Message-ID: <D1FB30BBA491D1118E6D006097BCAE39153DFC@Probe-nt-2a.Probe.co.uk>
From: Shawn Hargreaves <ShawnH AT Probe DOT co DOT uk>
To: djgpp AT delorie DOT com
Subject: Re: Allegro: no_persp_project?
Date: Fri, 13 Mar 1998 09:23:52 -0000
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Anthony Salter writes:
> I'm currently writing a 3D isometric engine a la Dungeon Keeper,
> Syndicate Wars, and Ultima IX (before it was turned into a 3D action
> game).  Which means that I DON'T want to correct the perspective with
> respect to the Z axis.  Anyone out there know a way to do this with
> Allegro's current functions, or am I going to have to come up with a
> no_persp_project?

An orthographic (ie. where the axis remain parallel, without any depth
perspective) projection is ridiculously easy to implement: you don't
have to do anything at all! Just plonk your 3d X and Y coordinates
down onto the 2d screen, and discard the Z (you will probably need to
scale them to the right units, and add an offset so things will be
centered in the middle of the screen rather than the top left corner).

	Shawn Hargreaves.