pymunk_demo_platformer_12.py Full Listing#
pymunk_demo_platformer_12.py#
1"""
2Example of Pymunk Physics Engine Platformer
3"""
4import math
5from typing import Optional
6import arcade
7
8SCREEN_TITLE = "PyMunk Platformer"
9
10# How big are our image tiles?
11SPRITE_IMAGE_SIZE = 128
12
13# Scale sprites up or down
14SPRITE_SCALING_PLAYER = 0.5
15SPRITE_SCALING_TILES = 0.5
16
17# Scaled sprite size for tiles
18SPRITE_SIZE = int(SPRITE_IMAGE_SIZE * SPRITE_SCALING_PLAYER)
19
20# Size of grid to show on screen, in number of tiles
21SCREEN_GRID_WIDTH = 25
22SCREEN_GRID_HEIGHT = 15
23
24# Size of screen to show, in pixels
25SCREEN_WIDTH = SPRITE_SIZE * SCREEN_GRID_WIDTH
26SCREEN_HEIGHT = SPRITE_SIZE * SCREEN_GRID_HEIGHT
27
28# --- Physics forces. Higher number, faster accelerating.
29
30# Gravity
31GRAVITY = 1500
32
33# Damping - Amount of speed lost per second
34DEFAULT_DAMPING = 1.0
35PLAYER_DAMPING = 0.4
36
37# Friction between objects
38PLAYER_FRICTION = 1.0
39WALL_FRICTION = 0.7
40DYNAMIC_ITEM_FRICTION = 0.6
41
42# Mass (defaults to 1)
43PLAYER_MASS = 2.0
44
45# Keep player from going too fast
46PLAYER_MAX_HORIZONTAL_SPEED = 450
47PLAYER_MAX_VERTICAL_SPEED = 1600
48
49# Force applied while on the ground
50PLAYER_MOVE_FORCE_ON_GROUND = 8000
51
52# Force applied when moving left/right in the air
53PLAYER_MOVE_FORCE_IN_AIR = 900
54
55# Strength of a jump
56PLAYER_JUMP_IMPULSE = 1800
57
58# Close enough to not-moving to have the animation go to idle.
59DEAD_ZONE = 0.1
60
61# Constants used to track if the player is facing left or right
62RIGHT_FACING = 0
63LEFT_FACING = 1
64
65# How many pixels to move before we change the texture in the walking animation
66DISTANCE_TO_CHANGE_TEXTURE = 20
67
68# How much force to put on the bullet
69BULLET_MOVE_FORCE = 4500
70
71# Mass of the bullet
72BULLET_MASS = 0.1
73
74# Make bullet less affected by gravity
75BULLET_GRAVITY = 300
76
77
78class PlayerSprite(arcade.Sprite):
79 """ Player Sprite """
80 def __init__(self,
81 ladder_list: arcade.SpriteList,
82 hit_box_algorithm):
83 """ Init """
84 # Let parent initialize
85 super().__init__()
86
87 # Set our scale
88 self.scale = SPRITE_SCALING_PLAYER
89
90 # Images from Kenney.nl's Character pack
91 # main_path = ":resources:images/animated_characters/female_adventurer/femaleAdventurer"
92 main_path = ":resources:images/animated_characters/female_person/femalePerson"
93 # main_path = ":resources:images/animated_characters/male_person/malePerson"
94 # main_path = ":resources:images/animated_characters/male_adventurer/maleAdventurer"
95 # main_path = ":resources:images/animated_characters/zombie/zombie"
96 # main_path = ":resources:images/animated_characters/robot/robot"
97
98 # Load textures for idle standing
99 self.idle_texture_pair = arcade.load_texture_pair(f"{main_path}_idle.png",
100 hit_box_algorithm=hit_box_algorithm)
101 self.jump_texture_pair = arcade.load_texture_pair(f"{main_path}_jump.png")
102 self.fall_texture_pair = arcade.load_texture_pair(f"{main_path}_fall.png")
103
104 # Load textures for walking
105 self.walk_textures = []
106 for i in range(8):
107 texture = arcade.load_texture_pair(f"{main_path}_walk{i}.png")
108 self.walk_textures.append(texture)
109
110 # Load textures for climbing
111 self.climbing_textures = []
112 texture = arcade.load_texture(f"{main_path}_climb0.png")
113 self.climbing_textures.append(texture)
114 texture = arcade.load_texture(f"{main_path}_climb1.png")
115 self.climbing_textures.append(texture)
116
117 # Set the initial texture
118 self.texture = self.idle_texture_pair[0]
119
120 # Hit box will be set based on the first image used.
