Ok, I think I found a good way for you to pass knowledge along to me. My idea is to make a test case that we could add to jme3.1 test examples.
This test example would demonstrate the following:
- How to create a moving physics node
- How to transfer an object/character from one space to the another.
Quote from advancedPhysics:
“To use the local applying to simulate e.g. the internal physics system of a train passing by, simply create another BulletAppState and add all models with physics controls in local mode to a node. When you move the node the physics will happen all the same but the objects will move along with the node.”
I used TestBetterCharacter from jme3test.bullet to make a small testcase to demonstrate what I am trying to do.
I added a new platform in a new BulletAppState and added a cube ontop of that platform. These two objects are attached to a node which is attached to the rootnode. The quote says that moving the node will move the objects with it but I can’t achieve this. For now, the physics are not following the meshes.
The following is runnable and does not use any special librairies:
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package jme3test.bullet;
import com.jme3.app.SimpleApplication;
import com.jme3.bullet.BulletAppState;
import com.jme3.bullet.PhysicsSpace;
import com.jme3.bullet.control.BetterCharacterControl;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.input.KeyInput;
import com.jme3.input.controls.ActionListener;
import com.jme3.input.controls.KeyTrigger;
import com.jme3.material.Material;
import com.jme3.math.FastMath;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.scene.CameraNode;
import com.jme3.scene.Geometry;
import com.jme3.scene.Node;
import com.jme3.scene.control.CameraControl.ControlDirection;
import com.jme3.scene.shape.Box;
import com.jme3.scene.shape.Sphere;
import com.jme3.system.AppSettings;
/**
* A walking physical character followed by a 3rd person camera. (No animation.)
*
* @author normenhansen, zathras
*/
public class TestBetterCharacter extends SimpleApplication implements ActionListener {
private BulletAppState bulletAppState;
private BulletAppState movingBulletAppState;
private BetterCharacterControl physicsCharacter;
private Node characterNode;
private Node movingPhysicsNode;
private CameraNode camNode;
boolean rotate = false;
private Vector3f walkDirection = new Vector3f(0, 0, 0);
private Vector3f viewDirection = new Vector3f(0, 0, 1);
boolean leftStrafe = false, rightStrafe = false, forward = false, backward = false,
leftRotate = false, rightRotate = false;
private Vector3f normalGravity = new Vector3f(0, -9.81f, 0);
private Geometry planet;
private Geometry movingPlatform;
public static void main(String[] args) {
TestBetterCharacter app = new TestBetterCharacter();
AppSettings settings = new AppSettings(true);
settings.setRenderer(AppSettings.LWJGL_OPENGL2);
settings.setAudioRenderer(AppSettings.LWJGL_OPENAL);
app.setSettings(settings);
app.start();
}
@Override
public void simpleInitApp() {
//setup keyboard mapping
setupKeys();
// activate physics
bulletAppState = new BulletAppState();
stateManager.attach(bulletAppState);
bulletAppState.setDebugEnabled(true);
movingBulletAppState = new BulletAppState();
stateManager.attach(movingBulletAppState);
movingBulletAppState.setDebugEnabled(true);
movingPhysicsNode = new Node();
rootNode.attachChild(movingPhysicsNode);
// init a physics test scene
PhysicsTestHelper.createPhysicsTestWorldSoccer(rootNode, assetManager, bulletAppState.getPhysicsSpace());
PhysicsTestHelper.createBallShooter(this, rootNode, bulletAppState.getPhysicsSpace());
setupPlanet();
setupMovingPlatform();
// Create a node for the character model
characterNode = new Node("character node");
characterNode.setLocalTranslation(new Vector3f(4, 5, 2));
// Add a character control to the node so we can add other things and
// control the model rotation
physicsCharacter = new BetterCharacterControl(0.3f, 2.5f, 8f);
characterNode.addControl(physicsCharacter);
getPhysicsSpace().add(physicsCharacter);
// Load model, attach to character node
Node model = (Node) assetManager.loadModel("Models/Jaime/Jaime.j3o");
model.setLocalScale(1.50f);
characterNode.attachChild(model);
// Add character node to the rootNode
rootNode.attachChild(characterNode);
// Set forward camera node that follows the character, only used when
// view is "locked"
camNode = new CameraNode("CamNode", cam);
camNode.setControlDir(ControlDirection.SpatialToCamera);
camNode.setLocalTranslation(new Vector3f(0, 2, -6));
Quaternion quat = new Quaternion();
// These coordinates are local, the camNode is attached to the character node!
