# node.awk

# Beispiel der Erzeugung eines VRML files ueber 
# mathematische definierte Flaechen 

# Aufruf:
#
# awk -f node.awk > sowieso.wrl

# benutzt werden Zylinderkoordinaten, hier gewuenschte Funktion einsetzen

function z(r,phi)
   {
   return r+phi;
   }

function print_points(r,phi)
   {
   printf("              %f %f %f\n",r*cos(phi),r*sin(phi),z(r,phi));
   }

BEGIN {
   PI=3.141
   r_max=40;
   r_inc=1;
   phi_max=2*PI
   phi_inc=2*PI/40.0;

   print "#VRML V2.0 utf8"
   print ""
   print "Transform "
   print "  {"
   print "  rotation -1 0 0 1.57"
   print "  children "
   print "    ["
   print "    Shape "
   print "      {"
   print "      appearance       Appearance "
   print "	{"
   print "	material 	Material "
   print "	  {"
   print "	  }"
   print "	}"
   print "      geometry       DEF INDEXFACESET IndexedFaceSet "
   print "	  {"
   print "	  coord 	Coordinate "
   print "	    {"
   print "	    point "
   print "	      ["

   for (r=0;r<r_max;r=r+r_inc)
      for (phi=0;phi<phi_max;phi=phi+phi_inc)
        {
        print_points(r,phi);
        print_points(r+r_inc,phi);
        print_points(r+r_inc,phi+phi_inc);
        print_points(r,phi+phi_inc);
        }
   print "	    ]"
   print "	  }"
   print "	coordIndex "
   print "	  ["
   coind=0;
   indexcount=0;
   for (phi=0;phi<phi_max;phi=phi+phi_inc)
      {
      printf("            %d %d %d %d -1\n",coind,coind+1,coind+2,coind+3);
      coind=coind+4;
      indexcount=indexcount+5;
      }
   print "	    ]"
   print "	  solid FALSE"
   print "	  }"
   print "	}"
   print "    ]"
   print "  }"
   print ""
   }

# Copyright (C) 2002 J. "MUFTI" Scheurich

# 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.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program (see the file "COPYING" for details); if 
# not, write to the Free Software Foundation, Inc., 675 Mass Ave, 
# Cambridge, MA 02139, USA.