121 self.hit_box = self.texture.hit_box_points
122
123 # Default to face-right
124 self.character_face_direction = RIGHT_FACING
125
126 # Index of our current texture
127 self.cur_texture = 0
128
129 # How far have we traveled horizontally since changing the texture
130 self.x_odometer = 0
131 self.y_odometer = 0
132
133 self.ladder_list = ladder_list
134 self.is_on_ladder = False
135
136 def pymunk_moved(self, physics_engine, dx, dy, d_angle):
137 """ Handle being moved by the pymunk engine """
138 # Figure out if we need to face left or right
139 if dx < -DEAD_ZONE and self.character_face_direction == RIGHT_FACING:
140 self.character_face_direction = LEFT_FACING
141 elif dx > DEAD_ZONE and self.character_face_direction == LEFT_FACING:
142 self.character_face_direction = RIGHT_FACING
143
144 # Are we on the ground?
145 is_on_ground = physics_engine.is_on_ground(self)
146
147 # Are we on a ladder?
148 if len(arcade.check_for_collision_with_list(self, self.ladder_list)) > 0:
149 if not self.is_on_ladder:
150 self.is_on_ladder = True
151 self.pymunk.gravity = (0, 0)
152 self.pymunk.damping = 0.0001
153 self.pymunk.max_vertical_velocity = PLAYER_MAX_HORIZONTAL_SPEED
154 else:
155 if self.is_on_ladder:
156 self.pymunk.damping = 1.0
157 self.pymunk.max_vertical_velocity = PLAYER_MAX_VERTICAL_SPEED
158 self.is_on_ladder = False
159 self.pymunk.gravity = None
160
161 # Add to the odometer how far we've moved
162 self.x_odometer += dx
163 self.y_odometer += dy
164
165 if self.is_on_ladder and not is_on_ground:
166 # Have we moved far enough to change the texture?
167 if abs(self.y_odometer) > DISTANCE_TO_CHANGE_TEXTURE:
168
169 # Reset the odometer
170 self.y_odometer = 0
171
172 # Advance the walking animation
173 self.cur_texture += 1
174
175 if self.cur_texture > 1:
176 self.cur_texture = 0
177 self.texture = self.climbing_textures[self.cur_texture]
178 return
179
180 # Jumping animation
181 if not is_on_ground:
182 if dy > DEAD_ZONE:
183 self.texture = self.jump_texture_pair[self.character_face_direction]
184 return
185 elif dy < -DEAD_ZONE:
186 self.texture = self.fall_texture_pair[self.character_face_direction]
187 return
188
189 # Idle animation
190 if abs(dx) <= DEAD_ZONE:
191 self.texture = self.idle_texture_pair[self.character_face_direction]
192 return
193
194 # Have we moved far enough to change the texture?
