Warp wrote:

>   That's actually one of the limitation of lightmaps: You can create superb
> shadows for *static* scenery, but you can't use them to calculate shadows
> for moving objects.

Yep, it's true.

(Well, if you have an "almost" static scene, you could perhaps include 
extra data for, say, when a door opens or something. I doubt it would be 
very accurate.)

>   There are two techniques to calculate shadows: Shadow volumes, which are
> based on shadow polygons (used, for example, by Doom3 and games using the
> same engine) and shadow mapping (used, for example, in the Splinter Cell
> games).
> 
>   Both have their advantages and disadvantages, which is why neither one
> is overwhelmingly popular (although shadow mapping might be a bit more
> popular because it's a bit easier to implement and has its own advantages).
> 
> http://en.wikipedia.org/wiki/Shadow_volume
> http://en.wikipedia.org/wiki/Shadow_mapping

Mmm, interesting.

I'm surprised shadow volumes didn't occur to me before. The intro to HL1 
features what I guess you could call a "light volume": a door opens and 
a semitransparent object representing the light flooding in is revealed. 
(This illusion is then nicely shattered by driving a truck through it 
without altering the geometry! But hey, it probably required no 
alteration to the Quake engine...)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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