I’m looking at the documentation on collisions to activate events.
I have a problem, according to the documentation, an addCollisionListener can be added to the physical space for later in the function detect collisions such as using the name of the collided nodes.
public void collision(PhysicsCollisionEvent CollisionesEncontradas){
if(CollisionesEncontradas.getNodeA().getName().equals("esfera")){
System.out.println("la esfera a entrado a un area de colision");
}
else if(CollisionesEncontradas.getNodeB().getName().equals("esfera")){
System.out.println("la esfera a entrado a un area de colision");
}
} //procesa las colisiones en las escena.
However when adding the ghostControl to the addcollisionListener I can not detect the collisions since the data type is not the same and I can not understand how it works
CODE:
private void FisicaEnLaEscena(){
///////////agrega propiedades físicas a los nodos/////////////////
fisica = new BulletAppState();//creo el objeto con las propiedades fisicas
stateManager.attach(fisica);//agrego propiedades fisicas a la escena
fisica.setDebugEnabled(true);//muestro las colisiones al renderizar
//------------------------------------------------------------------------------//
} //agrega propiedades físicas a los nodos
private void cubosConFisica(){
///creo las colisiones a todos los cubos
cubos = ((Node)((Node)Escena_principal).getChild("ConjuntoCajas")).getChild("Scene");//busco al nodo
listaCubos = ((Node)cubos).getChildren();//guardo todos los nodos en una lista
for(Spatial i : listaCubos){ //creo un bucle foreach
i = ((Node)i).getChild(0);
//crearColisiones(i, 1.0f,-200.0f);
crearAreasColisionesFantasmas(i);
//crearColisiones(i, 1.0f, -200);
i.setMaterial(madera);
}
} //agrega fisica a los cubos
private void crearAreasColisionesFantasmas(Spatial i){
////creo un rigidbody control a las CAJAS le agrego las físicas
//colisiones
CollisionShape cajasColision = CollisionShapeFactory.createBoxShape(i);//creo la colision
//cuerpo rigido
GhostControl cuerpofantasmaCajas = new GhostControl(cajasColision);//creo el control del cuerpo y por parametro agrego la colision y la masa
cuerpofantasmaCajas.addCollideWithGroup(0);
i.addControl(cuerpofantasmaCajas);//agrego un controlador de fisica a ese objeto
fisica.getPhysicsSpace().add(cuerpofantasmaCajas);//agrego a las fisicas del space
fisica.getPhysicsSpace().addCollisionListener(cuerpofantasmaCajas);
} //crea las colisiones fantasmas para detectar cuando un objeto entra
public void collision(PhysicsCollisionEvent CollisionesEncontradas){
if(CollisionesEncontradas.getNodeA().getName().equals("esfera")){
System.out.println("la esfera a entrado a un area de colision");
}
else if(CollisionesEncontradas.getNodeB().getName().equals("esfera")){
System.out.println("la esfera a entrado a un area de colision");
}
} //procesa las colisiones en las escena.
Thank you very much, it works, but why does it detect so many collisions if it only collides one time? If you look at the console you see that the message is executed many times on the screen
If I want to activate a sound it will sound many times then …
But the message repeated 9 times is only shown when colliding with 1 object … what am I doing wrong … How is that filter … thanks for your time you are helping me a lot.
Well thank you very much, you have helped me a lot, I will think about everything you said to me. When I solve this problem I will do a tutorial in Spanish.
Physics collisions are reported multiple times because the listener is invoked once for every “contact manifold” and there can be up to 4 contact manifolds per collision object. And since there are 2 collision objects involved, you can get up to 8 invocations for a single collision.
Most of the time, you can just ignore the duplicates.
How can I ignore those duplicates? It’s the big doubt I had all day …
both in godot engine and unity there is a function that produces an event when a body enters a non-collisionable area, however I can not find something similar in Jmonkey Engine.
What function would I have to create for that? Because that’s my problem, I want the first collision to stop colliding so that for example, I can add a point.
In jMonkeyEngine, there are at least 3 methods to have physics collisions without generating contact forces:
You can use a PhysicsGhostObject instead of a PhysicsRigidBody. This is the oldest solution, but it isn’t much help for characters or vehicles.
You can use .setContactResponse(false) to disable contact forces for particular collision objects. This is my preferred solution, but it’s relatively new. It was added to Minie v0.5.1 and jme3-bullet v3.3.0-alpha1. It also exists in master-branch jme3-jbullet, but hasn’t appeared in any jme3-jbullet release yet.
I’ve heard you can use a PhysicsCollisionGroupListener listener which returns false. I’ve never tried this, so I don’t know how well it works.
