//寻路主要逻辑，通过调用该方法来获取路径信息，由一串Point2代表
public List <APoint> FindPath(APoint beginPos, APoint endPos)
{
List <APoint> result = new List <APoint>();
this.endPos = endPos;
APoint currentPos = beginPos;
openSet.Add(currentPos);
while (!currentPos.Equals(this.endPos))
{
UpdatePath(currentPos);
if (openSet.Count == 0)
{
return(null);
}
currentPos = openTree.First().Value.First();
}
APoint path = currentPos;
while (!path.Equals(beginPos))
{
result.Add(path);
path = allNodes[path].parent.position;
currentPath = result;
}
result.Add(beginPos);
return(result);
}
//找到某节点的所有相邻节点
private List <APoint> FindNeighbor(APoint nodePos)
{
List <APoint> result = new List <APoint>();
for (int x = -1; x < 2; x++)
{
for (int y = -1; y < 2; y++)
{
if (x == 0 && y == 0)
{
continue;
}
APoint currentPos = new APoint(nodePos.X + x, nodePos.Y + y);
if (currentPos.X >= gridSize.X || currentPos.Y >= gridSize.Y || currentPos.X < 0 || currentPos.Y < 0)
{
continue; //out of bondary
}
if (closeSet.Contains(currentPos))
{
continue; // already in the close list
}
if (allNodes[currentPos].isWall)
{
continue; // the node is a wall
}
result.Add(currentPos);
}
}
return(result);
}
//将旧节点更新为新节点
private void UpdateNode(PathNode newNode, PathNode oldNode)
{
APoint nodePos = newNode.position;
int oldCost = oldNode.fCost;
allNodes[nodePos] = newNode;
List <APoint> sameCost;
if (openTree.TryGetValue(oldCost, out sameCost))
{
sameCost.Remove(nodePos);
if (sameCost.Count == 0)
{
openTree.Remove(oldCost);
}
}
if (openTree.TryGetValue(newNode.fCost, out sameCost))
{
sameCost.Add(nodePos);
}
else
{
sameCost = new List <APoint> {
nodePos
};
openTree.Add(newNode.fCost, sameCost);
}
}
//新建一个PathGrid，包含了网格大小和障碍物信息
//public PathGrid(int x, int y, List<APoint> walls)
public PathGrid(int x, int y, int[,] walls)
{
gridSize = new APoint(x, y);
for (int i = 0; i < x; i++)
{
for (int j = 0; j < y; j++)
{
APoint newPos = new APoint(i, j);
allNodes.Add(newPos, new PathNode(walls[i, j] == 1, newPos));
}
}
}
//将目标节点移出开启列表
private void RemoveOpen(APoint pos, PathNode node)
{
openSet.Remove(pos);
List <APoint> sameCost;
if (openTree.TryGetValue(node.fCost, out sameCost))
{
sameCost.Remove(pos);
if (sameCost.Count == 0)
{
openTree.Remove(node.fCost);
}
}
}
//将目标节点加入开启列表
private void AddOpen(APoint pos, PathNode node)
{
openSet.Add(pos);
List <APoint> sameCost;
if (openTree.TryGetValue(node.fCost, out sameCost))
{
sameCost.Add(pos);
}
else
{
sameCost = new List <APoint> {
pos
};
openTree.Add(node.fCost, sameCost);
}
}
//寻路
private void UpdatePath(APoint currentPos)
{
closeSet.Add(currentPos);
RemoveOpen(currentPos, allNodes[currentPos]);
List <APoint> neighborNodes = FindNeighbor(currentPos);
foreach (APoint nodePos in neighborNodes)
{
PathNode newNode = new PathNode(false, nodePos);
newNode.parent = allNodes[currentPos];
int g;
int h;
g = currentPos.X == nodePos.X || currentPos.Y == nodePos.Y ? 10 : 14;
int xMoves = Math.Abs(nodePos.X - endPos.X);
int yMoves = Math.Abs(nodePos.Y - endPos.Y);
int min = Math.Min(xMoves, yMoves);
int max = Math.Max(xMoves, yMoves);
h = min * 14 + (max - min) * 10;
newNode.gCost = g + newNode.parent.gCost;
newNode.hCost = h;
PathNode originNode = allNodes[nodePos];
if (openSet.Contains(nodePos))
{
if (newNode.fCost < originNode.fCost)
{
UpdateNode(newNode, originNode);
}
}
else
{
allNodes[nodePos] = newNode;
AddOpen(nodePos, newNode);
}
}
}
public PathNode(bool isWall, APoint position)
{
this.isWall = isWall;
this.position = position;
}