Pymunk Physics Engine - Stacks of Boxes#
This uses the Pymunk physics engine to manage stacks of boxes. The user can interact with the boxes using the mouse.
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 | """ Use Pymunk physics engine. For more info on Pymunk see: https://www.pymunk.org/en/latest/ To install pymunk: pip install pymunk Artwork from https://kenney.nl If Python and Arcade are installed, this example can be run from the command line with: python -m arcade.examples.pymunk_box_stacks Click and drag with the mouse to move the boxes. """ import arcade import pymunk import timeit import math SCREEN_WIDTH = 1800 SCREEN_HEIGHT = 800 SCREEN_TITLE = "Pymunk test" class PhysicsSprite(arcade.Sprite): def __init__(self, pymunk_shape, filename): super().__init__(filename, center_x=pymunk_shape.body.position.x, center_y=pymunk_shape.body.position.y) self.pymunk_shape = pymunk_shape class CircleSprite(PhysicsSprite): def __init__(self, pymunk_shape, filename): super().__init__(pymunk_shape, filename) self.width = pymunk_shape.radius * 2 self.height = pymunk_shape.radius * 2 class BoxSprite(PhysicsSprite): def __init__(self, pymunk_shape, filename, width, height): super().__init__(pymunk_shape, filename) self.width = width self.height = height class MyGame(arcade.Window): """ Main application class. """ def __init__(self, width, height, title): super().__init__(width, height, title) arcade.set_background_color(arcade.color.DARK_SLATE_GRAY) # -- Pymunk self.space = pymunk.Space() self.space.iterations = 35 self.space.gravity = (0.0, -900.0) # Lists of sprites or lines self.sprite_list: arcade.SpriteList[PhysicsSprite] = arcade.SpriteList() self.static_lines = [] # Used for dragging shapes around with the mouse self.shape_being_dragged = None self.last_mouse_position = 0, 0 self.draw_time = 0 self.processing_time = 0 # Create the floor floor_height = 80 body = pymunk.Body(body_type=pymunk.Body.STATIC) shape = pymunk.Segment(body, [0, floor_height], [SCREEN_WIDTH, floor_height], 0.0) shape.friction = 10 self.space.add(shape, body) self.static_lines.append(shape) # Create the stacks of boxes for row in range(10): for column in range(10): size = 32 mass = 1.0 x = 500 + column * 32 y = (floor_height + size / 2) + row * size moment = pymunk.moment_for_box(mass, (size, size)) body = pymunk.Body(mass, moment) body.position = pymunk.Vec2d(x, y) shape = pymunk.Poly.create_box(body, (size, size)) shape.elasticity = 0.2 shape.friction = 0.9 self.space.add(body, shape) # body.sleep() sprite = BoxSprite(shape, ":resources:images/tiles/boxCrate_double.png", width=size, height=size) self.sprite_list.append(sprite) def on_draw(self): """ Render the screen. """ # This command has to happen before we start drawing self.clear() # Start timing how long this takes draw_start_time = timeit.default_timer() # Draw all the sprites self.sprite_list.draw() # Draw the lines that aren't sprites for line in self.static_lines: body = line.body pv1 = body.position + line.a.rotated(body.angle) pv2 = body.position + line.b.rotated(body.angle) arcade.draw_line(pv1.x, pv1.y, pv2.x, pv2.y, arcade.color.WHITE, 2) # Display timings output = f"Processing time: {self.processing_time:.3f}" arcade.draw_text(output, 20, SCREEN_HEIGHT - 20, arcade.color.WHITE, 12) output = f"Drawing time: {self.draw_time:.3f}" arcade.draw_text(output, 20, SCREEN_HEIGHT - 40, arcade.color.WHITE, 12) self.draw_time = timeit.default_timer() - draw_start_time def on_mouse_press(self, x, y, button, modifiers): if button == arcade.MOUSE_BUTTON_LEFT: self.last_mouse_position = x, y # See if we clicked on anything shape_list = self.space.point_query((x, y), 1, pymunk.ShapeFilter()) # If we did, remember what we clicked on if len(shape_list) > 0: self.shape_being_dragged = shape_list[0] elif button == arcade.MOUSE_BUTTON_RIGHT: # With right mouse button, shoot a heavy coin fast. mass = 60 radius = 10 inertia = pymunk.moment_for_circle(mass, 0, radius, (0, 0)) body = pymunk.Body(mass, inertia) body.position = x, y body.velocity = 2000, 0 shape = pymunk.Circle(body, radius, pymunk.Vec2d(0, 0)) shape.friction = 0.3 self.space.add(body, shape) sprite = CircleSprite(shape, ":resources:images/items/coinGold.png") self.sprite_list.append(sprite) def on_mouse_release(self, x, y, button, modifiers): if button == arcade.MOUSE_BUTTON_LEFT: # Release the item we are holding (if any) self.shape_being_dragged = None def on_mouse_motion(self, x, y, dx, dy): if self.shape_being_dragged is not None: # If we are holding an object, move it with the mouse self.last_mouse_position = x, y self.shape_being_dragged.shape.body.position = self.last_mouse_position self.shape_being_dragged.shape.body.velocity = dx * 20, dy * 20 def on_update(self, delta_time): start_time = timeit.default_timer() # Check for balls that fall off the screen for sprite in self.sprite_list: if sprite.pymunk_shape.body.position.y < 0: # Remove balls from physics space self.space.remove(sprite.pymunk_shape, sprite.pymunk_shape.body) # Remove balls from physics list sprite.remove_from_sprite_lists() # Update physics # Use a constant time step, don't use delta_time # See "Game loop / moving time forward" # https://www.pymunk.org/en/latest/overview.html#game-loop-moving-time-forward self.space.step(1 / 60.0) # If we are dragging an object, make sure it stays with the mouse. Otherwise # gravity will drag it down. if self.shape_being_dragged is not None: self.shape_being_dragged.shape.body.position = self.last_mouse_position self.shape_being_dragged.shape.body.velocity = 0, 0 # Move sprites to where physics objects are for sprite in self.sprite_list: sprite.center_x = sprite.pymunk_shape.body.position.x sprite.center_y = sprite.pymunk_shape.body.position.y sprite.angle = math.degrees(sprite.pymunk_shape.body.angle) # Save the time it took to do this. self.processing_time = timeit.default_timer() - start_time def main(): MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE) arcade.run() if __name__ == "__main__": main() |