View Full Version : lightmapped shadows....

09-04-2003, 04:18 AM
I want to have a heightmapped terrain with trees, rockes, ect... and I want to have shadows placed on the ground that are projected by these objects but also have the objects be self shadowed, can i do this with lightmaps? or do I need shadowmapping? Plus if my terrain is very big i can't use a single shadowmap unless it's about 1024x1024 because it won't look very realistic at all. Any ideas?

09-04-2003, 06:52 AM
www.vetrrain.org (http://www.vetrrain.org)

Also, look for "perspective shadow maps" on Google.

09-04-2003, 08:24 AM
I use lightmaps for my terrain software, aeliom ( www.iluac.com/aeliom (http://www.iluac.com/aeliom) ).

My engine compress the lightmaps (via S3TC) to let them fit into the video memory. But Iím not sure that such a method is flexible enough, and I meet some restrictions with it (dynamic sun, dynamic objects, memory consumption...). I try some other way for aeliom 2...

Shadow volumes perform very well with terrain like rendering, but are "rendering" limited (soft shadows are complex, small objects like leaves are hard to manage). I think that perspective shadow map should be a good approach, and a solution to the shadow map aera problems with sun-terrain lighting....

[This message has been edited by kard (edited 09-04-2003).]

09-05-2003, 04:57 AM
For the heightmapped terrain itself, horizon mapping may be the best solution for a dynamic sun.

09-05-2003, 08:47 AM
The problem with horizon maps is that they don't shadow other objects; the shadow only shadows the terrain. If you add object shadowing via other methods, then the horizon map can look a bit out of place, as the two methods will never be perfectly aligned.