public bool ShouldCollide(Fixture fixtureA, Fixture fixtureB) { Filter filterA; fixtureA.GetFilterData(out filterA); Filter filterB; fixtureB.GetFilterData(out filterB); if (filterA.groupIndex == filterB.groupIndex && filterA.groupIndex != 0) { return(filterA.groupIndex > 0); } bool collide = (filterA.maskBits & filterB.categoryBits) != 0 && (filterA.categoryBits & filterB.maskBits) != 0; return(collide); }