public static Coordinate2D FindFirstEmpty(Level level)
{
foreach (Coordinate2D coord in level.InsideCoordinates)
{
if (level.IsEmpty(coord))
{
return coord;
}
}
return Coordinate2D.Undefined;
}
private void AddDisplacedBoxNoTarget(State state, Level level)
{
if (distance == 0)
{
AddRandomBox(state, level);
return;
}
List<Coordinate2D> coordList = new List<Coordinate2D>();
foreach (Coordinate2D coord in level.InsideCoordinates)
{
// Skip occupied coordinates.
if (!level.IsEmpty(coord))
{
continue;
}
// Find nearest target.
int nearestTargetDistance = int.MaxValue;
foreach (Coordinate2D targetCoord in level.TargetCoordinates)
{
int targetDistance = Coordinate2D.GetDiagonalDistance(coord, targetCoord);
nearestTargetDistance = Math.Min(nearestTargetDistance, targetDistance);
}
// Check whether the nearest target is near enough.
if (nearestTargetDistance <= (distance == 0 ? int.MaxValue : distance))
{
coordList.Add(coord);
}
}
if (coordList.Count == 0)
{
state.Log.DebugPrint("no available squares to add squares to");
return;
}
Coordinate2D boxCoord = coordList[state.Random.Next(coordList.Count)];
level[boxCoord] |= Cell.Box;
}
private Coordinate2D GetRandomEmptySquare(State state, Level level)
{
List<Coordinate2D> coordList = new List<Coordinate2D>();
foreach (Coordinate2D coord in level.InsideCoordinates)
{
if (level.IsEmpty(coord))
{
coordList.Add(coord);
}
}
if (coordList.Count == 0)
{
return Coordinate2D.Undefined;
}
return coordList[state.Random.Next(coordList.Count)];
}
private static Level TryNormalizeLoops(Level level)
{
// A loop is a tunnel that you cannot push a box through.
// Any square that it is impossible or not useful to push
// a box to is a no-box square. All the squares in a loop
// are no-box squares. A level may have several disconnected
// no-box regions. Within one no-box region we can
// optimize the path by removing islands that only
// lengthen the loop without changing its function.
// Finally, a normalized loop only needs to be one square
// wide.
// Copy the level and get island and no-box maps.
bool modifiedLevel = false;
Level newLevel = new Level(level);
Array2D<bool> islandMap = LevelUtils.GetIslandMap(level);
Array2D<int> noBoxMap = LevelUtils.GetNoBoxMap(level);
// Any island that only contacts other walls and one or more
// no-box squares in the same region can be removed.
foreach (Coordinate2D coord in newLevel.Coordinates)
{
if (islandMap[coord])
{
int wallCount = 0;
int noBoxCount = 0;
int region = 0;
foreach (Coordinate2D neighbor in coord.FourNeighbors)
{
if (newLevel.IsWall(neighbor))
{
wallCount++;
}
else if (noBoxMap[neighbor] != 0)
{
// Check whether we've encountered any no-box regions.
if (region == 0)
{
region = noBoxMap[neighbor];
}
// Only count no-box squares that match the first region.
if (noBoxMap[neighbor] == region)
{
noBoxCount++;
}
}
}
if (wallCount + noBoxCount == 4 && noBoxCount >= 1)
{
newLevel[coord] = Cell.Empty;
noBoxMap[coord] = 1;
islandMap[coord] = false;
modifiedLevel = true;
}
}
}
// Make a map of all the inside squares we want to keep, initialized to false.
Array2D<bool> keepMap = new Array2D<bool>(newLevel.Height, newLevel.Width);
foreach (Coordinate2D coord in newLevel.InsideCoordinates)
{
if (noBoxMap[coord] != 0)
{
// Keep all the no-box squares that contact box islands.
foreach (Coordinate2D neighbor in coord.EightNeighbors)
{
if (newLevel.IsValid(neighbor) && islandMap[neighbor])
{
keepMap[coord] = true;
break;
}
}
// Keep all the no-box squares that contact box squares.
foreach (Coordinate2D neighbor in coord.FourNeighbors)
{
if (newLevel.IsFloor(neighbor) && noBoxMap[neighbor] == 0)
{
keepMap[coord] = true;
break;
}
}
}
else
{
// Keep all the box squares.
keepMap[coord] = true;
}
}
// Fill in the no-box squares that we can safely remove.
Coordinate2D sokobanCoord = newLevel.SokobanCoordinate;
foreach (Coordinate2D coord in newLevel.InsideCoordinates)
{
if (!keepMap[coord])
{
newLevel[coord] = Cell.Wall;
modifiedLevel = true;
}
}
// If the sokoban was on one of the cells we didn't keep,
// move it to a nearby box square.
if (!newLevel.IsSokoban(sokobanCoord))
{
Level boxLevel = FillBoxSquaresWithBoxes(level, noBoxMap);
PathFinder finder = PathFinder.CreateInstance(boxLevel);
finder.Find(sokobanCoord);
foreach (Coordinate2D coord in finder.AccessibleCoordinates)
{
if (newLevel.IsEmpty(coord))
{
newLevel[coord] = Cell.Sokoban;
break;
}
}
}
// Return the new level only if we made changes.
if (modifiedLevel)
{
return newLevel;
}
return null;
}
protected Exception Abort(string message)
{
string bugMessage = String.Format("bug: {0}", message);
Log.DebugPrint(bugMessage);
Level fullLevel = new Level(level);
if (fullLevel.Sokobans == 0 && fullLevel.IsEmpty(current.SokobanRow, current.SokobanColumn))
{
fullLevel.AddSokoban(current.SokobanRow, current.SokobanColumn);
}
Log.DebugPrint(fullLevel.AsText);
return new InvalidOperationException(bugMessage);
}
