Exemple of collision detection with ghost physics

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1

Hy,



just wanted to share my way to detect collisions, not sure that’s the best one, but can be usefull for someone. If you know a better way, I/m there to learn :wink:



[java]package jme3test.helloworld.collision;



import com.jme3.app.SimpleBulletApplication;

import com.jme3.bullet.collision.shapes.SphereCollisionShape;

import com.jme3.bullet.nodes.PhysicsGhostNode;

import com.jme3.material.Material;

import com.jme3.math.ColorRGBA;

import com.jme3.math.FastMath;

import com.jme3.math.Vector3f;

import com.jme3.system.AppSettings;



public class ThreeBallsCollision extends SimpleBulletApplication{



private PhysicsGhostNode pgnA, pgnB, pgnC;

private int cpt = 0;



public static void main(String[] args){

ThreeBallsCollision app = new ThreeBallsCollision();

AppSettings settings = new AppSettings(true);

settings.setResolution(1280, 720);

settings.setFrameRate(60);

app.setSettings(settings);

//app.setShowSettings(false);

app.start();

}



public void simpleInitApp(){

cam.setLocation(new Vector3f(0,-20,0));

cam.lookAt(Vector3f.ZERO, new Vector3f(0, 1,0));



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

matBlue.setColor(“m_Color”, ColorRGBA.Blue);

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

matRed.setColor(“m_Color”, ColorRGBA.Red);

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

matGreen.setColor(“m_Color”, ColorRGBA.Green);



pgnA = new PhysicsGhostNode(new SphereCollisionShape(1));

pgnA.setName(“A (blue)”);

pgnA.attachDebugShape(matBlue);

rootNode.attachChild(pgnA);

getPhysicsSpace().add(pgnA);



pgnB = new PhysicsGhostNode(new SphereCollisionShape(1));

pgnB.setName(“B (red)”);

pgnB.attachDebugShape(matRed);

rootNode.attachChild(pgnB);

getPhysicsSpace().add(pgnB);



pgnC = new PhysicsGhostNode(new SphereCollisionShape(1));

pgnC.setName(“C (green)”);

pgnC.attachDebugShape(matGreen);

rootNode.attachChild(pgnC);

getPhysicsSpace().add(pgnC);

}



public void simpleUpdate(float tpf) {

pgnA.setLocalTranslation(5FastMath.cos(cpttpf), 0, 0);

pgnB.setLocalTranslation(0, 0, 5FastMath.cos(cpttpf));

pgnC.setLocalTranslation(5FastMath.cos(2cpttpf), 0, 5FastMath.sin(cpttpf));



//without this reset the application have a weird behaviour (probably because of FastMath.cos/sin(>> 2xPI))

if((cpttpf) > 2*FastMath.PI) cpt=0;



fpsText.setText(cpt+"(f) - "+

"A (blue) overLap : “+pgnA.getOverlappingObjects().toString()+” | "+

"B (red) overLap : “+pgnB.getOverlappingObjects().toString()+” | "+

"C (green) overLap : "+pgnC.getOverlappingObjects().toString());



cpt++;

}

}[/java]