DirectX based screen capturer logic

webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h

+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_
+
+#include "webrtc/modules/desktop_capture/screen_capturer.h"
+
+#include <comdef.h>
+#include <D3DCommon.h>
+#include <D3D11.h>
+#include <DXGI.h>
+#include <DXGI1_2.h>
+#include <windows.h>
+#include <wrl/client.h>
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/base/thread_annotations.h"
+#include "webrtc/modules/desktop_capture/desktop_capture_options.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+#include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
+#include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
+
+namespace webrtc {
+
+// ScreenCapturerWinDirectx captures 32bit RGBA using DirectX. This
+// implementation won't work when ScreenCaptureFrameQueue.kQueueLength is not 2.
+class ScreenCapturerWinDirectx : public ScreenCapturer {
+ public:
+  // Initializes DirectX related components. Returns false if any error
+  // happened, any instance of this class won't be able to work in such status.
+  // Thread safe, guarded by initialize_lock.
+  static bool Initialize();
+
+  explicit ScreenCapturerWinDirectx(const DesktopCaptureOptions& options);
+  virtual ~ScreenCapturerWinDirectx();
+
+  void Start(Callback* callback) override;
+  void SetSharedMemoryFactory(
+      std::unique_ptr<SharedMemoryFactory> shared_memory_factory) override;
+  void Capture(const DesktopRegion& region) override;
+  bool GetScreenList(ScreenList* screens) override;
+  bool SelectScreen(ScreenId id) override;
+
+ private:
+  // Texture is a pair of an ID3D11Texture2D and an IDXGISurface. Refer to its
+  // implementation in source code for details.
+  class Texture;
+
+  // An implementation of DesktopFrame to return data from a Texture instance.
+  class DxgiDesktopFrame;
+
+  static bool DoInitialize();
+
+  // Initializes DxgiOutputDuplication. If current DxgiOutputDuplication
+  // instance is existing, this function takes no-op and returns true. Returns
+  // false if it fails to execute windows api.
+  static bool DuplicateOutput();
+
+  // Deprecates current DxgiOutputDuplication instance and calls DuplicateOutput
+  // to reinitialize it.
+  static bool ForceDuplicateOutput();
+
+  // Detects update regions in last frame, if anything wrong, returns false.
+  // ProcessFrame will insert a whole desktop size as updated region instead.
+  static bool DetectUpdatedRegion(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                                  DesktopRegion* updated_region);
+
+  // A helper function to handle _com_error result in DetectUpdatedRegion.
+  // Returns false if the _com_error shows an error.
+  static bool HandleDetectUpdatedRegionError(const _com_error& error,
+                                             const char* stage);
+
+  // Processes one frame received from AcquireNextFrame function, returns a
+  // nullptr if anything wrong, and Capture function will call
+  // callback_->OnCaptureCompleted(nullptr), otherwise
+  // callback_->OnCaptureCompleted(frame) will be called.
+  std::unique_ptr<DesktopFrame> ProcessFrame(
+      const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+      IDXGIResource* resource);
+
+  // A shortcut to execute callback with current frame in frames.
+  void EmitCurrentFrame();
+
+  ScreenCaptureFrameQueue<rtc::scoped_refptr<Texture>> surfaces_;
+  ScreenCaptureFrameQueue<SharedDesktopFrame> frames_;
+  std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;
+  Callback* callback_ = nullptr;
+
+  bool set_thread_execution_state_failed_ = false;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCapturerWinDirectx);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_