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|
#!/usr/bin/env python
#Copyright (c) 2011 Walter Bender
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
import os
from math import pi, sin, cos, sqrt, atan2
from random import uniform
from gettext import gettext as _
from sugar.datastore import datastore
from sugar import profile
from plugins.plugin import Plugin
from TurtleArt.tapalette import make_palette
from TurtleArt.talogo import primitive_dictionary
from TurtleArt.tautils import debug_output, json_dump, get_path, round_int
import logging
_logger = logging.getLogger('turtleart-activity physics plugin')
THRESHOLD = 0.1 # default distance metric for hits
class Physics(Plugin):
SCALE_FACTOR = 10.
LINE_SCALE = 24.
TOOTH_SCALE = 10
TOOTH_ANGLE = 75 * pi / 180.
def __init__(self, parent):
self._tw = parent
self._status = True
self._scale = self.SCALE_FACTOR / self._tw.canvas.width
self._id = 1
self._density = 1.
self._friction = 0.5
self._bounce = 0.15
self._dynamic = True
self._polygon = []
self._dict = {'bodylist': [],
'jointlist': [],
'controllerlist': [],
'additional_vars': {}}
self._prim_box2d_reset()
self._gear_radius = 0
def setup(self):
# set up physics specific blocks
palette = make_palette('physics',
colors=['#50A000', '#60C020'],
help_string=_('Palette of physics blocks'))
primitive_dictionary['box2dcircle'] = self._prim_box2d_circle
primitive_dictionary['box2dtriangle'] = self._prim_box2d_triangle
primitive_dictionary['box2drectangle'] = self._prim_box2d_rectangle
primitive_dictionary['box2dgear'] = self._prim_box2d_gear
primitive_dictionary['box2dradius'] = self._prim_box2d_radius
primitive_dictionary['savebox2d'] = self._prim_save_box2d
primitive_dictionary['box2ddensity'] = self._prim_box2d_density
primitive_dictionary['box2dfriction'] = self._prim_box2d_friction
primitive_dictionary['box2dbounce'] = self._prim_box2d_bounce
primitive_dictionary['box2ddynamic'] = self._prim_box2d_dynamic
primitive_dictionary['box2dmotor'] = self._prim_box2d_motor
primitive_dictionary['box2dpin'] = self._prim_box2d_motor
primitive_dictionary['box2dreset'] = self._prim_box2d_reset
primitive_dictionary['box2djoint'] = self._prim_box2d_joint
primitive_dictionary['box2dstartpolygon'] = \
self._prim_box2d_start_polygon
primitive_dictionary['box2daddpoint'] = self._prim_box2d_add_point
primitive_dictionary['box2dendpolygon'] = self._prim_box2d_end_polygon
primitive_dictionary['box2dendfilledpolygon'] = \
self._prim_box2d_end_filled_polygon
palette.add_block('density',
style='basic-style-1arg',
label=_('density'),
default=100,
help_string=_('Set the density property for objects \
(density can be any positive number).'),
prim_name='box2ddensity')
self._tw.lc.def_prim(
'box2ddensity', 1,
lambda self, x: primitive_dictionary['box2ddensity'](x))
palette.add_block('friction',
style='basic-style-1arg',
label=_('friction'),
default=50,
help_string=_('Set the friction property for \
objects (value from 0 to 100, where 0 turns friction off and 100 is strong \
friction).'),
prim_name='box2dfriction')
self._tw.lc.def_prim(
'box2dfriction', 1,
lambda self, x: primitive_dictionary['box2dfriction'](x))
palette.add_block('bounce',
style='basic-style-1arg',
label=_('bounciness'),
default=15,
help_string=_('Set the bounciness property for \
objects (a value from 0 to 100, where 0 means no bounce and 100 is very \
bouncy).'),
prim_name='box2dbounce')
self._tw.lc.def_prim(
'box2dbounce', 1,
lambda self, x: primitive_dictionary['box2dbounce'](x))
palette.add_block('dynamic',
style='basic-style-1arg',
label=_('dynamic'),
hidden=True, # hide until we debug it
default=1,
help_string=_('If dynamic = 1, the object can move; \
if dynamic = 0, it is fixed in position.'),
prim_name='box2ddynamic')
self._tw.lc.def_prim(
'box2ddynamic', 1,
lambda self, x: primitive_dictionary['box2ddynamic'](x))
palette.add_block('startpolygon',
style='basic-style-extended-vertical',
label=_('start polygon'),
help_string=_('Begin defining a new polygon based \
on the current Turtle xy position.'),
prim_name='box2dstartpolygon')
self._tw.lc.def_prim(
'box2dstartpolygon', 0,
lambda self: primitive_dictionary['box2dstartpolygon']())
palette.add_block('addpoint',
style='basic-style-extended-vertical',
