Initial version rendering 2D path for O3D. This will eventually allow O3D app...

core/cross/renderer.h

Index: core/cross/renderer.h
===================================================================
--- core/cross/renderer.h	(revision 57528)
+++ core/cross/renderer.h	(working copy)
@@ -277,12 +277,12 @@
   void SetViewport(const Float4& rectangle, const Float2& depth_range);
 
   // Clears the current buffers.
-  void Clear(const Float4 &color,
-             bool color_flag,
-             float depth,
-             bool depth_flag,
-             int stencil,
-             bool stencil_flag);
+  virtual void Clear(const Float4 &color,
+                     bool color_flag,
+                     float depth,
+                     bool depth_flag,
+                     int stencil,
+                     bool stencil_flag);
 
   // Renders this Element using the parameters from override first, followed by
   // the draw_element, followed by params on this Primitive and material.
@@ -298,10 +298,10 @@
                      ParamCache* param_cache);
 
   // Pushes rendering states.
-  void PushRenderStates(State *state);
+  virtual void PushRenderStates(State *state);
 
   // Pops rendering states to back to their previous settings.
-  void PopRenderStates();
+  virtual void PopRenderStates();
 
   // Binds the passed surfaces to the color and depth buffers of the
   // renderer.