NetNews Usenet Archive 1993 #3/NN_1993_3.iso/spool/alt/3d/1765

Internet Message Format | 1993-01-22 | 1.2 KB

Xref: sparky alt.3d:1765 comp.graphics:14113 comp.graphics.animation:1721 rec.games.programmer:5489
Organization: Sophomore, Mathematics, Carnegie Mellon, Pittsburgh, PA
Path: sparky!uunet!spool.mu.edu!uwm.edu!linac!pacific.mps.ohio-state.edu!cis.ohio-state.edu!news.sei.cmu.edu!bb3.andrew.cmu.edu!crabapple.srv.cs.cmu.edu!andrew.cmu.edu!ps1o+
Newsgroups: alt.3d,comp.graphics,comp.graphics.animation,rec.games.programmer
Message-ID: <[e-mail]>
Date: Fri, 22 Jan 1993 08:42:52 -0500
From: Philip John Stroffolino <[e-mail]>
Subject: Re: 3D mapping
In-Reply-To: <[e-mail]>
References: <[e-mail]>
Lines: 30

Here's a method that will produce a 3d mapping:

let d represent depth, (d>=0)
let h represent horizontal position, -(1+d) <= h <= (1+d)
let v represent height

m := 1/(1+d)
x := m*h
y := m*(d+v)

output: square centered at (0,0) with side length 2; {(-1,-1) to (+1,+1)}


test demo: plots a grid of points, 3d style

v:=-1; {plot grid as viewed from above}
for d:=0 to max step .25 do {max should be bigger than 5}
begin
 m:=1/(1+d);
 for x:=-(1+d) to (1+d) step .25 do
 begin
  x:=m*h;
  y:=m*(d+v);
  plot ((x+1)*HalfScreenWith,(1-y)*HalfScreenHeight); {scale to window}
 end;
end;



- Phil -