label=_('add point'),
help_string=_('Add a new point to the current \
polygon based on the current Turtle xy position.'),
prim_name='box2daddpoint')
self._tw.lc.def_prim(
'box2daddpoint', 0,
lambda self: primitive_dictionary['box2daddpoint']())
palette.add_block('endpolygon',
style='basic-style-extended-vertical',
label=_('end polygon'),
help_string=_('Define a new polygon.'),
prim_name='box2dendpolygon')
self._tw.lc.def_prim(
'box2dendpolygon', 0,
lambda self: primitive_dictionary['box2dendpolygon']())
palette.add_block('endfilledpolygon',
style='basic-style-extended-vertical',
label=_('end filled polygon'),
# hidden=True, # until it is debugged
help_string=_('Define a new flled polygon.'),
prim_name='box2dendfilledpolygon')
self._tw.lc.def_prim(
'box2dendfilledpolygon', 0,
lambda self: primitive_dictionary['box2dendfilledpolygon'](
triangulate=True))
palette.add_block('triangle',
style='basic-style-2arg',
label=[_('triangle'), _('base'), _('height')],
# make an equilateral triangle by default
default=[100, round_int(100 * sin(pi / 3))],
help_string=_('Add a triangle object to the \
project.'),
prim_name='box2dtriangle')
self._tw.lc.def_prim(
'box2dtriangle', 2,
lambda self, x, y: primitive_dictionary['box2dtriangle'](x, y))
palette.add_block('circle',
style='basic-style-1arg',
label=_('circle'),
default=100,
help_string=_('Add a circle object to the project.'),
prim_name='box2dcircle')
self._tw.lc.def_prim(
'box2dcircle', 1,
lambda self, x: primitive_dictionary['box2dcircle'](x))
palette.add_block('rectangle',
style='basic-style-2arg',
label=[_('rectangle'), _('width'), _('height')],
default=[100, 100],
help_string=_('Add a rectangle object to the \
project.'),
prim_name='box2drectangle')
self._tw.lc.def_prim(
'box2drectangle', 2,
lambda self, x, y: primitive_dictionary['box2drectangle'](x, y))
palette.add_block('gear',
style='basic-style-1arg',
label=_('gear'),
default=12,
help_string=_('Add a gear object to the project.'),
prim_name='box2dgear')
self._tw.lc.def_prim(
'box2dgear', 1,
lambda self, x: primitive_dictionary['box2dgear'](x))
palette.add_block('gearradius',
style='number-style-1arg',
label=_('gear radius'),
default=12,
help_string=_('Return the radius of a gear.'),
prim_name='box2dradius')
self._tw.lc.def_prim(
'box2dradius', 1,
lambda self, x: primitive_dictionary['box2dradius'](x))
palette.add_block('reset',
hidden=True,
style='basic-style-extended-vertical',
label=_('reset'),
help_string=_('Reset the project; clear the object \
list.'),
prim_name='box2dreset')
self._tw.lc.def_prim(
'box2dreset', 0,
lambda self: primitive_dictionary['box2dreset']())
palette.add_block('motor',
style='basic-style-2arg',
label=[_('motor'), _('torque'), _('speed')],
default=[900, -10],
help_string=_('Motor torque and speed range from 0 \
(off) to positive numbers; motor is placed on the most recent object \
created.'),
prim_name='box2dmotor')
self._tw.lc.def_prim(
'box2dmotor', 2,
lambda self, x, y: primitive_dictionary['box2dmotor'](x, y))
palette.add_block('pin',
style='basic-style-extended-vertical',
label=_('pin'),
help_string=_('Pin an object down so that it cannot \
fall.'),
prim_name='box2dpin')
self._tw.lc.def_prim(
'box2dpin', 0,
lambda self: primitive_dictionary['box2dmotor'](0, 0))
palette.add_block('joint',
style='basic-style-2arg',
label=[_('joint'), _('x'), _('y')],
default=[0, 0],
help_string=_('Join two objects together (the most \
recent object created and the object at point x, y).'),
prim_name='box2djoint')
self._tw.lc.def_prim(
'box2djoint', 2,
lambda self, x, y: primitive_dictionary['box2djoint'](x, y))
palette.add_block('savebox2d',
style='basic-style-1arg',
label=_('save as Physics activity'),
default='physics project',
help_string=_('Save the project to the Journal as \
a Physics activity.'),
prim_name='savebox2d')
self._tw.lc.def_prim(
'savebox2d', 1,
lambda self, x: primitive_dictionary['savebox2d'](x))
def _status_report(self):
''' Required method '''
debug_output('Reporting physics status: %s' % (str(self._status)))
return self._status
def clear(self):
''' Erase button pressed or clean block executed '''
self._prim_box2d_reset()
# Block primitives used in talogo
def _prim_box2d_reset(self):
''' Clear the body list '''
self._id = 1
self._density = 1.
