pymunk_demo_platformer_11.py Full Listing#
pymunk_demo_platformer_11.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 """ Init """
82 # Let parent initialize
83 super().__init__()
84
85 # Set our scale
86 self.scale = SPRITE_SCALING_PLAYER
87
88 # Images from Kenney.nl's Character pack
89 # main_path = ":resources:images/animated_characters/female_adventurer/femaleAdventurer"
90 main_path = ":resources:images/animated_characters/female_person/femalePerson"
91 # main_path = ":resources:images/animated_characters/male_person/malePerson"
92 # main_path = ":resources:images/animated_characters/male_adventurer/maleAdventurer"
93 # main_path = ":resources:images/animated_characters/zombie/zombie"
94 # main_path = ":resources:images/animated_characters/robot/robot"
95
96 # Load textures for idle standing
97 self.idle_texture_pair = arcade.load_texture_pair(f"{main_path}_idle.png")
98 self.jump_texture_pair = arcade.load_texture_pair(f"{main_path}_jump.png")
99 self.fall_texture_pair = arcade.load_texture_pair(f"{main_path}_fall.png")
100
101 # Load textures for walking
102 self.walk_textures = []
103 for i in range(8):
104 texture = arcade.load_texture_pair(f"{main_path}_walk{i}.png")
105 self.walk_textures.append(texture)
106
107 # Set the initial texture
108 self.texture = self.idle_texture_pair[0]
109
110 # Hit box will be set based on the first image used.
111 self.hit_box = self.texture.hit_box_points
112
113 # Default to face-right
114 self.character_face_direction = RIGHT_FACING
115
116 # Index of our current texture
117 self.cur_texture = 0
118
119 # How far have we traveled horizontally since changing the texture
120 self.x_odometer = 0
121
122 def pymunk_moved(self, physics_engine, dx, dy, d_angle):
123 """ Handle being moved by the pymunk engine """
124 # Figure out if we need to face left or right
125 if dx < -DEAD_ZONE and self.character_face_direction == RIGHT_FACING:
126 self.character_face_direction = LEFT_FACING
127 elif dx > DEAD_ZONE and self.character_face_direction == LEFT_FACING:
128 self.character_face_direction = RIGHT_FACING
129
130 # Are we on the ground?
131 is_on_ground = physics_engine.is_on_ground(self)
132
133 # Add to the odometer how far we've moved
134 self.x_odometer += dx
135
136 # Jumping animation
137 if not is_on_ground:
138 if dy > DEAD_ZONE:
139 self.texture = self.jump_texture_pair[self.character_face_direction]
140 return
141 elif dy < -DEAD_ZONE:
142 self.texture = self.fall_texture_pair[self.character_face_direction]
143 return
144
145 # Idle animation
146 if abs(dx) <= DEAD_ZONE:
147 self.texture = self.idle_texture_pair[self.character_face_direction]
148 return
149
150 # Have we moved far enough to change the texture?
151 if abs(self.x_odometer) > DISTANCE_TO_CHANGE_TEXTURE:
152
153 # Reset the odometer
154 self.x_odometer = 0
155
156 # Advance the walking animation
157 self.cur_texture += 1
158 if self.cur_texture > 7:
159 self.cur_texture = 0
160 self.texture = self.walk_textures[self.cur_texture][self.character_face_direction]
161
162
163class BulletSprite(arcade.SpriteSolidColor):
164 """ Bullet Sprite """
165 def pymunk_moved(self, physics_engine, dx, dy, d_angle):
166 """ Handle when the sprite is moved by the physics engine. """
167 # If the bullet falls below the screen, remove it
168 if self.center_y < -100:
169 self.remove_from_sprite_lists()
170
171
172class GameWindow(arcade.Window):
173 """ Main Window """
174
175 def __init__(self, width, height, title):
176 """ Create the variables """
177
178 # Init the parent class
179 super().__init__(width, height, title)
180
181 # Player sprite
182 self.player_sprite: Optional[PlayerSprite] = None
183
184 # Sprite lists we need
185 self.player_list: Optional[arcade.SpriteList] = None
186 self.wall_list: Optional[arcade.SpriteList] = None
187 self.bullet_list: Optional[arcade.SpriteList] = None
188 self.item_list: Optional[arcade.SpriteList] = None
189 self.moving_sprites_list: Optional[arcade.SpriteList] = None
190
191 # Track the current state of what key is pressed
192 self.left_pressed: bool = False
193 self.right_pressed: bool = False
194
195 # Physics engine
196 self.physics_engine = Optional[arcade.PymunkPhysicsEngine]
197
198 # Set background color
199 arcade.set_background_color(arcade.color.AMAZON)
200
201 def setup(self):
202 """ Set up everything with the game """
203
204 # Create the sprite lists
205 self.player_list = arcade.SpriteList()
206 self.bullet_list = arcade.SpriteList()
207
208 # Map name
209 map_name = ":resources:/tiled_maps/pymunk_test_map.json"
210
211 # Load in TileMap
212 tile_map = arcade.load_tilemap(map_name, SPRITE_SCALING_TILES)
213
214 # Pull the sprite layers out of the tile map
215 self.wall_list = tile_map.sprite_lists["Platforms"]
216 self.item_list = tile_map.sprite_lists["Dynamic Items"]
217
218 # Create player sprite
219 self.player_sprite = PlayerSprite()
220
221 # Set player location
222 grid_x = 1
223 grid_y = 1
224 self.player_sprite.center_x = SPRITE_SIZE * grid_x + SPRITE_SIZE / 2
225 self.player_sprite.center_y = SPRITE_SIZE * grid_y + SPRITE_SIZE / 2
226 # Add to player sprite list
227 self.player_list.append(self.player_sprite)
228
229 # Moving Sprite
230 self.moving_sprites_list = arcade.tilemap.process_layer(my_map,
231 'Moving Platforms',
232 SPRITE_SCALING_TILES)
233
234 # --- Pymunk Physics Engine Setup ---
235
236 # The default damping for every object controls the percent of velocity
237 # the object will keep each second. A value of 1.0 is no speed loss,
238 # 0.9 is 10% per second, 0.1 is 90% per second.
