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On 7/28/2011 12:25 PM, PC John wrote:
>>> To simplify the things, I want to have one pigment for OpenGL
>>> emissive color and another pigment for OpenGL diffuse color.
>>> POV-Ray should compute the lighting on both of them and the
>>> final color would be sum of these. Is it possible to do
>>> this in POV-Ray?
>>
>> If I get it correctly:
>> OpenGL povray
>> =========+=========
>> emissive | ambient
>> diffuse | diffuse
>>
>> To perform a sum, use the average pigment with relevant map
>>
>>> http://wiki.povray.org/content/Documentation:Reference_Section_5.3#Average
>
> Things are more difficult:
>
> OpenGL povray
> ===============+================
> ambient COLOR | ambient COLOR
> diffuse COLOR | diffuse float
> specular COLOR | specular float
> emission COLOR | (no equivalent, but can be emulated by ambient)
>
> In OpenGL, ambient color is real color used for the computation of ambient light
> contribution to the final color, while ambient on povray side is just pigment
> filter.
>
> In OpenGL diffuse, specular and emission are all colors that can be completely
> different colors while povray's diffuse and specular is just float multiplying
> pigment color.
>
> As a result, OpenGL allows to specify for example blue diffuse color - e.g.
> object is blue when lit by the light coming from the scene, and red ambient
> light (e.g. surface shines red, provided that there is global ambient light in
> the scene).
>
> You may wonder why I need this, but it would allow to correctly show all the
> models that are used in OpenSceneGraph, OpenGL, DirectX, and real-time graphics
> in general.
>
> Thanks for any good advice,
> John
>
>
Hmm. This may be a kind of interesting point. Not sure if such exists,
but its not completely improbable that an objects optical properties
would cause its "reflective" color to be slightly different than its
real one, like red, when looked at directly, but say, blue when seeing
the diffuse/specular results. Maybe the odd paint they make that seems
to change color, by angle, as an example, where its the reflected light
that determines that?
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