package matrix;

// Homogenous Vector3D class to represent
// homogenous 3D coordinates whose represented 
// cartesian coordinate is obtained
// with the homogenize() function.
// This is useful for 3D graphics transformations.
class Vector3Dh extends Vector3D
{
  public double w;

  public Vector3Dh(double x, double y, double z)
  {
    super(x, y, z);
    w = 1;
  		//{{INIT_CONTROLS
		//}}
}

  public Vector3Dh(double x, double y, double z, double w)
  {
    super(x, y, z);
    this.w = w;
  }

  public Vector3Dh(Vector3D v)
  {
    super(v.x(), v.y(), v.z());
    w = 1;
  }

  // Get the homogenized Cartesian coordinate
  // by dividing x, y, and z by w.
  // If w = 0, PointInfinity exception is thrown.
  public Vector3D homogenized() throws PointAtInfinity
  {
    if (w == 0) throw new PointAtInfinity(this);
    return (Vector3D)this.mult(1/w);
  }

  // Get the 2D homogenized Vector -- for projecting
  // a 3D point onto a 2D plane.
  Vector2D homogenized2D() throws PointAtInfinity
  {
    if (w == 0) throw new PointAtInfinity(this);
    return new Vector2D(x()/w, y()/w);
  }

  // Get a homogenized Cartesian coordinate
  // by dividing x and y (leaving z alone) by w.	
  // This is useful for perspective transformations
  // where x and y are homogenized to get a screen
  // coordinate and z is retained so the distance
  // is still known.
  // If w = 0, PointAtInfinity exception is thrown.
  Vector3D xyHomogenized() throws PointAtInfinity
  {
    if (w == 0) throw new PointAtInfinity(this);
    return new Vector3D(x()/w, y()/w, z());
  }
	//{{DECLARE_CONTROLS
	//}}
}