Picking question

Troubleshooting General Help
1

I’m just wondering how do I get the class of the object from a collision result using a ray.

By class, I mean the thing I created in the game, I didn’t know if class was the right word to use…

I can do as much as getting the geometry from the object, but I want to get a custom variable from it.

I tried doing a brief search but never got much as I never really knew what I was looking for…



Edit: I wanted to have RTS style selections and stuff. Maybe there could be a better way that someone could point me to?

2

I’m not very experimented, so check my answer twice :wink:



[java]CollisionResults results = new CollisionResults();

Ray ray = new Ray( G.camera.getLocation(), G.camera.getDirection() );

node.collideWith( ray, results );



CollisionResult closest = results.getClosestCollision();

if ( closest != null )

{

System.out.println( closest.getGeometry().getName() );

}

[/java]



Maybe you can use a HashMap and attach your variable to the Geometry’s name ?

You could also extend Geometry to customize it with a variable.

3

Do not extend Geometry for this.



Every spatial already has user data and you can attach all kinds of things to it… no reason to subclass just for that.



http://hub.jmonkeyengine.org/javadoc/com/jme3/scene/Spatial.html#setUserData(java.lang.String,%20java.lang.Object)



http://hub.jmonkeyengine.org/javadoc/com/jme3/scene/Spatial.html#getUserData(java.lang.String)

4

I see.

Do different objects using the same model have different values?

Also is it possible to link to the object itself through the user data?

5

Yes. They can have different values. Spatials can only have one parent so that are cloned and not shared in the case of a shared model. Only the meshes are shared for real.



It is possible put custom objects in user data but (unfortunately) they must implement the Saveable (sp?) interface. I usually find it better to stick and ID in there and use a map.



…or… depending on what kind of object it is and what it is used for, sometimes a Control is better. Or a Control that wraps your object. These can be looked up by class on the spatial.

6

http://hub.jmonkeyengine.org/groups/development-discussion-jme3/forum/topic/bare-bones-shooting-framework/#post-130906



I used a list of stuff, with each thing’s geometry’s name being its position in the list.