Items collide and fly trough the landscape

zzuegg · October 3, 2011, 3:06pm

Following the tutorial i reached the physics part. I tested the physics with a small object and all seems to work fine.

a) The problems are following, when i load two or more small objects they collide right after initialisation and fly trough the map.

b) When i load a bigger Object it sink’s half into the landscape and after some time it fly’s up and lands correctly on the ground.

Here is the code i wrote for loading the terrain and the objects and setting up the physics. (I can’t attache a screenshot because the objects are not visible on the pictures)

The GameUnit.java should load a model and attach it to the root node and BulletAppState.

[java]package mygame;

import com.jme3.asset.AssetManager;

import com.jme3.bullet.BulletAppState;

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

import com.jme3.bullet.control.CharacterControl;

import com.jme3.bullet.control.RigidBodyControl;

import com.jme3.math.Vector3f;

import com.jme3.renderer.queue.RenderQueue.ShadowMode;

import com.jme3.scene.Node;

import com.jme3.scene.Spatial;

import java.util.ArrayList;

import java.util.Stack;

/**

*

@author zzuegg

/

public class GameUnit {

Node position;

Node rootNode;

Spatial mesh;

RigidBodyControl unit_physics;

//AssetManager

AssetManager assetManager;

//PHYSICS

BulletAppState bulletAppState;

BoxCollisionShape collisionShape;

CharacterControl playerControl;

int id;

public boolean isMovable;

public boolean isRotable;

Stack<Vector3f> waypoint;

ArrayList subUnits;

public GameUnit(Node rootNode,Vector3f position,AssetManager assetManager, BulletAppState bulletAppState, int id,String modelName) {

this.position=new Node();

this.position.setLocalTranslation(position);

this.bulletAppState = bulletAppState;

this.assetManager=assetManager;

this.id = id;

this.rootNode=rootNode;

this.load(modelName);

}

private void load(String modelName){

this.mesh=assetManager.loadModel(modelName);

this.mesh.setShadowMode(ShadowMode.CastAndReceive);

//Collision Model

this.collisionShape= new BoxCollisionShape(new Vector3f(1f,1f,1f));

this.playerControl=new CharacterControl(this.collisionShape,1);

//Physic Modlel

this.unit_physics = new RigidBodyControl(2f);

this.mesh.addControl(this.unit_physics);

//Attach mesh to node.

this.position.attachChild(this.mesh);

//Add object to physic system

this.playerControl.setPhysicsLocation(this.position.getWorldTranslation());

this.bulletAppState.getPhysicsSpace().add(this.playerControl);

this.bulletAppState.getPhysicsSpace().add(this.unit_physics);

waypoint=new Stack();

}

public Node getNode(){

return (this.position);

}

}[/java]

This is the MapLoader:

[java]

/
To change this template, choose Tools | Templates
and open the template in the editor.

*/

package mygame;

import com.jme3.asset.AssetManager;

import com.jme3.bullet.BulletAppState;

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

import com.jme3.bullet.control.RigidBodyControl;

import com.jme3.bullet.util.CollisionShapeFactory;

import com.jme3.light.DirectionalLight;

import com.jme3.math.Vector3f;

import com.jme3.post.FilterPostProcessor;

import com.jme3.renderer.ViewPort;

import com.jme3.scene.Node;

import com.jme3.scene.Spatial;

import com.jme3.shadow.PssmShadowRenderer;

import com.jme3.water.WaterFilter;

/**

*
@author zzuegg

*/

public class ManagerMapLoader {

Node loadNewMap(int id,Node rootNode,AssetManager assetManager,BulletAppState bulletAppState, ViewPort viewPort){

Node map=new Node();

//LOAD VARIABLES

Vector3f lightDirection=new Vector3f(-40.9f, -10.3f, 0.9f);

Spatial terrain=assetManager.loadModel("Scenes/Map_Demo1/Map_Demo1_scene.j3o");

float waterHeight=-1.5f;

//ADD LIGHT AND TERRAIN

DirectionalLight sun = new DirectionalLight();

sun.setDirection(lightDirection);

rootNode.addLight(sun);

map.attachChild(terrain);

