一个老外是这么说的:
Never, ever, ever use DrawPrimitiveUP if you can avoid it. The only time I *ever* use it, is just to show people what it is, and what it does, so they can avoid ever using it.
UP系列没有创建LOCAL的VERTEXBUFFER,只需要指定SYSTEM MEM的顶点数组就可以,所以使用起来非常方便,特别是调试的时候,不需要写一堆CREATE,RELEASE,LOCK/UNLOCK,也不用设置什么STREAMSOURCE
但是唯一的缺点,很明显,就是慢,所以在非调试状态下,的确是NEVER USING IT