quat.lookAt(Vector3f.UNIT_Z, Vector3f.UNIT_Y);
camNode.setLocalRotation(quat);
characterNode.attachChild(camNode);
// Disable by default, can be enabled via keyboard shortcut
camNode.setEnabled(false);
}
@Override
public void simpleUpdate(float tpf) {
// Apply planet gravity to character if close enough (see below)
checkPlanetGravity();
// Get current forward and left vectors of model by using its rotation
// to rotate the unit vectors
Vector3f modelForwardDir = characterNode.getWorldRotation().mult(Vector3f.UNIT_Z);
Vector3f modelLeftDir = characterNode.getWorldRotation().mult(Vector3f.UNIT_X);
// WalkDirection is global!
// You *can* make your character fly with this.
walkDirection.set(0, 0, 0);
if (leftStrafe) {
walkDirection.addLocal(modelLeftDir.mult(5));
} else if (rightStrafe) {
walkDirection.addLocal(modelLeftDir.negate().multLocal(5));
}
if (forward) {
walkDirection.addLocal(modelForwardDir.mult(5));
} else if (backward) {
walkDirection.addLocal(modelForwardDir.negate().multLocal(5));
}
physicsCharacter.setWalkDirection(walkDirection);
// ViewDirection is local to characters physics system!
// The final world rotation depends on the gravity and on the state of
// setApplyPhysicsLocal()
if (leftRotate) {
Quaternion rotateL = new Quaternion().fromAngleAxis(FastMath.PI * tpf, Vector3f.UNIT_Y);
rotateL.multLocal(viewDirection);
} else if (rightRotate) {
Quaternion rotateR = new Quaternion().fromAngleAxis(-FastMath.PI * tpf, Vector3f.UNIT_Y);
rotateR.multLocal(viewDirection);
}
physicsCharacter.setViewDirection(viewDirection);
fpsText.setText("Touch da ground = " + physicsCharacter.isOnGround());
if (!lockView) {
cam.lookAt(characterNode.getWorldTranslation().add(new Vector3f(0, 2, 0)), Vector3f.UNIT_Y);
}
processPlatform(tpf);
}
private void processPlatform(float tpf){
movingPhysicsNode.move(0.1f*tpf,0,0);
}
private void setupPlanet() {
Material material = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
material.setTexture("ColorMap", assetManager.loadTexture("Interface/Logo/Monkey.jpg"));
//immovable sphere with mesh collision shape
Sphere sphere = new Sphere(64, 64, 20);
planet = new Geometry("Sphere", sphere);
planet.setMaterial(material);
planet.setLocalTranslation(30, -15, 30);
planet.addControl(new RigidBodyControl(0));
planet.getControl(RigidBodyControl.class).setKinematic(true);
rootNode.attachChild(planet);
getPhysicsSpace().add(planet);
}
private void setupMovingPlatform(){
Material material = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
material.setTexture("ColorMap", assetManager.loadTexture("Interface/Logo/Monkey.jpg"));
//Platform for testing motion
Box platform = new Box(16, 0.3f, 8);
movingPlatform = new Geometry("Platform", platform);
movingPlatform.setMaterial(material);
movingPlatform.setLocalTranslation(0, 1f, -20);
movingPlatform.addControl(new RigidBodyControl(0));
movingPlatform.getControl(RigidBodyControl.class).setKinematic(true);
movingPlatform.getControl(RigidBodyControl.class).setApplyPhysicsLocal(true);
movingPhysicsNode.attachChild(movingPlatform);
getMovingPhysicsSpace().add(movingPlatform);
//Box put ontop of platform for localPhysics test
Box box = new Box(1, 1, 1);
Geometry cube = new Geometry("Cube", box);
cube.setMaterial(material);
cube.setLocalTranslation(0, 10f, -20);
cube.addControl(new RigidBodyControl(1000));
