I did a quick look through your most recent code and was kind of shocked to find out you still didn’t have a more efficient Broad Phase. So I decided to write one for your engine during my break. I tried to make it simple instead of optimized for ease of understanding.
public
class SweepAndPrune
{
delegate void CollisionCallback(Wrapper w1, Wrapper w2); class Wrapper
{ public Node xBegin; public Node xEnd; public Node yBegin; public Node yEnd; public Geometry geometry; public List<Geometry> colliders; public Wrapper(Geometry geometry) { this.geometry = geometry; this.colliders = new List<Geometry>(); this.xBegin = new Node(this, true); this.xEnd = new Node(this, false); this.yBegin = new Node(this, true); this.yEnd = new Node(this, false);
} public void Update() { colliders.Clear(); xBegin.value = geometry.AABB.Min.X; xEnd.value = geometry.AABB.Max.X; yBegin.value = geometry.AABB.Min.Y; yEnd.value = geometry.AABB.Max.Y; } } class Node { public bool begin; public float value; public Wrapper wrapper; public Node(Wrapper wrapper, bool begin) { this.wrapper = wrapper; this.begin = begin; } } List<Wrapper> wrappers = new List<Wrapper>(); List<Node> xList = new List<Node>(); List<Node> yList = new List<Node>(); public void AddGeometry(Geometry item) { Wrapper wrapper = new Wrapper(item); wrappers.Add(wrapper); xList.Add(wrapper.xBegin); xList.Add(wrapper.xEnd); yList.Add(wrapper.yBegin); yList.Add(wrapper.yEnd); } public void RemoveDisposed() { if (wrappers.RemoveAll(delegate(Wrapper w) { return w.geometry.Body.IsDisposed; }) > 0) { xList.RemoveAll(delegate(Node n) { return n.wrapper.geometry.Body.IsDisposed; }); yList.RemoveAll(delegate(Node n) { return n.wrapper.geometry.Body.IsDisposed; }); } } public void Run() { Update(); RunAxis(xList, HandleFirstCollision); RunAxis(yList, HandleSecondCollision); } /// <summary> /// Updates the nodes and sorts them. /// </summary> void Update() { foreach (Wrapper wrapper in wrappers) { wrapper.Update(); } xList.Sort(delegate(Node l, Node r) { return l.value.CompareTo(r.value); }); yList.Sort(delegate(Node l, Node r) { return l.value.CompareTo(r.value); }); } /// <summary> /// Runs the collision detection on a axis /// </summary> void RunAxis(List<Node> list, CollisionCallback callback) { LinkedList<Wrapper> proximityList = new LinkedList<Wrapper>(); foreach (Node node in list) { if (node.begin) { foreach (Wrapper wrapper in proximityList) { callback(node.wrapper, wrapper); } proximityList.AddLast(node.wrapper); } else { proximityList.Remove(node.wrapper); } } } /// <summary> /// when there is a collsion along the first axis /// and if there is no early fail conditions then they are /// added to each others colliders list /// </summary> void HandleFirstCollision(Wrapper w1, Wrapper w2) { //if(early fail conditions) {return;} w1.colliders.Add(w2.geometry); w2.colliders.Add(w1.geometry); } /// <summary> /// when there is a collision along the second axis then /// it checks to see if there was a collision along the first. /// if there is then the 2 geometries bounding boxes are colliding. /// </summary> void HandleSecondCollision(Wrapper w1, Wrapper w2) { if (w1.colliders.Contains(w2.geometry)) { //this is a confirmed broadphase collision //so add a new arbiter or something for //w1.geometry and w2.geometry } }
}
