Re: Some questions: OpenGL and free 3D models

[Steve Baker <sjbaker1@airmail.net>]

Keith Lucas wrote:

> >I like to think of vertices as being 12-dimensional points
> >(x,y,z,s,t,nx,ny,nz,r,g,b,a), we view them in 3D by dropping
> >the last 9 coordinates. The vertices that lie along the texture
> 
> What's nx,ny,nz? position,texture,something,colour..?

Sorry, normal-x, normal-y, normal-z - the surface normal at
that vertex.  If you need a hard edge in your model (one
that isn't smoothed over) then you need different normals
on the two polygons...hence they are 'different' points and
can't share.

> I'm having enough of a headache dealing with all the
> objects having 4D positions specified...

You are using glVertex4 calls?  You hardly ever need to
do that in practice - what makes you think you care about
the 4th component?

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Steve Baker                (817)619-2657 (Vox/Vox-Mail)
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