import java.awt.*;
import java.util.*;
import Renderable;

/**
 *
 *   An instructional Ray-Tracing Renderer written
 *   for MIT 6.837  Fall '98 by Leonard McMillan.
 *
 */

class Ray {
  public static final float MAX_T = Float.MAX_VALUE;
  Vector3D origin;
  Vector3D direction;
  float t;
  Renderable object;

  public Ray(Vector3D eye, Vector3D dir) {
    origin = new Vector3D(eye);
    direction = Vector3D.normalize(dir);
  }

  public boolean trace(Vector objects) {
    Enumeration objList = objects.elements();
    t = MAX_T;
    object = null;
    while (objList.hasMoreElements()) {
      Renderable object = (Renderable) objList.nextElement();
      object.intersect(this);
    }
    return (object != null);
  }

  // The following method is not strictly needed, and most likely
  // adds unnecessary overhead, but I prefered the syntax
  //
  //            ray.Shade(...)
  // to
  //            ray.object.Shade(ray, ...)
  //
  public final Color Shade(Vector lights, Vector objects, Color bgnd, int depth) {
    return object.Shade(this, lights, objects, bgnd, depth);
  }

  public String toString() {
    return ("ray origin = "+origin+"  direction = "+direction+"  t = "+t);
  }
}