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KlaHyMan
05-09-2000, 12:10 PM
I'd like to add volumetric fog to my terrain. Is fog coordinate extension a possible way to achieve the result?
If so, can you tell me where I can get the c header for the extension functions and tokens?

skw|d
05-09-2000, 06:39 PM
What you are describing doesn't sound like volumetric fog.

Your best bet is to tessellate the fog volume to a certain custon degree and then perform a ray trace to each generated point from the camera to get the fog density. Then apply the color value at that point according to the distance traveled in the fog volume.

dmy
05-10-2000, 04:08 AM
that's right, but just one consideration: the fogging stage takes place after texturing, instead material color assignement takes place before.

using material colors as fog-blending will make textures not apper well, since the only thing you can do with the standard material+texture approach, is to dampen each RGB component.

this way you cannot get your texture to appear as a solid color other than black.

imo, you have to not calculate fog as a color but as a fogging value, then pass this to opengl as fog coordinate.

Dolo/\/\ightY

PS: welcome back skw|d !



[This message has been edited by dmy (edited 05-11-2000).]

skw|d
05-11-2000, 07:55 PM
thanx man, it's good to be back

abhijeet_maharana
07-13-2003, 08:05 PM
Nehe has added a new tutorial on volumetric fog. Tutorial 41 uses glfogcoordf extension to create the effect. I don't know anything about volumetric fog so I can't say if tis is what u r looking for but u could give this a try.

Regards

[This message has been edited by abhijeet_maharana (edited 07-13-2003).]