[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/dxgi_output_duplicator.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_DXGI_OUTPUT_DUPLICATOR_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_OUTPUT_DUPLICATOR_H_
+
+#include <comdef.h>
+#include <wrl/client.h>
+#include <DXGI.h>
+#include <DXGI1_2.h>
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/base/criticalsection.h"
+#include "webrtc/base/thread_annotations.h"
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+#include "webrtc/modules/desktop_capture/win/d3d_device.h"
+#include "webrtc/modules/desktop_capture/win/dxgi_texture.h"
+
+namespace webrtc {
+
+// Duplicates the content on one IDXGIOutput, i.e. one monitor attached to one
+// video card. None of functions in this class is thread-safe.
+// TODO(zijiehe): Understand the meaning of rotation.
+class DxgiOutputDuplicator {
+ public:
+  struct Context {
+    // The updated region DxgiOutputDuplicator::DetectUpdatedRegion() output
+    // during last Duplicate() function call. It's a DesktopRegion translated by
+    // offset of each DxgiOutputDuplicator instance.
+    DesktopRegion updated_region;
+  };
+
+  // Creates an instance of DxgiOutputDuplicator from a D3dDevice and one of its
+  // IDXGIOutput1. Caller must maintain the lifetime of device, to make sure it
+  // outlives this instance. Only DxgiAdapterDuplicator can create an instance.
+  DxgiOutputDuplicator(const D3dDevice& device,
+                       const Microsoft::WRL::ComPtr<IDXGIOutput1>& output,
+                       const DXGI_OUTPUT_DESC& desc);
+
+  // To allow this class to work with vector.
+  DxgiOutputDuplicator(DxgiOutputDuplicator&& other);
+
+  // Destructs this instance. We need to make sure texture_ has been released
+  // before duplication_.
+  ~DxgiOutputDuplicator();
+
+  // Initializes duplication_ object.
+  bool Initialize();
+
+  // Copies the content of current IDXGIOutput to the |target|. To improve the
+  // performance, this function copies only regions merged from
+  // |last_frame|.updated_region and DetectUpdatedRegion(). The |offset| decides
+  // the
+  // offset in the |target| where the content should be copied to. i.e. this
+  // function copies the content to the rectangle of (offset.x(), offset.y()) to
+  // (offset.x() + desktop_rect_.width(), offset.y() + desktop_rect_.height()).
+  // The |last_frame| is always expected to be translated by the same offset.
+  // Returns false in case of a failure.
+  bool Duplicate(Context* context,
+                 const DesktopFrame* last_frame,
+                 const DesktopVector offset,
+                 DesktopFrame* target);
+
+  // Returns the desktop rect covered by this DxgiOutputDuplicator.
+  DesktopRect desktop_rect() const { return desktop_rect_; }
+
+ private:
+  friend class DxgiAdapterDuplicator;
+
+  // Detects updated region translated by offset from IDXGIOutput1. This
+  // function will set the |updated_region| as entire DesktopRect starts from
+  // offset if it failed to execute Windows APIs.
+  void DetectUpdatedRegion(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                           const DesktopVector offset,
+                           DesktopRegion* updated_region);
+
+  // Returns untranslated updated region, which are directly returned by Windows
+  // APIs. Returns false in case of a failure.
+  bool DoDetectUpdatedRegion(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                             DesktopRegion* updated_region);
+
+  bool ReleaseFrame();
+
+  // Initializes duplication_ instance. Expects duplication_ is in empty status.
+  // Returns false if system does not support IDXGIOutputDuplication.
+  bool DuplicateOutput();
+
+  // Returns a DesktopRect with the same size of desktop_size_, but translated
+  // by offset.
+  DesktopRect TranslatedDesktopRect(const DesktopVector offset);
+
+  void Setup(Context* context);
+
+  void Unregister(const Context* const context);
+
+  // Spreads changes from |context| to other registered Context(s) in
+  // contexts_.
+  void SpreadContextChange(const Context* const context);
+
+  const D3dDevice& device_;
+  const Microsoft::WRL::ComPtr<IDXGIOutput1> output_;
+  const DesktopRect desktop_rect_;
+  Microsoft::WRL::ComPtr<IDXGIOutputDuplication> duplication_;
+  DXGI_OUTDUPL_DESC desc_;
+  std::vector<uint8_t> metadata;
+  std::unique_ptr<DxgiTexture> texture_;
+
+  // After each AcquireNextFrame() function call, updated_region_(s) of all
+  // active Context(s) need to be updated. Since they have missed the
+  // change this time. And during next Duplicate() function call, their
+  // updated_region_ will be merged and copied.
+  std::vector<Context*> contexts_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_OUTPUT_DUPLICATOR_H_