#! /usr/bin/gawk -f
# Last edited on 1999-02-13 16:21:12 by stolfi

BEGIN {
  abort = -1;
  usage = ( \
    "ring-make.awk \\\n" \
    "  < ring-props.txt \\\n" \
    "  > ring.incx" \
  );
  
  # Generates a POVRay declaration that defines an object called
  # ring_pebbles. For each pebble, reads a record with fields X Y Z SX
  # SY RSZ AGE GUN, and writes an instance of the object
  # "pebble_core_K_NN" where K is the GUN (0..2) and NN is the
  # particle's age (quantified to 0..15).
  #
  # Assumes that the objects "pebble_K_NN" have been defined previously
  
  pi = 3.1415926; twopi = 2*pi;
  
  printf "creating povray file...\n" > "/dev/stderr";
  write_pov_header();
  npb = 0;
}

(abort >= 0) { exit abort;} 

/./ {
  if (NF != 8) { file_error("bad format"); }
  x = $1; y = $2; z = $3;
  sx = $4; sy = $5;
  rsz = $6; age = $7; gun = $8;

  write_pebble(x,y,z, sx,sy, rsz,gun,age);
  npb++;
  next;
}

END{
  write_pov_tailer();
  printf "%d pebbles generated\n", npb > "/dev/stderr";
}

function write_pov_header(   k,nn)
{
  printf "//  Ring of pebbles\n";
  printf "//  Created by ring-povify.awk - DO NOT EDIT\n";
  printf "\n";
  printf "//  Requires\n";
  printf "//    pebble_K_NN\n";
  printf "//      where K={0,1,2} NN={00..15}\n";
  printf "//    ring_pebble_size\n";
  printf "//  Defines\n";
  printf "//    ring\n";
  printf "\n";
  printf "#include \"pebbles.incx\"\n";
  printf "\n";
  printf "#declare psz = ring_pebble_size;\n";
  printf "\n";
  printf "#declare ring_pebbles = union{\n";
  printf "\n";
}

function write_pebble(x,y,z, sx,sy, rsz,gun,age,   s,rz,ry)
{
  # printf "#ifdef(pebble_%d_%02d)\n", gun, age;
  printf "  object{pebble_%d_%02d scale %.3f*psz\n", gun, int(15*age + 0.5), rsz;
  if ((sx != 0) || (sy != 0))
    { rz = (180/pi)*atan2(sy,sx);
      ry = (180/pi)*atan2(sqrt(sx*sx+sy*sy),1);
      printf "    rotate <0,0,%.0f> rotate <0,%.0f,%.0f>\n", -rz, -ry, rz;
    }
  printf "    translate <%+.3f,%+.3f,%+.3f>\n", x, y, z;
  printf "  }\n";
  # printf "#end\n";
  printf "\n";
}

function write_pov_tailer()
{
  printf "}\n";
  printf "//  Done.\n";
}

function file_error(msg)
{
  printf "*** line %d: %s\n", NFR, msg > "/dev/stderr";
  abort = 1; exit abort;
}

function arg_error(msg)
{
  printf "*** %s\n", msg > "/dev/stderr";
  abort = 1; exit abort;
}