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I am trying to apply a force to a bunch of b2_dynamicBodys, but it seems to only work for a random number of items and then stops with an error.

     //create some items to move
     bodyDef.type = b2Body.b2_dynamicBody;
     for(var i = 0; i < 5; ++i) {
        fixDef.shape = new b2PolygonShape;
        fixDef.shape.SetAsBox(1,1);
        fixDef.friction = 1;
        fixDef.restitution = .1;
        bodyDef.position.x = Math.random() * 10;
        bodyDef.position.y = Math.random() * 10;
        bodyDef.linearDamping=1;
        bodyDef.angularDamping=.8;
        itemsArray.push(world.CreateBody(bodyDef).CreateFixture(fixDef));  // store for later
     }

then i try to apply a force later with:

angle = 20;
for (var xIdx=0; xIdx<itemArray.length; xIdx++) {
    itemsArray[xIdx].GetBody().ApplyImpulse(new b2Vec2(50*Math.cos(angle*Math.PI/180),50*Math.sin(angle*Math.PI/180)););
}

the error I receive is

TypeError: 'undefined' is not an object (evaluating 'c.x')

Is there something wrong with saving the items for later use when I am creating them? Does anyone know what is causing this.

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1 Answer 1

up vote 1 down vote accepted

Is diceArray.length used in this code:

for (var xIdx=0; xIdx<diceArray.length; xIdx++) {

the same as itemsArray.length when referencing itemsArray in the same loop?

itemsArray[xIdx].GetBody()....

So, itemsArray size is definitely 5, is diceArray size 5 too?

Edited now jfiddle source given: ApplyImpulse requires 2 parameters and you are only passing in 1.

I added {x:200,y:200} and all is fine

diceArray[xIdx].GetBody().ApplyImpulse(actionVec, {x:200,y:200});
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sorry typo, yes they are the same. I renamed the array. jsfiddle.net/nycynik/LGq63 –  nycynik Nov 3 '12 at 15:40
    
after adding that fiddle, i think i see that it never works, its not random at all. –  nycynik Nov 3 '12 at 15:43
    
See edit above for solution –  John Nov 3 '12 at 15:54
    
Oh! Yes it does public function ApplyImpulse(impulse:b2Vec2,point:b2Vec2):voidParameters The point is the origin of the force. Thank you! –  nycynik Nov 3 '12 at 16:00
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