Stencil Buffer Shadow Overlapping

[Sam Kovalev]

I have 3 questions:
1.I have more than a single one light source. How to enable real look-like overlapping between shadows casting from different light sources.Maybe using glBlendFunc()?
(By the way how to make shadows from transparent objects)
2.Sometimes i am using stencil buffer for creating pseudo lighting from a spot light. How to make it to be attenuated?
3.I am also creating a dust effect room simply by drawing clipping volume from a lamp(pseudo light),but this volume goes through the different objects.How to stop the volume when it crosses another object.Maybe Depth Buffer can help?

[dorbie]

1) Clear the stencil between each light and project a light volume for each light individually to stencil test illumination true on your *illumination* pass not shadows on a shadow pass.
Use glBlendFunc(GL_ONE, GL_ONE); for each light source contribution.

2) Attenuate the illumination in the lighting pass. Use texture, math or whatever it takes.

3) If I understand correctly, you need to stop the light volume when it intersects with an object. Investigate beam trees :-)