Re: Refection in the RayShade renderer

[James W. <ja...@fr...>]

Jose' Cruanyes wrote:
> Il giorno 27/apr/07, alle ore 22:45, James Walker ha scritto:
> 
>> Roger Holmes wrote:
>>> On 27 Apr, 2007, at 13:45, Jose' Cruanyes wrote:
>>>> this parameter controls how big is the reflection light spot on the
>>>> figure.
>>>>
>>>> in GL it goes from
>>>>
>>>> 0 (no spot (because too big) and hence rough and hence not  
>>>> reflecting)
>>>> to
>>>> 128 (pointy spot, hence polish hence reflecting)
>>> Is it the other way round perhaps?
>> No, it is not the other way around, but it is a bit more complicated,
>> because specular color is also involved.  In OpenGL it is more  
>> accurate
>> to say that you get a non-reflecting surface by setting the specular
>> color to black, never mind the value of GL_SHININESS.
> 
> I've think about it, to make the reflection value based in the  
> luminance of the specular color, but at last I've opted for the  
> reasoning in the previous mail, to have a parameter easier to set by  
> the user
> 
> I'm open to suggestions

There is no perfect way to map two degrees of freedom to one.  But 
perhaps you could use some function of the product of specular control 
and specular luminance.
-- 
   James W. Walker, Innoventive Software LLC
   <http://www.frameforge3d.com/>