Hello,

POV-Ray 3.7 beta 39, Windows XP

I am multiplying a pigment by a color and applying it in a material. 
However in the renders the material with the multiplied pigment shows a 
pattern of dots. This problem disappears if no interpolation is used or 
if anti-aliasing is used. Although the problem can be easily fixed with 
anti-aliasing I would like to know if it is related to the way the 
material is implemented or maybe just the fact that I am using the beta. 
I reproduced the problem with tiff, jpg and tga maps.

The scene is a square made up of two triangles with different materials 
(m1 and m2). The top left (m1) is the raw map and on the bottom right 
(m2) the same map is multiplied by orange (1,0.5,0.25). There is one 
parallel light.

link to image (20kB):
http://mysite.verizon.net/sfg0000/files/test_simple_face.png

link to scene (10kB):
http://mysite.verizon.net/sfg0000/files/noisy_mat_scene.zip

Any insight on this problem would be appreciated.

FlyerX

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> Hello,
>
> POV-Ray 3.7 beta 39, Windows XP
>
> I am multiplying a pigment by a color and applying it in a material.
> However in the renders the material with the multiplied pigment shows a
> pattern of dots. This problem disappears if no interpolation is used or
> if anti-aliasing is used. Although the problem can be easily fixed with
> anti-aliasing I would like to know if it is related to the way the
> material is implemented or maybe just the fact that I am using the beta.
> I reproduced the problem with tiff, jpg and tga maps.
>

   Yes, I can confirm this problem... I'm also suffering it when trying to 
put the lightmaps into use. As you say, seems to be caused by interpolation 
in the image_map. And it doesn't happens with 3.6 or MegaPOV.

   My solution for the moment is to use min() in the multiplying function:

   function { fp_texture(x,y,z).red * min(fp_lightmap(x,y,z).red,1) }

   Hope this helps for the moment...

-- 
Jaime Vives Piqueres

http://www.ignorancia.org

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