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"""
This file is part of the 'Elements' Project
Elements is a 2D Physics API for Python (supporting Box2D2)
Copyright (C) 2008, The Elements Team, <elements@linuxuser.at>
Home: http://elements.linuxuser.at
IRC: #elements on irc.freenode.org
Code: http://www.assembla.com/wiki/show/elements
svn co http://svn2.assembla.com/svn/elements
License: GPLv3 | See LICENSE for the full text
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
from locals import *
from elements import box2d
# Imports
from math import pi
from math import sqrt
from math import asin
import tools_poly
class Add:
element_count = 0
def __init__(self, parent):
self.parent = parent
def ground(self):
""" Add a static ground to the scene
Return: box2d.b2Body
"""
return self._rect((-10.0, 0.0), 50.0, 0.1, dynamic=False)
def triangle(self, pos, sidelength, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
""" Add a triangle | pos & a in the current input unit system (meters or pixels)
Parameters:
pos .... position (x,y)
sidelength ...... sidelength
other .. see [physics parameters]
Return: box2d.b2Body
"""
vertices = [(-sidelength, 0.0), (sidelength, 0.0), (0.0, 2*sidelength)]
return self.poly(pos, vertices, dynamic, density, restitution, friction, screenCoord)
def ball(self, pos, radius, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
""" Add a dynamic ball at pos after correcting the positions and legths to the internal
meter system if neccessary (if INPUT_PIXELS), then call self._add_ball(...)
Parameters:
pos ..... position (x,y)
radius .. circle radius
other ... see [physics parameters]
Return: box2d.b2Body
"""
# Bring coordinates into the world coordinate system (flip, camera offset, ...)
if screenCoord: x, y = self.parent.to_world(pos)
else: x, y = pos
if self.parent.input == INPUT_PIXELS:
x /= self.parent.ppm
y /= self.parent.ppm
radius /= self.parent.ppm
return self._ball((x,y), radius, dynamic, density, restitution, friction)
def _ball(self, pos, radius, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
# Add a ball without correcting any settings
# meaning, pos and vertices are in meters
# Define the body
x, y = pos
bodyDef = box2d.b2BodyDef()
bodyDef.position=(x, y)
userData = { 'color' : self.parent.get_color() }
bodyDef.userData = userData
# Create the Body
if not dynamic:
density = 0
body = self.parent.world.CreateBody(bodyDef)
self.parent.element_count += 1
# Add a shape to the Body
circleDef = box2d.b2CircleDef()
circleDef.density = density
circleDef.radius = radius
circleDef.restitution = restitution
circleDef.friction = friction
body.CreateShape(circleDef)
body.SetMassFromShapes()
return body
def rect(self, pos, width, height, angle=0, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
""" Add a dynamic rectangle with input unit according to self.input (INPUT_PIXELS or INPUT_METERS)
Correcting the positions to meters and calling self._add_rect()
Parameters:
pos ..... position (x,y)
width ....... horizontal line
height ....... vertical line
angle ........ in degrees (0 .. 360)
other ... see [physics parameters]
Return: box2d.b2Body
"""
# Bring coordinates into the world coordinate system (flip, camera offset, ...)
if screenCoord: x, y = self.parent.to_world(pos)
else: x, y = pos
# If required, translate pixel -> meters
if self.parent.input == INPUT_PIXELS:
x /= self.parent.ppm
y /= self.parent.ppm
width /= self.parent.ppm
height /= self.parent.ppm
# grad -> radians
angle = (angle * pi) / 180
return self._rect((x,y), width, height, angle, dynamic, density, restitution, friction)
def wall(self, pos1, pos2, width=5, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
""" Add a static rectangle between two arbitrary points with input unit according to self.input
(INPUT_PIXELS or INPUT_METERS) Correcting the positions to meters and calling self._add_rect()
Return: box2d.b2Body
"""
if width < 5: width = 5
if (pos1[0] < pos2[0]):
x1, y1 = pos1
x2, y2 = pos2
else:
x1, y1 = pos2
x2, y2 = pos1
# Bring coordinates into the world coordinate system (flip, camera offset, ...)
if screenCoord:
x1, y1 = self.parent.to_world((x1, y1))
x2, y2 = self.parent.to_world((x2, y2))
# If required, translate pixel -> meters
if self.parent.input == INPUT_PIXELS:
x1 /= self.parent.ppm
y1 /= self.parent.ppm
x2 /= self.parent.ppm
y2 /= self.parent.ppm
width /= self.parent.ppm
length = sqrt( (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) )*0.5
if width > 0:
halfX = x1 + (x2-x1)*0.5
halfY = y1 + (y2-y1)*0.5
angle = asin( (y2-halfY)/length )
return self._rect((halfX, halfY), length, width, angle, False, density, restitution, friction)
def _rect(self, pos, width, height, angle=0, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
# Add a rect without correcting any settings
# meaning, pos and vertices are in meters
# angle is now in radians ((degrees * pi) / 180))
x, y = pos
bodyDef = box2d.b2BodyDef()
bodyDef.position=(x, y)
userData = { 'color' : self.parent.get_color() }
bodyDef.userData = userData
# Create the Body
if not dynamic:
density = 0
body = self.parent.world.CreateBody(bodyDef)
self.parent.element_count += 1
# Add a shape to the Body
boxDef = box2d.b2PolygonDef()
boxDef.SetAsBox(width, height, (0,0), angle)
boxDef.density = density
boxDef.restitution = restitution
boxDef.friction = friction
body.CreateShape(boxDef)
body.SetMassFromShapes()
return body
def poly(self, pos, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
""" Add a dynamic polygon, which has the vertices arranged around the poly's center at pos
Correcting the positions to meters if INPUT_PIXELS, and calling self._add_poly()
Parameters:
pos ....... position (x,y)
vertices .. vertices arranged around the center
other ... see [physics parameters]
Return: box2d.b2Body
"""