self._friction = 0.5
self._bounce = 0.15
self._dynamic = True
self._polygon = []
self._dict['bodylist'] = []
self._dict['jointlist'] = []
# Always start with a ground plane
self._dict['bodylist'].append(
{'userData': {'color': [114, 114, 185], 'saveid': 1},
'linearVelocity': [0.0, 0.0],
'dynamic': False,
'angularVelocity': 0.0,
'shapes': [{'restitution': 0.15,
'type': 'polygon',
'vertices': [[-50.0, -0.1],
[50.0, -0.1],
[50.0, 0.1],
[-50.0, 0.1]],
'friction': 0.5,
'density': 0.0}],
'position': [-10.0, 0.0],
'angle': 0.0})
def _prim_box2d_density(self, density):
''' set the density to be used when creating box2d objects '''
try:
self._density = abs(float(density) / 100.)
except ValueError:
debug_output('bad argument to density: must be positive float',
self._tw.running_sugar)
self._density = 1.
def _prim_box2d_friction(self, friction):
''' set the friction to be used when creating box2d objects '''
try:
self._friction = abs(float(friction) / 100.)
if self._friction > 1:
self._friction == 1
debug_output('max friction value is 100',
self._tw.running_sugar)
except ValueError:
debug_output('bad argument to friction: must be positive float',
self._tw.running_sugar)
self._friction = 0.5
def _prim_box2d_bounce(self, bounce):
''' set the bounce to be used when creating box2d objects '''
try:
self._bounce = abs(float(bounce) / 100.)
if self._bounce > 1.:
self._bounce == 1.
debug_output('max bounce value is 100',
self._tw.running_sugar)
except ValueError:
debug_output('bad argument to bounce: must be a positive float',
self._tw.running_sugar)
self._bounce = 0.5
def _prim_box2d_dynamic(self, value):
''' set the dynamic flag to be used when creating box2d objects '''
if str(value).lower() in [_('false'), _('no'), '0']:
self._dynamic = False
else:
self._dynamic = True
def _prim_box2d_start_polygon(self):
''' start of a collection of points to create a polygon '''
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
self._polygon = [(x + self._tw.canvas.width / 2.,
y + self._tw.canvas.height / 2.)]
def _prim_box2d_add_point(self):
''' add an point to a collection of points to create a polygon '''
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
if self._polygon == []:
self._polygon.append((x, y))
elif not (x == self._polygon[-1][0] and y == self._polygon[-1][1]):
self._polygon.append((x, y))
def _prim_box2d_end_polygon(self):
''' add a polygon object to box2d dictionary '''
if not self._status:
return
if self._polygon == []:
return
else:
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
# Only append the last point if it is not redundant
if not self._near((x, y), (self._polygon[-1])):
self._polygon.append((x, y))
# Box2d chokes on polygons with just 1 point
if len(self._polygon) == 1:
