public void _addTraversableTiles(Godot.Collections.Array tiles)
{
foreach (Vector2 tile in tiles)
{
int id = getPointID((int)tile.x, (int)tile.y);
if (!_aStar.HasPoint(id))
{
_aStar.AddPoint(id, tile, 1);
_tilestoWorld.Add(id, _tileMap.MapToWorld(tile) + _halfCellSize);
ColorRect colorRect = new ColorRect();
_grid.AddChild(colorRect);
colorRect.Color = _enableColor;
colorRect.Modulate = new Color(1, 1, 1, 0.5f);
_gridRects.Add(id, colorRect);
colorRect.MouseFilter = Control.MouseFilterEnum.Ignore;
colorRect.SetSize(_tileMap.CellSize);
// Color Rect's x calculation is lightly different, so need to add 1.5f to position correctly
colorRect.RectPosition = new Vector2(_tileMap.MapToWorld(tile).x + (_tileMap.CellSize.x * 1.5f), _tileMap.MapToWorld(tile).y);
}
}
}
//Calculates the Minimum Spanning Tree (MST) for given points and returns an `AStar2D` graph using Prim's algorithm.
// https://en.wikipedia.org/wiki/Prim%27s_algorithm
// https://en.wikipedia.org/wiki/Minimum_spanning_tree
public static AStar2D MST(List <Vector2> pointsList)
{
var result = new AStar2D();
var firstPoint = pointsList.LastOrDefault();
//Start from an arbitrary point in the list of points
result.AddPoint(result.GetAvailablePointId(), firstPoint);
pointsList.Remove(firstPoint);
//Loop through all points, erasing them as we connect them.
while (pointsList.Any())
{
var currentPosition = Vector2.Zero;
var minPosition = Vector2.Zero;
var minDistance = float.PositiveInfinity;
foreach (int point1Id in result.GetPoints())
{
//Compare each point added to the Astar2D graph to each remaining point to find the closest one
var point1Position = result.GetPointPosition(point1Id);
foreach (var point2Position in pointsList)
{
var distance = point1Position.DistanceTo(point2Position);
if (minDistance > distance)
{
//We use the variables to store the coordinates of the closest point.
//We have to loop over all points to ensure it's the closest.
currentPosition = point1Position;
minPosition = point2Position;
minDistance = distance;
}
}
}
//Connect the point closest to the "current position" with our new point
var pointId = result.GetAvailablePointId();
result.AddPoint(pointId, minPosition);
result.ConnectPoints(result.GetClosestPoint(currentPosition), pointId);
pointsList.Remove(minPosition);
}
return(result);
}
private void ConnectCornerCells()
{
// find all cells with a higher (lower on the screen) y value AND an x value to the right (if right corner) or to the left (if left corner) AND within the max distance
foreach (var cornerCell in _astarCornerCells)
{
IEnumerable <AstarCell> cellsToConnect;
if (cornerCell.IsLeftCorner)
{
cellsToConnect = _astarCells
.Where(cell =>
cell.Position.y > cornerCell.Position.y &&
cell.Position.x < cornerCell.Position.x - 2 &&
cell.Position.DistanceSquaredTo(cornerCell.Position) <= MAX_CELL_DISTANCE * MAX_CELL_DISTANCE
);
}
else
{
cellsToConnect = _astarCells
.Where(cell =>
cell.Position.y > cornerCell.Position.y &&
cell.Position.x > cornerCell.Position.x + 2 &&
cell.Position.DistanceSquaredTo(cornerCell.Position) <= MAX_CELL_DISTANCE * MAX_CELL_DISTANCE
);
}
// for each cell that matches the above conditions
// create a new astar cell at the corner position with a weight equal to the distance of the cell to connect to
// then connect the two cells together
foreach (var toConnectCell in cellsToConnect)
{
var dist = toConnectCell.Position.DistanceTo(cornerCell.Position);
_astar.AddPoint(_astarId, cornerCell.Position, dist);
_astar.ConnectPoints(toConnectCell.Id, _astarId, true);
// connect new corner cell to "real" corner cell to complete the loop
if (_positionToCell.ContainsKey(cornerCell.Position))
{
_astar.ConnectPoints(_positionToCell[cornerCell.Position].Id, _astarId, true);
}
_astarId++;
}
}
}
private List <Vector2> CalculateAStarWalkableCells(List <Vector2> obstacleCells)
{
List <Vector2> walkableCells = new List <Vector2>();
for (int y = 0; y < this.mapSize.y; y++)
{
for (int x = 0; x < this.mapSize.x; x++)
{
Vector2 cell = new Vector2(x, y);
if (!obstacleCells.Contains(cell))
{
walkableCells.Add(cell);
int cellIndex = CalculateCellIndex(cell);
aStarNode.AddPoint(cellIndex, new Vector2(cell.x, cell.y));
}
}
}
return(walkableCells);
}
