// makering.java
//
// This program will generate a POV include file to make a particle ring like
// the rings of Saturn. The user passes in the number of particles.
//
// Written by: Henry Wagner (henryw@panix.com)

import java.io.*;
import java.util.*;

public class MakeRing {
   public static void CreateRing(String filename) throws IOException {
      File o = new File(filename);
      int c1, nParticles = 5000;
      Random myRand = new Random();
      FileOutputStream os = new FileOutputStream(o);
      PrintStream ps = new PrintStream(os);

      ps.println( "// rings.inc" );
      ps.println( "//" );
      ps.println( "// Written by: Henry Wagner (henryw@panix.com)" );

      ps.println( "#declare Saturn_Ring = union {" );
      for( c1 = 0; c1 < nParticles; c1++ ) {
         ps.println( "   object {" );
         ps.println( "      Particle" );
         ps.println( "      rotate < " + myRand.nextInt()%360 + ", 0, 0 >" );
         ps.println( "      rotate <  0, " + myRand.nextInt()%360 + ", 0 >");
         ps.println( "      rotate <  0, 0, " + myRand.nextInt()%360 + " >");
         ps.println( "      translate < " + myRand.nextInt()%20000 + ", 0, 0 >");
         ps.println( "      rotate < 0, " + myRand.nextFloat() * 360.0 + ", 0 >");
         ps.println( "   }" );
      }
      ps.println( "   texture { T_Brass_4C }" );
      ps.println( "}" );

      ps.close();
      os.close();
   }

   public static void main (String[] argv) {
      if (argv.length == 0) {
         System.out.println("ERROR: You didn't pass in the number of particles");
         System.exit(0);
      }
      try {
         CreateRing("rings.inc");
      } catch(IOException e) {
         System.err.println(e.getMessage());
      }
   }
}