pymunk_demo_platformer_06.py Full Listing
pymunk_demo_platformer_06.py
1"""
2Example of Pymunk Physics Engine Platformer
3"""
4from typing import Optional
5import arcade
6
7SCREEN_TITLE = "PyMunk Platformer"
8
9# How big are our image tiles?
10SPRITE_IMAGE_SIZE = 128
11
12# Scale sprites up or down
13SPRITE_SCALING_PLAYER = 0.5
14SPRITE_SCALING_TILES = 0.5
15
16# Scaled sprite size for tiles
17SPRITE_SIZE = int(SPRITE_IMAGE_SIZE * SPRITE_SCALING_PLAYER)
18
19# Size of grid to show on screen, in number of tiles
20SCREEN_GRID_WIDTH = 25
21SCREEN_GRID_HEIGHT = 15
22
23# Size of screen to show, in pixels
24SCREEN_WIDTH = SPRITE_SIZE * SCREEN_GRID_WIDTH
25SCREEN_HEIGHT = SPRITE_SIZE * SCREEN_GRID_HEIGHT
26
27# --- Physics forces. Higher number, faster accelerating.
28
29# Gravity
30GRAVITY = 1500
31
32# Damping - Amount of speed lost per second
33DEFAULT_DAMPING = 1.0
34PLAYER_DAMPING = 0.4
35
36# Friction between objects
37PLAYER_FRICTION = 1.0
38WALL_FRICTION = 0.7
39DYNAMIC_ITEM_FRICTION = 0.6
40
41# Mass (defaults to 1)
42PLAYER_MASS = 2.0
43
44# Keep player from going too fast
45PLAYER_MAX_HORIZONTAL_SPEED = 450
46PLAYER_MAX_VERTICAL_SPEED = 1600
47
48# Force applied while on the ground
49PLAYER_MOVE_FORCE_ON_GROUND = 8000
50
51class GameWindow(arcade.Window):
52 """ Main Window """
53
54 def __init__(self, width, height, title):
55 """ Create the variables """
56
57 # Init the parent class
58 super().__init__(width, height, title)
59
60 # Player sprite
61 self.player_sprite: Optional[arcade.Sprite] = None
62
63 # Sprite lists we need
64 self.player_list: Optional[arcade.SpriteList] = None
65 self.wall_list: Optional[arcade.SpriteList] = None
66 self.bullet_list: Optional[arcade.SpriteList] = None
67 self.item_list: Optional[arcade.SpriteList] = None
68
69 # Track the current state of what key is pressed
70 self.left_pressed: bool = False
71 self.right_pressed: bool = False
72
73 # Physics engine
74 self.physics_engine = Optional[arcade.PymunkPhysicsEngine]
75
76 # Set background color
77 self.background_color = arcade.color.AMAZON
78
79 def setup(self):
80 """ Set up everything with the game """
81
82 # Create the sprite lists
83 self.player_list = arcade.SpriteList()
84 self.bullet_list = arcade.SpriteList()
85
86 # Map name
87 map_name = ":resources:/tiled_maps/pymunk_test_map.json"
88
89 # Load in TileMap
90 tile_map = arcade.load_tilemap(map_name, SPRITE_SCALING_TILES)
91
92 # Pull the sprite layers out of the tile map
93 self.wall_list = tile_map.sprite_lists["Platforms"]
94 self.item_list = tile_map.sprite_lists["Dynamic Items"]
95
96 # Create player sprite
97 self.player_sprite = arcade.Sprite(":resources:images/animated_characters/female_person/femalePerson_idle.png",
98 SPRITE_SCALING_PLAYER)
99 # Set player location
100 grid_x = 1
101 grid_y = 1
102 self.player_sprite.center_x = SPRITE_SIZE * grid_x + SPRITE_SIZE / 2
103 self.player_sprite.center_y = SPRITE_SIZE * grid_y + SPRITE_SIZE / 2
104 # Add to player sprite list
105 self.player_list.append(self.player_sprite)
106
107 # --- Pymunk Physics Engine Setup ---
108
109 # The default damping for every object controls the percent of velocity
110 # the object will keep each second. A value of 1.0 is no speed loss,
111 # 0.9 is 10% per second, 0.1 is 90% per second.
