applyForce on collisionStart event

Hi liabru, I have a question. How can I use “Matter.Body.applyForce” within “collisionStart” event ??

From this I can use “Matter.Body.translate”, but not “applyForce”.

I tried this but it does not work for me:

Events.on(engine, ‘collisionStart’, function (event) { for (var i = 0; i < event.pairs.length; i++) { var pair = event.pairs[i];

  if (pair.bodyB.label == 'regla' && pair.bodyA.label == 'dominoTableB18' ) {
     Matter.Body.applyForce(lemmon, { x: 0, y: 0 }, { x: 0.1, y: 0 });
  }

} });

Thanks!

[nicksantan]

I’m still having trouble getting this to work using the method you describe. Am I misunderstanding the logic?

Events.on(engine, 'beforeUpdate', function(event) {
    for (i = 0; i<bodiesToBeMovedNextFrame.length; i++){
        var theBody = bodiesToBeMovedNextFrame[i];
        Body.applyForce(theBody, { x: 0, y: 0 }, {x: 100, y: 100});
    }
});
Events.on(engine, 'collisionStart', function(event) {
    var pairs = event.pairs;
    for (var i = 0; i < pairs.length; i++) {
        var pair = pairs[i];
        if (pair.bodyA.label == 'outerHex' && pair.bodyB.label = 'outerHex'){
                bodiesToBeMovedNextFrame.push(pair.bodyA);
                bodiesToBeMovedNextFrame.push(pair.bodyB);
        }
    }
});

[liabru]

As it stands, forces get cleared in Engine.update right after the event is emitted, so they won’t ever get applied.

This probably should be changed, but for now you should cache the forces you need to apply in some place outside of the event or in some custom body property, then apply them in the next engine beforeUpdate event.