glextensions.h Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the demonstration applications of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "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.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #ifndef GLEXTENSIONS_H
  #define GLEXTENSIONS_H

  #include <QtOpenGL>

  /*
  Functions resolved:

  glGenFramebuffersEXT
  glGenRenderbuffersEXT
  glBindRenderbufferEXT
  glRenderbufferStorageEXT
  glDeleteFramebuffersEXT
  glDeleteRenderbuffersEXT
  glBindFramebufferEXT
  glFramebufferTexture2DEXT
  glFramebufferRenderbufferEXT
  glCheckFramebufferStatusEXT

  glActiveTexture
  glTexImage3D

  glGenBuffers
  glBindBuffer
  glBufferData
  glDeleteBuffers
  glMapBuffer
  glUnmapBuffer
  */

  #ifndef Q_OS_MAC
  # ifndef APIENTRYP
  #   ifdef APIENTRY
  #     define APIENTRYP APIENTRY *
  #   else
  #     define APIENTRY
  #     define APIENTRYP *
  #   endif
  # endif
  #else
  # define APIENTRY
  # define APIENTRYP *
  #endif

  #ifndef GL_VERSION_1_2
  #define GL_TEXTURE_3D 0x806F
  #define GL_TEXTURE_WRAP_R 0x8072
  #define GL_CLAMP_TO_EDGE 0x812F
  #define GL_BGRA 0x80E1
  #endif

  #ifndef GL_VERSION_1_3
  #define GL_TEXTURE0 0x84C0
  #define GL_TEXTURE1 0x84C1
  #define GL_TEXTURE2 0x84C2
  #define GL_TEXTURE_CUBE_MAP 0x8513
  #define GL_TEXTURE_CUBE_MAP_POSITIVE_X 0x8515
  //#define GL_TEXTURE_CUBE_MAP_NEGATIVE_X 0x8516
  //#define GL_TEXTURE_CUBE_MAP_POSITIVE_Y 0x8517
  //#define GL_TEXTURE_CUBE_MAP_NEGATIVE_Y 0x8518
  //#define GL_TEXTURE_CUBE_MAP_POSITIVE_Z 0x8519
  //#define GL_TEXTURE_CUBE_MAP_NEGATIVE_Z 0x851A
  #endif

  #ifndef GL_ARB_vertex_buffer_object
  typedef ptrdiff_t GLsizeiptrARB;
  #endif

  #ifndef GL_VERSION_1_5
  #define GL_ARRAY_BUFFER 0x8892
  #define GL_ELEMENT_ARRAY_BUFFER 0x8893
  #define GL_READ_WRITE 0x88BA
  #define GL_STATIC_DRAW 0x88E4
  #endif

  #ifndef GL_EXT_framebuffer_object
  #define GL_RENDERBUFFER_EXT 0x8D41
  #define GL_FRAMEBUFFER_EXT 0x8D40
  #define GL_FRAMEBUFFER_COMPLETE_EXT 0x8CD5
  #define GL_COLOR_ATTACHMENT0_EXT 0x8CE0
  #define GL_DEPTH_ATTACHMENT_EXT 0x8D00
  #endif

  typedef void (APIENTRY *_glGenFramebuffersEXT) (GLsizei, GLuint *);
  typedef void (APIENTRY *_glGenRenderbuffersEXT) (GLsizei, GLuint *);
  typedef void (APIENTRY *_glBindRenderbufferEXT) (GLenum, GLuint);
  typedef void (APIENTRY *_glRenderbufferStorageEXT) (GLenum, GLenum, GLsizei, GLsizei);
  typedef void (APIENTRY *_glDeleteFramebuffersEXT) (GLsizei, const GLuint*);
  typedef void (APIENTRY *_glDeleteRenderbuffersEXT) (GLsizei, const GLuint*);
  typedef void (APIENTRY *_glBindFramebufferEXT) (GLenum, GLuint);
  typedef void (APIENTRY *_glFramebufferTexture2DEXT) (GLenum, GLenum, GLenum, GLuint, GLint);
  typedef void (APIENTRY *_glFramebufferRenderbufferEXT) (GLenum, GLenum, GLenum, GLuint);
  typedef GLenum (APIENTRY *_glCheckFramebufferStatusEXT) (GLenum);

