BSP edge list

Greg Lewis (
Tue, 18 Jun 1996 16:50:25 -0400 (EDT)

Date: Tue, 18 Jun 1996 16:50:25 -0400 (EDT)
From: Greg Lewis <>
Subject: BSP edge list

I've got a question concerning the edge lists. I'm iterating the
surface data to find and draw all of the edges onscreen. From the Qspec
3.1 I assumed that if I go through the List of Edges and take the sign
into account, the edges will always be given in a counterclockwise order
around the surface. And, thus I would only need to compute half of the
vertices (since the start of one is the end of the next edge). However,
while going through the list it looks like the end of one edge is NOT
always the same position as the start of the next edge. (I believe the
first time this happens is surface 9, edge 1.) Can anyone confirm/deny
this? It seems to me like the edges should form a closed polygon, i.e.
each vertex is the start of one line and the end of another (after taking
the sign flip into account).


P.S. CC's to me are appreciated, as I am on the digest and would like an
answer soon. :)