Note As of DirectX 8, the cost of changing vertex buffer is no longer as expensive as it was with previous versions, but it is still good practice to avoid vertex buffer changes where possible.

• 改变绘制状态会成为代价昂贵的操作，特别是在改变纹理时。因为如此，所以要尽可能的减少每帧的状态改变操作。同样也要尽量减少顶点缓存或者索引缓存的切换。