I’m having a little problem: I need to display back facing polygons with some basic standard GL lighting.
Easy you’ll think, and indeed it is in most cases, but I need to do this on GeForce 2 with VAR enabled. As two sided lighting falls back to software on GF2, it crawls horribly !
Does anyone have a nice idea to invert polygon normals via GL, in this context, without having to touch my geometry ?
Yep, that’s what I first thought - and did - but the problem is still there: the normals are still pointing is the ‘front face’ direction - and as I have to disable the ‘two sided lighting’ - the faces are not lit correctly (their normals should be negated).
I was hoping that a modelview matrix trick could safe my life, but it seems that I’m bound to play with my geometry instead…
I was hoping that a modelview matrix trick could safe my life, but it seems that I’m bound to play with my geometry instead…
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That shouldn’t be a bother, all you need to do is store a reversed set of normals.
Or maybe you can transform the light(s) relative to the object? (ie. Your normals stay pointing the same way but you put the light(s) on the opposite side of the objects origin)