Re: vertex ordering for primitive shapes

Chris Marrin ([email protected])
Fri, 20 Oct 1995 18:29:13 -0700

On Oct 20, 2:59pm, Bernie Roehl wrote:
> Subject: vertex ordering for primitive shapes
> Chris Laurel writes:
> > In this example, the vertexOrdering is set to CLOCKWISE before a
> > Cylinder node is used . . . this is done because the intial camera
> > position is inside tme cylinder. Is the assumption that a spec
> > compliant browser will generate primitives with counterclockwise
> > vertex ordering valid?
>
> No.
>
> Cylinders don't *have* vertices, therefore the vertex ordering does not
> apply to them.
>
> In fact, there's no guarantee that all renderers will tesselate the
> cylinder at all; current ones do, but that's strictly a function of
> the rendering technology being used.

Well, if you look at Sandy Ressler's QTVR demo in VRML posted today you'll
notice a ShapeHints of CLOCKWISE for the cylinder upon which the texture
is mapped. This is so the inside of the cylinder can be seen and the
shape can still be SOLID. So vertex ordering should apply to the
primitive shapes. I believe this is being clarified by the VAG.

-- 
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