public BVHNode(BVHNode Parent, Collidable Body)
{
Children[0] = null;
Children[1] = null;
this.Body = Body;
this.Volume = Body.GetBoundingSphere();
this.Parent = Parent;
}
public void FindPotentialCollisionsWith(List<Contact> Potentials, BVHNode other)
{
if (!CollidesWith(other))
{
if (!this.isLeaf())
this.FindPotentialCollisions(Potentials);
if (!other.isLeaf())
other.FindPotentialCollisions(Potentials);
return;
}
if (this.isLeaf() && other.isLeaf())
{
Contact temp = new Contact(this.Body, other.Body);
if (!temp.BothFixed())
Potentials.Add(temp);
}
else if (other.isLeaf() && !this.isLeaf())
{
this.Children[0].FindPotentialCollisionsWith(Potentials, other);
this.Children[1].FindPotentialCollisionsWith(Potentials, other);
this.FindPotentialCollisions(Potentials);
}
else if (this.isLeaf() && !other.isLeaf())
{
other.Children[0].FindPotentialCollisionsWith(Potentials, this);
other.Children[1].FindPotentialCollisionsWith(Potentials, this);
}
else
{
other.Children[0].FindPotentialCollisionsWith(Potentials, this.Children[0]);
other.Children[0].FindPotentialCollisionsWith(Potentials, this.Children[1]);
other.Children[1].FindPotentialCollisionsWith(Potentials, this.Children[0]);
other.Children[1].FindPotentialCollisionsWith(Potentials, this.Children[1]);
this.FindPotentialCollisions(Potentials);
other.FindPotentialCollisions(Potentials);
}
}
/// <summary>
/// Since we are dealing with primatives only now, there is no need for a fine and
/// coarse collision phases, just using ReDetect to generate the list, but when we
/// expand the project to accept more complex structures, the whole algorithm will
/// need reassembling.
/// </summary>
public List<Contact> ReDetect()
{
//detections.Clear();
//foreach (Collidable body0 in Shapes)
//{
// foreach (Collidable body1 in Shapes)
// {
// if (body0 != body1)
// {
// Contact temp = new Contact(body0, body1);
// if (
// //(!detections.Any((contact) => (temp.Equals(temp)))) &&
// !temp.BothFixed()
// )
// detections.Add(temp);
// }
// }
//}
//return detections;
didDetect = true;
BVHNode Hierarchy = new BVHNode(null, Shapes.First.Value);
/// The following statements guarantee that the LinkedList is not modified.
/// Other ways: defining a class for the hierarcy (will consume O(n) checks).
/// AsList() (will consume a lot).
Collidable saver = Shapes.First.Value;
Shapes.RemoveFirst();
foreach (Collidable shape in Shapes)
{
Hierarchy.Insert(shape);
}
Shapes.AddFirst(saver);
detections.Clear();
Hierarchy.FindPotentialCollisions(detections); // Detect Collidables Collisions
DetectPlaneCollisions(Hierarchy); // Detect Plane-Collidable Collisions
return detections;
}
private void DetectPlaneCollisions(BVHNode Hierarchy)
{
foreach (HalfSpace P in planes)
Hierarchy.FindPotentialCollisionsWithPlane(detections, P);
}
protected bool CollidesWith(BVHNode other)
{
return Volume.Intersects(other.Volume);
}
public void Insert(Collidable Body)
{
if (this.isLeaf())
{
Children[0] = new BVHNode(this, this.Body);
Children[1] = new BVHNode(this, Body);
this.Body = null;
RecalculateBoundingVolume();
}
else
{
BoundingSphere Temp = Body.GetBoundingSphere();
if (BoundingSphere.CreateMerged(Children[0].Volume, Temp).Radius
< BoundingSphere.CreateMerged(Children[1].Volume, Temp).Radius)
Children[0].Insert(Body);
else
Children[1].Insert(Body);
}
}