/* Auteur: Nicolas JANEY                                */
/* nicolas.janey@univ-fcomte.fr                         */
/* Novembre 2006                                        */
/* Transformation geometrique en coordonnees homogenes  */
/* pour la realisation de rotations autour d'un axe     */
/* arbitraire passant ou non par l'origine              */

public class Rotation extends Transformation {

  public Rotation(float a,
                  float dx,float dy,float dz) throws ArithmeticException {
    super();
    remplissage(a,dx,dy,dz);
  }

  public Rotation(float a,
                  Direction d) throws ArithmeticException {
    super();
    remplissage(a,d.getX(),d.getY(),d.getZ());
  }

  public Rotation(float a,
                  float x,float y,float z,
                  float dx,float dy,float dz) throws ArithmeticException {
    super();
    remplissage(a,x,y,z,dx,dy,dz);
  }

  public Rotation(float a,
                  Position p,Direction d) throws ArithmeticException {
    super();
    remplissage(a,p.getX(),p.getY(),p.getZ(),d.getX(),d.getY(),d.getZ());
  }

  private void remplissage(float a,
                           float x,float y,float z) throws ArithmeticException {
    a = a/180.0F*(float) Math.PI;
    float c =(float) Math.cos(a);
    float s =(float) Math.sin(a);
    float d =(float) Math.sqrt(x*x+y*y+z*z);
    if ( d == 0 ) {
      throw new ArithmeticException(); }
    x /= d;
    y /= d;
    z /= d;
    float x2 = x*x;
    float y2 = y*y;
    float z2 = z*z;
    float xs = x*s;
    float ys = y*s;
    float zs = z*s;
    float mc = 1.0F - c;
    float xymc = x*y*mc;
    float xzmc = x*z*mc;
    float yzmc = y*z*mc;
    this.c[0][0] = x2+c*(1.0F-x2);
    this.c[0][1] = xymc-zs;
    this.c[0][2] = xzmc+ys;
    this.c[1][0] = xymc+zs;
    this.c[1][1] = y2+c*(1.0F-y2);
    this.c[1][2] = yzmc-xs;
    this.c[2][0] = xzmc-ys;
    this.c[2][1] = yzmc+xs;
    this.c[2][2] = z2+c*(1.0F-z2);
  }

  private void remplissage(float a,
                           float px,float py,float pz,
                           float ax,float ay,float az) throws ArithmeticException {
    Translation ti = new Translation(-px,-py,-pz);
    Rotation r = new Rotation(a,ax,ay,az);
    Translation tf = new Translation(px,py,pz);
    Transformation t = tf.multiplication(r).multiplication(ti);
    for ( int i = 0 ; i < 4 ; i++ )
      for ( int j = 0 ; j < 4 ; j++ )
        c[i][j] = t.c[i][j];
  }
}