195 if abs(self.x_odometer) > DISTANCE_TO_CHANGE_TEXTURE:
196
197 # Reset the odometer
198 self.x_odometer = 0
199
200 # Advance the walking animation
201 self.cur_texture += 1
202 if self.cur_texture > 7:
203 self.cur_texture = 0
204 self.texture = self.walk_textures[self.cur_texture][self.character_face_direction]
205
206class BulletSprite(arcade.SpriteSolidColor):
207 """ Bullet Sprite """
208 def pymunk_moved(self, physics_engine, dx, dy, d_angle):
209 """ Handle when the sprite is moved by the physics engine. """
210 # If the bullet falls below the screen, remove it
211 if self.center_y < -100:
212 self.remove_from_sprite_lists()
213
214class GameWindow(arcade.Window):
215 """ Main Window """
216
217 def __init__(self, width, height, title):
218 """ Create the variables """
219
220 # Init the parent class
221 super().__init__(width, height, title)
222
223 # Player sprite
224 self.player_sprite: Optional[PlayerSprite] = None
225
226 # Sprite lists we need
227 self.player_list: Optional[arcade.SpriteList] = None
228 self.wall_list: Optional[arcade.SpriteList] = None
229 self.bullet_list: Optional[arcade.SpriteList] = None
230 self.item_list: Optional[arcade.SpriteList] = None
231 self.moving_sprites_list: Optional[arcade.SpriteList] = None
232 self.ladder_list: Optional[arcade.SpriteList] = None
233
234 # Track the current state of what key is pressed
235 self.left_pressed: bool = False
236 self.right_pressed: bool = False
237 self.up_pressed: bool = False
238 self.down_pressed: bool = False
239
240 # Physics engine
241 self.physics_engine: Optional[arcade.PymunkPhysicsEngine] = None
242
243 # Set background color
244 arcade.set_background_color(arcade.color.AMAZON)
245
246 def setup(self):
247 """ Set up everything with the game """
248
249 # Create the sprite lists
250 self.player_list = arcade.SpriteList()
251 self.bullet_list = arcade.SpriteList()
252
253 # Map name
254 map_name = ":resources:/tiled_maps/pymunk_test_map.json"
255
256 # Load in TileMap
257 tile_map = arcade.load_tilemap(map_name, SPRITE_SCALING_TILES)
258
259 # Pull the sprite layers out of the tile map
260 self.wall_list = tile_map.sprite_lists["Platforms"]
261 self.item_list = tile_map.sprite_lists["Dynamic Items"]
262 self.ladder_list = tile_map.sprite_lists["Ladders"]
263 self.moving_sprites_list = tile_map.sprite_lists['Moving Platforms']
264
265 # Create player sprite
266 self.player_sprite = PlayerSprite(self.ladder_list, hit_box_algorithm="Detailed")
267
268 # Set player location
269 grid_x = 1
270 grid_y = 1
271 self.player_sprite.center_x = SPRITE_SIZE * grid_x + SPRITE_SIZE / 2
272 self.player_sprite.center_y = SPRITE_SIZE * grid_y + SPRITE_SIZE / 2
273 # Add to player sprite list
274 self.player_list.append(self.player_sprite)
275
276 # --- Pymunk Physics Engine Setup ---
277
278 # The default damping for every object controls the percent of velocity
279 # the object will keep each second. A value of 1.0 is no speed loss,
280 # 0.9 is 10% per second, 0.1 is 90% per second.
281 # For top-down games, this is basically the friction for moving objects.
282 # For platformers with gravity, this should probably be set to 1.0.
283 # Default value is 1.0 if not specified.
284 damping = DEFAULT_DAMPING
285
286 # Set the gravity. (0, 0) is good for outer space and top-down.
287 gravity = (0, -GRAVITY)
288
289 # Create the physics engine
290 self.physics_engine = arcade.PymunkPhysicsEngine(damping=damping,
291 gravity=gravity)
292
293 def wall_hit_handler(bullet_sprite, _wall_sprite, _arbiter, _space, _data):
294 """ Called for bullet/wall collision """
295 bullet_sprite.remove_from_sprite_lists()
296
297 self.physics_engine.add_collision_handler("bullet", "wall", post_handler=wall_hit_handler)
298
299 def item_hit_handler(bullet_sprite, item_sprite, _arbiter, _space, _data):
300 """ Called for bullet/wall collision """
301 bullet_sprite.remove_from_sprite_lists()
302 item_sprite.remove_from_sprite_lists()
303
304 self.physics_engine.add_collision_handler("bullet", "item", post_handler=item_hit_handler)
305
306 # Add the player.
307 # For the player, we set the damping to a lower value, which increases
308 # the damping rate. This prevents the character from traveling too far
309 # after the player lets off the movement keys.
310 # Setting the moment to PymunkPhysicsEngine.MOMENT_INF prevents it from
311 # rotating.
312 # Friction normally goes between 0 (no friction) and 1.0 (high friction)
313 # Friction is between two objects in contact. It is important to remember
314 # in top-down games that friction moving along the 'floor' is controlled
315 # by damping.
316 self.physics_engine.add_sprite(self.player_sprite,
317 friction=PLAYER_FRICTION,
318 mass=PLAYER_MASS,
319 moment=arcade.PymunkPhysicsEngine.MOMENT_INF,
320 collision_type="player",
321 max_horizontal_velocity=PLAYER_MAX_HORIZONTAL_SPEED,
322 max_vertical_velocity=PLAYER_MAX_VERTICAL_SPEED)
323
324 # Create the walls.
