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#!/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 Gears (Framework):
name="Gears"
joint1=None
joint2=None
joint3=None
joint4=None
joint5=None
_pickle_vars = ['joint1', 'joint2', 'joint3', 'joint4', 'joint5']
def __init__(self):
super(Gears, self).__init__()
bd=box2d.b2BodyDef()
bd.position = (0.0, -10.0)
ground = self.world.CreateBody(bd)
sd=box2d.b2PolygonDef()
sd.SetAsBox(50.0, 10.0)
ground.CreateShape(sd)
circle1=box2d.b2CircleDef()
circle1.radius = 1.0
circle1.density = 5.0
circle2=box2d.b2CircleDef()
circle2.radius = 2.0
circle2.density = 5.0
box=box2d.b2PolygonDef()
box.SetAsBox(0.5, 5.0)
box.density = 5.0
bd1=box2d.b2BodyDef()
bd1.position = (-3.0, 12.0)
body1 = self.world.CreateBody(bd1)
body1.CreateShape(circle1)
body1.SetMassFromShapes()
jd1=box2d.b2RevoluteJointDef()
jd1.body1 = ground
jd1.body2 = body1
jd1.localAnchor1 = ground.GetLocalPoint(bd1.position)
jd1.localAnchor2 = body1.GetLocalPoint(bd1.position)
jd1.referenceAngle = body1.GetAngle() - ground.GetAngle()
self.joint1 = self.world.CreateJoint(jd1).getAsType()
bd2=box2d.b2BodyDef()
bd2.position = (0.0, 12.0)
body2 = self.world.CreateBody(bd2)
body2.CreateShape(circle2)
body2.SetMassFromShapes()
jd2=box2d.b2RevoluteJointDef()
jd2.Initialize(ground, body2, bd2.position)
self.joint2 = self.world.CreateJoint(jd2).getAsType()
bd3=box2d.b2BodyDef()
bd3.position = (2.5, 12.0)
body3 = self.world.CreateBody(bd3)
body3.CreateShape(box)
body3.SetMassFromShapes()
jd3=box2d.b2PrismaticJointDef()
jd3.Initialize(ground, body3, bd3.position, (0.0, 1.0))
jd3.lowerTranslation = -5.0
jd3.upperTranslation = 5.0
jd3.enableLimit = True
self.joint3 = self.world.CreateJoint(jd3).getAsType()
jd4=box2d.b2GearJointDef()
jd4.body1 = body1
jd4.body2 = body2
jd4.joint1 = self.joint1
jd4.joint2 = self.joint2
jd4.ratio = circle2.radius / circle1.radius
self.joint4 = self.world.CreateJoint(jd4).getAsType()
jd5=box2d.b2GearJointDef()
jd5.body1 = body2
jd5.body2 = body3
jd5.joint1 = self.joint2
jd5.joint2 = self.joint3
jd5.ratio = -1.0 / circle2.radius
self.joint5 = self.world.CreateJoint(jd5).getAsType()
def Step(self, settings):
if self.joint1 and self.joint2 and self.joint3 and self.joint4 and self.joint5:
ratio = self.joint4.GetRatio()
value = self.joint1.GetJointAngle() + ratio * self.joint2.GetJointAngle()
self.DrawStringCR("theta1 + %.2f * theta2 = %.2f" % (ratio, value))
ratio = self.joint5.GetRatio()
value = self.joint2.GetJointAngle() + ratio * self.joint3.GetJointTranslation()
self.DrawStringCR("theta2 + %.2f * delta = %.2f" % (ratio, value))
super(Gears, self).Step(settings)
if __name__=="__main__":
main(Gears)
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