void CacheCollision(CPhysics a, CPhysics b)
{
var intersection = IntersectionSystem.CheckIntersection(a.Collider, b.Collider);
if (intersection.Collided)
{
// Calculating some collision data right away, since it will be reused multiple times.
var manifold = intersection.GenerateManifold();
var i = _collisionsPool.Take();
_collisionsPool[i].A = a;
_collisionsPool[i].B = b;
_collisionsPool[i].Intersection = intersection;
_collisionsPool[i].Manifold = manifold;
_collisionsPool[i].InvMassSum = a.InverseMass + b.InverseMass;
_collisionsPool[i].ElasticityDirection = (1 + Math.Min(a.Elasticity, b.Elasticity)) * manifold.Direction
// Secret sauce that makes platformer stacking work. Should point in the gravity direction.
+ Vector2.Min(a.DirectionalElasticity, b.DirectionalElasticity) * manifold.Direction;
a.HadCollision = true;
b.HadCollision = true;
}
}
/// <summary>
/// Returns a list of all physics bodies which intersect with given
/// collider and are not the specified owner.
/// </summary>
public static List <CPhysics> GetAllCollisions(ICollider collider, CPhysics owner = null)
{
var topLeft = collider.Position - collider.HalfSize;
var bottomRight = collider.Position + collider.HalfSize;
var cells = Grid.GetFilledCellsInRange(topLeft, bottomRight);
var leaves = new List <QuadTreeNode>();
for (var i = 0; i < cells.Count; i += 1)
{
cells[i].GetLeavesInRange(leaves, topLeft, bottomRight);
}
var collisions = new List <CPhysics>();
for (var i = 0; i < leaves.Count; i += 1)
{
for (var k = 0; k < leaves[i].ItemsCount; k += 1)
{
var physics = leaves[i].GetItem(k);
if (physics != owner && IntersectionSystem.CheckIntersection(collider, physics.Collider).Collided)
{
collisions.Add(physics);
}
}
for (var k = 0; k < leaves[i].ImmovableItemsCount; k += 1)
{
var physics = leaves[i].GetImmovableItem(k);
if (physics != owner && IntersectionSystem.CheckIntersection(collider, physics.Collider).Collided)
{
collisions.Add(physics);
}
}
}
return(collisions);
}
/// <summary> /// Returns a list of all physics bodies which intersect with given physics body. /// </summary> public static List <CPhysics> GetAllCollisions(CPhysics owner) => GetAllCollisions(owner.Collider, owner);
/// <summary> /// Returns the first physics body which intersects with given physics body. /// </summary> public static CPhysics GetCollision(CPhysics owner) => GetCollision(owner.Collider, owner);