I’ve been working on a plugin for the past few weeks to help me build my world in the SDK. One of the many features of this plugin is to be able to add a “physics barrier”, which is a simple quad geometry with a rigid body control attached to it.
Now to do so, I created a class “PhysicsBarrier” that extends Geometry, and I’ve also created a class “JmePhysicsBarrier” that extends JmeGeometry, so that I can have it as a custom node in the scene explorer. The classes are shown below:
PhysicsBarrier
package com.fadorico.plugins.tiledTerrainLib.spatials;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.gde.core.scene.SceneApplication;
import com.jme3.material.Material;
import com.jme3.scene.Geometry;
import com.jme3.scene.shape.Quad;
import java.io.IOException;
public class PhysicsBarrier extends Geometry{
private float width;
private float height;
private RigidBodyControl physicsControl;
public PhysicsBarrier(){
this(5, 5);
}
public PhysicsBarrier(float width, float height){
super("Physics barrier", new Quad(width, height));
this.width = width;
this.height = height;
physicsControl = new RigidBodyControl(0);
addControl(physicsControl);
setCullHint(CullHint.Always);
//Material mat = new Material(SceneApplication.getApplication().getAssetManager(), "Common/MatDefs/Misc/Unshaded.j3md");
//setMaterial(mat);
}
public float getWidth(){
return width;
}
public float getHeight(){
return height;
}
public void setWidth(float width){
this.width = width;
((Quad)getMesh()).updateGeometry(width, height);
physicsControl.setEnabled(false);
physicsControl.setEnabled(true);
}
public void setHeight(float height){
this.height = height;
((Quad)getMesh()).updateGeometry(width, height);
physicsControl.setEnabled(false);
physicsControl.setEnabled(true);
}
@Override
public void write(JmeExporter ex) throws IOException {
super.write(ex);
OutputCapsule capsule = ex.getCapsule(this);
capsule.write(width, "Width", 5);
capsule.write(height, "Height", 5);
}
@Override
public void read(JmeImporter im) throws IOException {
super.read(im);
InputCapsule capsule = im.getCapsule(this);
width = capsule.readFloat("Width", 5);
height = capsule.readFloat("Height", 5);
}
}
JmePhysicsBarrier
package com.fadorico.plugins.tiledTerrainLib.spatials;
import com.jme3.gde.core.sceneexplorer.nodes.JmeGeometry;
import com.jme3.gde.core.sceneexplorer.nodes.JmeSpatial;
import com.jme3.gde.core.sceneexplorer.nodes.JmeSpatialChildren;
import com.jme3.gde.core.sceneexplorer.nodes.SceneExplorerNode;
import com.jme3.scene.Geometry;
import java.awt.Image;
import java.io.File;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.openide.loaders.DataObject;
import org.openide.nodes.Sheet;
import org.openide.util.ImageUtilities;
@org.openide.util.lookup.ServiceProvider(service=SceneExplorerNode.class)
public class JmePhysicsBarrier extends JmeSpatial{
private static Image smallImage = ImageUtilities.loadImage("com/fadorico/plugins/tiledTerrainLib/icons/barrier.gif");
private PhysicsBarrier physicsBarrier;
public JmePhysicsBarrier(){
}
public JmePhysicsBarrier(PhysicsBarrier spatial, JmeSpatialChildren children){
super(spatial, children);
getLookupContents().add(spatial);
physicsBarrier = spatial;
setName(spatial.getName());
}
@Override
public Image getIcon(int type) {
return smallImage;
}
@Override
public Image getOpenedIcon(int type) {
return smallImage;
}
@Override
protected Sheet createSheet() {
Sheet sheet = super.createSheet();
Sheet.Set set = Sheet.createPropertiesSet();
set.setDisplayName("Physics barrier");
set.setName(PhysicsBarrier.class.getName());
if (physicsBarrier == null) {
return sheet;
}
set.put(makeProperty(physicsBarrier, float.class, "getWidth", "setWidth", "Width"));
set.put(makeProperty(physicsBarrier, float.class, "getHeight", "setHeight", "Height"));
sheet.put(set);
return sheet;
}
@Override
public Class getExplorerNodeClass(){
return JmePhysicsBarrier.class;
}
@Override
public Class getExplorerObjectClass(){
return PhysicsBarrier.class;
}
@Override
public org.openide.nodes.Node[] createNodes(Object key, DataObject key2, boolean readOnly) {
JmeSpatialChildren children=new JmeSpatialChildren((com.jme3.scene.Spatial)key);
children.setReadOnly(readOnly);
return new org.openide.nodes.Node[]{new JmePhysicsBarrier((PhysicsBarrier) key, children).setReadOnly(readOnly)};
}
}
I can successfully add my physics barrier into the scene explorer. However, when I save & close and then try to reopen my scene, I get this weird exception:
java.lang.ClassCastException: com.fadorico.plugins.tiledTerrainLib.spatials.PhysicsBarrier cannot be cast to com.fadorico.plugins.tiledTerrainLib.spatials.PhysicsBarrier
at com.fadorico.plugins.tiledTerrainLib.spatials.JmePhysicsBarrier.createNodes(JmePhysicsBarrier.java:75)
at com.jme3.gde.core.sceneexplorer.nodes.JmeSpatialChildren.createNodes(JmeSpatialChildren.java:138)
at org.openide.nodes.Children$Keys$KE.nodes(Children.java:1662)
............
Does anyone know why I would be getting this??? I mean clearly I’m trying to cast the right object but for some reason it doesn’t recognize it.
I guess its also worth mentioning that I’ve been following this tutorial here http://wiki.jmonkeyengine.org/doku.php/sdk:development:sceneexplorer and that I use the last available nightly build.
. But the problem, I figured, is actually that I create my spatials dynamically through the plugin. The NewSpatialAction class is created through the class loader of the plugin, thus when I create a new instance of the physics barrier, its created through the same class loader as the NewSpatialAction, being the plugin’s class loader. When I close and save the file, the barrier is saved using the write(), from that same class loader. But when I reopen the file in the SDK, the SceneApplication’s asset manager opens the file, using its own class loader. But since the barrier was saved with an instance of the plugin’s class loader, I get the exception.