private CollEvent findMatch(GameObject a, GameObject b)
{
foreach (CollEvent e in collision_events) {
GameObject e0 = e.getColliders()[0];
GameObject e1 = e.getColliders()[1];
// if the object signalling the collision exists in another event - there is a duplicate
if (b.GetInstanceID() == e0.GetInstanceID() || a.GetInstanceID() == e1.GetInstanceID()) {
return e;
}
}
return null;
}