# Bring coordinates into the world coordinate system (flip, camera offset, ...)
if screenCoord: x, y = self.parent.to_world(pos)
else: x, y = pos
# If required, translate pixel -> meters
if self.parent.input == INPUT_PIXELS:
# translate pixel -> meters
x /= self.parent.ppm
y /= self.parent.ppm
# Translate vertices from pixels to meters
v_new = []
for v in vertices:
vx, vy = v
v_new.append((vx/self.parent.ppm, vy/self.parent.ppm))
vertices = v_new
return self._poly((x,y), vertices, dynamic, density, restitution, friction)
def _poly(self, pos, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
# add a centered poly at pos without correcting any settings
# meaning, pos and vertices are in meters
x, y = pos
bodyDef = box2d.b2BodyDef()
bodyDef.position=(x, y)
userData = { 'color' : self.parent.get_color() }
bodyDef.userData = userData
# Create the Body
if not dynamic:
density = 0
body = self.parent.world.CreateBody(bodyDef)
self.parent.element_count += 1
# Add a shape to the Body
polyDef = box2d.b2PolygonDef()
polyDef.setVertices(vertices)
polyDef.density = density
polyDef.restitution = restitution
polyDef.friction = friction
body.CreateShape(polyDef)
body.SetMassFromShapes()
return body
def concavePoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
# 1. Step: Reduce
# Detect if the polygon is closed or open
if vertices[0] != vertices[-1]:
is_closed = False
else:
is_closed = True
# Continue reducing the vertecs
x, y = c = tools_poly.calc_center(vertices)
vertices = tools_poly.poly_center_vertices(vertices)
# Bring coordinates into the world coordinate system (flip, camera offset, ...)
if screenCoord: x, y = self.parent.to_world(c)
else: x, y = c
# If required, translate pixel -> meters
if self.parent.input == INPUT_PIXELS:
# translate pixel -> meters
x /= self.parent.ppm
y /= self.parent.ppm
# Let's add the body
bodyDef = box2d.b2BodyDef()
bodyDef.position=(x, y)
userData = { 'color' : self.parent.get_color() }
bodyDef.userData = userData
# Create the Body
if not dynamic:
density = 0
body = self.parent.world.CreateBody(bodyDef)
self.parent.element_count += 1
# Create the reusable Box2D polygon and circle definitions
polyDef = box2d.b2PolygonDef()
polyDef.vertexCount = 4 # rectangle
polyDef.density = density
polyDef.restitution = restitution
polyDef.friction = friction
circleDef = box2d.b2CircleDef()
circleDef.density = density
circleDef.radius = 0.086
circleDef.restitution = restitution
circleDef.friction = friction
# Set the scale factor
factor = 8.0
v2 = box2d.b2Vec2(*vertices[0])
for v in vertices[1:]:
v1 = v2.copy()
v2 = box2d.b2Vec2(*v)
vdir = v2-v1 # (v2x-v1x, v2y-v1y)
vdir.Normalize()
# we need a little size for the end part
vn = box2d.b2Vec2(-vdir.y*factor, vdir.x*factor)
v = [ v1+vn, v1-vn, v2-vn, v2+vn ]
# Create a line (rect) for each part of the polygon,
# and attach it to the body
polyDef.setVertices( [vi / self.parent.ppm for vi in v] )
try:
polyDef.checkValues()
except ValueError:
print "concavePoly: Created an invalid polygon!"
return None
body.CreateShape(polyDef)
# Now add a circle to the points between the rects
# to avoid sharp edges and gaps
if not is_closed and v2.tuple() == vertices[-1]:
# Don't add a circle at the end
break
circleDef.localPosition = v2 / self.parent.ppm
body.CreateShape(circleDef)
# Now, all shapes have been attached
body.SetMassFromShapes()
# Return hard and soft reduced vertices
return body
def complexPoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
# 1. Step: Reduce
# 2. Step: See if start and end are close, if so then close the polygon
# 3. Step: Detect if convex or concave
# 4. Step: Start self.convexPoly or self.concavePoly
vertices, is_convex = tools_poly.reduce_poly_by_angle(vertices)
#print "->", is_convex
# If start and endpoints are close to each other, close polygon
x1, y1 = vertices[0]
x2, y2 = vertices[-1]
dx = x2 - x1
dy = y2 - y1
l = sqrt((dx*dx)+(dy*dy))
if l < 50:
vertices[-1] = vertices[0]
else:
# Never convex if open (we decide so :)
is_convex = False
if tools_poly.is_line(vertices):
