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 <windows.h>
+#include <wrl/client.h>
+
+#include <memory>
+#include <vector>
+
+#include <D3DCommon.h>
+#include <D3D11.h>
+#include <DXGI1_2.h>
+
+#include "webrtc/base/scoped_ptr.h"
+#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/win/desktop_frame_win_dxgi.h"
+
+namespace webrtc {
+
+// ScreenCapturerWinDirectX captures 32bit RGBA using DirectX.
+class ScreenCapturerWinDirectX : public ScreenCapturer {

[Sergey Ulanov, 2016/04/08 21:22:26]

please call it ScreenCapturerWinDirectx, with lower-case x at the end. Style
guide says:
 Prefer to capitalize acronyms as single words (i.e. StartRpc(), not
StartRPC()).

[Hzj_jie, 2016/04/11 22:19:16]

Done.

+ 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(
+      rtc::scoped_ptr<SharedMemoryFactory> shared_memory_factory) override;
+  void Capture(const DesktopRegion& region) override;
+  bool GetScreenList(ScreenList* screens) override;
+  bool SelectScreen(ScreenId id) override;
+
+ private:
+  // In milliseconds, consistent with windows api.
+  static const uint32_t kAcquireTimeout = 10;
+  // Wait time between two DuplicateOutput operations, DuplicateOutput may fail
+  // if display mode is changing.
+  static const uint32_t kDuplicateOutputWait = 50;
+  // How many times we attempt to DuplicateOutput before returning an error to
+  // upstream components.
+  static const int kDuplicateOutputAttempts = 10;
+
+  static bool DoInitialize();
+
+  // Initializes dxgi_output_duplication. Returns false if it fails to execute
+  // windows api.
+  static bool DuplicateOutput();
+
+  // Detect 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,
+                                  DesktopFrame* frame);
+
+  // Process one frame received from AcquireNextFrame function, returns false if
+  // anything wrong, and Capture function will call
+  // callback_->OnCaptureCompleted(nullptr), otherwise
+  // callback_->OnCaptureCompleted(frame) will be called.
+  bool ProcessFrame(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                    IDXGIResource* resource);
+
+  void EmitCurrentFrame();
+
+  // A shortcut to replace current frame to DesktopFrameWinDxgi if it is null.
+  // Returns the created or original DesktopFrameWinDxgi instance. Never returns
+  // nullptr.
+  DesktopFrameWinDxgi* ReplaceCurrentFrameIfEmpty();
+
+  ScreenCaptureFrameQueue frames_;
+  std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;
+  Callback* callback_;
+
+  bool set_thread_execution_state_failed_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCapturerWinDirectX);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_