public AstarNode(int _x, int _y) //自定义构造函数
{
this.x = _x;
this.y = _y;
this.parent = null;
this.g = 0;
this.h = 0;
}
private void addToOpenList(AstarNode parent, int x, int y) //【方法】 将点加入开启列表（以parent为父节点在开启列表中加入点（x，y））【包含估价函数】
{
int absX = Math.Abs(endX - x);
int absY = Math.Abs(endY - y);
if (!isValid(x, y)) //是否在地图中
{
return;
}
if (inOpenList(x, y) || inCloseList(x, y)) //是否在列表中
{
return;
}
if (!canWalk(x, y) && parent != null) //是否可走或有父节点
{
return;
}
AstarNode node = new AstarNode(x, y);
node.Parent = parent;
if (parent == null)
{
node.G = 0;
node.H = 0;
}
else
{
if (Math.Abs(parent.X - x) + Math.Abs(parent.Y - y) == 2)
{
node.G = 14;
}
else
{
node.G = 10;
}
node.H = 10 * ((Math.Abs(endX - x) + Math.Abs(endY - y)) + (1.414 - 2) * Math.Min(absX, absY)); //预估H：切比雪夫距离
}
openList.Add(node);
openList.Sort(delegate(AstarNode lhs, AstarNode rhs) //方法 按 lhs比rhs大的 升序排列
{
if (lhs.F < rhs.F)
{
return(-1);
}
else if (lhs.F > rhs.F)
{
return(1);
}
return(0);
});
}
private AstarNode openToCloseWithBest() //【方法】 将最优点由 开启列表 转到 关闭列表
{
AstarNode node = getBestNodeFromOpenList();
if (node == null)
{
return(null);
}
openToClose(node);
return(node);
}
private AstarNode findNearPointFromList(List <AstarNode> list, int x, int y) //【方法】找列表中到点（x，y）之切比雪夫距离最小点
{
AstarNode result = null;
double minDistance = int.MaxValue; //MaxValue 一个特大值
foreach (AstarNode node in list)
{
//【下面距离公式用作开启列表节点筛选的引导】
double dist = node.F;
if (dist < minDistance)
{
minDistance = dist;
result = node;
}
}
return(result);
}
public List <AstarNode> findPath(int _startX, int _startY, int _endX, int _endY) //【方法】找路
{
this.endX = _endX;
this.endY = _endY;
this.openList.Clear();
this.closeList.Clear();
List <AstarNode> result = new List <AstarNode>();
AstarNode currNode = null;
bool findPathFlag = false;
if (canWalk(endX, endY)) //添加。 防止因终点不可用造成崩溃
//终点可用
{
addToOpenList(null, _startX, _startY); //此时Parent==null
while (openList.Count > 0)
{
currNode = openToCloseWithBest(); //将最优点(开启列表第一个)由开启列表转到关闭列表
if (currNode == null)
{
break;
}
if (currNode.X == _endX && currNode.Y == _endY)
{
findPathFlag = true;
break;
}
genAroundNode(currNode);
}
if (!findPathFlag)
{
currNode = findNearPointFromList(closeList, endX, endY); //此为欧几里得距离判断，减少不必要点的判断
}
if (currNode == null)
{
return(null);
}
while (true)
{
result.Add(currNode);
if (currNode.X == _startX && currNode.Y == _startY)
{
break;
}
currNode = currNode.Parent;
}
result.Reverse();
return(result);
}
else //终点不可用
{
result = null; //停止循迹
return(result);
}
}
private void genAroundNode(AstarNode node) //【方法】 加入相邻点，八点以及直角障碍判别
{
int x = node.X;
int y = node.Y;
addToOpenList(node, node.X - 1, node.Y);
addToOpenList(node, node.X, node.Y - 1);
addToOpenList(node, node.X, node.Y + 1);
addToOpenList(node, node.X + 1, node.Y);
if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1)) //1
{
addToOpenList(node, node.X + 1, node.Y - 1);
addToOpenList(node, node.X + 1, node.Y + 1);
}
else if (canWalk(x - 1, y) && !canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1)) //2
{
addToOpenList(node, node.X - 1, node.Y - 1);
addToOpenList(node, node.X + 1, node.Y - 1);
}
else if (canWalk(x - 1, y) && canWalk(x, y + 1) && !canWalk(x + 1, y) && canWalk(x, y - 1)) //3
{
addToOpenList(node, node.X - 1, node.Y - 1);
addToOpenList(node, node.X - 1, node.Y + 1);
}
else if (canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && !canWalk(x, y - 1)) //4
{
addToOpenList(node, node.X - 1, node.Y + 1);
addToOpenList(node, node.X + 1, node.Y + 1);
}
else if (!canWalk(x - 1, y) && !canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1)) //5
{
addToOpenList(node, node.X + 1, node.Y - 1);
}
else if (canWalk(x - 1, y) && !canWalk(x, y + 1) && canWalk(x + 1, y) && !canWalk(x, y - 1)) //6
{
}
else if (canWalk(x - 1, y) && !canWalk(x, y + 1) && !canWalk(x + 1, y) && canWalk(x, y - 1)) //7
{
addToOpenList(node, node.X - 1, node.Y - 1);
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && !canWalk(x, y - 1)) //8
{
addToOpenList(node, node.X + 1, node.Y + 1);
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && !canWalk(x + 1, y) && canWalk(x, y - 1)) //9
{
}
else if (canWalk(x - 1, y) && canWalk(x, y + 1) && !canWalk(x + 1, y) && !canWalk(x, y - 1)) //10
{
addToOpenList(node, node.X - 1, node.Y + 1);
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1))
{
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1))
{
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1))
{
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1))
{
}
else if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1))
{
} //15 全是障碍
else //16 没有障碍
{
addToOpenList(node, node.X - 1, node.Y - 1);
addToOpenList(node, node.X - 1, node.Y + 1);
addToOpenList(node, node.X + 1, node.Y - 1);
addToOpenList(node, node.X + 1, node.Y + 1);
}
//if (!canWalk(x - 1, y) && canWalk(x, y + 1) && canWalk(x + 1, y) && canWalk(x, y - 1)) { }
}
private void openToClose(AstarNode node) //【方法】 开启列表 转到 关闭列表
{
openList.Remove(node);
closeList.Add(node);
}
