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      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 #include "base/gtest_prod_util.h"
     12 
     13 namespace content {
     14 
     15 // Provides caching of the compile-and-link step for shader programs at runtime
     16 // since, once compiled and linked, the programs can be shared.  Callers invoke
     17 // one of the UseXXX() methods to glUseProgram() the program and have its
     18 // uniform variables bound with the given parameters.
     19 //
     20 // Note: All public methods must be invoked within the the same GL context!
     21 class CompositingIOSurfaceShaderPrograms {
     22  public:
     23   CompositingIOSurfaceShaderPrograms();
     24   ~CompositingIOSurfaceShaderPrograms();
     25 
     26   // Reset the cache, deleting any references to currently-cached shader
     27   // programs.  This must be called within an active OpenGL context just before
     28   // destruction.
     29   void Reset();
     30 
     31   // Begin using the "blit" program, which is set up to sample the texture at
     32   // GL_TEXTURE_0.  Returns false on error.
     33   bool UseBlitProgram();
     34 
     35   // Begin using the program that just draws solid white very efficiently.
     36   // Returns false on error.
     37   bool UseSolidWhiteProgram();
     38 
     39   // Begin using one of the two RGB-to-YV12 color conversion programs, as
     40   // specified by |pass_number| 1 or 2.  The programs will sample the texture at
     41   // GL_TEXTURE0, and account for scaling in the X direction by |texel_scale_x|.
     42   // Returns false on error.
     43   bool UseRGBToYV12Program(int pass_number, float texel_scale_x);
     44 
     45   // |format| argument to use for glReadPixels() when reading back textures
     46   // generated by the RGBToYV12 program.
     47   GLenum rgb_to_yv12_output_format() const {
     48     return rgb_to_yv12_output_format_;
     49   }
     50 
     51  protected:
     52   FRIEND_TEST_ALL_PREFIXES(CompositingIOSurfaceTransformerTest,
     53                            TransformsRGBToYV12);
     54 
     55   // Side effect: Calls Reset(), deleting any cached programs.
     56   void SetOutputFormatForTesting(GLenum format);
     57 
     58  private:
     59   enum { kNumShaderPrograms = 4 };
     60 
     61   // Helper methods to cache uniform variable locations.
     62   GLuint GetShaderProgram(int which);
     63   void BindUniformTextureVariable(int which, int texture_unit_offset);
     64   void BindUniformTexelScaleXVariable(int which, float texel_scale_x);
     65 
     66   // Cached values for previously-compiled/linked shader programs, and the
     67   // locations of their uniform variables.
     68   GLuint shader_programs_[kNumShaderPrograms];
     69   GLint texture_var_locations_[kNumShaderPrograms];
     70   GLint texel_scale_x_var_locations_[kNumShaderPrograms];
     71 
     72   // Byte order of the quads generated by the RGBToYV12 shader program.  Must
     73   // always be GL_BGRA (default) or GL_RGBA (workaround case).
     74   GLenum rgb_to_yv12_output_format_;
     75 
     76   DISALLOW_COPY_AND_ASSIGN(CompositingIOSurfaceShaderPrograms);
     77 };
     78 
     79 }  // namespace content
     80 
     81 #endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_
     82