325 # By setting the body type to PymunkPhysicsEngine.STATIC the walls can't
326 # move.
327 # Movable objects that respond to forces are PymunkPhysicsEngine.DYNAMIC
328 # PymunkPhysicsEngine.KINEMATIC objects will move, but are assumed to be
329 # repositioned by code and don't respond to physics forces.
330 # Dynamic is default.
331 self.physics_engine.add_sprite_list(self.wall_list,
332 friction=WALL_FRICTION,
333 collision_type="wall",
334 body_type=arcade.PymunkPhysicsEngine.STATIC)
335
336 # Create the items
337 self.physics_engine.add_sprite_list(self.item_list,
338 friction=DYNAMIC_ITEM_FRICTION,
339 collision_type="item")
340
341 # Add kinematic sprites
342 self.physics_engine.add_sprite_list(self.moving_sprites_list,
343 body_type=arcade.PymunkPhysicsEngine.KINEMATIC)
344
345 def on_key_press(self, key, modifiers):
346 """Called whenever a key is pressed. """
347
348 if key == arcade.key.LEFT:
349 self.left_pressed = True
350 elif key == arcade.key.RIGHT:
351 self.right_pressed = True
352 elif key == arcade.key.UP:
353 self.up_pressed = True
354 # find out if player is standing on ground, and not on a ladder
355 if self.physics_engine.is_on_ground(self.player_sprite) \
356 and not self.player_sprite.is_on_ladder:
357 # She is! Go ahead and jump
358 impulse = (0, PLAYER_JUMP_IMPULSE)
359 self.physics_engine.apply_impulse(self.player_sprite, impulse)
360 elif key == arcade.key.DOWN:
361 self.down_pressed = True
362
363 def on_key_release(self, key, modifiers):
364 """Called when the user releases a key. """
365
366 if key == arcade.key.LEFT:
367 self.left_pressed = False
368 elif key == arcade.key.RIGHT:
369 self.right_pressed = False
370 elif key == arcade.key.UP:
371 self.up_pressed = False
372 elif key == arcade.key.DOWN:
373 self.down_pressed = False
374
375 def on_mouse_press(self, x, y, button, modifiers):
376 """ Called whenever the mouse button is clicked. """
377
378 bullet = BulletSprite(20, 5, arcade.color.DARK_YELLOW)
379 self.bullet_list.append(bullet)
380
381 # Position the bullet at the player's current location
382 start_x = self.player_sprite.center_x
383 start_y = self.player_sprite.center_y
384 bullet.position = self.player_sprite.position
385
386 # Get from the mouse the destination location for the bullet
387 # IMPORTANT! If you have a scrolling screen, you will also need
388 # to add in self.view_bottom and self.view_left.
389 dest_x = x
390 dest_y = y
391
392 # Do math to calculate how to get the bullet to the destination.
393 # Calculation the angle in radians between the start points
394 # and end points. This is the angle the bullet will travel.
395 x_diff = dest_x - start_x
396 y_diff = dest_y - start_y
397 angle = math.atan2(y_diff, x_diff)
398
399 # What is the 1/2 size of this sprite, so we can figure out how far
400 # away to spawn the bullet
401 size = max(self.player_sprite.width, self.player_sprite.height) / 2
402
403 # Use angle to to spawn bullet away from player in proper direction
404 bullet.center_x += size * math.cos(angle)
405 bullet.center_y += size * math.sin(angle)
406
407 # Set angle of bullet
408 bullet.angle = math.degrees(angle)
409
410 # Gravity to use for the bullet
411 # If we don't use custom gravity, bullet drops too fast, or we have
412 # to make it go too fast.
413 # Force is in relation to bullet's angle.
414 bullet_gravity = (0, -BULLET_GRAVITY)
415
416 # Add the sprite. This needs to be done AFTER setting the fields above.
417 self.physics_engine.add_sprite(bullet,
418 mass=BULLET_MASS,
419 damping=1.0,
420 friction=0.6,
421 collision_type="bullet",
422 gravity=bullet_gravity,
423 elasticity=0.9)
424
425 # Add force to bullet
426 force = (BULLET_MOVE_FORCE, 0)
427 self.physics_engine.apply_force(bullet, force)
428
429 def on_update(self, delta_time):
430 """ Movement and game logic """
431
432 is_on_ground = self.physics_engine.is_on_ground(self.player_sprite)
433 # Update player forces based on keys pressed
434 if self.left_pressed and not self.right_pressed:
435 # Create a force to the left. Apply it.
