static int __render_gl(int id, SDL_Surface* surface, int srcX, int srcY, int dstX,
                        int dstY, int width, int height)
{
    GLuint texture;
    GLenum texture_format;
    /* Get the texture format.
     */
    if (surface->format->BytesPerPixel == 4) {
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
        if (surface->format->Rmask == 0xff000000)
#else
        if (surface->format->Rmask == 0x000000ff)
#endif
            texture_format = GL_RGBA;
        else
            texture_format = GL_BGRA;
    } else if (surface->format->BytesPerPixel == 3) {
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
        if (surface->format->Rmask == 0xff000000)
#else
        if (surface->format->Rmask == 0x000000ff)
#endif
            texture_format = GL_RGB;
        else
            texture_format = GL_BGR;
    } else {
        sgeSetError("%s: Surface %d has unknown/invalid format", __func__,
                                id);
        return -1;
    }
    /* Generate & set up the texture object.
     */
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, surface->format->BytesPerPixel, width,
        height, 0, texture_format, GL_UNSIGNED_BYTE, surface->pixels);
    /* Draw the texture.
     */
    glBindTexture(GL_TEXTURE_2D, texture);
    glBegin(GL_QUADS);
        /* Bottem-left vertex. */
        glTexCoord2i(0, 0);
        glVertex3f(dstX,         dstY, 0.f);
        /* Bottom-right vertex. */
        glTexCoord2i(1, 0);
        glVertex3f(dstX + width, dstY, 0.f);
        /* Top-right vertex. */
        glTexCoord2i(1, 1);
        glVertex3f(dstX + width, dstY + height, 0.f);
        /* Top-left vertex. */
        glTexCoord2i(0, 1);
        glVertex3f(dstX,         dstY + height, 0.f);

    glEnd();
    glDeleteTextures(1, &texture);
    return 0;
}