This is a modification of the TickTockCollision example.
When I carefully move one Box nea the other there are
some 'spots' where one of the two Boxes detects
a (faulty) collision (box changes color to green).
I'm using 'WakeupOnCollisionEntry.USE_GEOMETRY',
when I use wakeup on BOUNDS there are no such
'spooky' problems but the collision happens toooo
early, no matter what bounds I am using (I use a
BoundingBox but there's no difference between correct
sized bounds and infinitvly smal bounding box).
Do I make something compleatly wrong ?
Mike
/*
* @(#)CollisionEx.java
*
*/
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.event.*;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.behaviors.picking.*;
import javax.media.j3d.*;
import javax.vecmath.*;
public class CollisionEx extends Applet {
public BranchGroup createSceneGraph(Canvas3D canvas) {
// Create the root of the branch graph
BranchGroup objRoot = new BranchGroup();
// Create a Transformgroup to scale all objects so they
// appear in the scene.
TransformGroup objScale = new TransformGroup();
Transform3D t3d = new Transform3D();
t3d.setScale(1.0);
objScale.setTransform(t3d);
objRoot.addChild(objScale);
// Create a bounds for the background and behaviors
BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0),
100.0);
// Set up the background
Color3f bgColor = new Color3f(0.5f, 0.5f, 1.0f);
Background bg = new Background(bgColor);
bg.setApplicationBounds(bounds);
objScale.addChild(bg);
// Now create a pair of rectangular boxes, each with a collision
// detection behavior attached. The behavior will highlight the
// object when it is in a state of collision.
Transform3D rotate = new Transform3D();
Transform3D temp = new Transform3D();
rotate.rotX(Math.PI/8.0d);
temp.rotY(-Math.PI/9.0d);
rotate.mul(temp);
TransformGroup objView = new TransformGroup(rotate);
objView.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
objScale.addChild(objView);
BranchGroup objTop = new BranchGroup();
objTop.setCapability(Group.ALLOW_CHILDREN_EXTEND);
objTop.setCapability(Group.ALLOW_CHILDREN_WRITE);
objTop.setCapability(Group.ALLOW_CHILDREN_READ);
objTop.setCapability(BranchGroup.ALLOW_DETACH);
objView.addChild(objTop);
Group box1 = createBox(1.0, new Vector3d(-0.4, 0.0, 0.0));
Group box2 = createBox(1.0, new Vector3d( 0.4, 0.0, 0.0));
objTop.addChild(box1);
objTop.addChild(box2);
// Behaviors
PickRotateBehavior behavior = new PickRotateBehavior(objRoot, canvas,
bounds, PickObject.USE_GEOMETRY);
objTop.addChild(behavior);
PickZoomBehavior behavior2 = new PickZoomBehavior(objRoot, canvas,
bounds, PickObject.USE_GEOMETRY);
objTop.addChild(behavior2);
PickTranslateBehavior behavior3 = new
PickTranslateBehavior(objRoot, canvas, bounds, PickObject.USE_GEOMETRY);
objTop.addChild(behavior3);
// Have Java 3D perform optimizations on this scene graph.
objRoot.compile();
return objRoot;
}
private Group createBox(double scale, Vector3d pos) {
// Create a transform group node to scale and position the object.
Transform3D t = new Transform3D();
t.set(scale, pos);
TransformGroup objTrans = new TransformGroup(t);
objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
objTrans.setCapability(TransformGroup.ENABLE_PICK_REPORTING);
// Create a simple shape leaf node and add it to the scene graph
Shape3D shape = new Box(0.4, 0.4, 0.4);
shape.setCapability(Shape3D.ALLOW_GEOMETRY_READ);
shape.setCapability(Shape3D.ALLOW_GEOMETRY_WRITE);
shape.setCapability(Shape3D.ALLOW_COLLISION_BOUNDS_READ);
shape.setCapability(Shape3D.ALLOW_COLLISION_BOUNDS_WRITE);
objTrans.addChild(shape);
// Create a new ColoringAttributes object for the shape's
// appearance and make it writable at runtime.