436 if is_on_ground or self.player_sprite.is_on_ladder:
437 force = (-PLAYER_MOVE_FORCE_ON_GROUND, 0)
438 else:
439 force = (-PLAYER_MOVE_FORCE_IN_AIR, 0)
440 self.physics_engine.apply_force(self.player_sprite, force)
441 # Set friction to zero for the player while moving
442 self.physics_engine.set_friction(self.player_sprite, 0)
443 elif self.right_pressed and not self.left_pressed:
444 # Create a force to the right. Apply it.
445 if is_on_ground or self.player_sprite.is_on_ladder:
446 force = (PLAYER_MOVE_FORCE_ON_GROUND, 0)
447 else:
448 force = (PLAYER_MOVE_FORCE_IN_AIR, 0)
449 self.physics_engine.apply_force(self.player_sprite, force)
450 # Set friction to zero for the player while moving
451 self.physics_engine.set_friction(self.player_sprite, 0)
452 elif self.up_pressed and not self.down_pressed:
453 # Create a force to the right. Apply it.
454 if self.player_sprite.is_on_ladder:
455 force = (0, PLAYER_MOVE_FORCE_ON_GROUND)
456 self.physics_engine.apply_force(self.player_sprite, force)
457 # Set friction to zero for the player while moving
458 self.physics_engine.set_friction(self.player_sprite, 0)
459 elif self.down_pressed and not self.up_pressed:
460 # Create a force to the right. Apply it.
461 if self.player_sprite.is_on_ladder:
462 force = (0, -PLAYER_MOVE_FORCE_ON_GROUND)
463 self.physics_engine.apply_force(self.player_sprite, force)
464 # Set friction to zero for the player while moving
465 self.physics_engine.set_friction(self.player_sprite, 0)
466
467 else:
468 # Player's feet are not moving. Therefore up the friction so we stop.
469 self.physics_engine.set_friction(self.player_sprite, 1.0)
470
471 # Move items in the physics engine
472 self.physics_engine.step()
473
474 # For each moving sprite, see if we've reached a boundary and need to
475 # reverse course.
476 for moving_sprite in self.moving_sprites_list:
477 if moving_sprite.boundary_right and \
478 moving_sprite.change_x > 0 and \
479 moving_sprite.right > moving_sprite.boundary_right:
480 moving_sprite.change_x *= -1
481 elif moving_sprite.boundary_left and \
482 moving_sprite.change_x < 0 and \
483 moving_sprite.left > moving_sprite.boundary_left:
484 moving_sprite.change_x *= -1
485 if moving_sprite.boundary_top and \
486 moving_sprite.change_y > 0 and \
487 moving_sprite.top > moving_sprite.boundary_top:
488 moving_sprite.change_y *= -1
489 elif moving_sprite.boundary_bottom and \
490 moving_sprite.change_y < 0 and \
491 moving_sprite.bottom < moving_sprite.boundary_bottom:
492 moving_sprite.change_y *= -1
493
494 # Figure out and set our moving platform velocity.
495 # Pymunk uses velocity is in pixels per second. If we instead have
496 # pixels per frame, we need to convert.
497 velocity = (moving_sprite.change_x * 1 / delta_time, moving_sprite.change_y * 1 / delta_time)
498 self.physics_engine.set_velocity(moving_sprite, velocity)
499
500 def on_draw(self):
501 """ Draw everything """
502 self.clear()
503 self.wall_list.draw()
504 self.ladder_list.draw()
505 self.moving_sprites_list.draw()
506 self.bullet_list.draw()
507 self.item_list.draw()
508 self.player_list.draw()
509
510 # for item in self.player_list:
511 # item.draw_hit_box(arcade.color.RED)
512 # for item in self.item_list:
513 # item.draw_hit_box(arcade.color.RED)
514
515def main():
516 """ Main function """
517 window = GameWindow(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
518 window.setup()
519 arcade.run()
520
521
522if __name__ == "__main__":
523 main()