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From: arthur@warwick.UUCP (John Vaudin)
Newsgroups: comp.graphics
Subject: Z-Buffer Edge effects
Message-ID: <1972@diamond.warwick.ac.uk>
Date: 31 Aug 89 18:28:15 GMT
Sender: news@warwick.ac.uk
Reply-To: arthur@flame.warwick.ac.uk (John Vaudin)
Organization: Computer Science, University of Warwick, UK.
Lines: 16

I have been playing with a simple polygon renderer which I wrote to
learn about how these things work. I have been trying to implement a
Z-buffer alogorithm and I have some problems with edge effects.

If I render a cube from an isometric view then the edges of the
back faces are visible. This is because the Z value for the pixels in
the edge of the front face and the edge of the back face are equal so the
visibility of the edge pixels is determined by the order in which the
drawn.

I do not understand how to get round this problem. If two pixels have
the same Z value what do you do ? How do real systems get round this ?

Thanx in advance

John Vaudin                arthur@flame.warwick.ac.uk