[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/dxgi_texture.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 MODULES_DESKTOP_CAPTURE_WIN_DXGI_TEXTURE_H_
+#define MODULES_DESKTOP_CAPTURE_WIN_DXGI_TEXTURE_H_
+
+#include <DXGI1_2.h>
+
+#include <memory>
+
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/desktop_region.h"

[Sergey Ulanov, 2016/07/20 19:05:17]

nit: Forward-declare DesktopRegion

[Hzj_jie, 2016/07/22 18:43:43]

Done.

+
+namespace webrtc {
+
+// A texture copied or mapped from a DXGI_OUTDUPL_FRAME_INFO and IDXGIResource.
+class DxgiTexture {
+ public:
+  // Creates a DxgiTexture instance, which represents the DesktopRect area of
+  // entire screen -- usually a monitor on the system.
+  explicit DxgiTexture(const DesktopRect& desktop_rect);
+
+  virtual ~DxgiTexture() = default;
+
+  // Copies selected regions of a frame represented by frame_info and resource.
+  // Returns false if anything wrong.
+  virtual bool CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
+                        IDXGIResource* resource,
+                        const DesktopRegion& region) = 0;
+
+  const DesktopRect& desktop_rect() const {
+    return desktop_rect_;
+  }
+
+  uint8_t* bits() const {
+    return static_cast<uint8_t*>(rect_.pBits);
+  }
+
+  int pitch() const {
+    return static_cast<int>(rect_.Pitch);
+  }
+
+  // Releases the resource currently holds by this instance. Returns false if
+  // anything wrong, and this instance should be deprecated in this state. bits,
+  // pitch and AsDesktopFrame are only valid after a success CopyFrom() call,
+  // but before Release() call.
+  bool Release();
+
+  // Returns a DesktopFrame snapshot of a DxgiTexture instance. This
+  // DesktopFrame is used to copy a DxgiTexture content to another DesktopFrame
+  // only. And it should not outlive its DxgiTexture instance.
+  const DesktopFrame& AsDesktopFrame();
+
+ protected:
+  DXGI_MAPPED_RECT rect_ = {0};

[Sergey Ulanov, 2016/07/20 19:05:17]

nit: = {}
See
https://randomascii.wordpress.com/2016/07/17/zeroing-memory-is-hard-vc-2015-a...

[Hzj_jie, 2016/07/22 18:43:43]

That's definitely interesting. I thought they were exactly same.

+
+ private:
+  class DxgiDesktopFrame : public DesktopFrame {

[Sergey Ulanov, 2016/07/20 19:05:17]

nit: does this class need to be nested?

[Hzj_jie, 2016/07/22 18:43:43]

I think,
1. This class is too simple.
2. This class should not be accessed by other classes. It's meaningless out of
DxgiTexture class.

But I do not have a strong opinion.

[Sergey Ulanov, 2016/07/22 19:23:25]

Right. My point is that you could put it in dxgi_texture.cc . It doesn't need to
be in this header nested in DxgiTexture.

+   public:
+    explicit DxgiDesktopFrame(const DxgiTexture& texture);
+    virtual ~DxgiDesktopFrame() = default;
+  };
+
+  virtual bool DoRelease() = 0;
+
+  const DesktopRect desktop_rect_;
+  std::unique_ptr<DesktopFrame> frame_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_DESKTOP_CAPTURE_WIN_DXGI_TEXTURE_H_