112 # For top-down games, this is basically the friction for moving objects.
113 # For platformers with gravity, this should probably be set to 1.0.
114 # Default value is 1.0 if not specified.
115 damping = DEFAULT_DAMPING
116
117 # Set the gravity. (0, 0) is good for outer space and top-down.
118 gravity = (0, -GRAVITY)
119
120 # Create the physics engine
121 self.physics_engine = arcade.PymunkPhysicsEngine(damping=damping,
122 gravity=gravity)
123
124 # Add the player.
125 # For the player, we set the damping to a lower value, which increases
126 # the damping rate. This prevents the character from traveling too far
127 # after the player lets off the movement keys.
128 # Setting the moment of inertia to PymunkPhysicsEngine.MOMENT_INF prevents it from
129 # rotating.
130 # Friction normally goes between 0 (no friction) and 1.0 (high friction)
131 # Friction is between two objects in contact. It is important to remember
132 # in top-down games that friction moving along the 'floor' is controlled
133 # by damping.
134 self.physics_engine.add_sprite(self.player_sprite,
135 friction=PLAYER_FRICTION,
136 mass=PLAYER_MASS,
137 moment_of_inertia=arcade.PymunkPhysicsEngine.MOMENT_INF,
138 collision_type="player",
139 max_horizontal_velocity=PLAYER_MAX_HORIZONTAL_SPEED,
140 max_vertical_velocity=PLAYER_MAX_VERTICAL_SPEED)
141
142 # Create the walls.
143 # By setting the body type to PymunkPhysicsEngine.STATIC the walls can't
144 # move.
145 # Movable objects that respond to forces are PymunkPhysicsEngine.DYNAMIC
146 # PymunkPhysicsEngine.KINEMATIC objects will move, but are assumed to be
147 # repositioned by code and don't respond to physics forces.
148 # Dynamic is default.
149 self.physics_engine.add_sprite_list(self.wall_list,
150 friction=WALL_FRICTION,
151 collision_type="wall",
152 body_type=arcade.PymunkPhysicsEngine.STATIC)
153
154 # Create the items
155 self.physics_engine.add_sprite_list(self.item_list,
156 friction=DYNAMIC_ITEM_FRICTION,
157 collision_type="item")
158
159 def on_key_press(self, key, modifiers):
160 """Called whenever a key is pressed. """
161
162 if key == arcade.key.LEFT:
163 self.left_pressed = True
164 elif key == arcade.key.RIGHT:
165 self.right_pressed = True
166
167 def on_key_release(self, key, modifiers):
168 """Called when the user releases a key. """
169
170 if key == arcade.key.LEFT:
171 self.left_pressed = False
172 elif key == arcade.key.RIGHT:
173 self.right_pressed = False
174
175 def on_update(self, delta_time):
176 """ Movement and game logic """
177
178 # Update player forces based on keys pressed
179 if self.left_pressed and not self.right_pressed:
180 # Create a force to the left. Apply it.
181 force = (-PLAYER_MOVE_FORCE_ON_GROUND, 0)
182 self.physics_engine.apply_force(self.player_sprite, force)
183 # Set friction to zero for the player while moving
184 self.physics_engine.set_friction(self.player_sprite, 0)
185 elif self.right_pressed and not self.left_pressed:
186 # Create a force to the right. Apply it.
187 force = (PLAYER_MOVE_FORCE_ON_GROUND, 0)
188 self.physics_engine.apply_force(self.player_sprite, force)
189 # Set friction to zero for the player while moving
190 self.physics_engine.set_friction(self.player_sprite, 0)
191 else:
192 # Player's feet are not moving. Therefore up the friction so we stop.
193 self.physics_engine.set_friction(self.player_sprite, 1.0)
194
195 # Move items in the physics engine
196 self.physics_engine.step()
197
198 def on_draw(self):
199 """ Draw everything """
200 self.clear()
201 self.wall_list.draw()
202 self.bullet_list.draw()
203 self.item_list.draw()
204 self.player_list.draw()
205
206def main():
207 """ Main function """
208 window = GameWindow(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
209 window.setup()
210 arcade.run()
211
212
213if __name__ == "__main__":
214 main()