content/browser/renderer_host/compositing_iosurface_shader_programs_mac.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_
   7
   8 #include <OpenGL/gl.h>
   9
  10 #include "base/basictypes.h"
  11
  12 namespace content {
  13
  14 // Provides caching of the compile-and-link step for shader programs at runtime
  15 // since, once compiled and linked, the programs can be shared.  Callers invoke
  16 // one of the UseXXX() methods within a GL context to glUseProgram() the program
  17 // and have its uniform variables bound with the given parameters.
  18 class CompositingIOSurfaceShaderPrograms {
  19  public:
  20   CompositingIOSurfaceShaderPrograms();
  21   ~CompositingIOSurfaceShaderPrograms();
  22
  23   // Reset the cache, deleting any references to currently-cached shader
  24   // programs.  This must be called within an active OpenGL context just before
  25   // destruction.
  26   void Reset();
  27
  28   // Begin using the "blit" program, which is set up to sample the texture at
  29   // GL_TEXTURE_0.  Returns false on error.
  30   bool UseBlitProgram();
  31
  32   // Begin using the program that just draws solid white very efficiently.
  33   // Returns false on error.
  34   bool UseSolidWhiteProgram();
  35
  36   // Begin using one of the two RGB-to-YV12 color conversion programs, as
  37   // specified by |pass_number| 1 or 2.  The programs will sample the texture at
  38   // GL_TEXTURE0, and account for scaling in the X direction by |texel_scale_x|.
  39   // Returns false on error.
  40   bool UseRGBToYV12Program(int pass_number, float texel_scale_x);
  41
  42  private:
  43   enum { kNumShaderPrograms = 4 };
  44
  45   // Helper methods to cache uniform variable locations.
  46   GLuint GetShaderProgram(int which);
  47   void BindUniformTextureVariable(int which, int texture_unit_offset);
  48   void BindUniformTexelScaleXVariable(int which, float texel_scale_x);
  49
  50   // Cached values for previously-compiled/linked shader programs, and the
  51   // locations of their uniform variables.
  52   GLuint shader_programs_[kNumShaderPrograms];
  53   GLint texture_var_locations_[kNumShaderPrograms];
  54   GLint texel_scale_x_var_locations_[kNumShaderPrograms];
  55
  56   DISALLOW_COPY_AND_ASSIGN(CompositingIOSurfaceShaderPrograms);
  57 };
  58
  59 }  // namespace content
  60
  61 #endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_