//ADD SHADOW

PssmShadowRenderer pssmRenderer=new PssmShadowRenderer(assetManager,1024,4);

pssmRenderer.setFilterMode(PssmShadowRenderer.FilterMode.PCF8);

pssmRenderer.setDirection(new Vector3f(-1,-1,-1).normalizeLocal());

viewPort.addProcessor(pssmRenderer);

//REGISTER PHYSICS

CollisionShape sceneShape=CollisionShapeFactory.createMeshShape((Node) terrain);

RigidBodyControl landscape= new RigidBodyControl(sceneShape,0);

terrain.addControl(landscape);

bulletAppState.getPhysicsSpace().add(landscape);

//ADD WATEREFFECT

FilterPostProcessor ffp=new FilterPostProcessor(assetManager);

WaterFilter water=new WaterFilter(map,lightDirection);

water.setWaterHeight(waterHeight);

ffp.addFilter(water);

viewPort.addProcessor(ffp);

return map;

}

}

[/java]

And finaly the main:

[java]

package mygame;

import com.jme3.app.SimpleApplication;

import com.jme3.bullet.BulletAppState;

import com.jme3.light.DirectionalLight;

import com.jme3.material.Material;

import com.jme3.math.ColorRGBA;

import com.jme3.math.Vector3f;

import com.jme3.renderer.RenderManager;

import com.jme3.scene.Geometry;

import com.jme3.scene.Spatial;

import com.jme3.scene.shape.Box;

import com.jme3.system.AppSettings;

/**
test
@author normenhansen

*/

public class Main extends SimpleApplication {

ManagerMapLoader MapManager;

ManagerPlayerInputControl InputManager;

BulletAppState bulletAppState;

public static void main(String[] args) {

Main app = new Main();

app.start();

}

@Override

public void simpleInitApp() {

this.flyCam.setEnabled(false);

settings.setRenderer(AppSettings.LWJGL_OPENGL3);

this.MapManager=new ManagerMapLoader();

this.InputManager=new ManagerPlayerInputControl();

this.InputManager.initPlayerControls(this.inputManager, this.cam);

this.bulletAppState=new BulletAppState();

this.bulletAppState.setThreadingType(BulletAppState.ThreadingType.PARALLEL);

this.stateManager.attach(this.bulletAppState);

this.rootNode.attachChild(MapManager.loadNewMap(0,this.rootNode, assetManager, this.bulletAppState, viewPort));

GameUnit tmp=new GameUnit(this.rootNode,new Vector3f(1,1,1),this.assetManager,this.bulletAppState,0,"Models/Rebellion_Radar_test1.j3o");

this.rootNode.attachChild(tmp.getNode());

//GameUnit tmp=new GameUnit(this.rootNode,new Vector3f(3,10,3),this.assetManager,this.bulletAppState,0,"Models/Rebellion_Headquarter_test1.j3o");

//this.rootNode.attachChild(tmp.getNode());

tmp=new GameUnit(this.rootNode,new Vector3f(10,10,20),this.assetManager,this.bulletAppState,0,"Models/Electro_turret1.j3o");

this.rootNode.attachChild(tmp.getNode());

}

@Override

public void simpleUpdate(float tpf) {

//TODO: add update code

this.InputManager.updatePlayerControls(tpf, inputManager, settings.getHeight(), settings.getWidth());

}

@Override

public void simpleRender(RenderManager rm) {

//TODO: add render code

}

}

[/java]

normen · October 3, 2011, 3:15pm

Enable the physics debug view, then it will probably become apparent whats wrong:

[java]this.bulletAppState.getPhysicsSpace().enableDebug(assetManager);[/java]

zzuegg · October 3, 2011, 3:40pm

Thank you for the reply. I assume the blue lines in the debug view shows the collision model?

As far i see everything looks good, beside that the larger object is not visible at all.

If i understood the physics part correctly i can skip the collisionShape and CharacterControl for now since i don’t want to influence the object at the moment. However, i managed to make a screenshot this time.

Here it is: http://imgur.com/mB3da.png

Note: The object stoped flying at the position where they are on the pictures.

normen · October 3, 2011, 3:49pm

The screenshot looks fine. You are probably just causing impossible situations where one object is created inside the other. Obviously they will be showing strange behavior in their attempts to bounce off each other.

zzuegg · October 3, 2011, 4:08pm

I found the problem:

I forgot to set the PhysicsLocation, i did it only for the collisionShape and not for the RigidBodyControl.