[Algorithms] Optimizing fill-rate for particle generators?

[Matt J <mjo...@gm...>]

Hi, I have a 200-400 particle generator that I released on my first
(private) game alpha. It represents the exhaust fumes of a futuristic
space ship. So this generator is pretty fast on the mobility raydeon
9700. However, when the camera gets very close to the particle
generator (ala the ship exhaust) it slows down noticeably. Well at
this early in the stage I want things running at full speed and glory,
not fill-rate limited! I'm assuming that the blending ops themselves
are taxing the system..not just because your sorting 400-800
textured/blended triangles, but because up close, all things being
constant, it simply can't fill enough pixels. Also it must be the
overdraw as well.. if I'm viewing it at an angle there won't be as
much overdraw as head-on.

So, Is there a way to create maybe a reverse level of detail so when
you zoom-up the particles decrease in count but add to the size ..? Is
there some way of reducing overdraw by simplication, stencil buffer,
anything? Or is this simply something that is handled by avoiding the
situation? I want zoom-ups for the cinematic parts of the game...

Thanks,

Matt
http://otowngraphics.blogspot.com