return
# The overall position will be relative to the first point
xpos = self._polygon[0][0] * self._scale
ypos = self._polygon[0][1] * self._scale
# Create the Physics object...
self._id += 1
self._dict['bodylist'].append(
{'userData': {'color': self._get_rgb(),
'saveid': self._id},
'linearVelocity': [0.0, 0.0],
'dynamic': self._dynamic,
'angularVelocity': 0.0,
'shapes': [],
'position': [xpos, ypos],
'angle': 0.0})
for i, p in enumerate(self._polygon):
if i == 0:
p0 = p[:]
continue
p1 = p[:]
self._dict['bodylist'][-1]['shapes'].append(
{'density': self._density,
'friction': self._friction,
'type': 'polygon',
'vertices': [],
'restitution': self._bounce})
a = atan2(p0[1] - p1[1], p0[0] - p1[0])
dx = sin(a) / self.LINE_SCALE
dy = -cos(a) / self.LINE_SCALE
poly = [[p0[0] * self._scale + dx - xpos,
p0[1] * self._scale + dy - ypos],
[p1[0] * self._scale + dx - xpos,
p1[1] * self._scale + dy - ypos],
[p1[0] * self._scale - dx - xpos,
p1[1] * self._scale - dy - ypos],
[p0[0] * self._scale - dx - xpos,
p0[1] * self._scale - dy - ypos]]
# Make sure points are counter-clockwise
if self._cross_product_area(poly) < 0:
poly = self._reverse_order(poly)[:]
self._dict['bodylist'][-1]['shapes'][-1][
'vertices'].append(poly[0])
self._dict['bodylist'][-1]['shapes'][-1][
'vertices'].append(poly[1])
self._dict['bodylist'][-1]['shapes'][-1][
'vertices'].append(poly[2])
self._dict['bodylist'][-1]['shapes'][-1][
'vertices'].append(poly[3])
if not (i + 1) == len(self._polygon):
self._dict['bodylist'][-1]['shapes'].append(
{'localPosition': [p1[0] * self._scale - xpos,
p1[1] * self._scale - ypos],
'density': self._density,
'friction': self._friction,
'radius': 1. / self.LINE_SCALE,
'type': 'circle',
'restitution': self._bounce})
p0 = p1[:]
# ... and draw the polygon on the Turtle canvas
self._tw.canvas.set_source_rgb()
self._tw.canvas.canvas.set_line_width(1.)
for s in self._dict['bodylist'][-1]['shapes']:
if s['type'] == 'polygon':
self._tw.canvas.canvas.new_path()
for i, p in enumerate(s['vertices']):
x, y = self._tw.turtles.turtle_to_screen_coordinates(
((p[0] + xpos) / self._scale - \
self._tw.canvas.width / 2.,
(p[1] + ypos) / self._scale - \
self._tw.canvas.height / 2.))
if i == 0:
self._tw.canvas.canvas.move_to(x, y)
else:
self._tw.canvas.canvas.line_to(x, y)
self._tw.canvas.canvas.close_path()
self._tw.canvas.canvas.fill()
elif s['type'] == 'circle':
x, y = self._tw.turtles.turtle_to_screen_coordinates(
((s['localPosition'][0] + xpos) / self._scale - \
self._tw.canvas.width / 2.,
(s['localPosition'][1] + ypos) / self._scale - \
self._tw.canvas.height / 2.))
self._tw.canvas.canvas.set_line_width(2. / (
self.LINE_SCALE * self._scale))
self._tw.canvas.canvas.move_to(x, y)
self._tw.canvas.canvas.line_to(x + 1, y + 1)
self._tw.canvas.canvas.stroke()
self._tw.canvas.canvas.set_line_width(
self._tw.turtles.get_active_turtle().get_pen_size())
self._tw.canvas.inval()
self._polygon = []
def _prim_box2d_end_filled_polygon(self, triangulate=False):
''' add a filled-polygon object to box2d dictionary '''
if not self._status:
return
if self._polygon == []:
return
else:
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
# Make sure there are no points too near each other
poly = []
p1 = self._polygon[-1]
for p2 in self._polygon:
if not self._near(p1, p2):
poly.append(p2)
p1 = p2[:]
self._polygon = poly[:]
if len(self._polygon) < 3:
return
# Physics requires polygons to be ordered counter clockwise
if self._cross_product_area(self._polygon) < 0:
self._polygon = self._reverse_order(self._polygon)[:]
# Divide the polygon into triangles
if triangulate:
triangles = self._triangulate(self._polygon)
if triangles is None:
debug_output(_('Not a simple polygon'),
self._tw.running_sugar)
self._tw.showlabel('syntaxerror',
_('Not a simple polygon'))
