152 lines
5.6 KiB
C#
152 lines
5.6 KiB
C#
using Logging;
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using Graph;
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namespace astar
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{
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public class Astar
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{
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/*
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* Resets the calculated previous nodes and distance to goal
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*/
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private static void Reset(ref Dictionary<ulong, Node> nodes)
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{
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foreach(Node n in nodes.Values)
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{
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n.previousNode = null;
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n.goalDistance = float.MaxValue;
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n.timeRequired = float.MaxValue;
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}
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}
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public static Route FindPath(ref Dictionary<ulong, Node> nodes, Node start, Node goal, Logger? logger)
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{
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Route _route = new Route();
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logger?.Log(LogLevel.INFO, "From {0:000.00000}#{1:000.00000} to {2:000.00000}#{3:000.00000} Great-Circle {4:00000.00}km", start.lat, start.lon, goal.lat, goal.lon, Utils.DistanceBetweenNodes(start, goal)/1000);
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Reset(ref nodes);
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List<Node> toVisit = new();
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toVisit.Add(start);
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Node currentNode = start;
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start.timeRequired = 0;
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start.goalDistance = Convert.ToSingle(Utils.DistanceBetweenNodes(start, goal));
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while (toVisit.Count > 0 && toVisit[0].timeRequired < goal.timeRequired)
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{
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if(currentNode == goal)
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{
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logger?.Log(LogLevel.INFO, "Way found, checking for shorter option.");
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}
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currentNode = toVisit.First();
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logger?.Log(LogLevel.VERBOSE, "toVisit-length: {0} path-length: {1} goal-distance: {2}", toVisit.Count, currentNode.timeRequired, currentNode.goalDistance);
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//Check all neighbors of current node
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foreach (Edge e in currentNode.edges)
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{
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if (e.neighbor.timeRequired > currentNode.timeRequired + e.time)
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{
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e.neighbor.goalDistance = Convert.ToSingle(Utils.DistanceBetweenNodes(e.neighbor, goal));
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e.neighbor.timeRequired = currentNode.timeRequired + e.time;
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e.neighbor.previousNode = currentNode;
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toVisit.Add(e.neighbor);
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}
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}
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toVisit.Remove(currentNode); //"Mark" as visited
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toVisit.Sort(CompareDistance);
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}
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if(goal.previousNode != null)
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{
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logger?.Log(LogLevel.INFO, "Way found, shortest option.");
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currentNode = goal;
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_route.routeFound = true;
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_route.time = goal.timeRequired;
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}
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else
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{
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logger?.Log(LogLevel.INFO, "No path between {0:000.00000}#{1:000.00000} and {2:000.00000}#{3:000.00000}", start.lat, start.lon, goal.lat, goal.lon);
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_route.routeFound = false;
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return _route;
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}
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List<Node> tempNodes = new();
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tempNodes.Add(goal);
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while(currentNode != start)
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{
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#pragma warning disable CS8604 // Route was found, so has to have a previous node
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tempNodes.Add(currentNode.previousNode);
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#pragma warning restore CS8604
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currentNode = currentNode.previousNode;
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}
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tempNodes.Reverse();
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for(int i = 0; i < tempNodes.Count - 1; i++)
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{
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#pragma warning disable CS8600, CS8604 // Route was found, so has to have an edge
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Edge e = tempNodes[i].GetEdgeToNode(tempNodes[i + 1]);
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_route.AddStep(tempNodes[i], e);
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#pragma warning restore CS8600, CS8604
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_route.distance += e.distance;
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}
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logger?.Log(LogLevel.INFO, "Path found");
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if(logger?.level > LogLevel.INFO)
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{
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float time = 0;
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float distance = 0;
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logger?.Log(LogLevel.DEBUG, "Route Distance: {0:00000.00km} Time: {1}", _route.distance/1000, TimeSpan.FromSeconds(_route.time));
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for(int i = 0; i < _route.steps.Count; i++)
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{
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Step s = _route.steps[i];
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time += s.edge.time;
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distance += s.edge.distance;
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logger?.Log(LogLevel.DEBUG, "Step {0:000} From {1:000.00000}#{2:000.00000} To {3:000.00000}#{4:000.00000} along {5:0000000000} after {6} and {7:0000.00}km", i, s.start.lat, s.start.lon, s.edge.neighbor.lat, s.edge.neighbor.lon, s.edge.id, TimeSpan.FromSeconds(s.start.timeRequired), distance/1000);
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}
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}
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return _route;
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}
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/*
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* Compares two nodes and returns the node closer to the goal
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* -1 => n1 smaller n2
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* 0 => n1 equal n2
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* 1 => n1 larger n2
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*/
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private static int CompareDistance(Node n1, Node n2)
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{
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if (n1 == null || n2 == null)
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return 0;
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else
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{
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if (n1.goalDistance < n2.goalDistance)
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return -1;
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else if (n1.goalDistance > n2.goalDistance)
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return 1;
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else return 0;
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}
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}
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/*
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* Compares two nodes and returns the node with the shorter path
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* -1 => n1 smaller n2
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* 0 => n1 equal n2
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* 1 => n1 larger n2
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*/
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private static int ComparePathLength(Node n1, Node n2)
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{
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if (n1 == null || n2 == null)
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return 0;
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else
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{
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if (n1.timeRequired < n2.timeRequired)
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return -1;
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else if (n1.timeRequired > n2.timeRequired)
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return 1;
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else return 0;
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}
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}
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}
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} |