/usr/share/doc/python-box2d-doc/examples/breakable.py is in python-box2d-doc 2.3.2~dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | #!/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 (b2Cross, b2EdgeShape, b2FixtureDef, b2PolygonShape, b2_pi)
class Breakable (Framework):
name = "Breakable bodies"
description = "With enough of an impulse, the single body will split [press b to manually break it]"
_break = False # Flag to break
broke = False # Already broken?
def __init__(self):
super(Breakable, self).__init__()
# The ground
self.world.CreateBody(shapes=b2EdgeShape(vertices=[(-40, 0), (40, 0)]))
# The breakable body
self.shapes = (b2PolygonShape(box=(0.5, 0.5, (-0.5, 0), 0)),
b2PolygonShape(box=(0.5, 0.5, (0.5, 0), 0))
)
self.body = self.world.CreateDynamicBody(
position=(0, 40),
angle=0.25 * b2_pi,
shapes=self.shapes,
shapeFixture=b2FixtureDef(density=1),
)
self.fixtures = self.body.fixtures
def PostSolve(self, contact, impulse):
# Already broken?
if self.broke:
return
# If the impulse is enough to split the objects, then flag it to break
if max(impulse.normalImpulses) > 40:
self._break = True
def Break(self):
# Create two bodies from one
body = self.body
center = body.worldCenter
body.DestroyFixture(self.fixtures[1])
self.fixture2 = None
body2 = self.world.CreateDynamicBody(
position=body.position,
angle=body.angle,
shapes=self.shapes[1],
shapeFixture=b2FixtureDef(density=1),
)
# Compute consistent velocities for new bodies based on cached
# velocity.
velocity1 = (self.velocity +
b2Cross(self.angularVelocity, body.worldCenter - center))
velocity2 = (self.velocity +
b2Cross(self.angularVelocity, body2.worldCenter - center))
body.angularVelocity = self.angularVelocity
body.linearVelocity = velocity1
body2.angularVelocity = self.angularVelocity
body2.linearVelocity = velocity2
def Step(self, settings):
super(Breakable, self).Step(settings)
if self._break:
self.Break()
self.broke = True
self._break = False
if not self.broke:
self.velocity = self.body.linearVelocity
self.angularVelocity = self.body.angularVelocity
def Keyboard(self, key):
if key == Keys.K_b and not self.broke:
self._break = True
if __name__ == "__main__":
main(Breakable)
|