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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 random import random
from math import sqrt, sin, cos
from Box2D import (b2BodyDef, b2CircleShape, b2Color, b2EdgeShape,
b2FixtureDef, b2PolygonShape, b2RayCastCallback, b2Vec2,
b2_dynamicBody, b2_pi)
class RayCastClosestCallback(b2RayCastCallback):
"""This callback finds the closest hit"""
def __repr__(self):
return 'Closest hit'
def __init__(self, **kwargs):
b2RayCastCallback.__init__(self, **kwargs)
self.fixture = None
self.hit = False
def ReportFixture(self, fixture, point, normal, fraction):
'''
Called for each fixture found in the query. You control how the ray
proceeds by returning a float that indicates the fractional length of
the ray. By returning 0, you set the ray length to zero. By returning
the current fraction, you proceed to find the closest point. By
returning 1, you continue with the original ray clipping. By returning
-1, you will filter out the current fixture (the ray will not hit it).
'''
self.hit = True
self.fixture = fixture
self.point = b2Vec2(point)
self.normal = b2Vec2(normal)
# NOTE: You will get this error:
# "TypeError: Swig director type mismatch in output value of
# type 'float32'"
# without returning a value
return fraction
class RayCastAnyCallback(b2RayCastCallback):
"""This callback finds any hit"""
def __repr__(self):
return 'Any hit'
def __init__(self, **kwargs):
b2RayCastCallback.__init__(self, **kwargs)
self.fixture = None
self.hit = False
def ReportFixture(self, fixture, point, normal, fraction):
self.hit = True
self.fixture = fixture
self.point = b2Vec2(point)
self.normal = b2Vec2(normal)
return 0.0
class RayCastMultipleCallback(b2RayCastCallback):
"""This raycast collects multiple hits."""
def __repr__(self):
return 'Multiple hits'
def __init__(self, **kwargs):
b2RayCastCallback.__init__(self, **kwargs)
self.fixture = None
self.hit = False
self.points = []
self.normals = []
def ReportFixture(self, fixture, point, normal, fraction):
self.hit = True
self.fixture = fixture
self.points.append(b2Vec2(point))
self.normals.append(b2Vec2(normal))
return 1.0
class Raycast (Framework):
name = "Raycast"
description = "Press 1-5 to drop stuff, d to delete, m to switch callback modes"
p1_color = b2Color(0.4, 0.9, 0.4)
s1_color = b2Color(0.8, 0.8, 0.8)
s2_color = b2Color(0.9, 0.9, 0.4)
def __init__(self):
super(Raycast, self).__init__()
self.world.gravity = (0, 0)
# The ground
ground = self.world.CreateBody(
shapes=b2EdgeShape(vertices=[(-40, 0), (40, 0)])
)
# The various shapes
w = 1.0
b = w / (2.0 + sqrt(2.0))
s = sqrt(2.0) * b
self.shapes = [
b2PolygonShape(vertices=[(-0.5, 0), (0.5, 0), (0, 1.5)]),
b2PolygonShape(vertices=[(-0.1, 0), (0.1, 0), (0, 1.5)]),
b2PolygonShape(
vertices=[(0.5 * s, 0), (0.5 * w, b), (0.5 * w, b + s),
(0.5 * s, w), (-0.5 * s, w), (-0.5 * w, b + s),
(-0.5 * w, b), (-0.5 * s, 0.0)]
),
b2PolygonShape(box=(0.5, 0.5)),
b2CircleShape(radius=0.5),
]
self.angle = 0
self.callbacks = [RayCastClosestCallback,
RayCastAnyCallback, RayCastMultipleCallback]
self.callback_class = self.callbacks[0]
def CreateShape(self, shapeindex):
try:
shape = self.shapes[shapeindex]
except IndexError:
return
pos = (10.0 * (2.0 * random() - 1.0), 10.0 * (2.0 * random()))
defn = b2BodyDef(
type=b2_dynamicBody,
fixtures=b2FixtureDef(shape=shape, friction=0.3),
position=pos,
angle=(b2_pi * (2.0 * random() - 1.0)),
)
if isinstance(shape, b2CircleShape):
defn.angularDamping = 0.02
self.world.CreateBody(defn)
def DestroyBody(self):
for body in self.world.bodies:
if not self.world.locked:
self.world.DestroyBody(body)
break
def Keyboard(self, key):
if key in (Keys.K_1, Keys.K_2, Keys.K_3, Keys.K_4, Keys.K_5):
self.CreateShape(key - Keys.K_1)
elif key == Keys.K_d:
self.DestroyBody()
elif key == Keys.K_m:
idx = ((self.callbacks.index(self.callback_class) + 1) %
len(self.callbacks))
self.callback_class = self.callbacks[idx]
def Step(self, settings):
super(Raycast, self).Step(settings)
def draw_hit(cb_point, cb_normal):
cb_point = self.renderer.to_screen(cb_point)
head = b2Vec2(cb_point) + 0.5 * cb_normal
cb_normal = self.renderer.to_screen(cb_normal)
self.renderer.DrawPoint(cb_point, 5.0, self.p1_color)
self.renderer.DrawSegment(point1, cb_point, self.s1_color)
self.renderer.DrawSegment(cb_point, head, self.s2_color)
# Set up the raycast line
length = 11
point1 = b2Vec2(0, 10)
d = (length * cos(self.angle), length * sin(self.angle))
point2 = point1 + d
callback = self.callback_class()
self.world.RayCast(callback, point1, point2)
# The callback has been called by this point, and if a fixture was hit it will have been
# set to callback.fixture.
point1 = self.renderer.to_screen(point1)
point2 = self.renderer.to_screen(point2)
if callback.hit:
if hasattr(callback, 'points'):
for point, normal in zip(callback.points, callback.normals):
draw_hit(point, normal)
else:
draw_hit(callback.point, callback.normal)
else:
self.renderer.DrawSegment(point1, point2, self.s1_color)
self.Print("Callback: %s" % callback)
if callback.hit:
self.Print("Hit")
if not settings.pause or settings.singleStep:
self.angle += 0.25 * b2_pi / 180
if __name__ == "__main__":
main(Raycast)
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