Character Movement using Babylon.js

Question

In a game demo I am putting up for school I need to move my character using the W-A-S-D keys and also the arrow keys. I put up a function and set up a switch case to listen for any of the key presses. Here is my code snippet:

//Handles the player's movement
var PlayerMovement = (function () {
    //Constructor
    function PlayerMovement() {
        this.gameObject = null;
        this.movementSpeed = 0;
        this.rotationSpeed = 0;
    }

    PlayerMovement.prototype.awake = function () {
        console.log("Awake");
    };

    PlayerMovement.prototype.update = function () {
        //console.log(Tools.getFps());
    }

PlayerMovement.prototype.onKeyPressed = function (key) {
        switch(key)
        {
            case KeyType.W:
            case KeyType.UpArrow:
                console.log("Moving up");
                this.gameObject.meshObject.position.z += (BABYLON.Vector3.Up() * this.movementSpeed * Tools.getDeltaTime());
                break;
            case KeyType.A:
            case KeyType.LeftArrow:
                //TODO: Do stuff
                break;
            case KeyType.S:
            case KeyType.DownArrow:
                //TODO: Do stuff
                break;
            case KeyType.D:
            case KeyType.RightArrow:
                //TODO: Do stuff
                break;
        }
    }
 return PlayerMovement;
})();

My issue is that my character jumps so far ahead that he vanishes from the screen. Can anyone help me figure out what is wrong with my calculation?

Answer 1

A few things -

• BABYLON.Vector3.Up() is (0,1,0) . Multiplying this object with any number will return NaN. I guess the object doesn't jump away from the screen, it simply disappears.
• Z is not up :-) position.y should be changed if you wish to jump up.

• If you want to translate using vectors (using the BABYLON.Vector3.Up() Vector) use the mesh.translate(vector, distance) function. In your case (assuming this is the right value you want to set):

  this.gameObject.meshObject.translate(BABYLON.Vector3.Up(), this.movementSpeed * Tools.getDeltaTime());
  

• I assume you did that already, but if not - turn the physics engine on and set gravity for your scene. You can learn about it in the BJS Docs : http://doc.babylonjs.com/page.php?p=22091

• A better way to implement a jump would be to apply acceleration in the right direction (up) and letting the physics engine do its magic. Check out "Applying impulse" here - http://blogs.msdn.com/b/eternalcoding/archive/2013/12/19/create-wonderful-interactive-games-for-the-web-using-webgl-and-a-physics-engine-babylon-js-amp-cannon-js.aspx