Find attached an improved version of the Behavior I posted earlier.
--
Renoir Sewjee
Software Engineer
ISS International (Welkom)
Tel: +27 (0)57 912 2702
Fax: +27 (0)57 912 2652
--
/**
* Picks a point out of a PointArray using a mouse press.
*
*/
import java.awt.AWTEvent;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.awt.event.InputEvent;
import java.util.Enumeration;
import java.util.ArrayList;
import com.sun.j3d.utils.picking.PickCanvas;
import com.sun.j3d.utils.picking.PickResult;
import com.sun.j3d.utils.picking.PickIntersection;
import javax.media.j3d.Behavior;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.WakeupOnAWTEvent;
import javax.media.j3d.WakeupCriterion;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.PointArray;
import javax.vecmath.Point3d;
import java.util.ArrayList;
import java.util.Iterator;
import com.sun.j3d.utils.picking.PickTool;
/*
* In the code the index of the vertex that was picked is written to the standard
error. A more elegant
* way to get this info to your other classes would be to maintain a list of
PointPickedListeners which
* you manage with the following methods:
*
* addPointPickedListener(PointPickedListener listener)
* removePointPickedListener(PointPickedListener listener)
* firePointPickedEvent(PointPickedEvent event)
*
*/
public class PointPicker extends Behavior
{
protected PickCanvas pickCanvas;
protected WakeupOnAWTEvent wakeupCriterion;
protected int x;
protected int y;
public PointPicker(Canvas3D canvas, BranchGroup scene)
{
pickCanvas = new PickCanvas(canvas, scene);
// Objects within this disstance from the mouse location will be picked.
pickCanvas.setTolerance(3.0f);
// We want to get info (indices of points) from the intersected geometry (the
PointArray).
pickCanvas.setMode(PickCanvas.GEOMETRY_INTERSECT_INFO);
}
public void initialize()
{
// Wake up when a mouse button is pressed.
wakeupCriterion = new WakeupOnAWTEvent(MouseEvent.MOUSE_PRESSED);
wakeupOn(wakeupCriterion);
}
public void processStimulus(Enumeration criteria)
{
while (criteria.hasMoreElements())
{
WakeupCriterion wakeup = (WakeupCriterion)criteria.nextElement();
if (wakeup instanceof WakeupOnAWTEvent)
{
AWTEvent[] events = ((WakeupOnAWTEvent)wakeup).getAWTEvent();
if (events.length > 0 && events[events.length-1] instanceof
MouseEvent)
{
MouseEvent event = (MouseEvent)events[events.length-1];
int id = event.getID();
int mod = event.getModifiers();
// If you wanted to pick only when you press certain
mouse buttons
// you would use an if statement similar to the
following:
// if (mod == InputEvent.BUTTON1_MASK)
// {
// THE CODE BELOW
// }
// The location of the mouse event.
x = event.getX();
y = event.getY();
// Pick the closest node
pickCanvas.setShapeLocation(x, y);
Point3d eyePos = pickCanvas.getStartPosition();
PickResult pickResult = pickCanvas.pickClosest();
// If nothing was picked (didn't click on one of the
points) the PickResult
// will be null. If we continue with a null result a
NullPointerException
// will be thrown and the wakeupOn(wakeupCriterion)
method will not be
// called, effectivly disabling the behavior.
if (pickResult != null)
{
// Get the closest intersection with the
geometry.
PickIntersection pickIntersection =
pickResult.getClosestIntersection(eyePos);
// Check that a PointArray was picked
if (pickIntersection.getGeometryArray()
instanceof PointArray)
{
// Get the vertex indices of the
intersected primitive,
// in this case the index of the
intersected point in the PointArray.
int[] indices =
pickIntersection.getPrimitiveVertexIndices();
// There should only be one index
since this is a PointArray,
// so we use indices[0].
System.err.println("Index of picked
point: " + String.valueOf(indices[0]));
}
}
}
}
}
wakeupOn(wakeupCriterion);
}
}
