POV-Ray : Newsgroups : povray.general : Vertex Color Map to UV mapped texture : Re: Vertex Color Map to UV mapped texture Server Time
1 Aug 2024 08:20:55 EDT (-0400)
  Re: Vertex Color Map to UV mapped texture  
From: Vincent LE CHEVALIER
Date: 18 Dec 2005 05:53:58
Message: <43a53fc6@news.povray.org>
Warp wrote:
> Herve <her### [at] hotmailcom> wrote:
> 
>>1st) to generate a UV map with the vertex color map of
>>the vrml object and 2nd) to use the generated UV map in moray to restore
>>the color of the imported vrml geometry.
> 
> 
>   I don't really understand what you are trying to say.
> 
>   UV-coordinates are just that, coordinates (more specifically,
> 2D coordinates). There's nothing else to them. Basically they have
> nothing to do with colors.
> 
>   UV coordinates can be used to map a texture onto the mesh. IOW the
> UV coordinates say how the texture should be "stretched" (if we can
> use that kind of description) and put onto the surface of the mesh.
> One could think of a UV coordinate (eg. <0.1, 0.2>) as saying
> "transform the texture so that the point at <0.1, 0.2> in the texture
> ends up at this point in space (ie. the location of the vertex)".
> 
>   This is a bit different from specifying a per-vertex texture (which
> can be just a single color).
> 
>   With UV coordinates one texture is applied to the mesh (and transformed
> so that the texture coordinates coincide with the vertex coordinates).
> With per-vertex textures several (non-transformed) textures are used and
> interpolation is done from one texture to another.
> 
I think that Herve is looking for something that would take the geometry 
and vertex colors as input, and output a UV-map (that is, an image 
containing color information, interpolated as needed) and the associated 
UV-coordinates for each vertex, in order to approximate per-vertex 
textures with a UV-map.
That said, I don't know of any such program...

-- 
Vincent


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