RE: [Algorithms] Stopping shadow volumes from going through geometry

[Joris M. <jor...@pa...>]

this is the answer i see all the time when ppl ask this question (please
dont take this personally), but as we all know this doesnt solve it,
even with the ledge casting a shadow you will get "double shadowing"
under the ledge.
So if anyone has a way of solving this which does not require
stencil-shadowing the entire scene ;) please reply as i dont know it
either :|
 
 
Joris

-----Original Message-----
From: gda...@li...
[mailto:gda...@li...] On Behalf Of
Gilles Marion
Sent: Thursday, November 21, 2002 10:17 PM
To: gda...@li...
Subject: Re: [Algorithms] Stopping shadow volumes from going through
geometry


Hi,
 
I think the ledge should also cast its shadow onto the ground, no ?
If so, it doesn't matter if the shadow volume is extruded past the
ledge.
If fillrate is your bottleneck, think about clipping (cpu intensive), or
try setting the far side 
of the shadow volume nearer from the character.
If it's a sun-like light, radiosity of the environment should make look
that 
correct to your eyes.
 
Gilles.
 
----- Original Message ----- 

From: Fong, Jay <mailto:JFong@Blackisle.com>  
To: 'gda...@li...' 
Sent: Thursday, November 21, 2002 9:29 PM
Subject: [Algorithms] Stopping shadow volumes from going through
geometry


Hello,
 
I was wondering if there is some way to prevent shadows, generated by
the stencil shadow volume technique, from being extruded through other
objects in the scene?  e.g. a character standing on an overhanging ledge
above ground casts a shadow on the ledge but also onto the ground below
the ledge.
 
I thought about clipping the extruded shadow polys against the world
geometry but I'm hoping for a more elegant (i.e. simpler) solution since
our world geometry is quite dense.
 
Any solutions or links/pointers to papers related to this issue would be
much appreciated!
 
Thanks,
Jay