Fix up mac capturer to flip image.

remoting/host/capturer_mac.cc

Index: remoting/host/capturer_mac.cc
diff --git a/remoting/host/capturer_mac.cc b/remoting/host/capturer_mac.cc
index e5b4c8a829bb4349747c718c40658d3dc2de0434..9b06ac6707aa68c777183c84c4047decffb95c6b 100644
--- a/remoting/host/capturer_mac.cc
+++ b/remoting/host/capturer_mac.cc
@@ -55,6 +55,7 @@ void CapturerMac::ScreenConfigurationChanged() {
   for (int i = 0; i < kNumBuffers; ++i) {
     buffers_[i].reset(new uint8[buffer_size]);
   }
+  flip_buffer_.reset(new uint8[buffer_size]);
   CGLPixelFormatAttribute attributes[] = {
     kCGLPFAFullScreen,
     kCGLPFADisplayMask,
@@ -92,18 +93,33 @@ void CapturerMac::CaptureRects(const InvalidRects& rects,
   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
 
   // Read a block of pixels from the frame buffer.
-  glReadPixels(0, 0, width(), height(), GL_BGRA, GL_UNSIGNED_BYTE,
-               buffers_[current_buffer_].get());
+  int h = height();
+  int w = width();
+  uint8* flip_buffer = flip_buffer_.get();
+  uint8* current_buffer = buffers_[current_buffer_].get();
+
+  glReadPixels(0, 0, w, h, GL_BGRA, GL_UNSIGNED_BYTE, flip_buffer);
   glPopClientAttrib();
 
+  // OpenGL reads with a vertical flip, and sadly there is no optimized
+  // way to get it flipped automatically.
+  DCHECK_EQ(bytes_per_row_ % sizeof(uint32_t), 0U);
+  for (int y = 0; y < h; ++y) {
+    uint32_t* flip_row = reinterpret_cast<uint32_t*>(
+        &(flip_buffer[y * bytes_per_row_]));
+    uint32_t* current_row = reinterpret_cast<uint32_t*>(
+        &(current_buffer[(h - (y + 1)) * bytes_per_row_]));
+    for (int x = 0; x < w; ++x) {

[Alpha Left Google, 2011/03/03 01:43:33]

Do a memcpy instead of doing yourself, memcpy is pretty optimized.

+      current_row[x] = flip_row[x];
+    }
+  }
+
   DataPlanes planes;
   planes.data[0] = buffers_[current_buffer_].get();
   planes.strides[0] = bytes_per_row_;
 
-  scoped_refptr<CaptureData> data(new CaptureData(planes,
-                                                  width(),
-                                                  height(),
-                                                  pixel_format()));
+  scoped_refptr<CaptureData> data(
+      new CaptureData(planes, w, h, pixel_format()));
   data->mutable_dirty_rects() = rects;
   FinishCapture(data, callback);
 }