return
# Create the Physics object...
xpos = self._polygon[0][0] * self._scale
ypos = self._polygon[0][1] * self._scale
self._id += 1
self._dict['bodylist'].append(
{'userData': {'color': self._get_rgb(),
'saveid': self._id},
'linearVelocity': [0.0, 0.0],
'dynamic': self._dynamic,
'angularVelocity': 0.0,
'shapes': [],
'position': [xpos, ypos],
'angle': 0.0})
if triangulate:
for triangle in triangles:
self._add_shape(triangle, xpos, ypos)
else:
self._add_shape(self._polygon, xpos, ypos)
# ...and draw it on the Turtle canvas
self._tw.canvas.set_source_rgb()
self._tw.canvas.canvas.set_line_width(1.)
if triangulate:
for triangle in triangles:
# Make each triangle distinct in the TA rendering
self._randomize_color()
self._draw_polygon(triangle)
# Restore canvas color
self._tw.canvas.set_source_rgb()
else:
self._draw_polygon(self._polygon)
self._tw.canvas.canvas.set_line_width(
self._tw.turtles.get_active_turtle().get_pen_size())
self._tw.canvas.inval()
self._polygon = []
def _bounds_check(self, value):
''' Make sure value is between 0 and 1 '''
if value < 0.:
value = 0.
elif value > 1.:
value = 1
return value
def _randomize_color(self):
''' Add a bit of noise to the turtle color '''
dr = uniform(-10, 10) / 100.
dg = uniform(-10, 10) / 100.
db = uniform(-10, 10) / 100.
rgb = self._get_rgb()
self._tw.canvas.canvas.set_source_rgb(
self._bounds_check((rgb[0] / 255.) + dr),
self._bounds_check((rgb[1] / 255.) + dg),
self._bounds_check((rgb[2] / 255.) + db))
def _draw_polygon(self, polygon):
''' Draw a polygon on the turtle canvas '''
self._tw.canvas.canvas.new_path()
for i, p in enumerate(polygon):
x, y = self._tw.turtles.turtle_to_screen_coordinates(
(p[0] - self._tw.canvas.width / 2.,
p[1] - self._tw.canvas.height / 2.))
if i == 0:
self._tw.canvas.canvas.move_to(x, y)
else:
self._tw.canvas.canvas.line_to(x, y)
self._tw.canvas.canvas.close_path()
self._tw.canvas.canvas.fill()
def _add_shape(self, polygon, xpos, ypos):
''' Add a polygon to the shape list '''
self._dict['bodylist'][-1]['shapes'].append(
{'density': self._density,
'friction': self._friction,
'type': 'polygon',
'vertices': [],
'restitution': self._bounce})
for i, p in enumerate(polygon):
self._dict['bodylist'][-1]['shapes'][-1][
'vertices'].append([p[0] * self._scale - xpos,
p[1] * self._scale - ypos])
def _prim_box2d_triangle(self, base, height):
''' add a triangle object to box2d dictionary '''
try:
float(base)
float(height)
except ValueError:
debug_output(
'bad argument to triangle: base, height must be float',
self._tw.running_sugar)
self._polygon = []
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
self._polygon.append([x - base / 2., y - height / 2.])
self._polygon.append([x, y + height / 2.])
self._polygon.append([x + base / 2., y - height / 2.])
h = self._tw.turtles.get_active_turtle().get_heading()
if h != 0:
self._rotate_polygon(x, y, h * pi / 180.)
self._prim_box2d_end_filled_polygon()
def _prim_box2d_rectangle(self, width, height):
''' add a rectangle object to box2d dictionary '''
try:
float(width)
float(height)
except ValueError:
debug_output(
'bad argument to rectangle: width, height must be float',
self._tw.running_sugar)
self._polygon = []
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
self._polygon.append([x - width / 2., y - height / 2.])
self._polygon.append([x + width / 2., y - height / 2.])
self._polygon.append([x + width / 2., y + height / 2.])
self._polygon.append([x - width / 2., y + height / 2.])
h = self._tw.turtles.get_active_turtle().get_heading()
if h != 0:
self._rotate_polygon(x, y, h * pi / 180.)