Appearance app = shape.getAppearance();
ColoringAttributes ca = new ColoringAttributes();
ca.setColor(0.0f, 0.0f, 0.0f);
app.setCapability(app.ALLOW_COLORING_ATTRIBUTES_WRITE);
app.setColoringAttributes(ca);
PolygonAttributes attr = new PolygonAttributes();
attr.setPolygonMode(PolygonAttributes.POLYGON_LINE);
attr.setCullFace(PolygonAttributes.CULL_NONE);
app.setPolygonAttributes(attr);
// Create a new Behavior object that will perform the collision
// detection on the specified object, and add it into
// the scene graph.
CollisionDetector cd = new CollisionDetector(shape);
BoundingBox bounds = new BoundingBox(new Point3d(-0.1,-0.1,-0.1),
new Point3d( 0.1, 0.1, 0.1));
cd.setSchedulingBounds(bounds);
// Add the behavior to the scene graph
objTrans.addChild(cd);
return objTrans;
}
public CollisionEx() {
setLayout(new BorderLayout());
Canvas3D c = new Canvas3D(null);
add("Center", c);
// Create a simple scene and attach it to the virtual universe
BranchGroup scene = createSceneGraph(c);
SimpleUniverse u = new SimpleUniverse(c);
// This will move the ViewPlatform back a bit so the
// objects in the scene can be viewed.
u.getViewingPlatform().setNominalViewingTransform();
u.addBranchGraph(scene);
}
//
// The following allows TickTockCollision to be run as an application
// as well as an applet
//
public static void main(String[] args) {
new MainFrame(new CollisionEx(), 700, 600);
}
/*
* @(#)CollisionDetector.java 1.4 98/02/20 14:30:17
*
*/
import java.util.Enumeration;
import javax.media.j3d.*;
import javax.vecmath.*;
public class CollisionDetector extends Behavior {
private static final Color3f highlightColor = new Color3f(1.0f, 0.0f,
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() {
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);
}
}
}
/*
* @(#)Box.java 1.5 98/04/08 14:54:49
*
*/
import javax.media.j3d.*;
import javax.vecmath.*;
public class Box extends Shape3D {
public Box(double xsize, double ysize, double zsize) {
super();
double xmin = -xsize/2.0;
double xmax = xsize/2.0;
double ymin = -ysize/2.0;
double ymax = ysize/2.0;
double zmin = -zsize/2.0;
double zmax = zsize/2.0;
QuadArray box = new QuadArray(24, QuadArray.COORDINATES);
box.setCapability(Geometry.ALLOW_INTERSECT);
Point3d verts[] = new Point3d[24];
// front face
verts[0] = new Point3d(xmax, ymin, zmax);
verts[1] = new Point3d(xmax, ymax, zmax);
verts[2] = new Point3d(xmin, ymax, zmax);
verts[3] = new Point3d(xmin, ymin, zmax);
// back face
verts[4] = new Point3d(xmin, ymin, zmin);
verts[5] = new Point3d(xmin, ymax, zmin);
verts[6] = new Point3d(xmax, ymax, zmin);
verts[7] = new Point3d(xmax, ymin, zmin);
// right face
verts[8] = new Point3d(xmax, ymin, zmin);
verts[9] = new Point3d(xmax, ymax, zmin);
verts[10] = new Point3d(xmax, ymax, zmax);
verts[11] = new Point3d(xmax, ymin, zmax);
// left face
verts[12] = new Point3d(xmin, ymin, zmax);
verts[13] = new Point3d(xmin, ymax, zmax);
verts[14] = new Point3d(xmin, ymax, zmin);
verts[15] = new Point3d(xmin, ymin, zmin);
// top face
verts[16] = new Point3d(xmax, ymax, zmax);
verts[17] = new Point3d(xmax, ymax, zmin);
verts[18] = new Point3d(xmin, ymax, zmin);
verts[19] = new Point3d(xmin, ymax, zmax);
// bottom face
verts[20] = new Point3d(xmin, ymin, zmax);
verts[21] = new Point3d(xmin, ymin, zmin);
verts[22] = new Point3d(xmax, ymin, zmin);
verts[23] = new Point3d(xmax, ymin, zmax);
box.setCoordinates(0, verts);
setGeometry(box);
setAppearance(new Appearance());
}
}
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