[Remoting] OpenGL Rendering Layer

remoting/client/gl_desktop.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/client/gl_desktop.h"
+
+#include "base/logging.h"
+#include "remoting/client/gl_canvas.h"
+#include "remoting/client/gl_render_layer.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
+
+namespace {
+
+const int kTextureId = 0;
+const int kBytesPerPixel = 4;

[Sergey Ulanov, 2016/07/09 01:01:20]

use webrtc::DesktopFrame::kBytesPerPixel

[Yuwei, 2016/07/11 22:38:23]

Done.

+
+}

[Sergey Ulanov, 2016/07/09 01:01:20]

// namespace

[Yuwei, 2016/07/11 22:38:23]

Done.

+
+namespace remoting {
+
+GlDesktop::GlDesktop() {}
+
+GlDesktop::~GlDesktop() {}
+
+void GlDesktop::SetCanvas(GlCanvas* canvas) {
+  if (!canvas) {
+    layer_.reset();
+    return;
+  }
+  layer_.reset(new GlRenderLayer(kTextureId, canvas));
+  if (last_frame_) {
+    layer_->SetTexture(last_frame_->data(), last_frame_->size().width(),
+                       last_frame_->size().height());
+  }
+}
+
+void GlDesktop::SetVideoFrame(std::unique_ptr<webrtc::DesktopFrame> frame) {
+  if (layer_) {
+    if (!last_frame_ || frame->size().width() != last_frame_->size().width() ||

[Sergey Ulanov, 2016/07/09 01:01:20]

!frame->size().equal(last_frame_->size())
to avoid comparing width and height separately.

[Yuwei, 2016/07/11 22:38:23]

Done.

+        frame->size().height() != last_frame_->size().height()) {
+      layer_->SetTexture(frame->data(), frame->size().width(),
+                         frame->size().height());
+    } else {
+      for (webrtc::DesktopRegion::Iterator i(frame->updated_region());
+          !i.IsAtEnd(); i.Advance()) {
+        const uint8_t* rect_start =
+            reinterpret_cast<const uint8_t*>(frame->data()) +

[Sergey Ulanov, 2016/07/09 01:01:20]

Don't need this cast.

[Yuwei, 2016/07/11 22:38:23]

Done.

+            frame->stride() * i.rect().top() + i.rect().left() * kBytesPerPixel;

[Sergey Ulanov, 2016/07/09 01:01:20]

Use DesktopFrame::GetFrameDataAtPos(i.rect().top_left());

+        layer_->UpdateTexture(rect_start, i.rect().left(), i.rect().top(),
+                              i.rect().width(), i.rect().height(),
+                              frame->stride() / kBytesPerPixel);

[Sergey Ulanov, 2016/07/09 01:01:20]

stride() may not be multiple of kBytesPerPixel. Pass stride as it is, in bytes?

[Yuwei, 2016/07/09 01:21:24]

Hmm... The problem is GL_UNPACK_ROW_LENGTH expects stride in pixel. Maybe in
UpdateTexture, if |stride| is not multiple of kBytesPerPixel, then manually pack
the updated region?

[Sergey Ulanov, 2016/07/13 04:42:11]

hm, yeah. I don't know of any real world scenario where stride() is not multiple
of 4, so there is no performance concern about it. It's just there is nothing
that requires stride() to be multiple of 4 and it's cleaner to always pass
stride measured in bytes.

[Yuwei, 2016/07/13 18:14:16]

Done. Acknowledged.

+      }
+    }
+  }
+  last_frame_ = std::move(frame);
+}
+
+void GlDesktop::Draw() {
+  if (layer_ && last_frame_) {
+    layer_->Draw();
+  }
+}
+
+}  // namespace remoting