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我正在尝试创建具有SDL_CreateRGBSurface和SDL_FillRect功能的纹理，但遗憾的是我没有这样做；我得到的只是一个黑色矩形。

为了完成该任务，我使用了以下代码（用于从文件加载纹理IMG_Load）：

#if SDL_BYTEORDER == SDL_BIG_ENDIAN
        rmask = 0xff000000;
        gmask = 0x00ff0000;
        bmask = 0x0000ff00;
        amask = 0x000000ff;
#else
        rmask = 0x000000ff;
        gmask = 0x0000ff00;
        bmask = 0x00ff0000;
        amask = 0xff000000;
#endif
        rect = SDL_CreateRGBSurface(SDL_SWSURFACE, _w,_h,24,rmask,gmask,bmask,amask);
        if(rect == NULL ) {
            fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
            exit(1);
        }

        Uint32 color = SDL_MapRGBA(rect->format,255,255,0,126);
        SDL_FillRect(rect,NULL,color);
        render.load(rect);

在纹理加载中使用以下代码

void Texture::load(SDL_Surface* surface){
    ogl_check_error("surface load");
    GLenum texture_format;
    GLint  nOfColors;
    if (  surface  ) { 

        // get the number of channels in the SDL surface
        nOfColors = surface->format->BytesPerPixel;

        if (nOfColors == 4)     // contains an alpha channel
        {
                if (surface->format->Rmask == 0x000000ff)
                        texture_format = GL_RGBA;
                else
                        texture_format = GL_BGRA;
        } else if (nOfColors == 3){    // no alpha channel

            if (surface->format->Rmask == 0x000000ff)
                    texture_format = GL_RGB;
            else
                    texture_format = GL_BGR;
         }else {
            cerr<<"bad surface"<<endl;
            exit(1);
            }

    // Have OpenGL generate a texture object handle for us
    glGenTextures( 1, &texture );

    // Bind the texture object
    glBindTexture( GL_TEXTURE_2D, texture );

    // Set the texture's stretching properties
        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );

    // Edit the texture object's image data using the information SDL_Surface gives us
    glTexImage2D( GL_TEXTURE_2D, 0, nOfColors, surface->w, surface->h, 0,
                    texture_format, GL_UNSIGNED_BYTE, surface->pixels );
} 
else {
    printf("SDL could not load image.bmp: %s\n", SDL_GetError());
    SDL_Quit();
    exit(1);
}    
ogl_check_error("after surface load");
width = surface->w;
height = surface -> h;


}
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2 回答 2

0

你在设置 sdl_gl_attributes 吗？

像 SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16); SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, 8);

于 2013-06-11T17:11:33.960 回答
0

对于后代-我为矩形设置了错误的深度，它应该是 32 而不是 24...。

于 2013-06-08T21:13:59.290 回答