gfx/gl/ForceDiscreteGPUHelperCGL.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef ForceDiscreteGPUHelperCGL_h_
   7 #define ForceDiscreteGPUHelperCGL_h_
   8
   9 #include <OpenGL/OpenGL.h>
  10
  11 /** This RAII helper guarantees that we're on the discrete GPU during its lifetime.
  12  *
  13  * As long as any ForceDiscreteGPUHelperCGL object is alive, we're on the discrete GPU.
  14  */
  15 class ForceDiscreteGPUHelperCGL
  16 {
  17     CGLPixelFormatObj mPixelFormatObj;
  18
  19 public:
  20     ForceDiscreteGPUHelperCGL()
  21     {
  22         // the code in this function is taken from Chromium, src/ui/gfx/gl/gl_context_cgl.cc, r122013
  23         // BSD-style license, (c) The Chromium Authors
  24         CGLPixelFormatAttribute attribs[1];
  25         attribs[0] = static_cast<CGLPixelFormatAttribute>(0);
  26         GLint num_pixel_formats = 0;
  27         CGLChoosePixelFormat(attribs, &mPixelFormatObj, &num_pixel_formats);
  28     }
  29
  30     ~ForceDiscreteGPUHelperCGL()
  31     {
  32         CGLReleasePixelFormat(mPixelFormatObj);
  33     }
  34 };
  35
  36 #endif // ForceDiscreteGPUHelperCGL_h_