              std::max(0, std::min(rect.origin.y, bufferSize.height));
          rects[i].right = std::max(
              0, std::min(rect.origin.x + rect.size.width, bufferSize.width));
          rects[i].bottom = std::max(
              0, std::min(rect.origin.y + rect.size.height, bufferSize.height));
        }

        DXGI_PRESENT_PARAMETERS params;
        PodZero(&params);
        params.DirtyRectsCount = aDirtyRects.Length();
        params.pDirtyRects = rects.data();

        HRESULT hr;
        hr = mSwapChain1->Present1(0, 0, &params);
        if (FAILED(hr) && hr != DXGI_STATUS_OCCLUDED) {
          gfxCriticalNote << "Present1 failed: " << gfx::hexa(hr);
          mFullRender = true;
        }
      }
    } else {
      mSwapChain->Present(0, 0);
    }
    auto end = TimeStamp::Now();
    mozilla::Telemetry::Accumulate(mozilla::Telemetry::COMPOSITE_SWAP_TIME,
                                   (end - start).ToMilliseconds() * 10.);
  }

  if (mDisablingNativeCompositor) {
    // During disabling native compositor, we need to wait all gpu tasks
    // complete. Otherwise, rendering window could cause white flash.
    WaitForPreviousGraphicsCommandsFinishedQuery(/* aWaitAll */ true);
    mDisablingNativeCompositor = false;
  }

  if (mDCLayerTree) {
    mDCLayerTree->MaybeUpdateDebug();
    mDCLayerTree->MaybeCommit();
  }

  return frameId;
}

bool RenderCompositorANGLE::WaitForGPU() {
  // Note: this waits on the query we inserted in the previous frame,
  // not the one we just inserted now. Example:
  //   Insert query #1
  //   Present #1
  //   (first frame, no wait)
  //   Insert query #2
  //   Present #2
  //   Wait for query #1.
  //   Insert query #3
  //   Present #3
  //   Wait for query #2.
  //
  // This ensures we're done reading textures before swapping buffers.
  return WaitForPreviousGraphicsCommandsFinishedQuery();
}

bool RenderCompositorANGLE::ResizeBufferIfNeeded() {
  MOZ_ASSERT(mSwapChain);

  LayoutDeviceIntSize size = mWidget->GetClientSize();

  // DXGI does not like 0x0 swapchains. ResizeBuffers() failed when 0x0 was set
  // when DComp is used.
  size.width = std::max(size.width, 1);
  size.height = std::max(size.height, 1);

  if (mBufferSize.isSome() && mBufferSize.ref() == size) {
    MOZ_ASSERT(mEGLSurface);
    return true;
  }

  // Release EGLSurface of back buffer before calling ResizeBuffers().
  DestroyEGLSurface();

  mBufferSize = Some(size);

  if (!CreateEGLSurface()) {
    mBufferSize.reset();
    return false;
  }

  if (mUsePartialPresent) {
    mFullRender = true;
  }
  return true;
}

bool RenderCompositorANGLE::CreateEGLSurface() {
  MOZ_ASSERT(mBufferSize.isSome());
  MOZ_ASSERT(mEGLSurface == EGL_NO_SURFACE);

  HRESULT hr;
  RefPtr<ID3D11Texture2D> backBuf;

  if (mBufferSize.isNothing()) {
    gfxCriticalNote << "Buffer size is invalid";
    return false;
  }

  const LayoutDeviceIntSize& size = mBufferSize.ref();

  // Resize swap chain
  DXGI_SWAP_CHAIN_DESC desc;
  hr = mSwapChain->GetDesc(&desc);
  if (FAILED(hr)) {
    gfxCriticalNote << "Failed to read swap chain description: "
                    << gfx::hexa(hr) << " Size : " << size;
    return false;
  }
  hr = mSwapChain->ResizeBuffers(desc.BufferCount, size.width, size.height,
                                 DXGI_FORMAT_B8G8R8A8_UNORM, 0);
  if (FAILED(hr)) {
    gfxCriticalNote << "Failed to resize swap chain buffers: " << gfx::hexa(hr)
                    << " Size : " << size;
    return false;
  }

  hr = mSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D),
                             (void**)getter_AddRefs(backBuf));
  if (hr == DXGI_ERROR_INVALID_CALL) {
    // This happens on some GPUs/drivers when there's a TDR.
    if (mDevice->GetDeviceRemovedReason() != S_OK) {
      gfxCriticalError() << "GetBuffer returned invalid call: " << gfx::hexa(hr)
                         << " Size : " << size;
      return false;
    }
  }

