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Shadow alpha test

by Phil Carlisle · in Torque Game Engine Advanced · 01/23/2007 (9:09 am) · 3 replies

Hey guys..

I've been thinking about the object shadows and I've come to the conclusion that its not going to work without at least alpha tests on the shadows.

The reason why I dont think its going to work, is that there are just so many situations where your objects arent just solid geometry. For instance a tree, or a propeller, or a railing, or a large oil tower, or a burnt out building shell or etc...

So, I dont think so far there is alpha tests on the shadows. But can it be that hard to implement? its basically an early out operation on the texture of the shadow caster isnt it?

Or am I missing something?

Phil.
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Torque 3D Owner Phil Carlisle
#1
01/26/2007 (1:01 pm)
I was thinking, its basically a matter of alpha testing any translucent objects when writing to the shadow buffer. If you have no alpha in the texture (only on translucent materials), then simply use a texkill op and dont write anything, or write a pass-through colour I guess.

The point is, with alpha test on the source object at least we have a chance to do some object silhouette based stuff.

I guess this is what happens in a projected shadow??

Associate Tom Spilman
Sickhead Games
#2
01/26/2007 (4:51 pm)
If this isn't working now Phil it should be. One of the major benefits of buffer based shadows is the ability to generate good looking silhouettes from alpha test materials. I suspect it's just broken at the moment.

Torque 3D Owner Phil Carlisle
#3
01/26/2007 (5:00 pm)
I dont know Tom, I got the impression John was having some problems with it. Right now afaik, translucent materials are simply not drawn. Is that right John?

I did some digging in the code, to see if I could squirt something into a shader to fix it. But doesnt look like it.