public float SphereCost(CameraGraphPortalNode Start, CameraGraphPortalNode End, CameraGraphSphereNode Focus)
{
// From http://www.oskam.ch/research/camera_control_2009.pdf Section 4.1
// C(e_ij) = d(i,j) + a*d(i,j)(1-v(e_ij)
// How much the cost is influenced by visibility.
const float Alpha = 100f;
// First, find the sphere shared between the portals
CameraGraphSphereNode Sphere;
if (Start.A == End.A)
{
Sphere = Start.A;
}
else
{
Sphere = Start.B;
}
float Dist = (Start.transform.position - End.transform.position).magnitude;
float Visibility = 0;
if (!Sphere.VisibilityValues.TryGetValue(Focus, out Visibility))
{
Debug.Log("Couldn't get visibility from " + Sphere + " to " + Focus);
Debug.DrawLine(Sphere.transform.position, Focus.transform.position, Color.magenta, 1.0f);
}
return(Dist + Alpha * Dist * (1 - Visibility));
}
IEnumerator GeneratePortals()
{
Debug.Log("Generating Portals");
// Tell each sphere node to connect to it's neighbors
// I'm gonna use n^2 because spheres are fast
for (int i = 0; i < Spheres.Count; ++i)
{
CameraGraphSphereNode A = Spheres[i] as CameraGraphSphereNode;
for (int j = i + 1; j < Spheres.Count; ++j)
{
CameraGraphSphereNode B = Spheres[j] as CameraGraphSphereNode;
// Check if the nodes intersect, and create a portal if they do
if (A.Intersects(B))
{
CameraGraphPortalNode Node = ConnectPortal(A, B);
Portals.Add(Node);
// Yield to main thread if we've done enough operations
if (ShouldOperationYield())
{
yield return(new WaitForEndOfFrame());
}
}
}
}
yield return(null);
}
CameraPath ComputePath(Vector3 Start, Vector3 End, Vector3 Focus)
{
CameraPath Path = new CameraPath();
Path.Next = Start;
// Figure out what portals we want
CameraGraphPortalNode StartNode = Graph.GetClosestPortal(Start);
CameraGraphPortalNode EndNode = Graph.GetClosestPortal(End);
CameraGraphSphereNode FocusEdge = Graph.GetClosestSphere(Focus);
// A* that shit!
List <CameraGraphPortalNode> PortalPath = GetPortalPath(StartNode, EndNode, FocusEdge);
// Get the points as positions
foreach (CameraGraphPortalNode Portal in PortalPath)
{
Path.Points.Enqueue(Portal.transform.position);
}
// Finally, add the endpoint to the back of the queue
Path.Points.Enqueue(End);
return(Path);
}
public float CostEstimate(CameraGraphPortalNode Start, CameraGraphPortalNode End)
{
// From http://www.oskam.ch/research/camera_control_2009.pdf Section 4.1
// H(n) = d(n, e)
float Dist = (End.transform.position - Start.transform.position).magnitude;
return(Dist);
}
private IEnumerator LinkPortals()
{
Debug.Log("Linking Portals");
// Figure out how big our graph is
int NumNodes = Portals.Count;
int NumArcs = 0;
// The number of arcs is equal to the sum of the number of spheres exit arcs - 1
for (int i = 0; i < SphereGraph.numNodes; ++i)
{
NumArcs += SphereGraph.NumArcsForNode(i) - 1;
}
// Remember to double your stuff
int BidirectionOffset = NumArcs;
NumArcs *= 2;
PortalGraph = new SimpleGraph(NumNodes, NumArcs);
// We can just look at all the spheres and connect their portals to make sure the web is complete
foreach (CameraGraphSphereNode Sphere in Spheres)
{
int SphereIndex = Spheres.IndexOf(Sphere);
for (int i = 0; i < Sphere.IntersectionPortals.Count; ++i)
{
CameraGraphPortalNode A = Sphere.IntersectionPortals[i] as CameraGraphPortalNode;
for (int j = i; j < Sphere.IntersectionPortals.Count; ++j)
{
CameraGraphPortalNode B = Sphere.IntersectionPortals[j] as CameraGraphPortalNode;
// Indices for the sphere nodes
int PortalAIndex = Portals.IndexOf(A);
int PortalBIndex = Portals.IndexOf(B);
// Link A and B bidirectionally
PortalGraph.SetNodeArc(PortalAIndex, SphereIndex, PortalBIndex);
PortalGraph.SetNodeArc(PortalBIndex, SphereIndex + BidirectionOffset, PortalAIndex);
// Debug draw
Debug.DrawLine(A.transform.position, B.transform.position, Color.magenta, 1.0f);
// Yield to draw
if (ShouldOperationYield())
{
yield return(new WaitForEndOfFrame());
}
}
}
}
