Fixed a lot of bugs with render surfaces and bitmaps.

samples/o3d-webgl/bitmap.js

 /*
  * Copyright 2010, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 56 matching lines @@
 o3d.Bitmap.FACE_NEGATIVE_X = 1;
 o3d.Bitmap.FACE_POSITIVE_Y = 2;
 o3d.Bitmap.FACE_NEGATIVE_Y = 3;
 o3d.Bitmap.FACE_POSITIVE_Z = 4;
 o3d.Bitmap.FACE_NEGATIVE_Z = 5;
 o3d.Bitmap.IMAGE = 6;
 o3d.Bitmap.SLICE = 7;
 
 
 /**
+ * The scratch canvas object.
+ * @private
+ */
+o3d.Bitmap.scratch_canvas_ = null;
+
+
+/**
+ * Gets a canvas to use for scratch work.
+ * @private
+ */
+o3d.Bitmap.getScratchCanvas_ = function() {
+  if (!o3d.Bitmap.scratch_canvas_)
+    o3d.Bitmap.scratch_canvas_ = document.createElement('CANVAS');
+  return o3d.Bitmap.scratch_canvas_;
+}
+
+
+/**
  * In webgl the bitmap object is represented by an offscreen canvas.
  * @type {Canvas}
  * @private
  */
 o3d.Bitmap.prototype.canvas_ = null;
 
 
 /**
  * Flips a bitmap vertically in place.
  */
 o3d.Bitmap.prototype.flipVertically = function() {
   this.defer_flip_vertically_to_texture_ = true;
 };
 
 
+
 /**
  * Generates mip maps from the source level to lower levels.
  * 
  * You can not currently generate mips for DXT textures although you can load
  * them from dds files.
  * 
  * @param {number} source_level The level to use as the source of the mips.
  * @param {number} num_levels The number of levels to generate below the
  *     source level.
  */
@@ skipping 53 matching lines @@
 
 
 /**
  * The Semantic of the bitmap.
  * @type {!o3d.Bitmap.Semantic}
  */
 o3d.Bitmap.prototype.semantic = o3d.Bitmap.UNKNOWN_SEMANTIC;