//package comp557.a5;

import javax.vecmath.Point3d;
import javax.vecmath.Vector3d;

public class Ray
{

    /** Originating point for the ray */
    public Point3d eyePoint = new Point3d(0, 0, 0);
    /** The direction of the ray */
    public Vector3d viewDirection = new Vector3d(0, 0, -1);

    /**
     * Default constructor.  Be careful not to use the ray before
     * setting the eye point and view direction!
     */
    public Ray()
    {
        // do nothing
    }

    /** 
     * Creates a new ray with the given eye point and view direction 
     * @param eyePoint
     * @param viewDirection
     */
    public Ray(Point3d eyePoint, Vector3d viewDirection)
    {
        this.eyePoint.set(eyePoint);
        this.viewDirection.set(viewDirection);
    }

    /**
     * Setup the ray.
     * @param eyePoint
     * @param viewDirection
     */
    public void set(Point3d eyePoint, Vector3d viewDirection)
    {
        this.eyePoint.set(eyePoint);
        this.viewDirection.set(viewDirection);
    }

    /**
     * Computes the location of a point along the ray using parameter t.
     * @param t
     * @param p
     */
    public void getPoint(double t, Point3d p)	// After the intersection, you will call this method to get the intersection point
    {
        p.scale(t, viewDirection);
        p.add(eyePoint);
    }
}