c++ - SDL/opengl 多重采样不起作用

Question

我正在尝试使用 SDL/opengl 进行多重采样，但 SDL 不接受设置 SDL_MULTISAMPLEBUFFERS 和 SDL_MULTISAMPLESAMPLES。相反，它们保留为 0，之后 SDL_SetVideoMode() 将失败。我知道我的硬件可以通过 4 倍多重采样处理这种像素格式。我正在运行 Ubuntu 10.10。

代码:

SDL_Init( SDL_INIT_VIDEO );
SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_ALPHA_SIZE, 0 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
SDL_GL_SetAttribute( SDL_GL_SWAP_CONTROL, 0 );
SDL_GL_SetAttribute( SDL_GL_ACCELERATED_VISUAL, 1 );
SDL_GL_SetAttribute( SDL_GL_MULTISAMPLEBUFFERS, 1 );
SDL_GL_SetAttribute( SDL_GL_MULTISAMPLESAMPLES, 4 );

Uint32 flags;
flags = SDL_OPENGL;
if( m_bFullscreen )
{
    flags = flags | SDL_FULLSCREEN;
}
SDL_SetVideoMode( m_sizeX, m_sizeY, 0, flags );

Answer 1

添加那些测试:

if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
    fprintf(stderr, "Unable to initialize SDL: %s\n", SDL_GetError());
    EXIT_FAILURE;
}

和

if ( SDL_SetVideoMode(m_sizeX, m_sizeY, 0, flags) == NULL ) {
    fprintf(stderr, "Unable to create OpenGL screen: %s\n", SDL_GetError());
    SDL_Quit();
    EXIT_FAILURE;
}

然后观察你的 stderr 输出。