Re: render particle

Andras has good advice.

But if you're reluctant to use OpenGL sprites because you want to use 
OpenGL 1.1, then you could also consider rendering each particle as a 
single billboarded (always facing the camera) triangle.

You can render them with alpha on and use a texture with a circular 
gradient (solid in the middle, transparent at the edges). If you use the 
"Flyweight" pattern you can treat all the particles in one as having 
common attributes and minimize state changes.

It's old technology, but it's been proven in many games. And if your 
target is that low, you probably want to consider it.

    Kent




Andras Balogh wrote:

> First, you'll probably be limited by fillrate way before you'll be 
> limited  by vertex transforms. But even if not, next you'll be limited 
> by bus  bandwidth, and points need 4 times less bandwidth than quads. 
> Finally, the  only time you might want to micro-optimize like this, is 
> when you're  competing with johnc, but then you probably wouldn't need 
> our advice ;)
>
> Trust me, getting rid of camera transformation is not an 
> optimization.  There's so much more going on that this won't make the 
> slightest  difference! I'm sure you've heard this before: "Premature 
> optimization is  the root of all evil". Always go with the simplest 
> solution, and then  optimize the bottleneck. It makes no sense to 
> optimize something that is  not even the bottleneck! You'll end up 
> with more complicated, less  flexible and probably slower code.
>
> Of course, sprites have their problems, like HW dependent size limit 
> (most  cards max out at 64x64 pixels), but that's not a speed issue, 
> but a  feature issue.
>
>
> Andras


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