Debug.Log("Linked " + PortalGraph.numNodes + " spheres with " + PortalGraph.numArcs + " arcs");
yield return(null);
}
public CameraGraphPortalNode GetClosestPortal(Vector3 Position)
{
float BestSqrDist = Mathf.Infinity;
CameraGraphPortalNode Best = Portals[0] as CameraGraphPortalNode;
// This is unoptimized
foreach (CameraGraphPortalNode Portal in Portals)
{
float SqrDist = (Position - Portal.transform.position).sqrMagnitude;
if (SqrDist < BestSqrDist)
{
BestSqrDist = SqrDist;
Best = Portal;
}
}
return(Best);
}
CameraGraphPortalNode GetLowest(Dictionary <CameraGraphPortalNode, float> D, HashSet <CameraGraphPortalNode> Set)
{
CameraGraphPortalNode BestPortal = null;
float BestValue = Mathf.Infinity;
foreach (CameraGraphPortalNode Portal in Set)
{
float PortalValue = Mathf.Infinity;
D.TryGetValue(Portal, out PortalValue);
if (PortalValue < BestValue)
{
BestValue = PortalValue;
BestPortal = Portal;
}
}
return(BestPortal);
}
private CameraGraphPortalNode ConnectPortal(CameraGraphSphereNode A, CameraGraphSphereNode B)
{
// Create the child object
GameObject PortalObj = new GameObject("Portal");
PortalObj.transform.SetParent(transform);
PortalObj.layer = gameObject.layer;
// Attatch the portal node logic
CameraGraphPortalNode Portal = PortalObj.AddComponent <CameraGraphPortalNode>();
Portal.Connect(A, B);
Portal.Graph = this;
// Tell the Spheres that there's a portal connecting them
A.IntersectionPortals.Add(Portal);
B.IntersectionPortals.Add(Portal);
return(Portal);
}
List <CameraGraphPortalNode> ReconstructPath(Dictionary <CameraGraphPortalNode, CameraGraphPortalNode> CameFrom, CameraGraphPortalNode Current)
{
List <CameraGraphPortalNode> Total = new List <CameraGraphPortalNode>();
Total.Add(Current);
while (CameFrom.ContainsKey(Current))
{
Current = CameFrom[Current];
Total.Insert(0, Current);
}
return(Total);
}
private List <CameraGraphPortalNode> GetPortalPath(CameraGraphPortalNode Start, CameraGraphPortalNode End, CameraGraphSphereNode Target)
{
// Nodes already evaluated
HashSet <CameraGraphPortalNode> Closed = new HashSet <CameraGraphPortalNode>();
// Nodes to be evaluated
HashSet <CameraGraphPortalNode> Open = new HashSet <CameraGraphPortalNode>();
// How we got to each node we visit
Dictionary <CameraGraphPortalNode, CameraGraphPortalNode> CameFrom
= new Dictionary <CameraGraphPortalNode, CameraGraphPortalNode>();
// The value of each of the nodes we've visited
Dictionary <CameraGraphPortalNode, float> GScore = new Dictionary <CameraGraphPortalNode, float>();
// The estimated total cost from start to each node
Dictionary <CameraGraphPortalNode, float> FScore = new Dictionary <CameraGraphPortalNode, float>();
// We start at the begining
Open.Add(Start);
GScore[Start] = 0;
FScore[Start] = Graph.CostEstimate(Start, End);
// Now the looping
while (Open.Count != 0)
{
// Current portal is the node in open with the lowest F score value
CameraGraphPortalNode Current = GetLowest(FScore, Open);
// Are we there?
if (Current == End)
{
return(ReconstructPath(CameFrom, Current));
}
// Mark the node as visited
Open.Remove(Current);
Closed.Add(Current);
Debug.Log("Visited " + Current);
// Add the node's neighbors to the open set
ArrayList Neighbors = new ArrayList();
Neighbors.AddRange(Current.A.IntersectionPortals);
Neighbors.AddRange(Current.B.IntersectionPortals);
foreach (CameraGraphPortalNode Neighbor in Neighbors)
{
// Skip nodes we've already visited
if (Closed.Contains(Neighbor))
{
continue;
}
float TentativeGScore = GScore[Current] + Graph.SphereCost(Current, Neighbor, Target);
// If the node is good enough, then add it to our path
if (!Open.Contains(Neighbor) || TentativeGScore < GScore[Neighbor])
{
CameFrom[Neighbor] = Current;
GScore[Neighbor] = TentativeGScore;
FScore[Neighbor] = TentativeGScore + Graph.CostEstimate(Neighbor, End);
if (!Open.Contains(Neighbor))
{
Open.Add(Neighbor);
}
}
}
}
// If we can't path, then we give up
Debug.Log("Camera Pathing failure!");
return(new List <CameraGraphPortalNode>());
}