collideWith Ray vs BoundingSphere and UnsupportedCollisionException

Troubleshooting
1

Hi All

I am trying to implement some sort of collision detection in my game. I am using a BoundingSphere, but it seems to only work when there are a couple of things to collide with - any more in the scenegraph and I get an UnsupportedCollisionException. If I use a ray, then it doesn’t seem to matter how many things there are…

If I have 13 nodes in my scene graph as below, then I can do collisions all day:

npcs (Node)
    generic characterNode a4711f67-2d17-4996-9c64-3b44eb22b519 (Node)
        generic spatial b405b184-9a2f-49db-8ac5-37623258c07f (Node)
            Oto-geom-1 (Geometry)
    generic characterNode 974f19a2-f862-4283-9184-531409169e26 (Node)
        generic spatial 458a33e5-4f35-4d15-a67c-3b10e30c6eab (Node)
            Oto-geom-1 (Geometry)
    generic characterNode db9ceaad-4c4c-4aa9-bb62-120cf61cae75 (Node)
        generic spatial 4d2fe784-43c9-4dae-b739-53f5c2819c37 (Node)
            Oto-geom-1 (Geometry)
    generic characterNode b78a11c9-8210-4ffe-bba7-99e076e73671 (Node)
        generic spatial 45f507cd-3600-49ec-8563-1cf5c5f53298 (Node)
            Oto-geom-1 (Geometry)

If I add one more characterNode which makes it 16 nodes in my scene graph as below, then I get UnsupportedCollisionException: With: BoundingSphere : as soon as I try and collide anything whether it collides or not:

npcs (Node)
    generic characterNode 33cbff0d-450b-46a4-9fbd-a9f2be533fc0 (Node)
        generic spatial 050ae9c1-d286-4cea-bd7d-1ad8d466613c (Node)
            Oto-geom-1 (Geometry)
    generic characterNode 81f9189b-9173-498a-bdb1-58aa18fcef52 (Node)
        generic spatial 02345d83-03eb-4c0b-9f78-3b37f5ad1c2b (Node)
            Oto-geom-1 (Geometry)
    generic characterNode ffbaeef8-c34f-4ab7-9c51-81445994f6a9 (Node)
        generic spatial faf6cf6c-1f5c-4b85-aff8-abbed9f9470b (Node)
            Oto-geom-1 (Geometry)
    generic characterNode 0a2aa0fb-4b83-43f0-95dc-57bbe69b6583 (Node)
        generic spatial fe49ba9d-7607-486c-8536-1e3f489037ee (Node)
            Oto-geom-1 (Geometry)
    generic characterNode 03c70abe-8eb3-4c64-9da9-08fa0a88703b (Node)
        generic spatial 6c75b57a-911e-4b7d-8db5-621f7dadd8fa (Node)
            Oto-geom-1 (Geometry)

Here is the full stack trace:

Oct 26, 2015 4:16:02 PM com.jme3.app.Application handleError
SEVERE: Uncaught exception thrown in Thread[jME3 Main,5,main]
com.jme3.collision.UnsupportedCollisionException: With: BoundingSphere
	at com.jme3.bounding.BoundingBox.collideWith(BoundingBox.java:822)
	at com.jme3.scene.Node.collideWith(Node.java:579)
	at mygame.InfluenceControl.controlUpdate(InfluenceControl.java:77)
	at com.jme3.scene.control.AbstractControl.update(AbstractControl.java:112)
	at com.jme3.scene.Spatial.runControlUpdate(Spatial.java:661)
	at com.jme3.scene.Spatial.updateLogicalState(Spatial.java:808)
	at com.jme3.scene.Node.updateLogicalState(Node.java:220)
	at com.jme3.scene.Node.updateLogicalState(Node.java:231)
	at com.jme3.app.SimpleApplication.update(SimpleApplication.java:249)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.runLoop(LwjglAbstractDisplay.java:152)
	at com.jme3.system.lwjgl.LwjglDisplay.runLoop(LwjglDisplay.java:192)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:233)
	at java.lang.Thread.run(Thread.java:745)