# Lines shall be drawn by self.concavePoly(...)
print "is line"
is_convex = False
if is_convex:
print "convex"
return self.convexPoly(vertices, dynamic, density, restitution, friction), vertices
else:
print "concave"
return self.concavePoly(vertices, dynamic, density, restitution, friction), vertices
def convexPoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
""" Add a complex polygon with vertices in absolute positions (meters or pixels, according
to INPUT_PIXELS or INPUT_METERS). This function does the reduction and convec hulling
of the poly, and calls add_poly(...)
Parameters:
vertices .. absolute vertices positions
other ..... see [physics parameters]
Return: box2d.b2Body
"""
# NOTE: Box2D has a maximum poly vertex count, defined in Common/box2d.b2Settings.h (box2d.b2_maxPolygonVertices)
# We need to make sure, that we reach that by reducing the poly with increased tolerance
# Reduce Polygon
tolerance = 10 #5
v_new = vertices
while len(v_new) > box2d.b2_maxPolygonVertices:
tolerance += 1
v_new = tools_poly.reduce_poly(vertices, tolerance)
print "convexPoly: Polygon reduced from %i to %i vertices | tolerance: %i" % (len(vertices), len(v_new), tolerance)
vertices = v_new
# So poly should be alright now
# Continue reducing the vertecs
vertices_orig_reduced = vertices
vertices = tools_poly.poly_center_vertices(vertices)
vertices = tools_poly.convex_hull(vertices)
if len(vertices) < 3:
return
# Define the body
x, y = c = tools_poly.calc_center(vertices_orig_reduced)
return self.poly((x,y), vertices, dynamic, density, restitution, friction)
def to_b2vec(self, pt):
# Convert vector to a b2vect
pt = self.parent.to_world(pt)
ptx, pty = pt
ptx /= self.parent.ppm
pty /= self.parent.ppm
pt = box2d.b2Vec2(ptx, pty)
return pt
def joint(self, *args):
print "* Add Joint:", args
if len(args) == 5:
# Tracking Joint
b1, b2, p1, p2, flag = args
p1 = self.to_b2vec(p1)
p2 = self.to_b2vec(p2)
jointDef = box2d.b2DistanceJointDef()
jointDef.Initialize(b1, b2, p1, p2)
jointDef.collideConnected = flag
self.parent.world.CreateJoint(jointDef)
elif len(args) == 4:
# Distance Joint
b1, b2, p1, p2 = args
p1 = self.to_b2vec(p1)
p2 = self.to_b2vec(p2)
jointDef = box2d.b2DistanceJointDef()
jointDef.Initialize(b1, b2, p1, p2)
jointDef.collideConnected = True
self.parent.world.CreateJoint(jointDef)
elif len(args) == 3:
# Revolute Joint between two bodies (unimplemented)
pass
elif len(args) == 2:
# Revolute Joint to the Background, at point
b1 = self.parent.world.GetGroundBody()
b2 = args[0]
p1 = self.to_b2vec(args[1])
jointDef = box2d.b2RevoluteJointDef()
jointDef.Initialize(b1, b2, p1)
self.parent.world.CreateJoint(jointDef)
elif len(args) == 1:
# Revolute Joint to the Background, body center
b1 = self.parent.world.GetGroundBody()
b2 = args[0]
p1 = b2.GetWorldCenter()
jointDef = box2d.b2RevoluteJointDef()
jointDef.Initialize(b1, b2, p1)
self.parent.world.CreateJoint(jointDef)
def motor(self, body, pt, torque=900, speed=-10):
# Revolute joint to the background with motor torque applied
b1 = self.parent.world.GetGroundBody()
pt = self.to_b2vec(pt)
jointDef = box2d.b2RevoluteJointDef()
jointDef.Initialize(b1, body, pt)
jointDef.maxMotorTorque = torque
jointDef.motorSpeed = speed
jointDef.enableMotor = True
self.parent.world.CreateJoint(jointDef)
def mouseJoint(self, body, pos, jointForce=100.0):
pos = self.parent.to_world(pos)
x, y = pos
x /= self.parent.ppm
y /= self.parent.ppm
mj = box2d.b2MouseJointDef()
mj.body1 = self.parent.world.GetGroundBody()
mj.body2 = body
mj.target = (x, y)
mj.maxForce = jointForce * body.GetMass()
if 'getAsType' in dir(box2d.b2Joint):
self.parent.mouseJoint = \
self.parent.world.CreateJoint(mj).getAsType()
else:
self.parent.mouseJoint = self.parent.world.CreateJoint(mj)
body.WakeUp()
def remove_mouseJoint(self):
if self.parent.mouseJoint:
self.parent.world.DestroyJoint(self.parent.mouseJoint)
self.parent.mouseJoint = None
|