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#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# C++ version Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
# Python version by Ken Lauer / sirkne at gmail dot 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 .framework import (Framework, Keys, main)
from Box2D import (b2EdgeShape, b2FixtureDef, b2PolygonShape, b2_dynamicBody,
b2_kinematicBody, b2_staticBody)
class BodyTypes(Framework):
name = "Body Types"
description = "Change body type keys: (d) dynamic, (s) static, (k) kinematic"
speed = 3 # platform speed
def __init__(self):
super(BodyTypes, self).__init__()
# The ground
ground = self.world.CreateBody(
shapes=b2EdgeShape(vertices=[(-20, 0), (20, 0)])
)
# The attachment
self.attachment = self.world.CreateDynamicBody(
position=(0, 3),
fixtures=b2FixtureDef(
shape=b2PolygonShape(box=(0.5, 2)), density=2.0),
)
# The platform
fixture = b2FixtureDef(
shape=b2PolygonShape(box=(4, 0.5)),
density=2,
friction=0.6,
)
self.platform = self.world.CreateDynamicBody(
position=(0, 5),
fixtures=fixture,
)
# The joints joining the attachment/platform and ground/platform
self.world.CreateRevoluteJoint(
bodyA=self.attachment,
bodyB=self.platform,
anchor=(0, 5),
maxMotorTorque=50,
enableMotor=True
)
self.world.CreatePrismaticJoint(
bodyA=ground,
bodyB=self.platform,
anchor=(0, 5),
axis=(1, 0),
maxMotorForce=1000,
enableMotor=True,
lowerTranslation=-10,
upperTranslation=10,
enableLimit=True
)
# And the payload that initially sits upon the platform
# Reusing the fixture we previously defined above
fixture.shape.box = (0.75, 0.75)
self.payload = self.world.CreateDynamicBody(
position=(0, 8),
fixtures=fixture,
)
def Keyboard(self, key):
if key == Keys.K_d:
self.platform.type = b2_dynamicBody
elif key == Keys.K_s:
self.platform.type = b2_staticBody
elif key == Keys.K_k:
self.platform.type = b2_kinematicBody
self.platform.linearVelocity = (-self.speed, 0)
self.platform.angularVelocity = 0
def Step(self, settings):
super(BodyTypes, self).Step(settings)
if self.platform.type == b2_kinematicBody:
p = self.platform.transform.position
v = self.platform.linearVelocity
if ((p.x < -10 and v.x < 0) or (p.x > 10 and v.x > 0)):
v.x = -v.x
self.platform.linearVelocity = v
if __name__ == "__main__":
main(BodyTypes)
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