Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> >   I suppose that if you are calculating the lightmaps into something else
> > than bitmaps you could do adaptive supersampling 

> Hmmm. Unless you're talking about how to turn a bunch of radiosity chips 
> in 3D into a bitmap of the 3D structure as seen from a particular point 
> in space, I am confused. Either you're talking about something other 
> than what I learned, or my memory of what I learned doesn't match what 
> the "radiosity" algorithm really does.

  When you wrote

"you could build it in a way that let the areas with lots of detail have
finer resolution than the areas with less detail"

it seemed clear to me that you were talking about the lightmap resolution.
Were you talking about something else?

  The basic radiosity algorithm is basically calculating the illumination
of surfaces into lightmaps (which can be applied to those surfaces).
A lightmap is basically just an image map, but instead of telling the
color of the surface at that point (which is something a texture map does)
it tells the lighting (ie. brightness and coloration) of the surface at
that point. A rendering engine filters the texture map with the light map
in order to get the final surface color.

  Radiosity is an algorithm for calculating such lightmaps. For each pixel
in the lightmap, the "camera" is put onto the surface of the object
corresponding to that lightmap pixel, facing outwards, and the half-world
seen from that point of view is averaged into that lightmap pixel. This is
done multiple times in order to get diffuse inter-reflection of light
between surfaces.

  The great thing about radiosity is that calculating the lightmaps can
be done with 3D hardware, making it quite fast (although still not
real-time).

-- 
                                                          - Warp

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