#!/bin/ksh
#################################################################
#
# OFF2TEK - A script to display OFF 3d data on the
# Tektronix 4014 terminal. Designed specially
# to bring 3D graphics to SDF users ;-)
#
# by Maciek Szymanski <
[email protected]>
#
# Release M1b - corrected coordinate transformation
# formulas.
# Release M1a - initial public release.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
#################################################################
# process command line parameters
while [ $# -gt 0 ]
do
case $1 in
-s) # -s - scale
SCALE=$2
shift
shift
;;
-x) # -x - x offset
XOFFS=$2
shift
shift
;;
-y) # -y - y offset
YOFFS=$2
shift
shift
;;
-f) # -f - file name
FILE=$2
shift
shift
;;
*) # display usage
cat << EOF
Usage: $0 [-s scale] [-x x offset] [-y y offset] [-f file name]
Displays the off 3D file on the Tektronix 4014 terminal or
a compatible emulator (eg. xterm).
EOF
exit 0
;;
esac
done
# run awk script to process off data
awk -v "SCA=${SCALE:-1}" -v "DX=${XOFFS:-512}" -v "DY=${YOFFS:-383}" \
'BEGIN {
# Parameters and constants
PI = 3.1415927;
# SCA global scale
# DX origin ofset
# DY
# Projection parameters
FiX = 30;
FiY = 120;
SX = 1;
SY = 1;
SZ = 0.5;
# recalculate angles
Alpha = FiX * PI / 180;
Beta = (FiY - 90) * PI / 180;
# clear terminal
clear_tek();
# Process input file
getline;
if ($0 ~ OFF) getline;
# Get data header
VERT = $1;
FAC = $2;
# Read vertices and project to 2D
i = 0;
while(i < VERT) {
getline;
vx[i] = (DX + SCA * proj_x($1, $2, $3));
vy[i] = (DY + SCA * proj_y($1, $2, $3));
i++;
}
# Read and draw faces
i = 0;
while(i < FAC) {
getline;
n = $1; # number of points
j = 2;
x0 = vx[$2];
y0 = vy[$2];
tek_graph();
while (j < n + 1) {
send_tek_xy(vx[$j], vy[$j]);
j++;
}
send_tek_xy(x0, y0);
i++;
}
}
# send coordinates in tek format
function send_tek_xy(x, y, HiY, LoY, HiX, LoX)
{
HiY = int(y / 32);
LoY = int(y - HiY * 32);
HiX = int(x / 32);
LoX = int(x - HiX * 32);
printf("%c%c%c%c", HiY + 32, LoY + 96, HiX + 32, LoX + 64);
}
# clear tek screen
function clear_tek()
{
printf("\033\014");
}
# switch to graphics mode
function tek_graph()
{
printf ("\035");
}
# functions to transform coordinates
# x,y,z -> 2d X
function proj_x(x, y, z)
{
x = x * SX;
y = y * SY;
return (x * cos(Alpha) - y * sin(Beta));
}
# x,y,z -> 2d Y
function proj_y(x, y , z)
{
x = x * SX;
y = y * SY;
z = z * SZ;
return x * sin(Alpha) + y * cos(Beta) + z;
}' $FILE
