RE: [Algorithms] Lightmap Terrain

[Pallister, K. <kim...@in...>]

I don't know that a radiosity solution would buy you that much in an outdoor
type environment, depending on how many light sources you have other than
the sun. 

If it's only the sun, I'd do the lightmap generation in two passes. First,
run over the texture and do the usual ambient + diffuse calculation using
the normals at each texel. Secondly, I'd run over the map doing a sort of
line tracing scheme to determine whether the given texel falls within shadow
of a mountain or not (from the texel, step towards the sun, increasing from
the texels height a bit, and if you hit a texel with a higher heightmap
value, you are in shadow). If you find a shadow, reset the color from the
first pass to ambient value.

Kim Pallister

We will find a way or we will make one.
                     - Hannibal


> -----Original Message-----
> From: sro...@te... [mailto:sro...@te...]
> Sent: Thursday, August 24, 2000 12:54 PM
> To: gda...@li...
> Subject: [Algorithms] Lightmap Terrain
> 
> 
> Hi!
> 
> I trying to find how to generate a lightmap/illumination/shadow on a
> terrain.
> Do you know some good tutorial/code/links talking about that?
> 
> I want something to generate a lightmap on a (1025x1025 
> terrain). A good
> generation
> if possible like compute the the light from a point. I want 
> generate the
> lightmap
> just before the use of the terrain and i dont want something 
> that i need to
> pre-calculate and put the result on a file or something like.
> 
> Thanks,
> Corrosif
> 
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