python
"""
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()这个程序使用了Pymunk物理引擎来模拟物理效果。在游戏窗口中，有一些方块和圆形对象受到重力影响并且可以与鼠标交互。
在初始化方法中，创建了一个Pymunk空间和一个静态地面，然后创建了一些方块对象并添加到空间中。这些方块对象对应的Sprite存储在sprite_list列表中。
在绘制方法中，首先清除屏幕，然后绘制所有的Sprite和静态线条。接着显示处理时间和绘制时间。
在鼠标按下方法中，如果按下的是左键并且点击到了一个对象，就将该对象设置为正在拖动的对象。如果按下的是右键，就在鼠标位置发射一个快速的重物。
在鼠标释放方法中，如果松开的是左键，则停止拖动对象的操作。
在鼠标移动方法中，如果正在拖动一个对象，就将对象的位置设置为鼠标位置，并更新对象的速度。
在更新方法中，首先检查是否有对象掉落出屏幕，如果有则从空间中移除该对象。接着更新物理引擎状态，如果有对象正在被拖动，则将其位置设置为鼠标位置，并将其速度设置为0。最后，将Sprite的位置更新为物理对象的位置，并保存处理时间。
最后，在main方法中创建游戏实例并运行游戏循环。