private void CalculateActorsCollisions(double dt)
{
if (Actors.Count == 1)
{
return;
}
Dictionary <Actor, List <Actor> > actorsToUnite = new Dictionary <Actor, List <Actor> >();
foreach (var actor1 in Actors)
{
foreach (var actor2 in Actors)
{
if (actor1.Id < actor2.Id && Box2.Overlap(actor1.Box, actor2.Box))
{
var collision = actor1.Box.CalcualteCollision(dt * (actor1.Velocity - actor2.Velocity), actor2.Box);
if (collision.IsNone)
{
continue;
}
bool isXCollision = collision.Vector.X != 0;
if (actor1.Size == actor2.Size && actor1.Orientation == actor2.Orientation)
{
var size = actor1.Size;
var orientation = actor1.Orientation;
var midpoint = actor1.Location + (actor2.Location - actor1.Location) / 2;
if (isXCollision && orientation != ActorOrientation.FLAT)
{
actorsToUnite.Add(new Actor(this, midpoint)
{
Orientation = orientation == ActorOrientation.TALL ? ActorOrientation.SQUARE : ActorOrientation.FLAT,
Size = orientation == ActorOrientation.TALL ? size * 2 : size,
},
new List <Actor> {
actor1, actor2
});
continue;
}
else if (!isXCollision && orientation != ActorOrientation.TALL)
{
actorsToUnite.Add(new Actor(this, new Point2(midpoint.X, Math.Min(actor1.Location.Y, actor2.Location.Y)))
{
Orientation = orientation == ActorOrientation.FLAT ? ActorOrientation.SQUARE : ActorOrientation.TALL,
Size = orientation == ActorOrientation.FLAT ? size * 2 : size,
},
new List <Actor> {
actor1, actor2
});
continue;
}
}
var unit = isXCollision ? Vector2.X_UNIT : Vector2.Y_UNIT;
var m1 = actor1.Mass;
var m2 = actor2.Mass;
var v1 = actor1.Velocity * unit;
var v2 = actor2.Velocity * unit;
var u2 = (2 * m1 * v1 + v2 * (m2 - m1)) / (m1 + m2);
var u1 = u2 + v2 - v1;
actor1.Velocity += unit * (u1 - v1);
actor2.Velocity += unit * (u2 - v2);
//todo: this is definitely wrong
actor1.Location -= collision.Vector / 2;
actor2.Location += collision.Vector / 2;
}
}
}
foreach (var item in actorsToUnite)
{
foreach (var oldActor in item.Value)
{
Actors.Remove(oldActor);
}
Actors.Add(item.Key);
OnActorUnion?.Invoke(item.Key);
}
}
Munch LocateOverlappingMunch(Actor actor) => Munches.FirstOrDefault(munch => Box2.Overlap(munch.Box, actor.Box));