From: Charles Mennerat <nambi AT club-internet DOT fr>
Newsgroups: comp.os.msdos.djgpp
Subject: 3D beginner (Allegro)
Date: Sat, 21 Mar 1998 18:51:33 +0100
Organization: Grolier Interactive Europe
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New to 3D I have a few questions.

In the 3d world when shapes have negatives values(for z negatif) the
perspective projection draws lines not the way we expect them.(they
cross one another)What can I do to enter z<0 values?(I use Allegro)

When you calculate (x,y,z) values rotating a shape, the shape doesn't
seem constant.For instance going left and after coming back right the
shape doesn't come back at the same place.What is my mistake?Do I have
to calculate the new coord using the first one entered,or must I use
last coord.(this way tiny errors become none tiny after several
calculations!).

Using Allegro, in rotation you must enter angles "in binary, 256 degrees
to a circle format".What does that meen?
What does this do: itofix(1) & itofix(256).Why can't we just enter an
angle?

Thanks for your help.