/*code of sun microsystems*/

import java.util.Enumeration;
import javax.media.j3d.*;
import javax.vecmath.*;

public class CollisionDetector extends Behavior {
    private static final Color3f highlightColor =
	new Color3f(0.0f, 1.0f, 0.0f);
    private static final ColoringAttributes highlight =
	new ColoringAttributes(highlightColor,
			       ColoringAttributes.SHADE_GOURAUD);

    private boolean inCollision = false;
    private Shape3D shape;
    private ColoringAttributes shapeColoring;
    private Appearance shapeAppearance;

    private WakeupOnCollisionEntry wEnter;
    private WakeupOnCollisionExit wExit;


    public CollisionDetector(Shape3D s) {
	shape = s;
 	shapeAppearance = shape.getAppearance();
	shapeColoring = shapeAppearance.getColoringAttributes();
	inCollision = false;
    }

    public void initialize() {
  /*by using WakeupOnCollision....USE_GEOMETRY*/
	wEnter = new WakeupOnCollisionEntry(shape, WakeupOnCollisionEntry.USE_GEOMETRY);
	wExit = new WakeupOnCollisionExit(shape, WakeupOnCollisionEntry.USE_GEOMETRY);
	wakeupOn(wEnter);
    }

    public void processStimulus(Enumeration criteria) {
	inCollision = !inCollision;

	if (inCollision) {
	    shapeAppearance.setColoringAttributes(highlight);
       wakeupOn(wExit);
	}
	else {
	    shapeAppearance.setColoringAttributes(shapeColoring);
       wakeupOn(wEnter);
	}
    }
}