Simple Collision

Troubleshooting General Help
1

Hi, I’m making a simple shoot em up to test, I need to check collision but I not find a simple example to check this, I wrote the following code

[java]

@Override

public void simpleInitApp() {



this.getFlyByCamera().setEnabled(false);

cam.setLocation(new Vector3f(cam.getLocation().x,

cam.getLocation().y,

cam.getLocation().z + 100));



Spatial s = assetManager.loadModel(“Models/Monkey3/Monkey3.j3o”);



Box b = new Box(Vector3f.ZERO, 1, 1, 1);

Geometry geom = new Geometry(“Box”, b);



Material mat = new Material(assetManager, “Common/MatDefs/Misc/Unshaded.j3md”);

mat.setColor(“Color”, ColorRGBA.Blue);

geom.setMaterial(mat);





rootNode.attachChild(geom);

rootNode.attachChild(s);



DirectionalLight sun = new DirectionalLight();



sun.setDirection(new Vector3f(-1.0f,0,-1.5f).normalizeLocal());

sun.setColor(ColorRGBA.White);

rootNode.addLight(sun);



s.setLocalTranslation(Vector3f.ZERO);

geom.setLocalTranslation(Vector3f.ZERO);

CollisionResults results = new CollisionResults();

geom.collideWith(s, results);

if (results.size() > 0)

System.out.println(“Colision!!!”);







}

[/java]



to display “Colision!!!” when the models collided. I have a geom box and a spatial monkey, both located in 0.0f,0.0f,0.0f, when I check the collision with the collideWith method, I take a exception



“com.jme3.collision.UnsupportedCollisionException

at com.jme3.collision.bih.BIHTree.collideWith(BIHTree.java:461)

at com.jme3.scene.Mesh.collideWith(Mesh.java:856)

at com.jme3.scene.Geometry.collideWith(Geometry.java:448)

at mygame.Main.simpleInitApp(Main.java:64)

at com.jme3.app.SimpleApplication.initialize(SimpleApplication.java:228)

at com.jme3.system.lwjgl.LwjglAbstractDisplay.initInThread(LwjglAbstractDisplay.java:129)

at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:205)

at java.lang.Thread.run(Thread.java:722)”



Can somebody give a simple example to check collision? It is a simple game in 2D with 3d models ( 2.5D :wink: ) I want to check collision only in x and y without physics.



Thanks.

Bye.

2

Check “Hello Picking”

3

Thanks, but i don’t know how apply that example to my issue, why the collideWith method work with Ray class and don’t work with geometry? I thing that maybe i can have and instance off standard Java Rectangle class for all models in scene and check the collisions with constaint method, in this case i have to know how i get the model,s size in x and y to define the rectangles. Maybe it is a complicate solutio, can any body help me with this, i have to manage collision in 2d.



Thanks.

4

It just doesn’t, you can use some bounding volumes or the bullet sweepTest.

5

Thanks normen, with the bounding volumes work fine, it have not very presision collision detection but is right for my case, I use the intersects method of bounding volumes



[java]

…

…

Box a = new Box(Vector3f.ZERO, 1, 1, 1);

Geometry geomA = new Geometry ("BoxA", a);

Material matA = new Material("Common/MatDefs/Misc/Unshaded.j3md");

matA.setColor("Color", ColorRGBA.Red);

geomA.setMaterial(matA);



Box b = new Box(Vector3f.ZERO, 1, 1, 1);

Geometry geomB = new Geometry ("BoxB", b);

Material matB = new Material("Common/MatDefs/Misc/Unshaded.j3md");

matB.setColor("Color", ColorRGBA.Blue);

geomB.setMaterial(matB);

…

…

if (geomA.getWorldBound().intersects(geomB.getWorldBound())

System.out.println("Collision!!!");



…

…

[/java]



Thanks you very much.