Re: Re[2]: [Algorithms] To D3DX or not to D3DX

[Steve H. <un...@bt...>]

> Actually, I don't think you can do inline SIMD code without explicitly
> targeting some platform (eg. the one that has SSE). You have to do
> separate compilations for platforms; or some function dispatch tables...

http://www.flipcode.com/cgi-bin/msg.cgi?showThread=Tip-AutomaticCPUDetection&forum=totd&id=24

I guess this is what you meant by a dispatch table although I'd call it a
jump table since dispatch to me implies a tad more structure or logic, which
you only pay for the first time here. The extra indirection with D3DX for
heavy maths functions isn't too bad, but if it bothers anyone then take a
look
at the rest of the thread. ;)

Of course for speed, the best option is to inline with a specific target and
switch at a higher level if need be. I just thought some people might be
wondering what D3DX is doing under the covers, although it's probably
been mentioned before in conferences presentations.

Steve Hill