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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, main)
from Box2D import (b2CircleShape, b2EdgeShape, b2FixtureDef, b2PolygonShape)
def create_bridge(world, ground, size, offset, plank_count, friction=0.6, density=1.0):
"""
Create a bridge with plank_count planks,
utilizing rectangular planks of size (width, height).
The bridge should start at x_offset, and continue to
roughly x_offset+width*plank_count.
The y will not change.
"""
width, height = size
x_offset, y_offset = offset
half_height = height / 2
plank = b2FixtureDef(
shape=b2PolygonShape(box=(width / 2, height / 2)),
friction=friction,
density=density,
)
bodies = []
prevBody = ground
for i in range(plank_count):
body = world.CreateDynamicBody(
position=(x_offset + width * i, y_offset),
fixtures=plank,
)
bodies.append(body)
world.CreateRevoluteJoint(
bodyA=prevBody,
bodyB=body,
anchor=(x_offset + width * (i - 0.5), y_offset)
)
prevBody = body
world.CreateRevoluteJoint(
bodyA=prevBody,
bodyB=ground,
anchor=(x_offset + width * (plank_count - 0.5), y_offset),
)
return bodies
class Bridge (Framework):
name = "Bridge"
numPlanks = 30 # Number of planks in the bridge
def __init__(self):
super(Bridge, self).__init__()
# The ground
ground = self.world.CreateBody(
shapes=b2EdgeShape(vertices=[(-40, 0), (40, 0)])
)
create_bridge(self.world, ground, (1.0, 0.25),
(-14.5, 5), self.numPlanks, 0.2, 20)
fixture = b2FixtureDef(
shape=b2PolygonShape(vertices=[(-0.5, 0.0),
(0.5, 0.0),
(0.0, 1.5),
]),
density=1.0
)
for i in range(2):
self.world.CreateDynamicBody(
position=(-8 + 8 * i, 12),
fixtures=fixture,
)
fixture = b2FixtureDef(shape=b2CircleShape(radius=0.5), density=1)
for i in range(3):
self.world.CreateDynamicBody(
position=(-6 + 6 * i, 10),
fixtures=fixture,
)
if __name__ == "__main__":
main(Bridge)
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