def wall_follower(maze):
"""Each time we have a pool of possible directions, we start by analysing the
one of the left of current one.
"""
cell_stack = [(maze[(0, 0)], EAST)]
while True:
(cell, curr_dir) = cell_stack.pop()
if cell.end:
break
curr_dir = (curr_dir - 1) # let's consider first our left
for dir in xrange(curr_dir, curr_dir + DIRECTIONS):
dir = (dir % DIRECTIONS)
if cell.directions[dir]:
neighbor = cell.neighbors[dir]
neighbor.active = True
cell.directions[dir] = False
neighbor.directions[opposite_direction(dir)] = False
cell_stack.append((cell, curr_dir))
cell_stack.append((neighbor, dir))
maze.modified = [neighbor.coords]
break
else:
cell.active = False
cell.backward = True
maze.modified = [cell.coords]
yield True
yield False
def recursive_backtracker(maze):
"""Pick up a a random cell and mark it as a visited. Then look for neighbors
which have not been visited yet, knock down the walls in between and set the
new cell as the current one. Add the old cell and the new one to the cell
stack and repeat the steps by extracting a cell from the stack untill all the
cells of the grid have been visited.
"""
(rows, columns) = maze.size
total = rows * columns
cell = maze.random()
cell.carved = True
carved = 1
cell_stack = [cell]
while carved < total:
cell = cell_stack.pop()
neighborhood = cell.neighbors
directions = range(len(neighborhood))
shuffle(directions)
for dir in directions:
neighbor = neighborhood[dir]
if neighbor and not neighbor.carved:
cell.knock_down(dir)
neighbor.knock_down(opposite_direction(dir))
neighbor.carved = True
carved += 1
cell_stack.append(cell)
cell_stack.append(neighbor)
maze.modified = [cell.coords, neighbor.coords]
yield True
break
yield False
def depth_first(maze):
"""Pick up the start cell and then look for open directions, choose one
randomly, and add the current cell together with the neighbor one to a cell
stack. Then pop a cell from the stack and repeat the steps untill the end
cell is found.
"""
cell_stack = [maze[(0, 0)]]
while True:
cell = cell_stack.pop()
if cell.end:
break
directions = cell.open_directions()
shuffle(directions)
for dir in directions:
neighbor = cell.neighbors[dir]
neighbor.active = True
cell.directions[dir] = False
neighbor.directions[opposite_direction(dir)] = False
cell_stack.append(cell)
cell_stack.append(neighbor)
maze.modified = [neighbor.coords]
break
else:
cell.active = False
cell.backward = True
maze.modified = [cell.coords]
yield True
yield False
def prim(maze):
"""Pick up a random cell, mark it as visited, and add its walls inside a
list of walls. Extract a random wall from the list: if the cell on the
opposite has not been yet visited, knock down the wall, mark the the new cell
as visited, and add its walls to the wall list. Repeat the process untill all
the cells have been visited.
"""
(rows, columns) = maze.size
cell = maze.random()
cell.carved = True
wall_stack = [(cell, dir) for dir in cell.intact_walls()]
while wall_stack:
i = randint(0, len(wall_stack) - 1)
(cell, dir) = wall_stack.pop(i)
neighbor = cell.neighbors[dir]
if neighbor and not neighbor.carved:
cell.knock_down(dir)
neighbor.knock_down(opposite_direction(dir))
neighbor.carved = True
wall_stack += \
[(neighbor, dir) for dir in neighbor.intact_walls()]
maze.modified = [cell.coords, neighbor.coords]
yield True
yield False