  const EGLint pbuffer_attribs[]{
      LOCAL_EGL_WIDTH,
      size.width,
      LOCAL_EGL_HEIGHT,
      size.height,
      LOCAL_EGL_FLEXIBLE_SURFACE_COMPATIBILITY_SUPPORTED_ANGLE,
      LOCAL_EGL_TRUE,
      LOCAL_EGL_NONE};

  const auto buffer = reinterpret_cast<EGLClientBuffer>(backBuf.get());

  const auto gl = RenderThread::Get()->SharedGL();
  const auto& gle = gl::GLContextEGL::Cast(gl);
  const auto& egl = gle->mEgl;
  const EGLSurface surface = egl->fCreatePbufferFromClientBuffer(
      egl->Display(), LOCAL_EGL_D3D_TEXTURE_ANGLE, buffer, mEGLConfig,
      pbuffer_attribs);

  EGLint err = egl->fGetError();
  if (err != LOCAL_EGL_SUCCESS) {
    gfxCriticalError() << "Failed to create Pbuffer of back buffer error: "
                       << gfx::hexa(err) << " Size : " << size;
    return false;
  }

  mEGLSurface = surface;

  return true;
}

void RenderCompositorANGLE::DestroyEGLSurface() {
  // Release EGLSurface of back buffer before calling ResizeBuffers().
  if (mEGLSurface) {
    const auto& gle = gl::GLContextEGL::Cast(gl());
    const auto& egl = gle->mEgl;
    gle->SetEGLSurfaceOverride(EGL_NO_SURFACE);
    egl->fDestroySurface(egl->Display(), mEGLSurface);
    mEGLSurface = nullptr;
  }
}

void RenderCompositorANGLE::Pause() {}

bool RenderCompositorANGLE::Resume() { return true; }

void RenderCompositorANGLE::Update() {
  // Update compositor window's size if it exists.
  // It needs to be called here, since OS might update compositor
  // window's size at unexpected timing.
  mWidget->AsWindows()->UpdateCompositorWndSizeIfNecessary();
}

bool RenderCompositorANGLE::MakeCurrent() {
  gl::GLContextEGL::Cast(gl())->SetEGLSurfaceOverride(mEGLSurface);
  return gl()->MakeCurrent();
}

LayoutDeviceIntSize RenderCompositorANGLE::GetBufferSize() {
  if (!UseCompositor()) {
    MOZ_ASSERT(mBufferSize.isSome());
    if (mBufferSize.isNothing()) {
      return LayoutDeviceIntSize();
    }
    return mBufferSize.ref();
  } else {
    return mWidget->GetClientSize();
  }
}

RefPtr<ID3D11Query> RenderCompositorANGLE::GetD3D11Query() {
  RefPtr<ID3D11Query> query;

  if (mRecycledQuery) {
    query = mRecycledQuery.forget();
    return query;
  }

  CD3D11_QUERY_DESC desc(D3D11_QUERY_EVENT);
  HRESULT hr = mDevice->CreateQuery(&desc, getter_AddRefs(query));
  if (FAILED(hr) || !query) {
    gfxWarning() << "Could not create D3D11_QUERY_EVENT: " << gfx::hexa(hr);
    return nullptr;
  }
  return query;
}

void RenderCompositorANGLE::InsertGraphicsCommandsFinishedWaitQuery(
    RenderedFrameId aFrameId) {
  RefPtr<ID3D11Query> query;
  query = GetD3D11Query();
  if (!query) {
    return;
  }

  mCtx->End(query);
  mWaitForPresentQueries.emplace(aFrameId, query);
}

bool RenderCompositorANGLE::WaitForPreviousGraphicsCommandsFinishedQuery(
    bool aWaitAll) {
  size_t waitLatency = mUseTripleBuffering ? 3 : 2;
  if (aWaitAll) {
    waitLatency = 1;
  }

  while (mWaitForPresentQueries.size() >= waitLatency) {
    auto queryPair = mWaitForPresentQueries.front();
    BOOL result;
    bool ret =
        layers::WaitForFrameGPUQuery(mDevice, mCtx, queryPair.second, &result);

    if (!ret) {
      mWaitForPresentQueries.pop();
      return false;
    }

    // Recycle query for later use.
    mRecycledQuery = queryPair.second;
    mLastCompletedFrameId = queryPair.first;
    mWaitForPresentQueries.pop();
  }
  return true;
}

