public (int totalSteps, List <(T tile, int distance)> poi) FloodFillDistanceFinder(int xStart, int yStart, IEnumerable <T> pointsOfInterest)
{
var poi = pointsOfInterest.ToHashSet();
var poiFound = new List <(T, int)>();
var frontier = new List <(int x, int y)> {
(xStart, yStart)
};
var floodedGrid = new Grid <bool>(false, originAtBottom);
floodedGrid[xStart, yStart] = true;
int steps = 0;
while (frontier.Any())
{
var nextFrontier = new List <(int x, int y)>();
foreach ((int x, int y) in frontier)
{
var neighbours = GetNeighbours(x, y);
var floodNeighbours = floodedGrid.GetNeighbours(x, y);
foreach (var key in neighbours.Keys)
{
if (!floodNeighbours[key])
{
var neighbourCoords = DirectionHelper.StepInDirection(key, x, y, 1);
if (poi.Contains(neighbours[key]))
{
poiFound.Add((neighbours[key], steps + 1));
}
if (passableTerrain.Contains(neighbours[key]))
{
nextFrontier.Add(neighbourCoords);
}
floodedGrid[neighbourCoords.x, neighbourCoords.y] = true;
}
}
}
frontier = nextFrontier;
steps++;
}
return(steps - 1, poiFound);
}
public Dictionary <Direction, T> GetNeighbours(int x, int y, bool includeDiagonal = false)
{
var directions = Enum.GetValues(typeof(Direction));
var neighbours = new Dictionary <Direction, T>();
foreach (Direction dir in directions)
{
if (includeDiagonal || ((int)dir % 2) == 0)
{
var actualDirection = originAtBottom ? dir : dir.Opposite();
var(modX, modY) = DirectionHelper.StepInDirection(dir, x, y, 1);
if (modX >= 0 && modY >= 0 && modX < grid.GetLength(0) && modY < grid.GetLength(1))
{
neighbours.Add(actualDirection, grid[modX, modY]);
}
else
{
neighbours.Add(actualDirection, defaultTile); //Alternative: not adding to dictionary, downside, different behaviour from Grid
}
}
}
return(neighbours);
}
