[HELP] Check whether two objects overlap

Troubleshooting physics
1

Hei guys!



I’ve tried around a bit and now I want to write some small test programs.

Now I would like to know from you whether there is a function that returns TRUE or FALSE

when two objects touch or overlap.



I hope you can help me!

THX…



schnacko

2

You need a CollisionListener:

[java]

package mygame;

import com.jme3.bullet.BulletAppState;

import com.jme3.bullet.collision.PhysicsCollisionEvent;

import com.jme3.bullet.collision.PhysicsCollisionListener;

import com.jme3.bullet.control.CharacterControl;

import com.jme3.bullet.control.RigidBodyControl;

public class MyCustomControl extends RigidBodyControl implements PhysicsCollisionListener{



public void collision(PhysicsCollisionEvent event) {

try{

System.out.println(event.getNodeA().getName() + " " + event.getNodeB().getName());

} catch (NullPointerException e){

}

}

public MyCustomControl(BulletAppState bulletAppState) {

bulletAppState.getPhysicsSpace().addCollisionListener(this);

}



} [/java]





And from the Main or where you will use it:



[java]MyCustomControl m = new MyCustomControl(bulletAppState);[/java]



It will output automatically - just like an AppState.



Credit must go to whoever first gave this code to me.

3

Thank you for your fast reply…



But what should i do with the >m< Objekt now?

m.collision and what… i don’t understand what you are doing with this methode…



schnacko

4

Oh sorry. This method works when you have two or more Physics Objects. For example, you have two RigidBodyControls and you need to check when they collide.

5

okay…



isn’t there a function: boolean checkCollision(Spatial object1,Spatial object2); or like that?

6

Dude, theres a manual :roll:

https://wiki.jmonkeyengine.org/legacy/doku.php/jme3:advanced:collision_and_intersection

2 Likes
7

That’s what I use… Never seen that normen. Thanks.

8

Thank you … i will try it out tomorrw… when i get problems i will tell :wink:



schnacko

9

@normen, sorry to hijack the thread. What would you recommend in an RPG where you need to check collisions? I think my method is called just like an AppState. On the other hand, I think that to check for collisions using the code in that link you would have to flood the update. Would I be better off to use Physics and use non-physical when collision detection is checked every frame?

10
@memonick said:
Would I be better off to use Physics and use non-physical when collision detection is checked every frame?

Mixing both systems is suboptimal, no.
11

So Physics would be good in an RPG?

12
@memonick said:
So Physics would be good in an RPG?

I thought we were talking about collision?
13

I meant - using RigidBodyControls and CharacterControls, then using the code I gave to the original poster to detect collisions.

14

It depends :roll:

1 Like
15

Hmm… I’ll get more advice once I advance more in the game. Thanks anyway :slight_smile:

16

I need help…

My code is here:

http://pastebin.com/sPEwn7YQ

But there is a fail!..

I don’t know what i have to do…



schnacko

17

You will not get help.



Because we don’t know what the problem is.





If you want to Get Answers, read this.

1 Like
18

sorry i try it again…



I tried out the code sample from the link norman gave me…

Yuo can see my code here: CollisionTest.java

When i run it I get this error:

it says to me on line 65 is a Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main]

com.jme3.collision.UnsupportedCollisionException



In the end I want to set a new position of node2 when node1 collide this…



so is it better this way?



schnacko

19

have I forgotten something?

I am new at JME3 and new at this Forum so… when i make mistakes please tell me…



schnacko

20

I don’t know enough about the subject of your question to help. You need to show the FULL exception (stack trace etc) though.



Have you tried googling the error message and/or looking at the source where the exception was thrown to see if that is helpful.