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Re: [help-3dldf] Fwd: Re: button-hole problem
From: |
L. Nobre G. |
Subject: |
Re: [help-3dldf] Fwd: Re: button-hole problem |
Date: |
Sun, 24 Apr 2005 17:07:18 +0100 (WEST) |
> Nobre has
> explained that in FEATPOST, he uses the pyramids whose bases are the polygons
> and whose points are his equivalent of Focus::position for occlusion. I
> believe the intersections of these polygons can be used to determine which one
> is in front, but I'm still trying to figure this out.
Take, for example, two parallel triangles.
A B
/\ /\
/ \/ \
/ /\ \
/ C/__\___\D
/________\
E F
If AEF is in front of BCD, then
A B
/\ /\
/ \/g \
/ \ \
/ \h__\D
/________\
E F
the plan containing A, F and Focus::position has cut BCD in two parts.
Cgh is occluded and BghD is not.
Greetings
Lu\'{\i}s Nobre Gon\c{c}alves - http://matagalatlante.org