Vissible Light (Volumetric?)

[hangt5]

How do you get light to appear like its passing through a bunch of particles like:

Example 1 (http://www.fh-fulda.de/caelabor/inhalte/Lightwave/einfuer/oldhouse/final-render.gif)
Example 2 (http://www.danlabgames.com/mini/j2.jpg)

So that it doesn't just effect the visibility of surfaces but the 'brightness' or i guess luminance of the area around the light too.

Sorry that i dont know the correct vocabulary, but i think the screenshots make my question pretty apparent.

[OneSadCookie]

draw transparent quads where the shafts of light are from the viewer's perspective.

[hangt5]

ah, so it has absolutely nothing to do with light...
Thanks for the tip.

[hangt5]

So do the shafts of light have to move relative to the viewer? Or are they static? It seems like they would be static... but "From the viewer's perspective" is throwing me off.

[OneSadCookie]

yeah, they're static in 3D space, but might still need to be drawn differently based on the viewer's perspective... you don't want to make it obvious that it's geometry, and you need to think about cases like the viewer being inside the volume...

[reubert]

I wonder if it would be better to do this with the stencil buffer... Basically do inverted stencil buffer shadows, but without the subtraction pass, then draw an additive blended textured quad over the whole scene where it passes the stencil test.

[OneSadCookie]

seems like it should work well, though of course you've got the fill requirements to worry about...