RenderedFrameId RenderCompositorANGLE::GetLastCompletedFrameId() {
  while (!mWaitForPresentQueries.empty()) {
    auto queryPair = mWaitForPresentQueries.front();
    if (mCtx->GetData(queryPair.second, nullptr, 0, 0) != S_OK) {
      break;
    }

    mRecycledQuery = queryPair.second;
    mLastCompletedFrameId = queryPair.first;
    mWaitForPresentQueries.pop();
  }

  return mLastCompletedFrameId;
}

RenderedFrameId RenderCompositorANGLE::UpdateFrameId() {
  RenderedFrameId frameId = GetNextRenderFrameId();
  InsertGraphicsCommandsFinishedWaitQuery(frameId);
  return frameId;
}

bool RenderCompositorANGLE::IsContextLost() {
  // XXX glGetGraphicsResetStatus sometimes did not work for detecting TDR.
  // Then this function just uses GetDeviceRemovedReason().
  if (mDevice->GetDeviceRemovedReason() != S_OK) {
    return true;
  }
  return false;
}

bool RenderCompositorANGLE::UseCompositor() {
  if (!mUseNativeCompositor) {
    return false;
  }

  if (!mDCLayerTree || !gfx::gfxVars::UseWebRenderCompositor()) {
    return false;
  }
  return true;
}

bool RenderCompositorANGLE::SupportAsyncScreenshot() {
  return !UseCompositor() && !mDisablingNativeCompositor;
}

bool RenderCompositorANGLE::ShouldUseNativeCompositor() {
  return UseCompositor();
}

uint32_t RenderCompositorANGLE::GetMaxUpdateRects() {
  if (UseCompositor() &&
      StaticPrefs::gfx_webrender_compositor_max_update_rects_AtStartup() > 0) {
    return 1;
  }
  return 0;
}

void RenderCompositorANGLE::CompositorBeginFrame() {
  mDCLayerTree->CompositorBeginFrame();
}

void RenderCompositorANGLE::CompositorEndFrame() {
  mDCLayerTree->CompositorEndFrame();
}

void RenderCompositorANGLE::Bind(wr::NativeTileId aId,
                                 wr::DeviceIntPoint* aOffset, uint32_t* aFboId,
                                 wr::DeviceIntRect aDirtyRect,
                                 wr::DeviceIntRect aValidRect) {
  mDCLayerTree->Bind(aId, aOffset, aFboId, aDirtyRect, aValidRect);
}

void RenderCompositorANGLE::Unbind() { mDCLayerTree->Unbind(); }

void RenderCompositorANGLE::CreateSurface(wr::NativeSurfaceId aId,
                                          wr::DeviceIntPoint aVirtualOffset,
                                          wr::DeviceIntSize aTileSize,
                                          bool aIsOpaque) {
  mDCLayerTree->CreateSurface(aId, aVirtualOffset, aTileSize, aIsOpaque);
}

void RenderCompositorANGLE::DestroySurface(NativeSurfaceId aId) {
  mDCLayerTree->DestroySurface(aId);
}

void RenderCompositorANGLE::CreateTile(wr::NativeSurfaceId aId, int aX,
                                       int aY) {
  mDCLayerTree->CreateTile(aId, aX, aY);
}

void RenderCompositorANGLE::DestroyTile(wr::NativeSurfaceId aId, int aX,
                                        int aY) {
  mDCLayerTree->DestroyTile(aId, aX, aY);
}

void RenderCompositorANGLE::AddSurface(wr::NativeSurfaceId aId,
                                       wr::DeviceIntPoint aPosition,
                                       wr::DeviceIntRect aClipRect) {
  mDCLayerTree->AddSurface(aId, aPosition, aClipRect);
}

CompositorCapabilities RenderCompositorANGLE::GetCompositorCapabilities() {
  CompositorCapabilities caps;

#ifdef USE_VIRTUAL_SURFACES
  caps.virtual_surface_size = VIRTUAL_SURFACE_SIZE;
#else
  caps.virtual_surface_size = 0;
#endif

  return caps;
}

void RenderCompositorANGLE::EnableNativeCompositor(bool aEnable) {
  // XXX Re-enable native compositor is not handled yet.
  MOZ_RELEASE_ASSERT(!mDisablingNativeCompositor);
  MOZ_RELEASE_ASSERT(!aEnable);

  if (!UseCompositor()) {
    return;
  }

  mUseNativeCompositor = false;
  mDCLayerTree->DisableNativeCompositor();

  bool useAlpha = mWidget->AsWindows()->HasGlass();
  DestroyEGLSurface();
  mBufferSize.reset();

