Re: [osg-users] How to make sure that both the back and the frontside of a polygon are lit...

[Alberto Luaces]

Jason Daly writes:

 Alberto Luaces wrote:

 If I reverse the normals the opposite side lights up as expected .. Am I 
 doing something wrong..


Just a clarification: I didn't wrote this, it was Sunil :)

Good point, Jason. I didn't thought about the case in that OP's light
could not be facing the surface he wanted to see...

-- 
Alberto

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Re: [osg-users] How to make sure that both the back and the frontside of a polygon are lit...

[Jason Daly]

Alberto Luaces wrote:

If I reverse the normals the opposite side lights up as expected .. Am I doing 
something wrong..
  


Are you expecting both sides to be lit identically (i.e.: the front lit 
as brightly as the back) ?  Keep in mind that OpenGL doesn't do global 
illumination (that is, light doesn't bounce), if a surface isn't 
facing a light source, it won't be lit.


If you only have one light source in the scene, and the front side is 
facing toward it, then the front side will be lit and the back won't.  
If you're trying to get both the front and back to be lit at a similar 
intensity, you may need to add one or more lights to the scene so that 
the back faces are also facing a light source.


--J
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