On Tue, 10 Dec 2002 10:55:58 +0100
Philippe Debar <phd### [at] wanadoobe> wrote:

> I made several mistakes...

  Not really difficult if my code is involved...
 
> Firstly, demo files D and E which should have shown how smoothly the
> two include files work together (in my dreams) do not run. That is
> because I used a beta-version of Jaime's lighting system and the file
> structure is different from the released one. Drats. 

  I haven't noticed it because I have not traced the demos...:) Sorry,
but I was just starting an outdoor scenes, I used Skylight for first
time on it, rather than first trying the demos.

> I think I made a grevious mistake while adapting Jaime's code. 
> Luminosity interaction is supposed not to be perfect. I think I should
> make the following adaptations :
> line 315 : vlength(lct) -> lct.gray
> line 327 : sqrt(vlength(lct)) -> lct.gray

  Well, I've tested this part and I've done my own modifications. It
even helped to find some faulty asumptions I was doing with the color
filter operations. Apart from this, I think you must not use at all
anyhting in the place of lm, and let the intensity control of the sun
to Skylight only. Just like this:

(((lct/REF_WHITE)+(<COLOR_FILTER.gray,COLOR_FILTER.gray,COLOR_FILTER.gr
ay>-COLOR_FILTER))*EXPOSURE) 

  This way, if I set EXPOSURE to 1, REF_WHITE to <1,1,1> and
COLOR_FILTER to <0,0,0>, the the resulting image is the same as if these
variables where not declared, whih is the correct behavior, I think. It
also works fine with the incoming version III, indeed.

  And one more thing, you can forget about compatibility with version
I, as it was just a mess.

  For the rest of the Skylight include, I must say that I'm really
impresed. I have not tried even to understand the code, but I see it is
very nicely done and the results seem almost perfect in terms of
colors. Only two things annoy me:

  1) The skydome texture is based on a luminous finish, with ambient,
wich is perhaps not handy for lazy people like me, wich uses global
ambient set to 0. I just have modified my copy to use "diffuse 1" and
it works great.

  2) Both with low and high tesselation, I see on the skydome
different "poligonal" zones, showing slighty different colors, but I
can't figure what is causing it. Will test it further, as I'm taking the
rest of the day free... :)

  Again: great work, Phillipe! 


-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org

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