Adding drawable to CRD andorid and iOS gl rendering pipeline.

remoting/client/display/canvas.h

 // 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.
 
-#ifndef REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_
-#define REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_
+#ifndef REMOTING_CLIENT_DISPLAY_CANVAS_H_
+#define REMOTING_CLIENT_DISPLAY_CANVAS_H_
 
 #include <array>
 
 #include "base/macros.h"
-#include "base/threading/thread_checker.h"
+#include "base/memory/weak_ptr.h"
 #include "remoting/client/display/sys_opengl.h"
 
 namespace remoting {
 
 // This class holds zoom and pan configurations of the canvas and is used to
 // draw textures on the canvas.
-// Must be constructed after the OpenGL surface is created and destroyed before
-// the surface is destroyed.
-class GlCanvas {
+class Canvas {
  public:
-  // gl_version: version number of the OpenGL ES context. Either 2 or 3.
-  GlCanvas(int gl_version);
+  Canvas(){};
+  virtual ~Canvas(){};

[Sergey Ulanov, 2017/01/10 23:24:01]

remove ; in these two lines

 
-  ~GlCanvas();
+  // Clears the frame.
+  virtual void Clear() = 0;
 
   // Sets the transformation matrix. This matrix defines how the canvas should
   // be shown on the view.
   // 3 by 3 transformation matrix, [ m0, m1, m2, m3, m4, m5, m6, m7, m8 ].
   // The matrix will be multiplied with the positions (with projective space,
   // (x, y, 1)) to draw the textures with the right zoom and pan configuration.
   //
   // | m0, m1, m2, |   | x |
   // | m3, m4, m5, | * | y |
   // | m6, m7, m8  |   | 1 |
   //
   // For a typical transformation matrix such that m1=m3=m6=m7=0 and m8=1, m0
   // and m4 defines the scaling factor of the canvas and m2 and m5 defines the
   // offset of the upper-left corner in pixel.
-  void SetTransformationMatrix(const std::array<float, 9>& matrix);
+  virtual void SetTransformationMatrix(const std::array<float, 9>& matrix) = 0;
 
   // Sets the size of the view in pixels.
-  void SetViewSize(int width, int height);
+  virtual void SetViewSize(int width, int height) = 0;
 
   // Draws the texture on the canvas. Nothing will happen if
   // SetNormalizedTransformation() has not been called.
   // vertex_buffer: reference to the 2x4x2 float vertex buffer.
   //                [ four (x, y) position of the texture vertices in pixel
   //                              with respect to the canvas,
   //                  four (x, y) position of the vertices in percentage
   //                              defining the visible area of the texture ]
   // alpha_multiplier: Will be multiplied with the alpha channel of the texture.
   //                   Passing 1 means no change of the transparency of the
   //                   texture.
-  void DrawTexture(int texture_id,
-                   GLuint texture_handle,
-                   GLuint vertex_buffer,
-                   float alpha_multiplier);
+  virtual void DrawTexture(int texture_id,
+                           GLuint texture_handle,
+                           GLuint vertex_buffer,

[Sergey Ulanov, 2017/01/10 23:24:01]

probably not for this CL: is this interface supposed to have dependency on
OpenGL. Right now it looks like gl headers need to be pulled just for GLuint
type, which is easy to avoid by using int instead of GLuint here.

[nicholss, 2017/01/11 18:56:43]

Done.

+                           float alpha_multiplier) = 0;
 
-  // Returns the version number of current OpenGL ES context. Either 2 or 3.
-  int GetGlVersion() const;
+  // Version if applicable to implementation.

[joedow, 2017/01/10 22:01:55]

Can this method be defined to return a specific value (say -1 or 0) if it is not
applicable to the underlying implementation?  Defining that value in the comment
here would be useful for consumers of the interface.

+  virtual int GetVersion() const = 0;
 
   // Returns the maximum texture resolution limitation. Neither the width nor
   // the height of the texture can exceed this limitation.
-  int GetMaxTextureSize() const;
+  virtual int GetMaxTextureSize() const = 0;
+
+  // Intended to be given to a Drawable to draw onto.
+  virtual base::WeakPtr<Canvas> GetWeakPtr() = 0;
 
  private:
-  int gl_version_;
-
-  int max_texture_size_ = 0;
-  bool transformation_set_ = false;
-  bool view_size_set_ = false;
-
-  // Handles.
-  GLuint vertex_shader_;
-  GLuint fragment_shader_;
-  GLuint program_;
-
-  // Locations of the corresponding shader attributes.
-  GLuint transform_location_;
-  GLuint view_size_location_;
-  GLuint texture_location_;
-  GLuint alpha_multiplier_location_;
-  GLuint position_location_;
-  GLuint tex_cord_location_;
-
-  base::ThreadChecker thread_checker_;
-
-  DISALLOW_COPY_AND_ASSIGN(GlCanvas);
+  DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace remoting
 
-#endif  // REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_
+#endif  // REMOTING_CLIENT_DISPLAY_CANVAS_H_