/* Auteur: Nicolas JANEY                                */
/* nicolas.janey@univ-fcomte.fr                         */
/* Octobre 2008                                         */
/* Une classe transformation geometrique 3D             */
/* en coordonnees homogenes                             */

public class TransformationGeometrique3D {
  protected double [][] c;

  public TransformationGeometrique3D() {
    c = new double[4][4];
    for ( int i = 0 ; i < 4 ; i++ )
      c[i][i] = 1.0;
  }
  
  public TransformationGeometrique3D(double [][] t) {
    c = new double[4][4];
    for ( int i = 0 ; i < 4 ; i++ )
      for ( int j = 0 ; j < 4 ; j++ )
        c[i][j] = t[i][j];
  }
  
  public TransformationGeometrique3D(TransformationGeometrique3D t) {
    c = new double[4][4];
    for ( int i = 0 ; i < 4 ; i++ )
      for ( int j = 0 ; j < 4 ; j++ )
        c[i][j] = t.c[i][j];
  }
  
  public Position3D transform(Position3D p) {
    double [] v = multiplication(p.getValue());
    return(new Position3D(v[0],v[1],v[2]));
  }
  
  public Direction3D transform(Direction3D d) {
    double [] v = multiplication(d.getValue());
    return(new Direction3D(v[0],v[1],v[2]));
  }  
  
  private double [] multiplication(double [] v) {
    double [] r = new double[4];
    for ( int i = 0 ; i < 4 ; i++ )
      for ( int j = 0 ; j < 4 ; j++ )
        r[i] += c[i][j]*v[j];
    return(r);
  }
  
  public TransformationGeometrique3D compose(TransformationGeometrique3D m) {
    TransformationGeometrique3D r = new TransformationGeometrique3D();
    for ( int i = 0 ; i < 4 ; i++ )
      for ( int j = 0 ; j < 4 ; j++ ) {
        r.c[i][j] = 0.0;
        for ( int k = 0 ; k < 4 ; k++ )
          r.c[i][j] += c[i][k]*m.c[k][j]; }
    return(r);
  }
  
  public static TransformationGeometrique3D compose(TransformationGeometrique3D m1,
                                                    TransformationGeometrique3D m2) {
    return(m1.compose(m2));
  }
  
  public String toString() {
    String s = "[";
    for ( int j = 0 ; j < c.length ; j++ ) {
      if ( j > 0 )
        s += " ";
      s += "[";
      for ( int i = 0 ; i < c[j].length ; i++ ) {
        s += c[j][i];
        if ( i < c[j].length-1 )
          s += ","; }
      s += "]";
      if ( j < c.length-1 )
        s += "\n"; }
    s += "]";
    return(s);
  }
}