  typedef void (APIENTRY *_glActiveTexture) (GLenum);
  typedef void (APIENTRY *_glTexImage3D) (GLenum, GLint, GLenum, GLsizei, GLsizei, GLsizei, GLint, GLenum, GLenum, const GLvoid *);

  typedef void (APIENTRY *_glGenBuffers) (GLsizei, GLuint *);
  typedef void (APIENTRY *_glBindBuffer) (GLenum, GLuint);
  typedef void (APIENTRY *_glBufferData) (GLenum, GLsizeiptrARB, const GLvoid *, GLenum);
  typedef void (APIENTRY *_glDeleteBuffers) (GLsizei, const GLuint *);
  typedef void *(APIENTRY *_glMapBuffer) (GLenum, GLenum);
  typedef GLboolean (APIENTRY *_glUnmapBuffer) (GLenum);

  struct GLExtensionFunctions
  {
      bool resolve(const QGLContext *context);

      bool fboSupported();
      bool openGL15Supported(); // the rest: multi-texture, 3D-texture, vertex buffer objects

      _glGenFramebuffersEXT GenFramebuffersEXT;
      _glGenRenderbuffersEXT GenRenderbuffersEXT;
      _glBindRenderbufferEXT BindRenderbufferEXT;
      _glRenderbufferStorageEXT RenderbufferStorageEXT;
      _glDeleteFramebuffersEXT DeleteFramebuffersEXT;
      _glDeleteRenderbuffersEXT DeleteRenderbuffersEXT;
      _glBindFramebufferEXT BindFramebufferEXT;
      _glFramebufferTexture2DEXT FramebufferTexture2DEXT;
      _glFramebufferRenderbufferEXT FramebufferRenderbufferEXT;
      _glCheckFramebufferStatusEXT CheckFramebufferStatusEXT;

      _glActiveTexture ActiveTexture;
      _glTexImage3D TexImage3D;

      _glGenBuffers GenBuffers;
      _glBindBuffer BindBuffer;
      _glBufferData BufferData;
      _glDeleteBuffers DeleteBuffers;
      _glMapBuffer MapBuffer;
      _glUnmapBuffer UnmapBuffer;
  };

  inline GLExtensionFunctions &getGLExtensionFunctions()
  {
      static GLExtensionFunctions funcs;
      return funcs;
  }

  #define glGenFramebuffersEXT getGLExtensionFunctions().GenFramebuffersEXT
  #define glGenRenderbuffersEXT getGLExtensionFunctions().GenRenderbuffersEXT
  #define glBindRenderbufferEXT getGLExtensionFunctions().BindRenderbufferEXT
  #define glRenderbufferStorageEXT getGLExtensionFunctions().RenderbufferStorageEXT
  #define glDeleteFramebuffersEXT getGLExtensionFunctions().DeleteFramebuffersEXT
  #define glDeleteRenderbuffersEXT getGLExtensionFunctions().DeleteRenderbuffersEXT
  #define glBindFramebufferEXT getGLExtensionFunctions().BindFramebufferEXT
  #define glFramebufferTexture2DEXT getGLExtensionFunctions().FramebufferTexture2DEXT
  #define glFramebufferRenderbufferEXT getGLExtensionFunctions().FramebufferRenderbufferEXT
  #define glCheckFramebufferStatusEXT getGLExtensionFunctions().CheckFramebufferStatusEXT

  #define glActiveTexture getGLExtensionFunctions().ActiveTexture
  #define glTexImage3D getGLExtensionFunctions().TexImage3D

  #define glGenBuffers getGLExtensionFunctions().GenBuffers
  #define glBindBuffer getGLExtensionFunctions().BindBuffer
  #define glBufferData getGLExtensionFunctions().BufferData
  #define glDeleteBuffers getGLExtensionFunctions().DeleteBuffers
  #define glMapBuffer getGLExtensionFunctions().MapBuffer
  #define glUnmapBuffer getGLExtensionFunctions().UnmapBuffer

  #endif