//extern crate nalgebra as na;
//
//use ncollide2d::broad_phase::BroadPhasePairFilter;
//use ncollide2d::shape::{Ball, ShapeHandle};
//use ncollide2d::world::{CollisionGroups, CollisionObject, CollisionWorld, GeometricQueryType};
//
//struct ParityFilter;
//
//impl BroadPhasePairFilter<f32, ()> for ParityFilter {
//    fn is_pair_valid(&self, b1: &CollisionObject<f32, ()>, b2: &CollisionObject<f32, ()>) -> bool {
//        b1.handle().uid() % 2 == b2.handle().uid() % 2
//    }
//}

fn main() {
    //    let shape = ShapeHandle::new(Ball::new(0.5f32));
    //    let groups = CollisionGroups::new();
    //    let query = GeometricQueryType::Contacts(0.0, 0.0);
    //
    //    let mut world = CollisionWorld::new(0.02);
    //
    //    world.register_broad_phase_pair_filter("Parity filter", ParityFilter);
    //
    //    world.add(na::one(), shape.clone(), groups, query, ());
    //    world.add(na::one(), shape.clone(), groups, query, ());
    //    world.add(na::one(), shape.clone(), groups, query, ());
    //    world.add(na::one(), shape.clone(), groups, query, ());
    //
    //    world.update();
    //
    //    // There will be only 2 contact pairs instead of 6.
    //    assert!(world.contact_pairs(true).count() == 2);
}