239 # For top-down games, this is basically the friction for moving objects.
240 # For platformers with gravity, this should probably be set to 1.0.
241 # Default value is 1.0 if not specified.
242 damping = DEFAULT_DAMPING
243
244 # Set the gravity. (0, 0) is good for outer space and top-down.
245 gravity = (0, -GRAVITY)
246
247 # Create the physics engine
248 self.physics_engine = arcade.PymunkPhysicsEngine(damping=damping,
249 gravity=gravity)
250
251 def wall_hit_handler(bullet_sprite, _wall_sprite, _arbiter, _space, _data):
252 """ Called for bullet/wall collision """
253 bullet_sprite.remove_from_sprite_lists()
254
255 self.physics_engine.add_collision_handler("bullet", "wall", post_handler=wall_hit_handler)
256
257 def item_hit_handler(bullet_sprite, item_sprite, _arbiter, _space, _data):
258 """ Called for bullet/wall collision """
259 bullet_sprite.remove_from_sprite_lists()
260 item_sprite.remove_from_sprite_lists()
261
262 self.physics_engine.add_collision_handler("bullet", "item", post_handler=item_hit_handler)
263
264 # Add the player.
265 # For the player, we set the damping to a lower value, which increases
266 # the damping rate. This prevents the character from traveling too far
267 # after the player lets off the movement keys.
268 # Setting the moment to PymunkPhysicsEngine.MOMENT_INF prevents it from
269 # rotating.
270 # Friction normally goes between 0 (no friction) and 1.0 (high friction)
271 # Friction is between two objects in contact. It is important to remember
272 # in top-down games that friction moving along the 'floor' is controlled
273 # by damping.
274 self.physics_engine.add_sprite(self.player_sprite,
275 friction=PLAYER_FRICTION,
276 mass=PLAYER_MASS,
277 moment=arcade.PymunkPhysicsEngine.MOMENT_INF,
278 collision_type="player",
279 max_horizontal_velocity=PLAYER_MAX_HORIZONTAL_SPEED,
280 max_vertical_velocity=PLAYER_MAX_VERTICAL_SPEED)
281
282 # Create the walls.
283 # By setting the body type to PymunkPhysicsEngine.STATIC the walls can't
284 # move.
285 # Movable objects that respond to forces are PymunkPhysicsEngine.DYNAMIC
286 # PymunkPhysicsEngine.KINEMATIC objects will move, but are assumed to be
287 # repositioned by code and don't respond to physics forces.
288 # Dynamic is default.
289 self.physics_engine.add_sprite_list(self.wall_list,
290 friction=WALL_FRICTION,
291 collision_type="wall",
292 body_type=arcade.PymunkPhysicsEngine.STATIC)
293
294 # Create the items
295 self.physics_engine.add_sprite_list(self.item_list,
296 friction=DYNAMIC_ITEM_FRICTION,
297 collision_type="item")
298
299 # Add kinematic sprites
300 self.physics_engine.add_sprite_list(self.moving_sprites_list,
301 body_type=arcade.PymunkPhysicsEngine.KINEMATIC)
302
303 def on_key_press(self, key, modifiers):
304 """Called whenever a key is pressed. """
305
306 if key == arcade.key.LEFT:
307 self.left_pressed = True
308 elif key == arcade.key.RIGHT:
309 self.right_pressed = True
310 elif key == arcade.key.UP:
311 # find out if player is standing on ground
312 if self.physics_engine.is_on_ground(self.player_sprite):
313 # She is! Go ahead and jump
314 impulse = (0, PLAYER_JUMP_IMPULSE)
315 self.physics_engine.apply_impulse(self.player_sprite, impulse)
316
317 def on_key_release(self, key, modifiers):
318 """Called when the user releases a key. """
319
320 if key == arcade.key.LEFT:
321 self.left_pressed = False
322 elif key == arcade.key.RIGHT:
323 self.right_pressed = False
324
325 def on_mouse_press(self, x, y, button, modifiers):
326 """ Called whenever the mouse button is clicked. """
327
328 bullet = BulletSprite(20, 5, arcade.color.DARK_YELLOW)
329 self.bullet_list.append(bullet)
330
331 # Position the bullet at the player's current location
332 start_x = self.player_sprite.center_x
333 start_y = self.player_sprite.center_y
334 bullet.position = self.player_sprite.position
335
336 # Get from the mouse the destination location for the bullet
337 # IMPORTANT! If you have a scrolling screen, you will also need
338 # to add in self.view_bottom and self.view_left.
