# Creating a Recursive Maze¶

maze_recursive.py
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365``` ```""" Create a maze using a recursive division method. For more information on the algorithm, see "Recursive Division Method" at https://en.wikipedia.org/wiki/Maze_generation_algorithm Artwork from http://kenney.nl If Python and Arcade are installed, this example can be run from the command line with: python -m arcade.examples.maze_recursive """ import random import arcade import timeit import os NATIVE_SPRITE_SIZE = 128 SPRITE_SCALING = 0.25 SPRITE_SIZE = NATIVE_SPRITE_SIZE * SPRITE_SCALING SCREEN_WIDTH = 1000 SCREEN_HEIGHT = 700 SCREEN_TITLE = "Maze Recursive Example" MOVEMENT_SPEED = 8 TILE_EMPTY = 0 TILE_CRATE = 1 # Maze must have an ODD number of rows and columns. # Walls go on EVEN rows/columns. # Openings go on ODD rows/columns MAZE_HEIGHT = 51 MAZE_WIDTH = 51 # How many pixels to keep as a minimum margin between the character # and the edge of the screen. VIEWPORT_MARGIN = 200 MERGE_SPRITES = True def create_empty_grid(width, height, default_value=TILE_EMPTY): """ Create an empty grid. """ grid = [] for row in range(height): grid.append([]) for column in range(width): grid[row].append(default_value) return grid def create_outside_walls(maze): """ Create outside border walls.""" # Create left and right walls for row in range(len(maze)): maze[row][0] = TILE_CRATE maze[row][len(maze[row])-1] = TILE_CRATE # Create top and bottom walls for column in range(1, len(maze[0]) - 1): maze[0][column] = TILE_CRATE maze[len(maze) - 1][column] = TILE_CRATE def make_maze_recursive_call(maze, top, bottom, left, right): """ Recursive function to divide up the maze in four sections and create three gaps. Walls can only go on even numbered rows/columns. Gaps can only go on odd numbered rows/columns. Maze must have an ODD number of rows and columns. """ # Figure out where to divide horizontally start_range = bottom + 2 end_range = top - 1 y = random.randrange(start_range, end_range, 2) # Do the division for column in range(left + 1, right): maze[y][column] = TILE_CRATE # Figure out where to divide vertically start_range = left + 2 end_range = right - 1 x = random.randrange(start_range, end_range, 2) # Do the division for row in range(bottom + 1, top): maze[row][x] = TILE_CRATE # Now we'll make a gap on 3 of the 4 walls. # Figure out which wall does NOT get a gap. wall = random.randrange(4) if wall != 0: gap = random.randrange(left + 1, x, 2) maze[y][gap] = TILE_EMPTY if wall != 1: gap = random.randrange(x + 1, right, 2) maze[y][gap] = TILE_EMPTY if wall != 2: gap = random.randrange(bottom + 1, y, 2) maze[gap][x] = TILE_EMPTY if wall != 3: gap = random.randrange(y + 1, top, 2) maze[gap][x] = TILE_EMPTY # If there's enough space, to a recursive call. if top > y + 3 and x > left + 3: make_maze_recursive_call(maze, top, y, left, x) if top > y + 3 and x + 3 < right: make_maze_recursive_call(maze, top, y, x, right) if bottom + 3 < y and x + 3 < right: make_maze_recursive_call(maze, y, bottom, x, right) if bottom + 3 < y and x > left + 3: make_maze_recursive_call(maze, y, bottom, left, x) def make_maze_recursion(maze_width, maze_height): """ Make the maze by recursively splitting it into four rooms. """ maze = create_empty_grid(maze_width, maze_height) # Fill in the outside walls create_outside_walls(maze) # Start the recursive process make_maze_recursive_call(maze, maze_height - 1, 0, 0, maze_width - 1) return maze class MyGame(arcade.Window): """ Main application class. """ def __init__(self, width, height, title): """ Initializer """ super().__init__(width, height, title) # Set the working directory (where we expect to find files) to the same # directory this .py file is in. You can leave this out of your own # code, but it is needed to easily run the examples using "python -m" # as mentioned at the top of this program. file_path = os.path.dirname(os.path.abspath(__file__)) os.chdir(file_path) # Sprite lists self.player_list = None self.wall_list = None # Player info self.score = 0 self.player_sprite = None # Physics engine self.physics_engine = None # Used to scroll self.view_bottom = 0 self.view_left = 0 # Time to process self.processing_time = 0 self.draw_time = 0 def setup(self): """ Set up the game and initialize the variables. """ # Sprite lists self.player_list = arcade.SpriteList() self.wall_list = arcade.SpriteList() # Set up the player self.score = 0 maze = make_maze_recursion(MAZE_WIDTH, MAZE_HEIGHT) # Create sprites based on 2D grid if not MERGE_SPRITES: # This is the simple-to-understand method. Each grid location # is a sprite. for row in range(MAZE_HEIGHT): for column in range(MAZE_WIDTH): if maze[row][column] == 1: wall = arcade.Sprite("images/grassCenter.png", SPRITE_SCALING) wall.center_x = column * SPRITE_SIZE + SPRITE_SIZE / 2 wall.center_y = row * SPRITE_SIZE + SPRITE_SIZE / 2 self.wall_list.append(wall) else: # This uses new Arcade 1.3.1 features, that allow me to create a # larger sprite with a repeating texture. So if there are multiple # cells in a row with a wall, we merge them into one sprite, with a # repeating texture for each cell. This reduces our sprite count. for row in range(MAZE_HEIGHT): column = 0 while column < len(maze): while column < len(maze) and maze[row][column] == 0: column += 1 start_column = column while column < len(maze) and maze[row][column] == 1: column += 1 end_column = column - 1 column_count = end_column - start_column + 1 column_mid = (start_column + end_column) / 2 wall = arcade.Sprite("images/grassCenter.png", SPRITE_SCALING, repeat_count_x=column_count) wall.center_x = column_mid * SPRITE_SIZE + SPRITE_SIZE / 2 wall.center_y = row * SPRITE_SIZE + SPRITE_SIZE / 2 wall.width = SPRITE_SIZE * column_count self.wall_list.append(wall) # Set up the player self.player_sprite = arcade.Sprite("images/character.png", SPRITE_SCALING) self.player_list.append(self.player_sprite) # Randomly place the player. If we are in a wall, repeat until we aren't. placed = False while not placed: # Randomly position self.player_sprite.center_x = random.randrange(MAZE_WIDTH * SPRITE_SIZE) self.player_sprite.center_y = random.randrange(MAZE_HEIGHT * SPRITE_SIZE) # Are we in a wall? walls_hit = arcade.check_for_collision_with_list(self.player_sprite, self.wall_list) if len(walls_hit) == 0: # Not in a wall! Success! placed = True self.physics_engine = arcade.PhysicsEngineSimple(self.player_sprite, self.wall_list) # Set the background color arcade.set_background_color(arcade.color.AMAZON) # Set the viewport boundaries # These numbers set where we have 'scrolled' to. self.view_left = 0 self.view_bottom = 0 print(f"Total wall blocks: {len(self.wall_list)}") def on_draw(self): """ Render the screen. """ # This command has to happen before we start drawing arcade.start_render() # Start timing how long this takes draw_start_time = timeit.default_timer() # Draw all the sprites. self.wall_list.draw() self.player_list.draw() # Draw info on the screen sprite_count = len(self.wall_list) output = f"Sprite Count: {sprite_count}" arcade.draw_text(output, self.view_left + 20, SCREEN_HEIGHT - 20 + self.view_bottom, arcade.color.WHITE, 16) output = f"Drawing time: {self.draw_time:.3f}" arcade.draw_text(output, self.view_left + 20, SCREEN_HEIGHT - 40 + self.view_bottom, arcade.color.WHITE, 16) output = f"Processing time: {self.processing_time:.3f}" arcade.draw_text(output, self.view_left + 20, SCREEN_HEIGHT - 60 + self.view_bottom, arcade.color.WHITE, 16) self.draw_time = timeit.default_timer() - draw_start_time def on_key_press(self, key, modifiers): """Called whenever a key is pressed. """ if key == arcade.key.UP: self.player_sprite.change_y = MOVEMENT_SPEED elif key == arcade.key.DOWN: self.player_sprite.change_y = -MOVEMENT_SPEED elif key == arcade.key.LEFT: self.player_sprite.change_x = -MOVEMENT_SPEED elif key == arcade.key.RIGHT: self.player_sprite.change_x = MOVEMENT_SPEED def on_key_release(self, key, modifiers): """Called when the user releases a key. """ if key == arcade.key.UP or key == arcade.key.DOWN: self.player_sprite.change_y = 0 elif key == arcade.key.LEFT or key == arcade.key.RIGHT: self.player_sprite.change_x = 0 def update(self, delta_time): """ Movement and game logic """ start_time = timeit.default_timer() # Call update on all sprites (The sprites don't do much in this # example though.) self.physics_engine.update() # --- Manage Scrolling --- # Track if we need to change the viewport changed = False # Scroll left left_bndry = self.view_left + VIEWPORT_MARGIN if self.player_sprite.left < left_bndry: self.view_left -= left_bndry - self.player_sprite.left changed = True # Scroll right right_bndry = self.view_left + SCREEN_WIDTH - VIEWPORT_MARGIN if self.player_sprite.right > right_bndry: self.view_left += self.player_sprite.right - right_bndry changed = True # Scroll up top_bndry = self.view_bottom + SCREEN_HEIGHT - VIEWPORT_MARGIN if self.player_sprite.top > top_bndry: self.view_bottom += self.player_sprite.top - top_bndry changed = True # Scroll down bottom_bndry = self.view_bottom + VIEWPORT_MARGIN if self.player_sprite.bottom < bottom_bndry: self.view_bottom -= bottom_bndry - self.player_sprite.bottom changed = True if changed: arcade.set_viewport(self.view_left, SCREEN_WIDTH + self.view_left, self.view_bottom, SCREEN_HEIGHT + self.view_bottom) # Save the time it took to do this. self.processing_time = timeit.default_timer() - start_time def main(): """ Main method """ window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE) window.setup() arcade.run() if __name__ == "__main__": main() ```