// <summary>
/// Splits our level up into a grid of nodes.
/// </summary>
private void InitializeSearchNodes(Map map)
{
searchNodes = new SearchNode[levelWidth, levelHeight];
//For each of the tiles in our map, we
// will create a search node for it.
for (int x = 0; x < levelWidth; x++)
{
for (int y = 0; y < levelHeight; y++)
{
//Create a search node to represent this tile.
SearchNode node = new SearchNode();
node.Position = new Point(x, y);
// Our enemies can only walk on grass tiles.
node.Walkable = map.mapTiles[x, y] == MapTileType.Empty;
// We only want to store nodes
// that can be walked on.
if (node.Walkable == true)
{
node.Neighbors = new SearchNode[4];
searchNodes[x, y] = node;//searchnode是保存可走的二维数组
}
}
}
// Now for each of the search nodes, we will
// connect it to each of its neighbours.
for (int x = 0; x < levelWidth; x++)
{
for (int y = 0; y < levelHeight; y++)
{
SearchNode node = searchNodes[x, y];
// We only want to look at the nodes that
// our enemies can walk on.
if (node == null || node.Walkable == false)
{
continue;
}
// An array of all of the possible neighbors this
// node could have. (We will ignore diagonals for now.)
Point[] neighbors = new Point[]
{
new Point (x, y - 1), // The node above the current node
new Point (x, y + 1), // The node below the current node.
new Point (x - 1, y), // The node left of the current node.
new Point (x + 1, y), // The node right of the current node
//new Point (x-1,y-1),
//new Point (x-1,y+1),
//new Point (x+1,y-1),
//new Point (x+1,y+1),
};
// We loop through each of the possible neighbors
for (int i = 0; i < neighbors.Length; i++)
{
Point position = neighbors[i];
// We need to make sure this neighbour is part of the level.
if (position.X < 0 || position.X > levelWidth - 1 ||
position.Y < 0 || position.Y > levelHeight - 1)
{
continue;
}
SearchNode neighbor = searchNodes[position.X, position.Y];
// We will only bother keeping a reference
// to the nodes that can be walked on.
if (neighbor == null || neighbor.Walkable == false)
{
continue;
}
// Store a reference to the neighbor.
node.Neighbors[i] = neighbor;
}
}
}
}
/// <summary>
/// Use the parent field of the search nodes to trace
/// a path from the end node to the start node.
/// </summary>
private List<Vector3> FindFinalPath(SearchNode startNode, SearchNode endNode)
{
closedList.Add(endNode);
SearchNode parentTile = endNode.Parent;
// Trace back through the nodes using the parent fields
// to find the best path.
while (parentTile != startNode)
{
closedList.Add(parentTile);
parentTile = parentTile.Parent;
}
List<Vector3> finalPath = new List<Vector3>();
// Reverse the path and transform into world space.
for (int i = closedList.Count - 1; i >= 0; i--)
{
finalPath.Add(Map.MapToWorld(closedList[i].Position));
}
return finalPath;
}