339 dest_x = x
340 dest_y = y
341
342 # Do math to calculate how to get the bullet to the destination.
343 # Calculation the angle in radians between the start points
344 # and end points. This is the angle the bullet will travel.
345 x_diff = dest_x - start_x
346 y_diff = dest_y - start_y
347 angle = math.atan2(y_diff, x_diff)
348
349 # What is the 1/2 size of this sprite, so we can figure out how far
350 # away to spawn the bullet
351 size = max(self.player_sprite.width, self.player_sprite.height) / 2
352
353 # Use angle to to spawn bullet away from player in proper direction
354 bullet.center_x += size * math.cos(angle)
355 bullet.center_y += size * math.sin(angle)
356
357 # Set angle of bullet
358 bullet.angle = math.degrees(angle)
359
360 # Gravity to use for the bullet
361 # If we don't use custom gravity, bullet drops too fast, or we have
362 # to make it go too fast.
363 # Force is in relation to bullet's angle.
364 bullet_gravity = (0, -BULLET_GRAVITY)
365
366 # Add the sprite. This needs to be done AFTER setting the fields above.
367 self.physics_engine.add_sprite(bullet,
368 mass=BULLET_MASS,
369 damping=1.0,
370 friction=0.6,
371 collision_type="bullet",
372 gravity=bullet_gravity,
373 elasticity=0.9)
374
375 # Add force to bullet
376 force = (BULLET_MOVE_FORCE, 0)
377 self.physics_engine.apply_force(bullet, force)
378
379 def on_update(self, delta_time):
380 """ Movement and game logic """
381
382 is_on_ground = self.physics_engine.is_on_ground(self.player_sprite)
383 # Update player forces based on keys pressed
384 if self.left_pressed and not self.right_pressed:
385 # Create a force to the left. Apply it.
386 if is_on_ground:
387 force = (-PLAYER_MOVE_FORCE_ON_GROUND, 0)
388 else:
389 force = (-PLAYER_MOVE_FORCE_IN_AIR, 0)
390 self.physics_engine.apply_force(self.player_sprite, force)
391 # Set friction to zero for the player while moving
392 self.physics_engine.set_friction(self.player_sprite, 0)
393 elif self.right_pressed and not self.left_pressed:
394 # Create a force to the right. Apply it.
395 if is_on_ground:
396 force = (PLAYER_MOVE_FORCE_ON_GROUND, 0)
397 else:
398 force = (PLAYER_MOVE_FORCE_IN_AIR, 0)
399 self.physics_engine.apply_force(self.player_sprite, force)
400 # Set friction to zero for the player while moving
401 self.physics_engine.set_friction(self.player_sprite, 0)
402 else:
403 # Player's feet are not moving. Therefore up the friction so we stop.
404 self.physics_engine.set_friction(self.player_sprite, 1.0)
405
406 # Move items in the physics engine
407 self.physics_engine.step()
408
409 # For each moving sprite, see if we've reached a boundary and need to
410 # reverse course.
411 for moving_sprite in self.moving_sprites_list:
412 if moving_sprite.boundary_right and \
413 moving_sprite.change_x > 0 and \
414 moving_sprite.right > moving_sprite.boundary_right:
415 moving_sprite.change_x *= -1
416 elif moving_sprite.boundary_left and \
417 moving_sprite.change_x < 0 and \
418 moving_sprite.left > moving_sprite.boundary_left:
419 moving_sprite.change_x *= -1
420 if moving_sprite.boundary_top and \
421 moving_sprite.change_y > 0 and \
422 moving_sprite.top > moving_sprite.boundary_top:
423 moving_sprite.change_y *= -1
424 elif moving_sprite.boundary_bottom and \
425 moving_sprite.change_y < 0 and \
426 moving_sprite.bottom < moving_sprite.boundary_bottom:
427 moving_sprite.change_y *= -1
428
429 # Figure out and set our moving platform velocity.
430 # Pymunk uses velocity is in pixels per second. If we instead have
431 # pixels per frame, we need to convert.
432 velocity = (moving_sprite.change_x * 1 / delta_time, moving_sprite.change_y * 1 / delta_time)
433 self.physics_engine.set_velocity(moving_sprite, velocity)
434
435 def on_draw(self):
436 """ Draw everything """
437 self.clear()
438 self.wall_list.draw()
439 self.moving_sprites_list.draw()
440 self.bullet_list.draw()
441 self.item_list.draw()
442 self.player_list.draw()
443
444def main():
445 """ Main function """
446 window = GameWindow(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
447 window.setup()
448 arcade.run()
449
450
451if __name__ == "__main__":
452 main()