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
|
#!/usr/bin/python
#
# C++ version Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
# Python version Copyright (c) 2008 kne / sirkne at gmail dot com
#
# Implemented using the pybox2d SWIG interface for Box2D (pybox2d.googlecode.com)
#
# This software is provided 'as-is', without any express or implied
# warranty. In no event will the authors be held liable for any damages
# arising from the use of this software.
# Permission is granted to anyone to use this software for any purpose,
# including commercial applications, and to alter it and redistribute it
# freely, subject to the following restrictions:
# 1. The origin of this software must not be misrepresented; you must not
# claim that you wrote the original software. If you use this software
# in a product, an acknowledgment in the product documentation would be
# appreciated but is not required.
# 2. Altered source versions must be plainly marked as such, and must not be
# misrepresented as being the original software.
# 3. This notice may not be removed or altered from any source distribution.
from test_main import *
class Pulleys (Framework):
name="Pulleys"
joint1=None
_pickle_vars=['joint1']
def __init__(self):
super(Pulleys, self).__init__()
sd=box2d.b2PolygonDef()
sd.SetAsBox(50.0, 10.0)
bd=box2d.b2BodyDef()
bd.position = (0.0, -10.0)
ground = self.world.CreateBody(bd)
ground.CreateShape(sd)
a = 2.0
b = 4.0
y = 16.0
L = 12.0
sd=box2d.b2PolygonDef()
sd.SetAsBox(a, b)
sd.density = 5.0
bd=box2d.b2BodyDef()
bd.position = (-10.0, y)
body1 = self.world.CreateBody(bd)
body1.CreateShape(sd)
body1.SetMassFromShapes()
bd.position = (10.0, y)
body2 = self.world.CreateBody(bd)
body2.CreateShape(sd)
body2.SetMassFromShapes()
pulleyDef=box2d.b2PulleyJointDef()
anchor1 =(-10.0, y + b)
anchor2 =( 10.0, y + b)
groundAnchor1=(-10.0, y + b + L)
groundAnchor2=( 10.0, y + b + L)
pulleyDef.Initialize(body1, body2, groundAnchor1, groundAnchor2, anchor1, anchor2, 2.0)
self.joint1 = self.world.CreateJoint(pulleyDef).getAsType()
def Step(self, settings):
super(Pulleys, self).Step(settings)
if not self.joint1:
return
ratio = self.joint1.GetRatio()
L = self.joint1.GetLength1() + ratio * self.joint1.GetLength2()
self.DrawStringCR("L1 + %.2f * L2 = %.2f" % (ratio, L))
if __name__=="__main__":
main(Pulleys)
|
