rendering_helper - Refactoring - remove the Client interface.

content/common/gpu/media/rendering_helper.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_COMMON_GPU_MEDIA_RENDERING_HELPER_H_
 #define CONTENT_COMMON_GPU_MEDIA_RENDERING_HELPER_H_
 
+#include <deque>
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_surface.h"
 
 namespace base {
 class MessageLoop;
 class WaitableEvent;
 }
 
 namespace content {
 
-struct RenderingHelperParams;
+class VideoFrame : public base::RefCounted<VideoFrame> {
+ public:
+  uint32 texture_id() const { return texture_id_; }
+  uint32 texture_target() const { return texture_target_; }
+
+  VideoFrame(uint32 texture_target,
+             uint32 texture_id,
+             const base::Closure& no_longer_needed_cb);
+  ~VideoFrame();
+
+ private:
+  uint32 texture_target_;
+  uint32 texture_id_;
+  base::Closure no_longer_needed_cb_;
+};
+
+struct RenderingHelperParams {
+  RenderingHelperParams();
+  ~RenderingHelperParams();
+
+  // The rendering FPS.
+  int rendering_fps;
+
+  // The desired size of each window. We play each stream in its own window
+  // on the screen.
+  std::vector<gfx::Size> window_sizes;
+
+  // The members below are only used for the thumbnail mode where all frames
+  // are rendered in sequence onto one FBO for comparison/verification purposes.
+
+  // Whether the frames are rendered as scaled thumbnails within a
+  // larger FBO that is in turn rendered to the window.
+  bool render_as_thumbnails;
+  // The size of the FBO containing all visible thumbnails.
+  gfx::Size thumbnails_page_size;
+  // The size of each thumbnail within the FBO.
+  gfx::Size thumbnail_size;
+};
 
 // Creates and draws textures used by the video decoder.
 // This class is not thread safe and thus all the methods of this class
 // (except for ctor/dtor) ensure they're being run on a single thread.
 class RenderingHelper {
  public:
-  // Interface for the content provider of the RenderingHelper.
-  class Client {
-   public:
-    // Callback to tell client to render the content.
-    virtual void RenderContent(RenderingHelper* helper) = 0;
-
-    // Callback to get the desired window size of the client.
-    virtual const gfx::Size& GetWindowSize() = 0;
-
-   protected:
-    virtual ~Client() {}
-  };
 
   RenderingHelper();
   ~RenderingHelper();
 
   static bool InitializeOneOff();
 
   // Create the render context and windows by the specified dimensions.
   void Initialize(const RenderingHelperParams& params,
                   base::WaitableEvent* done);
 
   // Undo the effects of Initialize() and signal |*done|.
   void UnInitialize(base::WaitableEvent* done);
 
   // Return a newly-created GLES2 texture id of the specified size, and
   // signal |*done|.
   void CreateTexture(uint32 texture_target,
                      uint32* texture_id,
                      const gfx::Size& size,
                      base::WaitableEvent* done);
 
   // Render thumbnail in the |texture_id| to the FBO buffer using target
   // |texture_target|.
   void RenderThumbnail(uint32 texture_target, uint32 texture_id);
 
-  // Render |texture_id| to the current view port of the screen using target
-  // |texture_target|.
-  void RenderTexture(uint32 texture_target, uint32 texture_id);
+  // Queues the VideoFrame for rendering.
+  void QueueVideoFrame(size_t window_id, scoped_refptr<VideoFrame> video_frame);
+
+  // Drops all the pending video frames of the specified window.
+  void DropPendingFrames(size_t window_id);
 
   // Delete |texture_id|.
   void DeleteTexture(uint32 texture_id);
 
   // Get the platform specific handle to the OpenGL display.
   void* GetGLDisplay();
 
   // Get the platform specific handle to the OpenGL context.
   void* GetGLContext();
 
   // Get rendered thumbnails as RGB.
   // Sets alpha_solid to true if the alpha channel is entirely 0xff.
   void GetThumbnailsAsRGB(std::vector<unsigned char>* rgb,
                           bool* alpha_solid,
                           base::WaitableEvent* done);
 
  private:
+  struct RenderedVideo {
+    // The rect on the screen where the video will be rendered.
+    gfx::Rect render_area;
+
+    // Ture if the last (and the only one) frame in pending_frames has

[Pawel Osciak, 2014/08/15 05:45:16]

s/Ture/True/

Also, I think you want to say not the last, but the oldest/front frame. Even if
we have more than one frame in pending, we still use last_frame_rendered to know
if we can return it...

Also please add:

We keep the last remaining frame in pending_frames even after it has been
rendered, so that we have something to display if the client is falling behind
on providing us with new frames during timer-driven playback.

[Owen Lin, 2014/08/18 09:03:08]

I have changed the documentation. But I am confused, if we have more than one
frame in pending, then last_frame_rendered won't be True.
Done. Thanks.

[Pawel Osciak, 2014/08/20 10:26:26]

Right, it was actually me who was confused. Please see my comment in the other
file about this.

+    // been rendered.
+    bool last_frame_rendered;
+
+    // The video frames pending for rendering.
+    std::deque<scoped_refptr<VideoFrame> > pending_frames;

[Pawel Osciak, 2014/08/15 05:45:16]

Oh I forgot to comment on this last time, you don't really need a deque I think,
std::queue should be enough?

[Owen Lin, 2014/08/18 09:03:08]

Done. Thanks. I got a feeling that deque is more efficient. But maybe that's
only for java's implementation.

+
+    RenderedVideo() : last_frame_rendered(false) {}
+  };
+
   void Clear();
 
   void RenderContent();
 
-  void LayoutRenderingAreas();
+  void LayoutRenderingAreas(const std::vector<gfx::Size>& window_sizes);
+
+  // Render |texture_id| to the current view port of the screen using target
+  // |texture_target|.
+  void RenderTexture(uint32 texture_target, uint32 texture_id);
 
   // Timer to trigger the RenderContent() repeatly.
   scoped_ptr<base::RepeatingTimer<RenderingHelper> > render_timer_;
   base::MessageLoop* message_loop_;
 
   scoped_refptr<gfx::GLContext> gl_context_;
   scoped_refptr<gfx::GLSurface> gl_surface_;
 
   gfx::AcceleratedWidget window_;
 
   gfx::Size screen_size_;
 
-  // The rendering area of each window on the screen.
-  std::vector<gfx::Rect> render_areas_;
-
-  std::vector<base::WeakPtr<Client> > clients_;
+  std::vector<RenderedVideo> videos_;
 
   bool render_as_thumbnails_;
   int frame_count_;
   GLuint thumbnails_fbo_id_;
   GLuint thumbnails_texture_id_;
   gfx::Size thumbnails_fbo_size_;
   gfx::Size thumbnail_size_;
   GLuint program_;
   base::TimeDelta frame_duration_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderingHelper);
 };
 
-struct RenderingHelperParams {
-  RenderingHelperParams();
-  ~RenderingHelperParams();
-
-  // The rendering FPS.
-  int rendering_fps;
-
-  // The clients who provide the content for rendering.
-  std::vector<base::WeakPtr<RenderingHelper::Client> > clients;
-
-  // Whether the frames are rendered as scaled thumbnails within a
-  // larger FBO that is in turn rendered to the window.
-  bool render_as_thumbnails;
-  // The size of the FBO containing all visible thumbnails.
-  gfx::Size thumbnails_page_size;
-  // The size of each thumbnail within the FBO.
-  gfx::Size thumbnail_size;
-};
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_RENDERING_HELPER_H_