private static InternalNode CreateNode(RTree <Edge> wallsTree, Point2D point)
{
var closestObstacle = wallsTree.GetKNearest(1, point, (edge, p) => Math.Sqrt(DistanceSquared(p, edge.Start, edge.End))).First().Data;
return(new InternalNode
{
Point = point,
Neighbors = new List <InternalNode>(),
MinDistanceToObstacleSquared = DistanceSquared(point, closestObstacle.Start, closestObstacle.End)
});
}
public static IReadOnlyList <TerrainNode> Analyze <TNode>(Map2D <TNode> map, Func <TNode, bool> isBlocking, int pruneDistanceToObstacleSquared, int maxDistanceToMergeSquared)
{
var tracingResult = ComponentLabeling.Trace(map, node => isBlocking(node) ? 1 : 0);
var contours = new List <List <Point2D> >();
foreach (var blob in tracingResult.Blobs)
{
contours.AddRange(
new[] { blob.ExternalContour }.Concat(blob.InternalContours).Select(
points => DouglasPeucker.Simplify(points.ToList(), 2 * 2, DistanceSquared)));
}
var edges = new List <Edge>();
var leftBorder = new List <int>();
var rightBorder = new List <int>();
var topBorder = new List <int>();
var bottomBorder = new List <int>();
var wallsTree = new RTree <Edge>(5, 9);
using (var voronoi = new BoostVoronoi())
{
foreach (var contour in contours)
{
var startPoint = contour.First();
foreach (var point in contour.Skip(1))
{
voronoi.AddSegment((int)startPoint.X, (int)startPoint.Y, (int)point.X, (int)point.Y);
wallsTree.Insert(new Edge {
Start = startPoint, End = point
}, new RTree <Edge> .Envelope(startPoint, point));
if ((int)startPoint.X == 0 && (int)point.X == 0)
{
leftBorder.Add((int)startPoint.Y);
leftBorder.Add((int)point.Y);
}
if ((int)startPoint.X == map.Width - 1 && (int)point.X == map.Width - 1)
{
rightBorder.Add((int)startPoint.Y);
rightBorder.Add((int)point.Y);
}
if ((int)startPoint.Y == 0 && (int)point.Y == 0)
{
topBorder.Add((int)startPoint.X);
topBorder.Add((int)point.X);
}
if ((int)startPoint.Y == map.Height - 1 && (int)point.Y == map.Height - 1)
{
bottomBorder.Add((int)startPoint.X);
bottomBorder.Add((int)point.X);
}
startPoint = point;
}
}
AddVerticalBorder(voronoi, wallsTree, leftBorder.OrderBy(x => x).ToList(), 0, map.Height - 1);
AddVerticalBorder(voronoi, wallsTree, rightBorder.OrderBy(x => x).ToList(), map.Width - 1, map.Height - 1);
AddHorizontalBorder(voronoi, wallsTree, topBorder.OrderBy(x => x).ToList(), 0, map.Width - 1);
AddHorizontalBorder(voronoi, wallsTree, bottomBorder.OrderBy(x => x).ToList(), map.Height - 1, map.Width - 1);
var visitedTwins = new List <long>();
voronoi.Construct();
for (long i = 0; i < voronoi.CountEdges; i++)
{
var edge = voronoi.GetEdge(i);
if (!edge.IsPrimary || !edge.IsFinite || visitedTwins.Contains(edge.Twin))
{
continue;
}
visitedTwins.Add(edge.Twin);
var start = voronoi.GetVertex(edge.Start);
var end = voronoi.GetVertex(edge.End);
if (double.IsNaN(start.X) || double.IsNaN(start.Y) || double.IsNaN(end.X) || double.IsNaN(end.Y))
{
continue;
}
if (edges.Any(
e => (int)e.Start.X == (int)start.X && (int)e.Start.Y == (int)start.Y &&
(int)e.End.X == (int)end.X && (int)e.End.Y == (int)end.Y ||
(int)e.Start.X == (int)end.X && (int)e.Start.Y == (int)end.Y &&
(int)e.End.X == (int)start.X && (int)e.End.Y == (int)start.Y))
{
continue;
}
edges.Add(new Edge
{
Start = new Point2D((int)start.X, (int)start.Y),
End = new Point2D((int)end.X, (int)end.Y)
});
}
}
var walkableEdges = edges.Where(edge => IsOnNonBlocking(edge, map, isBlocking)).ToList();
var nodes = new List <InternalNode>();
foreach (var node in walkableEdges)
{
if (node.Start == node.End)
{
continue;
}
var startNode = nodes.Find(x => x.Point == node.Start);
if (startNode == null)
{
startNode = CreateNode(wallsTree, node.Start);
nodes.Add(startNode);
}
var endNode = nodes.Find(x => x.Point == node.End);
if (endNode == null)
{
endNode = CreateNode(wallsTree, node.End);
nodes.Add(endNode);
}
startNode.Neighbors.Add(endNode);
endNode.Neighbors.Add(startNode);
}
PruneNodes(nodes, pruneDistanceToObstacleSquared);
GetPointsOfInterest(nodes, pruneDistanceToObstacleSquared, maxDistanceToMergeSquared);
var mergedNodes = MergeNodes(nodes, maxDistanceToMergeSquared);
return(MapToTerrainNodes(mergedNodes, wallsTree));
}
private static IReadOnlyList <TerrainNode> MapToTerrainNodes(IEnumerable <InternalNode> nodes, RTree <Edge> wallsTree)
{
var mappedNodes = new Dictionary <InternalNode, TerrainNode>();
var terrainNodes = new List <TerrainNode>();
foreach (var node in nodes)
{
if (mappedNodes.TryGetValue(node, out var terrainNode))
{
terrainNodes.Add(terrainNode);
continue;
}
terrainNodes.Add(MapToTerrainNode(node, mappedNodes, wallsTree));
}
return(terrainNodes);
}
private static TerrainNode MapToTerrainNode(InternalNode internalNode, IDictionary <InternalNode, TerrainNode> mappedNodes, RTree <Edge> wallsTree)
{
if (mappedNodes.TryGetValue(internalNode, out var terrainNode))
{
return(terrainNode);
}
var neighbors = new List <TerrainNode>();
terrainNode = new TerrainNode(internalNode.Point, internalNode.Type == InternalNode.NodeType.Choke, neighbors);
if (internalNode.Type == InternalNode.NodeType.Choke)
{
var chokeEdge = wallsTree.GetKNearest(1, internalNode.Point, (edge, p) => Math.Sqrt(DistanceSquared(p, edge.Start, edge.End))).First().Data;
terrainNode.ChokeRadius = (int)(Math.Sqrt(DistanceSquared(internalNode.Point, chokeEdge.Start, chokeEdge.End)));
}
mappedNodes[internalNode] = terrainNode;
neighbors.AddRange(internalNode.Neighbors.Select(x => MapToTerrainNode(x, mappedNodes, wallsTree)));
return(terrainNode);
}