Iam trying to create a 3D game in Libgdx, so I created a 3d World with physics, and added just a small terrain and capulse (the Player) .

I want to make the game first person, so I created a player class and managed to move the player (Capulse) by joystick.

Like this :-

    public void create() {
        // load enviroment
        environment = new Environment();
        environment.set(new ColorAttribute(ColorAttribute.AmbientLight, 0.4f, 0.4f, 0.4f, 1f));
        environment.add(new DirectionalLight().set(0.8f, 0.8f, 0.8f, -1f, -0.8f, -0.2f));
        // setup camera
        cam = new PerspectiveCamera(67, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
        cam.position.set(10f, 10f, 10f);
        cam.lookAt(0, 0, 0);
        cam.near = 0.001f;
        cam.far = 3000f;
        // setup controller for camera
        camController = new CameraInputController(cam);
        // load the models
        assets = new AssetManager();
        assets.load("ground_stairs.g3db", Model.class);
        assets.load("gathering_node.g3db", Model.class);
        loading = true;
        modelBatch = new ModelBatch();

        // setup bulletphysics
        collisionConfig = new btDefaultCollisionConfiguration();
        dispatcher = new btCollisionDispatcher(collisionConfig);
        broadphase = new btDbvtBroadphase();
        constraintSolver = new btSequentialImpulseConstraintSolver();
        dynamicsWorld = new btDiscreteDynamicsWorld(dispatcher, broadphase, constraintSolver, collisionConfig);
        dynamicsWorld.setGravity(new Vector3(0, -10f, 0));
        contactListener = new MyContactListener();

    private void loadPlayer() {
        // setup player/camera movement
        pc = new PlayerController(instances,cam,dynamicsWorld);

    private void doneLoading() {
        loading = false;
        onDoneLoadingStatic("ground_stairs.g3db", GROUND);
        onDoneLoadingStatic("gathering_node.g3db", GATHERING_NODE);
        gatheringNode = instances.get(instances.size() - 1);

    public btRigidBody onDoneLoadingStatic(String fileName, int id) {
        Model model = assets.get(fileName, Model.class);
        ModelInstance instance = new ModelInstance(model);

        btBvhTriangleMeshShape shape = new btBvhTriangleMeshShape(instance.model.meshParts);
        btRigidBody body = new btRigidBody(0, null, shape, new Vector3(0, 0, 0));
        // set id to find with collision detection
        return body;

    public void render() {
        if (loading && assets.update()) {

        final float delta = Math.min(1f / 30f, Gdx.graphics.getDeltaTime());
        dynamicsWorld.stepSimulation(delta, 5, 1f / 60f);

        Gdx.gl20.glClearColor(0, 0.5f, 1, 1);
        Gdx.gl20.glViewport(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
        Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
        modelBatch.render(instances, environment);

    public void dispose() {


    private class MyContactListener extends ContactListener {

        public void onContactStarted(int userValue0, int userValue1) {
            if (userValue0 == PLAYER && userValue1 == GATHERING_NODE) {
                ((ColorAttribute) gatheringNode.materials.first().get(ColorAttribute.Diffuse)).color.set(Color.RED);
            if (userValue0 == PLAYER && userValue1 == GROUND) {
                PlayerController.canJump = true;

        public void onContactEnded(int userValue0, int userValue1) {
            if (userValue0 == PLAYER && userValue1 == GATHERING_NODE) {
                ((ColorAttribute) gatheringNode.materials.first().get(ColorAttribute.Diffuse)).color.set(Color.BLUE);


public class PlayerController
    private btRigidBody playerBody;
    private ModelInstance player;
    private float speed = 1f;
    public static boolean canJump = true;
    private PerspectiveCamera cam;
    private List<ModelInstance> instances = new ArrayList<ModelInstance>();
    private static final int PLAYER = 1;
    public static float xposition;
    public static float yposition;
    private btDynamicsWorld dynamicsWorld;
    public static float angleX;
    public PlayerController(List<ModelInstance> instances,PerspectiveCamera cam,btDynamicsWorld dynamicWorld) {
        this.instances = instances;
        this.cam = cam;
        this.dynamicsWorld = dynamicWorld;
        player = new ModelInstance(new ModelBuilder()
                                   .createCapsule(0.25f, 3, 10, new Material(ColorAttribute.createAmbient(Color.BLACK)), Usage.Normal | Usage.Position)
        player.transform.translate(5, 7, 0);
        // load player rigid body
        btCapsuleShape playerShape = new btCapsuleShape(0.25f, 2.5f);
        float mass = 10;
        Vector3 localInertia = new Vector3();
        playerShape.calculateLocalInertia(mass, localInertia);
        playerBody = new btRigidBody(mass, null, playerShape, localInertia);
        playerBody.setCollisionFlags(playerBody.getCollisionFlags() | btCollisionObject.CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK);
        // set id to find with collision detection

    public void update() {
        // make sure to activate the player body so bullet doesnt put it to sleep
        // prevent the capsule from falling over
        playerBody.setAngularFactor(new Vector3(0, 0, 0));
        Vector3 velocity = new Vector3(0, playerBody.getLinearVelocity().y, 0);
        velocity.x = xposition;
        velocity.z = yposition;


And this is the output :-

the Player move perfectly with joystick

Now I want the camera to be at the top of the player (the Capulse) , and move with the player, so I added this


In update method in PlayerController

And this the output : just a blue screen So, my question how to make the camera move we it the player like first person?

enter image description here


Solved : I added this line in update method of player controller

cam.position.set(player.transform.getTranslation(new Vector3()));

Now the camera move with the player, but I can't now make it rotate with the player.


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