From: Timo Asikainen <thka AT lyseo DOT edu DOT ouka DOT fi>
Newsgroups: comp.os.msdos.djgpp
Subject: Problems with Allegro's texturemapping
Date: Sun, 12 Jul 1998 18:03:58 -0700
Organization: Oulu Polytechnic, Institute of Technology, Finland
Lines: 27
Message-ID: <35A95CFE.2518@lyseo.edu.ouka.fi>
Reply-To: thka AT lyseo DOT edu DOT ouka DOT fi
NNTP-Posting-Host: anne86.wnet.opoy.fi
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

I'm programming a landscape engine for a game. The method I use is
simple:

I have a mesh in which all vertices have a height. These vertices are
connected to each other by lines which form triangles.

(Here's a nice ASCII pic:-))

+-+-+-+
|\|\|\|
+-+-+-+
|\|\|\|<---- a triangle
+-+-+-+<-----a vertex

Now, what I try to do is texturemap these triangles. I want to
texturemap them so that I can map a big photograph of for example grass
or rock onto this landscape. Or if the texture is a small one (for
example 64x64) I could tile it on the landscape. The problem is that in
Allegro I have to calculate proper texturemap coords. for each vertex of
a triangle and I don't know any good algorithm for calculating the
texmap coords. so that I could achieve what I want to do.

If anyone knows any good netsites on the subject or have some good
algorithms please let me know about them..

------
Timo Asikainen