[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc

Index: webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
diff --git a/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc b/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7478728143d0d8f93c274709e5d9207fc67073d4
--- /dev/null
+++ b/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
@@ -0,0 +1,149 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/win/dxgi_texture_staging.h"
+
+#include <comdef.h>
+#include <unknwn.h>
+#include <DXGI.h>
+#include <DXGI1_2.h>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/system_wrappers/include/logging.h"
+
+using Microsoft::WRL::ComPtr;
+
+namespace webrtc {
+
+DxgiTextureStaging::DxgiTextureStaging(const DesktopRect& desktop_rect,
+                                       const D3dDevice& device)
+    : DxgiTexture(desktop_rect), device_(device) {}
+
+DxgiTextureStaging::~DxgiTextureStaging() = default;
+
+bool DxgiTextureStaging::InitializeStage(ID3D11Texture2D* texture) {
+  RTC_DCHECK(texture);
+  D3D11_TEXTURE2D_DESC desc = {0};
+  texture->GetDesc(&desc);
+  if (static_cast<int>(desc.Width) != desktop_rect().width() ||
+      static_cast<int>(desc.Height) != desktop_rect().height()) {
+    LOG(LS_ERROR) << "Texture size is not consistent with current DxgiTexture.";
+    return false;
+  }
+
+  desc.BindFlags = 0;
+  desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
+  desc.MiscFlags = 0;
+  desc.Usage = D3D11_USAGE_STAGING;
+  if (stage_) {
+    AssertStageAndSurfaceAreSameObject();
+    D3D11_TEXTURE2D_DESC current_desc;
+    stage_->GetDesc(&current_desc);
+    if (memcmp(&desc, &current_desc, sizeof(D3D11_TEXTURE2D_DESC)) == 0) {
+      return true;
+    }
+
+    // The descriptions are not consistent, we need to create a new
+    // ID3D11Texture2D instance.
+    stage_.Reset();
+    surface_.Reset();
+  } else {
+    RTC_DCHECK(!surface_);
+  }
+
+  _com_error error = _com_error(device_.d3d_device()->CreateTexture2D(
+      &desc, nullptr, stage_.GetAddressOf()));
+  if (error.Error() != S_OK || !stage_) {
+    LOG(LS_ERROR) << "Failed to create a new ID3D11Texture2D as stage, error "
+                  << error.ErrorMessage() << ", code " << error.Error();
+    return false;
+  }
+
+  error = _com_error(stage_.As(&surface_));
+  if (error.Error() != S_OK || !surface_) {
+    LOG(LS_ERROR) << "Failed to convert ID3D11Texture2D to IDXGISurface, error "
+                  << error.ErrorMessage() << ", code " << error.Error();
+    return false;
+  }
+
+  return true;
+}
+
+void DxgiTextureStaging::AssertStageAndSurfaceAreSameObject() {
+  ComPtr<IUnknown> left;
+  ComPtr<IUnknown> right;
+  bool left_result = SUCCEEDED(stage_.As(&left));
+  bool right_result = SUCCEEDED(surface_.As(&right));
+  RTC_DCHECK(left_result);
+  RTC_DCHECK(right_result);
+  RTC_DCHECK(left.Get() == right.Get());
+}
+
+bool DxgiTextureStaging::CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                                  IDXGIResource* resource,
+                                  const DesktopRegion& region) {
+  RTC_DCHECK(resource && frame_info.AccumulatedFrames > 0);
+  ComPtr<ID3D11Texture2D> texture;
+  _com_error error = resource->QueryInterface(
+      __uuidof(ID3D11Texture2D),
+      reinterpret_cast<void**>(texture.GetAddressOf()));
+  if (error.Error() != S_OK || !texture) {
+    LOG(LS_ERROR) << "Failed to convert IDXGIResource to ID3D11Texture2D, "
+                     "error "
+                  << error.ErrorMessage() << ", code " << error.Error();
+    return false;
+  }
+
+  // AcquireNextFrame returns a CPU inaccessible IDXGIResource, so we need to
+  // copy it to a CPU accessible staging ID3D11Texture2D.
+  if (!InitializeStage(texture.Get())) {
+    return false;
+  }
+
+  for (DesktopRegion::Iterator it(region); !it.IsAtEnd(); it.Advance()) {
+    DesktopRect rect(it.rect());
+    rect.Translate(-desktop_rect().left(), -desktop_rect().top());
+    D3D11_BOX box;
+    box.left = rect.left();
+    box.top = rect.top();
+    box.right = rect.right();
+    box.bottom = rect.bottom();
+    box.front = 0;
+    box.back = 1;
+    device_.context()->CopySubresourceRegion(
+        static_cast<ID3D11Resource*>(stage_.Get()), 0, rect.left(), rect.top(),
+        0, static_cast<ID3D11Resource*>(texture.Get()), 0, &box);
+  }
+
+  rect_ = {0};
+  error = _com_error(surface_->Map(&rect_, DXGI_MAP_READ));
+  if (error.Error() != S_OK) {
+    rect_ = {0};
+    LOG(LS_ERROR) << "Failed to map the IDXGISurface to a bitmap, error "
+                  << error.ErrorMessage() << ", code " << error.Error();
+    return false;
+  }
+
+  return true;
+}
+
+bool DxgiTextureStaging::DoRelease() {
+  _com_error error = _com_error(surface_->Unmap());
+  if (error.Error() != S_OK) {
+    stage_.Reset();
+    surface_.Reset();
+  }
+  // If using staging mode, we only need to recreate ID3D11Texture2D instance.
+  // This will happen during next CopyFrom call. So this function always returns
+  // true.
+  return true;
+}
+
+}  // namespace webrtc