cube.getControl(RigidBodyControl.class).setApplyPhysicsLocal(true);
movingPhysicsNode.attachChild(cube);
getMovingPhysicsSpace().add(cube);
}
private void checkPlanetGravity() {
Vector3f planetDist = planet.getWorldTranslation().subtract(characterNode.getWorldTranslation());
if (planetDist.length() < 24) {
physicsCharacter.setGravity(planetDist.normalizeLocal().multLocal(9.81f));
} else {
physicsCharacter.setGravity(normalGravity);
}
}
private PhysicsSpace getPhysicsSpace() {
return bulletAppState.getPhysicsSpace();
}
private PhysicsSpace getMovingPhysicsSpace() {
return movingBulletAppState.getPhysicsSpace();
}
public void onAction(String binding, boolean value, float tpf) {
if (binding.equals("Strafe Left")) {
if (value) {
leftStrafe = true;
} else {
leftStrafe = false;
}
} else if (binding.equals("Strafe Right")) {
if (value) {
rightStrafe = true;
} else {
rightStrafe = false;
}
} else if (binding.equals("Rotate Left")) {
if (value) {
leftRotate = true;
} else {
leftRotate = false;
}
} else if (binding.equals("Rotate Right")) {
if (value) {
rightRotate = true;
} else {
rightRotate = false;
}
} else if (binding.equals("Walk Forward")) {
if (value) {
forward = true;
} else {
forward = false;
}
} else if (binding.equals("Walk Backward")) {
if (value) {
backward = true;
} else {
backward = false;
}
} else if (binding.equals("Jump")) {
physicsCharacter.jump();
} else if (binding.equals("Duck")) {
if (value) {
physicsCharacter.setDucked(true);
} else {
physicsCharacter.setDucked(false);
}
} else if (binding.equals("Lock View")) {
if (value && lockView) {
lockView = false;
} else if (value && !lockView) {
lockView = true;
}
flyCam.setEnabled(!lockView);
camNode.setEnabled(lockView);
}
}
private boolean lockView = false;
private void setupKeys() {
inputManager.addMapping("Strafe Left",
new KeyTrigger(KeyInput.KEY_U),
new KeyTrigger(KeyInput.KEY_Z));
inputManager.addMapping("Strafe Right",
new KeyTrigger(KeyInput.KEY_O),
new KeyTrigger(KeyInput.KEY_X));
inputManager.addMapping("Rotate Left",
new KeyTrigger(KeyInput.KEY_J),
new KeyTrigger(KeyInput.KEY_LEFT));
inputManager.addMapping("Rotate Right",
new KeyTrigger(KeyInput.KEY_L),
new KeyTrigger(KeyInput.KEY_RIGHT));
inputManager.addMapping("Walk Forward",
new KeyTrigger(KeyInput.KEY_I),
new KeyTrigger(KeyInput.KEY_UP));
inputManager.addMapping("Walk Backward",
new KeyTrigger(KeyInput.KEY_K),
new KeyTrigger(KeyInput.KEY_DOWN));
inputManager.addMapping("Jump",
new KeyTrigger(KeyInput.KEY_F),
new KeyTrigger(KeyInput.KEY_SPACE));
inputManager.addMapping("Duck",
new KeyTrigger(KeyInput.KEY_G),
new KeyTrigger(KeyInput.KEY_LSHIFT),
new KeyTrigger(KeyInput.KEY_RSHIFT));
inputManager.addMapping("Lock View",
new KeyTrigger(KeyInput.KEY_RETURN));
inputManager.addListener(this, "Strafe Left", "Strafe Right");
inputManager.addListener(this, "Rotate Left", "Rotate Right");
inputManager.addListener(this, "Walk Forward", "Walk Backward");
inputManager.addListener(this, "Jump", "Duck", "Lock View");
}
@Override
public void simpleRender(RenderManager rm) {
}
}
P.S. What do I need to put at start and end of code sections again? I did this putting 4 spaces infront of all lines of code 
If it’s not automatic, then it’s identical to my suggested solution.
That makes it easy, if player uses it , he gets transfered to the other.