/// <summary>
/// Builds the A* map to be used for NPC pathfinding
/// </summary>
/// <param name="spriteTileReferences"></param>
protected void InitializeAStarMap(TileReferences spriteTileReferences)
{
Debug.Assert(TheMap != null);
Debug.Assert(TheMap.Length > 0);
int nXTiles = TheMap[0].Length;
int nYTiles = TheMap.Length;
// load the A-Star compatible map into memory
AStarNodes = Utils.Init2DList <Node>(nXTiles, nYTiles);
for (int x = 0; x < nXTiles; x++)
{
for (int y = 0; y < nYTiles; y++)
{
TileReference currentTile = spriteTileReferences.GetTileReference(TheMap[x][y]);
bool bIsWalkable =
currentTile.IsWalking_Passable || currentTile.Index ==
spriteTileReferences.GetTileReferenceByName("RegularDoor").Index ||
currentTile.Index == spriteTileReferences
.GetTileReferenceByName("RegularDoorView").Index ||
currentTile.Index == spriteTileReferences
.GetTileReferenceByName("LockedDoor").Index ||
currentTile.Index == spriteTileReferences
.GetTileReferenceByName("LockedDoorView").Index;
float fWeight = GetAStarWeight(spriteTileReferences, new Point2D(x, y));
Node node = new Node(new System.Numerics.Vector2(x, y), bIsWalkable, fWeight);
AStarNodes[x].Add(node);
}
}
AStar = new AStar(AStarNodes);
}
/// <summary>
/// Calculates an appropriate A* weight based on the current tile as well as the surrounding tiles
/// </summary>
/// <param name="spriteTileReferences"></param>
/// <param name="xy"></param>
/// <returns></returns>
protected override float GetAStarWeight(TileReferences spriteTileReferences, Point2D xy)
{
bool isPreferredIndex(int nSprite)
{
bool bIsPreferredIndex = nSprite == spriteTileReferences.GetTileReferenceByName("BrickFloor").Index || spriteTileReferences.IsPath(nSprite);
return(bIsPreferredIndex);
}
const int fDefaultDeduction = 2;
TileReference currentTile = spriteTileReferences.GetTileReference(TheMap[xy.X][xy.Y]);
float fCost = 10;
// we reduce the weight for the A* for each adjacent brick floor or path tile
if (xy.X - 1 >= 0)
{
fCost -= isPreferredIndex(TheMap[xy.X - 1][xy.Y]) ? fDefaultDeduction : 0;
}
if (xy.X + 1 < XTILES)
{
fCost -= isPreferredIndex(TheMap[xy.X + 1][xy.Y]) ? fDefaultDeduction : 0;
}
if (xy.Y - 1 >= 0)
{
fCost -= isPreferredIndex(TheMap[xy.X][xy.Y - 1]) ? fDefaultDeduction : 0;
}
if (xy.Y + 1 < YTILES)
{
fCost -= isPreferredIndex(TheMap[xy.X][xy.Y + 1]) ? fDefaultDeduction : 0;
}
return(fCost);
}
