|
|
@@ -0,0 +1,121 @@ |
|
|
|
|
|
class Node(): |
|
|
"""A node class for A* Pathfinding""" |
|
|
|
|
|
def __init__(self, parent=None, position=None): |
|
|
self.parent = parent |
|
|
self.position = position |
|
|
|
|
|
self.g = 0 |
|
|
self.h = 0 |
|
|
self.f = 0 |
|
|
|
|
|
def __eq__(self, other): |
|
|
return self.position == other.position |
|
|
|
|
|
|
|
|
def astar(maze, start, end): |
|
|
"""Returns a list of tuples as a path from the given start to the given end in the given maze""" |
|
|
|
|
|
# Create start and end node |
|
|
start_node = Node(None, start) |
|
|
start_node.g = start_node.h = start_node.f = 0 |
|
|
end_node = Node(None, end) |
|
|
end_node.g = end_node.h = end_node.f = 0 |
|
|
|
|
|
# Initialize both open and closed list |
|
|
open_list = [] |
|
|
closed_list = [] |
|
|
|
|
|
# Add the start node |
|
|
open_list.append(start_node) |
|
|
|
|
|
# Loop until you find the end |
|
|
while len(open_list) > 0: |
|
|
|
|
|
# Get the current node |
|
|
current_node = open_list[0] |
|
|
current_index = 0 |
|
|
for index, item in enumerate(open_list): |
|
|
if item.f < current_node.f: |
|
|
current_node = item |
|
|
current_index = index |
|
|
|
|
|
# Pop current off open list, add to closed list |
|
|
open_list.pop(current_index) |
|
|
closed_list.append(current_node) |
|
|
|
|
|
# Found the goal |
|
|
if current_node == end_node: |
|
|
path = [] |
|
|
current = current_node |
|
|
while current is not None: |
|
|
path.append(current.position) |
|
|
current = current.parent |
|
|
return path[::-1] # Return reversed path |
|
|
|
|
|
# Generate children |
|
|
children = [] |
|
|
for new_position in [(0, -1), (0, 1), (-1, 0), (1, 0), (-1, -1), (-1, 1), (1, -1), (1, 1)]: # Adjacent squares |
|
|
|
|
|
# Get node position |
|
|
node_position = (current_node.position[0] + new_position[0], current_node.position[1] + new_position[1]) |
|
|
|
|
|
# Make sure within range |
|
|
if node_position[0] > (len(maze) - 1) or node_position[0] < 0 or node_position[1] > (len(maze[len(maze)-1]) -1) or node_position[1] < 0: |
|
|
continue |
|
|
|
|
|
# Make sure walkable terrain |
|
|
if maze[node_position[0]][node_position[1]] != 0: |
|
|
continue |
|
|
|
|
|
# Create new node |
|
|
new_node = Node(current_node, node_position) |
|
|
|
|
|
# Append |
|
|
children.append(new_node) |
|
|
|
|
|
# Loop through children |
|
|
for child in children: |
|
|
|
|
|
# Child is on the closed list |
|
|
for closed_child in closed_list: |
|
|
if child == closed_child: |
|
|
continue |
|
|
|
|
|
# Create the f, g, and h values |
|
|
child.g = current_node.g + 1 |
|
|
child.h = ((child.position[0] - end_node.position[0]) ** 2) + ((child.position[1] - end_node.position[1]) ** 2) |
|
|
child.f = child.g + child.h |
|
|
|
|
|
# Child is already in the open list |
|
|
for open_node in open_list: |
|
|
if child == open_node and child.g > open_node.g: |
|
|
continue |
|
|
|
|
|
# Add the child to the open list |
|
|
open_list.append(child) |
|
|
|
|
|
|
|
|
def main(): |
|
|
|
|
|
maze = [[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0], |
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]] |
|
|
|
|
|
start = (0, 0) |
|
|
end = (7, 6) |
|
|
|
|
|
path = astar(maze, start, end) |
|
|
print(path) |
|
|
|
|
|
|
|
|
if __name__ == '__main__': |
|
|
main() |
Nicholas-Swift revised this gist