cocos2d python 画一个圆在pymunk重力下自由下落
在cocos2d python界面画一个圆，在pymunk重力下自由下落，以下代码如何修改？# coding: utf-8import cocos
import pymunk
from pyglet.gl import *
from math import cos, tan, pi
class Hello(cocos.layer.Layer):
def __init__(self):
super(Hello, self).__init__()
self.ball_body, self.ball_shape = create_ball(self)
self.space.add(self.ball_body, self.ball_shape)
# 创建Pymunk空间
self.space = pymunk.Space()
self.space.gravity = (0, -300)
self.elapsed = 0
self.schedule(self.update)
# 创建圆的Pymunk body和shape
radius = 20
mass = 1000
moment = pymunk.moment_for_circle(mass, 0, radius)
self.cbody = pymunk.Body(mass, moment)
self.cbody.position = 300, 300
self.c = pymunk.Circle(self.cbody, radius)
self.space.add(self.cbody, self.c)
def create_ball(self):
super().draw()
self.circle_center = (300, 300)
self.circle_radius = 20
# 设置颜色为绿色并绘制圆
glColor4ub(0, 255, 0, 255)
num_segments = 100
theta = 2 * pi / num_segments
tangetial_factor = tan(theta)# Calculate the tangential factor
radial_factor = cos(theta)# Calculate the radial factor
x = self.circle_radius# Start at angle = 0
y = 0
glBegin(GL_LINE_LOOP)
for i in range(num_segments):
glVertex2f(x + self.circle_center, y + self.circle_center)
tx = -y
ty = x
x += tx * tangetial_factor
y += ty * tangetial_factor
x *= radial_factor
y *= radial_factor
glEnd()
self.ball_body = pymunk.Body(body_type=pymunk.Body.KINEMATIC)
self.ball_shape = pymunk.Poly(self.ball_body, self.circle)
self.ball_shape.friction = 0.5
self.ball_shape.collision_type = 1
self.ball_shape.density = 0.1
return self.ball_body, self.ball_shape
def update(self, dt):
self.space.step(dt)
self.ball.position = self.cbody.position
if __name__ == "__main__":
cocos.director.director.init()
hello_layer = Hello()
main_scene = cocos.scene.Scene(hello_layer)
cocos.director.director.run(main_scene) 要在 Cocos2d-python 中使用 Pymunk 实现一个圆在重力下自由下落，您需要正确创建和更新圆的物理表现和显示。以下是对您提供的代码的修正，以确保圆正确地在重力影响下下落：
import cocos
import pymunk
from pyglet.gl import *
from math import cos, tan, pi
class Hello(cocos.layer.Layer):
def __init__(self):
super(Hello, self).__init__()
# 创建Pymunk空间
self.space = pymunk.Space()
self.space.gravity = (0, -300)
# 创建圆的Pymunk body和shape
radius = 20
mass = 10# 质量设为较小的值以便测试
moment = pymunk.moment_for_circle(mass, 0, radius)
self.cbody = pymunk.Body(mass, moment)
self.cbody.position = (300, 300)
self.c = pymunk.Circle(self.cbody, radius)
self.c.friction = 0.5
self.c.elasticity = 0.9# 加入一点弹性
self.space.add(self.cbody, self.c)
self.schedule(self.update)
def draw(self):
# 设置颜色为绿色并绘制圆
glColor4ub(0, 255, 0, 255)
num_segments = 100
theta = 2 * pi / num_segments
tangetial_factor = tan(theta)# 计算切线因子
radial_factor = cos(theta)# 计算径向因子
x = self.c.radius# 起始点为角度0
y = 0
glPushMatrix()
glTranslatef(self.cbody.position.x, self.cbody.position.y, 0)
glBegin(GL_LINE_LOOP)
for i in range(num_segments):
glVertex2f(x, y)
tx = -y
ty = x
x += tx * tangetial_factor
y += ty * tangetial_factor
x *= radial_factor
y *= radial_factor
glEnd()
glPopMatrix()
def update(self, dt):
self.space.step(dt)
if __name__ == "__main__":
cocos.director.director.init()
hello_layer = Hello()
main_scene = cocos.scene.Scene(hello_layer)
cocos.director.director.run(main_scene)
### 修改要点：
1. **创建Pymunk Body的类型和设置**：我将body的类型设置为动态（去掉了KINEMATIC类型），它会自然地受到重力影响。
2. **正确绘制圆**：确保每次绘制时都是以 `self.cbody.position` 作为中心来进行绘制，以体现下落效果。
3. **物理属性**：调整了弹性（elasticity）和摩擦力（friction），以简单模拟现实效果。
4. **删除冗余代码**：去掉了不必要的代码和重复定义的函数参数。
这些修改确保了圆的物理行为和图形显示能够同步，即圆能够因重力而下落并在屏幕上看到其移动。
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