GL EXT framebuffer multisample

Examples :

When GL_EXT_framebuffer_multisample is supported, GL_EXT_framebuffer_object and GL_EXT_framebuffer_blit are also supported.

  uint fboID, ColorBufferID, DepthBufferID;
  sint samples;
  schar ErrorMessage[1024];
  //We need to find out what the maximum supported samples is
  glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
  //----------------------
  //If for example, 16 is returned, then you can attempt to make a FBO with samples=0 to 16
  //0 means no multiple. This is like using glFramebufferRenderbufferEXT instead of glRenderbufferStorageMultisampleEXT
  //You can attempt to make sample from 1 to 16, but some of them might fail
  //Now, let's make a FBO
  glGenFramebuffersEXT(1, &fboID);
  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fboID);
  //----------------------
  //Now make a multisample color buffer
  glGenRenderbuffersEXT(1, &ColorBufferID);
  glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, ColorBufferID);
  //samples=4, format=GL_RGBA8, width=256, height=256
  glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, 4, GL_RGBA8, 256, 256);
  //----------------------
  //Make a depth multisample depth buffer
  //You must give it the same samples as the color RB, same width and height as well
  //else you will either get a GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT or some other error
  glGenRenderbuffersEXT(1, &DepthBufferID);
  glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthBufferID);
  //samples=4, format=GL_DEPTH_COMPONENT24, width=256, height=256
  glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, 4, GL_DEPTH_COMPONENT24, 256, 256);
  //----------------------
  //It's time to attach the RBs to the FBO
  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_RENDERBUFFER_EXT, ColorBufferID);
  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, DepthBufferID);
  //----------------------
  //Make sure FBO status is good
  value=glExtCheckFramebufferStatus(ErrorMessage);

  sint glExtCheckFramebufferStatus(schar *errorMessage)
  {
  GLenum status;
  status=glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
  switch(status)
  {
  case GL_FRAMEBUFFER_COMPLETE_EXT:
  break;
  case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
  //Choose different formats
  strcpy(errorMessage, "Framebuffer object format is unsupported by the video hardware. (GL_FRAMEBUFFER_UNSUPPORTED_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
  strcpy(errorMessage, "Incomplete attachment. (GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
  strcpy(errorMessage, "Incomplete missing attachment. (GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
  strcpy(errorMessage, "Incomplete dimensions. (GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
  strcpy(errorMessage, "Incomplete formats. (GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
  strcpy(errorMessage, "Incomplete draw buffer. (GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
  strcpy(errorMessage, "Incomplete read buffer. (GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT)(FBO - 820)");
  return -1;
  case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
  strcpy(errorMessage, "Incomplete multisample buffer. (GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT)(FBO - 820)");
  return -1;
  default:
  //Programming error; will fail on all hardware
  strcpy(errorMessage, "Some video driver error or programming error occured. Framebuffer object status is invalid. (FBO - 823)");
  return -2;
  }
  return 1;
  }