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package tesseract;
import java.awt.Color;
import javax.media.j3d.Appearance;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.ColoringAttributes;
import javax.media.j3d.Group;
import javax.media.j3d.Node;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import javax.vecmath.Color3f;
import javax.vecmath.Vector3f;
import com.sun.j3d.utils.geometry.Sphere;
/**
* This class is the parent of all objects in the world.
*
* @author Jesse Morgan
*/
public abstract class PhysicalObject {
/**
* The inverse of the object's mass.
*/
protected float inverseMass;
/**
* The object's current position.
*/
private Vector3f myPosition;
/**
* The object's previous position.
*/
private Vector3f myPrevPosition;
private Vector3f myVelocity;
private BranchGroup BG;
private TransformGroup TG;
public PhysicalObject(final Vector3f position, final float mass) {
inverseMass = 1 / mass;
myPosition = new Vector3f(position);
myPrevPosition = new Vector3f(position);
}
public Particle(Color3f color, Vector3f position, Vector3f velocity) {
inverseMass = 1;
this.position = new Vector3f(position);
prevPosition = new Vector3f(position);
this.velocity = new Vector3f(velocity);
force = new Vector3f();
TG = new TransformGroup();
TG.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
TG.addChild(createShape(color));
BG = new BranchGroup();
BG.setCapability(BranchGroup.ALLOW_DETACH);
BG.addChild(TG);
updateTransformGroup();
}
public float getInverseMass() {
return inverseMass;
}
public Vector3f getPosition() {
return myPosition;
}
public Vector3f getPreviousPosition() {
return myPrevPosition;
}
public Vector3f getVelocity() {
return velocity;
}
public Group getGroup() {
return BG;
}
public void detach() {
BG.detach();
}
public void addForce(Vector3f force) {
this.force.add(force);
}
public void updateState(float duration) {
// The force vector now becomes the acceleration vector.
force.scale(inverseMass);
prevPosition.set(position);
position.scaleAdd(duration, velocity, position);
position.scaleAdd(duration * duration / 2, force, position);
velocity.scaleAdd(duration, force, velocity);
// The force vector is cleared.
force.x = force.y = force.z = 0;
updateTransformGroup();
}
public void updateTransformGroup() {
Transform3D tmp = new Transform3D();
tmp.setTranslation(position);
TG.setTransform(tmp);
}
private Node createShape(Color3f color) {
ColoringAttributes cAttr;
if (color == null) {
Color randomColor = Color.getHSBColor((float)Math.random(), 1, 1);
color = new Color3f(randomColor);
}
cAttr = new ColoringAttributes(color, ColoringAttributes.FASTEST);
Appearance appearance = new Appearance();
appearance.setColoringAttributes(cAttr);
return new Sphere(RADIUS, 0, 8, appearance);
}
}
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