private void CheckForCollisions(ICollidable collidable, IEnumerable <ICollidable> candidates)
{
var vel = GetEffectiveVelocity(collidable);
var velX = new Vector2(vel.X, 0);
var velY = new Vector2(0, vel.Y);
var modelX = new CollisionModel(collidable.Bounds, velX);
var modelY = new CollisionModel(collidable.Bounds, velY);
foreach (var other in candidates)
{
var otherVel = GetEffectiveVelocity(other);
// var otherModel = new CollisionModel(other.Bounds, otherVel);
// var collision = model.GetCollision(otherModel);
// if (!collision.IsNullCollision())
// {
// collidable.OnCollideWith(other, collision.ReversePolarity(), this);
// other.OnCollideWith(collidable, collision, this);
// this.Collision?.Invoke(this, new CollisionEventArgs(collidable, other, collision));
// }
var otherVelX = new Vector2(otherVel.X, 0);
var otherVelY = new Vector2(0, otherVel.Y);
var otherModelX = new CollisionModel(other.Bounds, otherVelX);
var otherModelY = new CollisionModel(other.Bounds, otherVelY);
var collisionX = modelX.GetCollision(otherModelX);
var collisionY = modelY.GetCollision(otherModelY);
if (!collisionY.IsNullCollision())
{
collidable.OnCollideWith(other, collisionY.ReversePolarity(), this);
other.OnCollideWith(collidable, collisionY, this);
this.Collision?.Invoke(this, new CollisionEventArgs(collidable, other, collisionY));
}
if (!collisionX.IsNullCollision())
{
collidable.OnCollideWith(other, collisionX.ReversePolarity(), this);
other.OnCollideWith(collidable, collisionX, this);
this.Collision?.Invoke(this, new CollisionEventArgs(collidable, other, collisionX));
}
}
var bounds = RectangleF.From(this.ContainerBounds);
if (!modelX.IsInside(bounds) || !modelY.IsInside(bounds))
{
var pseg = new LineSegment(collidable.Position, vel);
var intersection = bounds.Intersection(pseg);
collidable.OnContainerExit(intersection, this);
}
}
public RectangleF Intersection(CollisionModel other)
{
var rself = this.R1;
var rother = other.R1;
var overlap = RectangleF.Intersect(rself, rother);
// return intersection rectangle, or empty rectangle if there is no intersection
if (overlap != RectangleF.Empty || !this.Intersects(other))
{
return(overlap);
}
return(RectangleF.Empty);
}
public bool Intersects(CollisionModel other)
{
if (R0.Intersects(other.R0) || R0.Intersects(other.R1))
{
return(true);
}
if (R1.Intersects(other.R0) || R1.Intersects(other.R1))
{
return(true);
}
return(this.moveEdges.Any(e0 => other.moveEdges.Any(e0.Intersects)));
}
public CollisionMoment GetCollision(CollisionModel other)
{
if (this.DoesNotIntersect(other))
{
return(CollisionMoment.NullCollision);
}
var overlap = RectangleF.Intersect(this.R1, other.R1);
var thisDv = MathUtils.Abs(this.Dv);
var len = thisDv.Length();
var dx = Math.Min(overlap.Width, thisDv.X);
var dy = Math.Min(overlap.Height, thisDv.Y);
var dvec = new Vector2(dx, dy);
var edges = this.DetermineEdges(other);
var alpha = len > 0 ? (1 - dvec.Length() / thisDv.Length()) : 1;
return(new CollisionMoment(edges.Item1, edges.Item2, alpha));
}
public bool DoesNotIntersect(CollisionModel other)
{
return(!this.Intersects(other));
}
private Tuple <CollisionEdge, CollisionEdge> DetermineEdges(CollisionModel other)
{
var thisEdge = CollisionEdge.None;
var otherEdge = CollisionEdge.None;
if (other.R1.Width <= 0 || other.R1.Height <= 0)
{
return(new Tuple <CollisionEdge, CollisionEdge>(thisEdge, otherEdge));
}
var otherEdgeMapping = new Dictionary <LineSegment, CollisionEdge>()
{
{ other.R1.LeftEdge, CollisionEdge.Left },
{ other.R1.RightEdge, CollisionEdge.Right },
{ other.R1.BottomEdge, CollisionEdge.Bottom },
{ other.R1.TopEdge, CollisionEdge.Top }
};
var intersections = new List <IntersectionPoint>();
foreach (var moveEdge in this.moveEdges)
{
foreach (var edge in otherEdgeMapping.Keys)
{
var p = moveEdge.Intersection(edge);
if (MathUtils.IsVectorNaN(p) || MathUtils.IsVectorInfinite(p))
{
continue;
}
var dist = Vector2.Distance(moveEdge.P0, p);
var otherIntersectionEdge = otherEdgeMapping[edge];
CollisionEdge thisIntersectionEdge;
if (otherIntersectionEdge.IsBottom() || otherIntersectionEdge.IsTop())
{
var top = this.R1.TopEdge;
var bottom = this.R1.BottomEdge;
thisIntersectionEdge = p.Distance(top) < p.Distance(bottom) ? CollisionEdge.Top : CollisionEdge.Bottom;
}
else
{
var left = this.R1.TopEdge;
var right = this.R1.BottomEdge;
thisIntersectionEdge = p.Distance(left) < p.Distance(right) ? CollisionEdge.Left : CollisionEdge.Right;
}
intersections.Add(new IntersectionPoint(dist, thisIntersectionEdge, otherIntersectionEdge));
}
}
intersections = intersections.OrderBy(t => t.Distance).ToList();
if (intersections.Any())
{
var min = intersections.First();
thisEdge = min.ThisEdge;
otherEdge = min.OtherEdge;
if (thisEdge == CollisionEdge.Bottom && otherEdge == CollisionEdge.Bottom && MathUtils.AreEqual(32, other.R0.Height))
{
}
}
return(new Tuple <CollisionEdge, CollisionEdge>(thisEdge, otherEdge));
}