Use SkMatrix44 for the underlying implementation of ui::Transform

ui/gfx/compositor/compositor_gl.cc

 // Copyright (c) 2011 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 "ui/gfx/compositor/compositor.h"
 
 #include <GL/gl.h>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 143 matching lines @@
   t.ConcatTranslate(-window_size.width()/2.0f, -window_size.height()/2.0f);
   t.ConcatScale(2.0f/window_size.width(), 2.0f/window_size.height());
 
   DCHECK(compositor_->program());
   glUseProgram(compositor_->program());
 
   glActiveTexture(GL_TEXTURE0);
   glUniform1i(compositor_->u_tex_loc(), 0);
   glBindTexture(GL_TEXTURE_2D, texture_id_);
 
+  const SkMatrix44& matrix = t.matrix();

[rjkroege, 2011/06/10 17:52:14]

Given Ganesh, there should be a single call into SKMatrix44 that returs an array
pointer that you can pass to glUniformMatrix4fv. 

+
   GLfloat m[16];
-  const SkMatrix& matrix = t.matrix();
-
-  // Convert 3x3 view transform matrix (row major) into 4x4 GL matrix (column
-  // major). Assume 2-D rotations/translations restricted to XY plane.
-
-  m[ 0] = matrix[0];
-  m[ 1] = matrix[3];
-  m[ 2] = 0;
-  m[ 3] = matrix[6];
-
-  m[ 4] = matrix[1];
-  m[ 5] = matrix[4];
-  m[ 6] = 0;
-  m[ 7] = matrix[7];
-
-  m[ 8] = 0;
-  m[ 9] = 0;
-  m[10] = 1;
-  m[11] = 0;
-
-  m[12] = matrix[2];
-  m[13] = matrix[5];
-  m[14] = 0;
-  m[15] = matrix[8];
+  for (int i = 0; i < 4; ++i) {
+    for (int j = 0; j < 4; ++j) {
+      m[i + j * 4] = matrix.get(i, j);
+    }
+  }
 
   const GLfloat vertices[] = { -1., -1., +0., +0., +1.,
                                +1., -1., +0., +1., +1.,
                                +1., +1., +0., +1., +0.,
                                -1., +1., +0., +0., +0. };
 
   glVertexAttribPointer(compositor_->a_pos_loc(), 3, GL_FLOAT,
                         GL_FALSE, 5 * sizeof(GLfloat), vertices);
   glVertexAttribPointer(compositor_->a_tex_loc(), 2, GL_FLOAT,
                         GL_FALSE, 5 * sizeof(GLfloat), &vertices[3]);
@@ skipping 224 matching lines @@
 
 // static
 Compositor* Compositor::Create(gfx::AcceleratedWidget widget) {
   if (gfx::GetGLImplementation() != gfx::kGLImplementationNone)
     return new CompositorGL(widget);
   return NULL;
 }
 #endif
 
 }  // namespace ui