DirectX based screen capturer logic

webrtc/modules/desktop_capture/desktop_frame_win.cc

 /*
  *  Copyright (c) 2013 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/desktop_frame_win.h"
 
 #include <utility>
 
 #include "webrtc/system_wrappers/include/logging.h"
 
 namespace webrtc {
 
+using Microsoft::WRL::ComPtr;
+
+namespace {
+
+int CalculateStrideFromDesktopSize(DesktopSize size) {
+  return size.width() * DesktopFrame::kBytesPerPixel;
+}
+
+}  // namespace
+
 DesktopFrameWin::DesktopFrameWin(DesktopSize size,
                                  int stride,
                                  uint8_t* data,
                                  std::unique_ptr<SharedMemory> shared_memory,
                                  HBITMAP bitmap)
     : DesktopFrame(size, stride, data, shared_memory.get()),
       bitmap_(bitmap),
       owned_shared_memory_(std::move(shared_memory)) {}
 
 DesktopFrameWin::~DesktopFrameWin() {
   DeleteObject(bitmap_);
 }
 
 // static
 DesktopFrameWin* DesktopFrameWin::Create(
     DesktopSize size,
     SharedMemoryFactory* shared_memory_factory,
     HDC hdc) {
-  int bytes_per_row = size.width() * kBytesPerPixel;
+  int bytes_per_row = CalculateStrideFromDesktopSize(size);
   int buffer_size = bytes_per_row * size.height();
 
   // Describe a device independent bitmap (DIB) that is the size of the desktop.
   BITMAPINFO bmi = {};
   bmi.bmiHeader.biHeight = -size.height();
   bmi.bmiHeader.biWidth = size.width();
   bmi.bmiHeader.biPlanes = 1;
-  bmi.bmiHeader.biBitCount = DesktopFrameWin::kBytesPerPixel * 8;
+  bmi.bmiHeader.biBitCount = DesktopFrame::kBytesPerPixel * 8;
   bmi.bmiHeader.biSize = sizeof(bmi.bmiHeader);
-  bmi.bmiHeader.biSizeImage = bytes_per_row * size.height();
+  bmi.bmiHeader.biSizeImage = buffer_size;
 
   std::unique_ptr<SharedMemory> shared_memory;
   HANDLE section_handle = nullptr;
   if (shared_memory_factory) {
     shared_memory = rtc::ScopedToUnique(
         shared_memory_factory->CreateSharedMemory(buffer_size));
     if (shared_memory)
       section_handle = shared_memory->handle();
   }
   void* data = nullptr;
   HBITMAP bitmap = CreateDIBSection(hdc, &bmi, DIB_RGB_COLORS, &data,
                                     section_handle, 0);
   if (!bitmap) {
     LOG(LS_WARNING) << "Failed to allocate new window frame " << GetLastError();
     return nullptr;
   }
 
   return new DesktopFrameWin(size, bytes_per_row,
                              reinterpret_cast<uint8_t*>(data),
                              std::move(shared_memory), bitmap);
 }
 
+DesktopFrameWinDXGI::~DesktopFrameWinDXGI() {}
+
+DesktopFrameWinDXGI::DesktopFrameWinDXGI(DesktopSize size,
+                                         ComPtr<IDXGISurface> surface,
+                                         DXGI_MAPPED_RECT rect) :

[Sergey Ulanov, 2016/03/31 18:41:15]

Do you really need to pass this parameter? It can be mapped from surface. Maybe
add DesktopFrameWinDXGI::Create() which maps the surface and then creates 
DesktopFrameWinDXGI, similar to DesktopFrameWin.

[Hzj_jie, 2016/04/05 23:15:17]

Yes, I can move the logic in ScreenCapturerWinDirectX::ProcessFrame into a
Create function.

+    DesktopFrame(size,
+                 CalculateStrideFromDesktopSize(size),

[Sergey Ulanov, 2016/03/31 18:41:15]

 DXGI_MAPPED_RECT  contains pitch field. Use it here?

[Hzj_jie, 2016/04/05 23:15:17]

Done.

+                 rect.pBits,
+                 nullptr),
+    surface_(surface) {}
+
+DesktopFrameWinDXGI::DesktopFrameWinDXGI(DesktopSize size) :
+    DesktopFrame(size,
+                 0,
+                 nullptr,
+                 nullptr) {}
+
 }  // namespace webrtc