/// <summary>
/// Finds a path and outputs it to <c>outputPath</c>. Note: outputPath is unpredictably changed.
/// </summary>
/// <returns>
/// Returns <c>true</c> if path was found and necessary, <c>false</c> if path to End is impossible or not found.
/// </returns>
/// <param name="startNode">Start node.</param>
/// <param name="endNode">End node.</param>
/// <param name="outputPath">Return path.</param>
public static bool FindPath(GridNode _startNode, GridNode _endNode, FastList <GridNode> _outputPath, int _unitSize = 1)
{
startNode = _startNode;
endNode = _endNode;
outputPath = _outputPath;
unitSize = _unitSize;
#region Broadphase and Preperation
if (endNode.Unwalkable)
{
return(false);
}
if (startNode.Unwalkable)
{
return(false);
}
outputPath.FastClear();
if (System.Object.ReferenceEquals(startNode, endNode))
{
outputPath.Add(endNode);
return(true);
}
GridHeap.FastClear();
GridClosedSet.FastClear();
#endregion
#region AStar Algorithm
GridHeap.Add(startNode);
GridNode.HeuristicTargetX = endNode.gridX;
GridNode.HeuristicTargetY = endNode.gridY;
GridNode.PrepareUnpassableCheck(unitSize); //Prepare Unpassable check optimizations
while (GridHeap.Count > 0)
{
currentNode = GridHeap.RemoveFirst();
GridClosedSet.Add(currentNode);
if (currentNode.gridIndex == endNode.gridIndex)
{
//Retraces the path then outputs it into outputPath
//Also Simplifies the path
DestinationReached();
return(true);
}
for (i = 0; i < 8; i++)
{
neighbor = currentNode.NeighborNodes [i];
if (neighbor.IsNull() || currentNode.Unpassable() || GridClosedSet.Contains(neighbor))
{
continue;
}
//0-3 = sides, 4-7 = diagonals
if (i < 4)
{
newMovementCostToNeighbor = currentNode.gCost + 100;
}
else
{
if (i == 4)
{
if (!GridManager.UseDiagonalConnections)
{
break;
}
}
newMovementCostToNeighbor = currentNode.gCost + 141;
}
if (!GridHeap.Contains(neighbor))
{
neighbor.gCost = newMovementCostToNeighbor;
//Optimized heuristic calculation
neighbor.CalculateHeuristic();
neighbor.parent = currentNode;
GridHeap.Add(neighbor);
}
else if (newMovementCostToNeighbor < neighbor.gCost)
{
neighbor.gCost = newMovementCostToNeighbor;
//Optimized heuristic calculation
neighbor.CalculateHeuristic();
neighbor.parent = currentNode;
GridHeap.UpdateItem(neighbor);
}
}
}
#endregion
return(false);
}
/// <summary>
/// Finds a path and outputs it to <c>outputPath</c>. Note: outputPath is unpredictably changed.
/// </summary>
/// <returns>
/// Returns <c>true</c> if path was found and necessary, <c>false</c> if path to End is impossible or not found.
/// </returns>
/// <param name="startNode">Start node.</param>
/// <param name="endNode">End node.</param>
/// <param name="outputPath">Return path.</param>
public static bool FindPath(GridNode startNode, GridNode endNode, FastList <GridNode> outputPath)
{
#region Broadphase and Preperation
if (endNode.Unwalkable)
{
return(false);
}
if (startNode.Unwalkable)
{
return(false);
}
outputPath.FastClear();
if (System.Object.ReferenceEquals(startNode, endNode))
{
outputPath.Add(endNode);
return(true);
}
System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
sw.Start();
GridHeap.FastClear();
GridClosedSet.FastClear();
#endregion
#region AStar Algorithm
GridHeap.Add(startNode);
GridNode.HeuristicTargetX = endNode.gridX;
GridNode.HeuristicTargetY = endNode.gridY;
while (GridHeap.Count > 0)
{
currentNode = GridHeap.RemoveFirst();
GridClosedSet.Add(currentNode);
if (currentNode.gridIndex == endNode.gridIndex)
{
//Retraces the path then outputs it into outputPath
//Also Simplifies the path
outputPath.FastClear();
TracePath.FastClear();
currentNode = endNode;
StartNodeIndex = startNode.gridIndex;
while (currentNode.gridIndex != StartNodeIndex)
{
TracePath.Add(currentNode);
oldNode = currentNode;
currentNode = currentNode.parent;
}
oldNode = startNode;
currentNode = TracePath [TracePath.Count - 1];
oldX = currentNode.gridX - oldNode.gridX;
oldY = currentNode.gridY - oldNode.gridY;
for (i = TracePath.Count - 2; i >= 0; i--)
{
oldNode = currentNode;
currentNode = TracePath.innerArray [i];
newX = currentNode.gridX - oldNode.gridX;
newY = currentNode.gridY - oldNode.gridY;
if (newX != oldX || newY != oldY)
{
outputPath.Add(oldNode);
oldX = newX;
oldY = newY;
}
//outputPath.Add (currentNode);
}
outputPath.Add(endNode);
return(true);
}
for (i = 0; i < 8; i++)
{
neighbor = currentNode.NeighborNodes [i];
if (neighbor == null || neighbor.Unwalkable || GridClosedSet.Contains(neighbor))
{
continue;
}
newMovementCostToNeighbor = currentNode.gCost + (GridNode.IsNeighborDiagnal [i] ? 141 : 100);
if (!GridHeap.Contains(neighbor))
{
neighbor.gCost = newMovementCostToNeighbor;
//Optimized heuristic calculation
neighbor.CalculateHeuristic();
neighbor.parent = currentNode;
GridHeap.Add(neighbor);
}
else if (newMovementCostToNeighbor < neighbor.gCost)
{
neighbor.gCost = newMovementCostToNeighbor;
//Optimized heuristic calculation
neighbor.CalculateHeuristic();
neighbor.parent = currentNode;
GridHeap.UpdateItem(neighbor);
}
}
}
#endregion
return(false);
}