public static void CompareCollision(int n, double radius)
{
Console.WriteLine("Running with {0} objects in a radius of {1} units", n, radius);
IGameObj[] gob = new IGameObj[n];
for (int i = 0; i < n; i++)
{
gob[i] = new DummyObj(Misc.PointWithin(radius), 0);
}
long collisions = 0;
Stopwatch time = new Stopwatch();
time.Start();
for (int i = 0; i < gob.Length; i++)
{
IGameObj o = gob[i];
// The j=i is why we don't use foreach here...
for (int j = i; j < gob.Length; j++)
{
IGameObj go = gob[j];
if (o.Id < go.Id && o.Colliding(go))
{
collisions += 1;
}
}
}
time.Stop();
Console.WriteLine("Brute force found {0} collisions in {1} ms", collisions, time.ElapsedMilliseconds);
Func <IGameObj, Vector2d> f = delegate(IGameObj o) {
return(o.Loc);
};
collisions = 0;
Stopwatch time2 = new Stopwatch();
time.Reset();
time.Start();
time2.Start();
KdTree <IGameObj> k = KdTree <IGameObj> .BuildByInsertion(f, gob);
time2.Stop();
foreach (IGameObj o in gob)
{
ICollection <IGameObj> c = k.GetWithin(o.Loc, 50);
foreach (IGameObj go in c)
{
// This conveniently prevents things from colliding twice or
// colliding with themselves.
if (o.Id > go.Id && o.Colliding(go))
{
collisions += 1;
}
}
}
time.Stop();
Console.WriteLine("kd-tree found {0} collisions in {1} ms, of which {2} ms was building the tree",
collisions, time.ElapsedMilliseconds, time2.ElapsedMilliseconds);
collisions = 0;
time.Reset();
time2.Reset();
time.Start();
time2.Start();
QuadTree <IGameObj> q = QuadTree <IGameObj> .Build(f, gob);
time2.Stop();
foreach (IGameObj o in gob)
{
ICollection <IGameObj> c = q.GetWithin(o.Loc, 50);
foreach (IGameObj go in c)
{
// This conveniently prevents things from colliding twice or
// colliding with themselves.
if (o.Id > go.Id && o.Colliding(go))
{
collisions += 1;
}
}
}
time.Stop();
Console.WriteLine("quadtree found {0} collisions in {1} ms, of which {2} ms was building the tree",
collisions, time.ElapsedMilliseconds, time2.ElapsedMilliseconds);
//Console.WriteLine(k);
}