  RefPtr<IDXGISwapChain1> swapChain1 =
      CreateSwapChainForDComp(mUseTripleBuffering, useAlpha);
  if (swapChain1) {
    mSwapChain = swapChain1;
    mUseAlpha = useAlpha;
    mDCLayerTree->SetDefaultSwapChain(swapChain1);
    // When alpha is used, we want to disable partial present.
    // See Bug 1595027.
    if (useAlpha) {
      mFullRender = true;
    }
    ResizeBufferIfNeeded();
  } else {
    gfxCriticalNote << "Failed to re-create SwapChain";
    RenderThread::Get()->HandleWebRenderError(WebRenderError::NEW_SURFACE);
    return;
  }
  mDisablingNativeCompositor = true;
}

void RenderCompositorANGLE::InitializeUsePartialPresent() {
  if (UseCompositor() || !mSwapChain1 ||
      mWidget->AsWindows()->HasFxrOutputHandler() ||
      gfx::gfxVars::WebRenderMaxPartialPresentRects() <= 0) {
    mUsePartialPresent = false;
  } else {
    mUsePartialPresent = true;
  }
}

bool RenderCompositorANGLE::UsePartialPresent() { return mUsePartialPresent; }

bool RenderCompositorANGLE::RequestFullRender() { return mFullRender; }

uint32_t RenderCompositorANGLE::GetMaxPartialPresentRects() {
  if (!mUsePartialPresent) {
    return 0;
  }
  return gfx::gfxVars::WebRenderMaxPartialPresentRects();
}

bool RenderCompositorANGLE::MaybeReadback(
    const gfx::IntSize& aReadbackSize, const wr::ImageFormat& aReadbackFormat,
    const Range<uint8_t>& aReadbackBuffer) {
  MOZ_ASSERT(aReadbackFormat == wr::ImageFormat::BGRA8);

  if (!UseCompositor()) {
    return false;
  }

  auto start = TimeStamp::Now();

  HDC nulldc = ::GetDC(NULL);
  HDC dc = ::CreateCompatibleDC(nulldc);
  ::ReleaseDC(nullptr, nulldc);
  if (!dc) {
    gfxCriticalError() << "CreateCompatibleDC failed";
    return false;
  }

  BITMAPV4HEADER header;
  memset(&header, 0, sizeof(BITMAPV4HEADER));
  header.bV4Size = sizeof(BITMAPV4HEADER);
  header.bV4Width = aReadbackSize.width;
  header.bV4Height = -LONG(aReadbackSize.height);  // top-to-buttom DIB
  header.bV4Planes = 1;
  header.bV4BitCount = 32;
  header.bV4V4Compression = BI_BITFIELDS;
  header.bV4RedMask = 0x00FF0000;
  header.bV4GreenMask = 0x0000FF00;
  header.bV4BlueMask = 0x000000FF;
  header.bV4AlphaMask = 0xFF000000;

  void* readbackBits = nullptr;
  HBITMAP bitmap =
      ::CreateDIBSection(dc, reinterpret_cast<BITMAPINFO*>(&header),
                         DIB_RGB_COLORS, &readbackBits, nullptr, 0);
  if (!bitmap) {
    ::DeleteDC(dc);
    gfxCriticalError() << "CreateDIBSection failed";
    return false;
  }

  ::SelectObject(dc, bitmap);

  UINT flags = PW_CLIENTONLY | PW_RENDERFULLCONTENT;
  HWND hwnd = mWidget->AsWindows()->GetHwnd();

  mDCLayerTree->WaitForCommitCompletion();

  BOOL result = ::PrintWindow(hwnd, dc, flags);
  if (!result) {
    ::DeleteObject(bitmap);
    ::DeleteDC(dc);
    gfxCriticalError() << "PrintWindow failed";
    return false;
  }

  ::GdiFlush();

  memcpy(&aReadbackBuffer[0], readbackBits, aReadbackBuffer.length());

  ::DeleteObject(bitmap);
  ::DeleteDC(dc);

  uint32_t latencyMs = round((TimeStamp::Now() - start).ToMilliseconds());
  if (latencyMs > 500) {
    gfxCriticalNote << "Readback took too long: " << latencyMs << " ms";
  }

  return true;
}

}  // namespace wr
}  // namespace mozilla