Re: Using Performer or GL for smoke like fx?

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Ran Yakir (rany++at++bvr.co.il)
Mon, 5 Feb 1996 18:23:47 +0000

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On Feb 5, 10:47am, Nicolas Gauvin wrote:
> Subject: Using Performer or GL for smoke like fx?
>
> What is the recommed way to do special effects such as smoke in Performer?
>
> I have code that uses straight GL to calls to rotate and draw the various
> smoke puffs. pfuSmoke also uses straight GL. How about using Performer
> primitives instead (pfGeoSet and pfGeoState) combined with the appropriate
> pfDCS, pfSequence and pfBillboard? Would this be too much overhead compared
> to using straight GL calls. Since the smoke puffs requires to be dynamically
> sized and positionned maybe the fixed nature of pfGeoSet make them less
> usable in such a context. I would like to know the opinions of people
> who have tried both approaches.

You can have the best of two worlds : Have a DCS and a Billboard for the smoke,
which will contain empty geometry (just update the DCS's bounding sphere). This
way - Performer culls your effect and rotates it to meet the eye.
In a draw callback of that node you can draw the puffs or whatever using
straight GL. You can skip the billboard and use pfSprite instead, inside the
draw callback.

Ran

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