Hers is the code, I hope its enough. You’ll note that I have tried it with a boundingbox as well, with the same unfortunate results:

package mygame;

import com.jme3.bounding.BoundingBox;
import com.jme3.bounding.BoundingSphere;
import com.jme3.bullet.BulletAppState;
import com.jme3.collision.CollisionResults;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.Savable;
import com.jme3.math.Ray;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.renderer.ViewPort;
import com.jme3.scene.Geometry;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import com.jme3.scene.control.AbstractControl;
import com.jme3.scene.control.Control;
import java.io.IOException;

public class InfluenceControl extends AbstractControl implements Savable, Cloneable {

    private Float updateNum = 0f;
    public Boolean influenceSpent = false;
    private BulletAppState bulletAppState;
    private float speed = 1100f;
    private Node nodeToInfluence;
    //private BoundingSphere bs;
    private Vector3f position;
    InfluenceInventory influence;
    Geometry anInfluenceArea;

    public InfluenceControl(BulletAppState bulletAppState, Node nodeToInfluence, Vector3f position, InfluenceInventory influence, Geometry anInfluenceArea) {
        this.bulletAppState = bulletAppState;
        this.nodeToInfluence = nodeToInfluence;
        this.influence = influence;
        this.position = position;
        this.anInfluenceArea = anInfluenceArea;
        /* sphere to begin with, but, influence.getMethod() will give us sphere, ray or arc which we should use */

    }

    /**
     * This method is called when the control is added to the spatial, and when
     * the control is removed from the spatial (setting a null value). It can be
     * used for both initialization and cleanup.
     */
    @Override
    public void setSpatial(Spatial spatial) {
        super.setSpatial(spatial);
        /* Example:
         if (spatial != null){
         // initialize
         }else{
         // cleanup
         }
         */
    }

    /**
     * Implement your spatial's behaviour here. From here you can modify the
     * scene graph and the spatial (transform them, get and set userdata, etc).
     * This loop controls the spatial while the Control is enabled.
     *
     * @param tpf
     */
    @Override
    protected void controlUpdate(float tpf) {
        if (!influenceSpent) {
            System.out.println("Influence Area testing collisions");
            BoundingSphere bs = new BoundingSphere(1f, new Vector3f(0, 0, 0));
            BoundingBox bb = new BoundingBox(new Vector3f(0, 0, 0), 1, 1, 1);
                    
            Ray ray = new Ray(new Vector3f(0, 0, 0), new Vector3f(10, 10, 10));
            
            CollisionResults results = new CollisionResults();

            nodeToInfluence.collideWith(bs, results);
            //nodeToInfluence.collideWith(ray, results);

            //anInfluenceArea.collideWith(nodeToInfluence , results);
            if (results.size() > 0) {
                System.out.println("Influenced this many " + results.size());

//                Iterator it = results.iterator();
//                
//                while(it.hasNext()){
//                    System.out.println(results.size() + "Influenced this" + it.next().toString());
//                }
            } else {
                System.out.println("Influenced Nothing");
            }

            if (updateNum > 3) {
                //System.out.println("Influence spent");
                influenceSpent = true;

                bulletAppState.getPhysicsSpace().removeAll(spatial);
                spatial.removeFromParent();
            }

            updateNum += tpf;
        }
    }

    @Override
    public Control cloneForSpatial(Spatial spatial) {
        final InfluenceControl control = new InfluenceControl(bulletAppState, nodeToInfluence, position, influence, anInfluenceArea);
        /* Optional: use setters to copy userdata into the cloned control */
        // control.setIndex(i); // example
        System.out.println("spatial is " + spatial);
        control.setSpatial(spatial);
        return control;
    }

    @Override
    protected void controlRender(RenderManager rm, ViewPort vp) {
        /* Optional: rendering manipulation (for advanced users) */
    }

    @Override
    public void read(JmeImporter im) throws IOException {
        super.read(im);
        // im.getCapsule(this).read(...);
    }

    @Override
    public void write(JmeExporter ex) throws IOException {
        super.write(ex);
        // ex.getCapsule(this).write(...);
    }

}
2

Actually, I meant to post this test app I made:

Its just a new JME BasicGame with the jme-test-data library for the model. Changing the limit in the for loop from 5 to 4 and it works, reporting 15968 collisions. With 5 collisions it fails. It breaches 16384 which is the limit for a 15 bit integer, but I can’t see how that would be relevant especially after looking at where its failing (BoundingBox.java:822), and googling “java 16384” reveals nothing special about that number.

package mygame;

import com.jme3.app.SimpleApplication;
import com.jme3.bounding.BoundingSphere;
import com.jme3.collision.CollisionResults;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import java.awt.Desktop;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.UUID;
import java.util.logging.Logger;

