/// <summary>
/// Updates the visibility of each tile within the room from a specified
/// origin of sight, with a given maximum view radius.
/// </summary>
/// <param name="origin">Position of the observer.</param>
/// <param name="maxRadius">Maximum view radius.</param>
/// <param name="time">Time at which visibility is being tested.</param>
/// <returns>True if any tiles are currently visible, and false otherwise.</returns>
public bool UpdateVisibility(Position origin, int maxRadius, ulong time)
{
if ((Room.Rect.NearestPosition(origin) - origin).LengthSquared > maxRadius * maxRadius) {
return false;
}
foreach (var pos in Room.Rect.Positions) {
if ((pos - origin).LengthSquared > maxRadius * maxRadius) continue;
var rel = pos - Room.Rect.TopLeft;
if (_mask[rel.X, rel.Y] >= time) continue;
foreach (var mid in origin.BresenhamLine(pos)) {
rel = mid - Room.Rect.TopLeft;
if (Room.RelativeRect.Intersects(rel)) {
Reveal(rel, time);
}
if (Room[rel].State != TileState.Floor) break;
}
}
return LastVisibleTime >= time;
}
