pymunk_demo_platformer_06.py Full Listing#

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