/**
 * test
 *
 * @author normenhansen
 */
public class Main extends SimpleApplication {

    public static void main(String[] args) {
        Main app = new Main();
        app.setShowSettings(false);

        app.start();
    }

    @Override
    public void simpleInitApp() {
        Node allGeometriesNode = new Node("allGeometriesNode");

        for (int i = 0; i < 5; i++) {
            Node aGeometryNode = new Node("aGeometryNode");
            Spatial spatial = assetManager.loadModel("Models/Oto/Oto.mesh.xml");
            spatial.setName(" spatial " + UUID.randomUUID().toString());

            aGeometryNode.attachChild(spatial);

            allGeometriesNode.attachChild(aGeometryNode);
        }

        rootNode.attachChild(allGeometriesNode);

        try {

            File f = File.createTempFile("node", ".html");

            FileWriter fw = new FileWriter(f);

            fw.write(mineNode(allGeometriesNode));

            fw.flush();

            fw.close();

            Desktop.getDesktop().open(f);

        } catch (IOException ex) {

            Logger.getLogger(this.getClass().getName()).log(java.util.logging.Level.SEVERE, "Error writing html file", ex);

        }

        BoundingSphere bs = new BoundingSphere(10f, new Vector3f(0, 0, 0));

        CollisionResults results = new CollisionResults();

        allGeometriesNode.collideWith(bs, results);

        if (results.size() > 0) {
            System.out.println("Collided with this many " + results.size());
        } else {
            System.out.println("Collided with Nothing");
        }

    }

    @Override
    public void simpleUpdate(float tpf) {
        //TODO: add update code
    }

    @Override
    public void simpleRender(RenderManager rm) {
        //TODO: add render code
    }

    private static String mineNode(Node parent) {

        String ptype = parent.getClass().getSimpleName();

        String s = parent.getName() + " (" + ptype + ")" + "<br><ul>";

        if (parent.getChildren().isEmpty()) {
            return parent.getName() + " (" + ptype + ")";
        } else {

            for (Spatial child : parent.getChildren()) {

                if (child instanceof Node) {

                    s = s + "<li>" + mineNode((Node) child) + "</li>";

                } else {

                    String type = child.getClass().getSimpleName();

                    s = s + "<li>" + child.getName() + " (" + type + ")" + "</li>";

                }

            }

        }

        s = s + "</ul>";

        return s;
    }

}
3

An “optimization” was committed to JME without proper testing and causes issues because of the way it short-circuits a check when a certain child threshold has been reached. This code may have been fixed recently in head.

I just looked at the code… and nope.

The problem is that rather than doing an intersects check it does a full CollisionResults style collision test (and ignores the CollisionResults). The problem with that is that bounding sphere to bounding box collisions are not supported by that.

I personally think this ‘if’ should be removed until a proper version is implemented but I haven’t had time to wade into it. In my opinion, it would be better to do an intersect() test in this case…

4

hmm, well I might get head and un-optimize the optimization so I can continue :smile:

5

It’s a good idea.

6

how does one like run the build? I downloaded the jme sources, and have sucessfully “gradle build”, but I can’t fine an executable or jar to run

7

gradlew dist

…then look in the dist folder for the jars

8

ah - similar to maven. I should have guessed…

9

And note: “gradlew” was not a type. It’s the gradle wrapper which will run the appropriate gradle version no matter which gradle you have installed. It’s safer since that’s the one that’s known to build everything properly.

10

Thanks :smiley:

11

That fixed it! running /dist/jMonkeyEngine3.jar just started the tests…

I copied /dist/lib/jme-core.jar to C:\Program Files\jmonkeyplatform3.1beta1\jmonkeyplatform\libs\jme3-core-3.1.0-alpha1.jar and that worked - which is what I realize you meant me to do…

12

For me, I usually just change my projects to depend on the dist jars instead of the SDK built-ins. That way I don’t potentially mess up projects that I still want to depend on the ‘published’ version.

…but I often have 20+ projects open at any given time, so my constraints are a little different. :slight_smile:

13

Oh okay haha - well, I’ll keep that in mind for the future if I end up hacking on jmonkeyengine itself

14

The must be another optimization somewhere, it doesn’t crash any more - but if I have too many objects to collide with I don’t seem to get any collisions…

I’ll have to dig deeper tomorrow.

EDIT: On my small test, I can spawn 100 objects and collisions work fine. Hmmm.