self._prim_box2d_end_filled_polygon()
def _prim_box2d_radius(self, tooth_count):
''' calculate gear radius '''
try:
if abs(int(tooth_count)) < 2:
raise ValueError
except ValueError:
debug_output('bad argument to gear: tooth count must be int > 1',
self._tw.running_sugar)
points = self._gear(int(tooth_count))
max_x = 0
for p in points:
max_x = max(p[0], max_x)
radius = int(max(0, max_x - self.TOOTH_SCALE / 4.))
return radius
def _prim_box2d_gear(self, tooth_count):
''' add a gear object to box2d dictionary '''
try:
if abs(int(tooth_count)) < 2:
raise ValueError
except ValueError:
debug_output('bad argument to gear: tooth count must be int > 1',
self._tw.running_sugar)
self._polygon = []
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
points = self._gear(int(tooth_count))
for p in points:
self._polygon.append([x + p[0], y + p[1]])
h = self._tw.turtles.get_active_turtle().get_heading()
if h != 0:
self._rotate_polygon(x, y, h * pi / 180.)
self._prim_box2d_end_filled_polygon(triangulate=True)
def _prim_box2d_circle(self, radius):
''' add a circle object to box2d dictionary '''
try:
float(radius)
except ValueError:
debug_output('bad argument to circle: radius must be float',
self._tw.running_sugar)
# Create the Physics object...
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
self._id += 1
self._dict['bodylist'].append(
{'userData': {'color': self._get_rgb(),
'saveid': self._id},
'linearVelocity': [0.0, 0.0],
'dynamic': self._dynamic,
'angularVelocity': 0.0,
'shapes': [{'localPosition': [0, 0],
'density': self._density,
'friction': self._friction,
'radius': radius * self._scale / 2.,
'type': 'circle',
'restitution': self._bounce}],
'position': [x * self._scale, y * self._scale],
'angle': 0.0})
# ...and draw it on the Turtle canvas
x, y = self._tw.turtles.turtle_to_screen_coordinates(
self._tw.turtles.get_active_turtle().get_xy())
self._tw.canvas.set_source_rgb()
self._tw.canvas.canvas.set_line_width(radius)
self._tw.canvas.canvas.move_to(x, y)
self._tw.canvas.canvas.line_to(x + 1, y + 1)
self._tw.canvas.canvas.stroke()
self._tw.canvas.canvas.set_line_width(
self._tw.turtles.get_active_turtle().get_pen_size())
self._tw.canvas.inval()
def _prim_box2d_motor(self, torque, speed):
''' add a motor to an object to box2d dictionary '''
try:
float(torque)
float(speed)
except ValueError:
debug_output('bad argument to motor: torque, speed must be float',
self._tw.running_sugar)
# Create the Physics object...
x = self._tw.turtles.get_active_turtle().get_x()
y = self._tw.turtles.get_active_turtle().get_y()
x += self._tw.canvas.width / 2.
y += self._tw.canvas.height / 2.
self._dict['jointlist'].append(
{'userData': None,
'collideConnected': False,
'maxMotorTorque': torque,
'motorSpeed': speed,
'body1': 0,
# Assume that the motor is attached to the most recent object
'body2': self._id,
'type': 'revolute',
'anchor': [x * self._scale, y * self._scale],
'enableMotor': False})
if speed != 0:
self._dict['jointlist'][-1]['enableMotor'] = True
# To do: search for body to attach to...
id = self._search((x * self._scale, y * self._scale))
if id is not None:
# debug_output('found a match for motor body2 (%d)' % (id),
# self._tw.running_sugar)
self._dict['jointlist'][-1]['body2']
# ...and draw it on the Turtle canvas
x, y = self._tw.turtles.turtle_to_screen_coordinates(
self._tw.turtles.get_active_turtle().get_xy())
if speed == 0:
self._tw.canvas.canvas.set_source_rgb(0., 0., 0.)
else:
self._tw.canvas.canvas.set_source_rgb(1., 1., 1.)
self._tw.canvas.canvas.set_line_width(3.)
self._tw.canvas.canvas.move_to(x, y)
self._tw.canvas.canvas.line_to(x + 1, y + 1)
self._tw.canvas.canvas.stroke()
self._tw.canvas.canvas.set_line_width(
self._tw.turtles.get_active_turtle().get_pen_size())
self._tw.canvas.inval()
def _prim_box2d_joint(self, x, y):
''' add a joint between two objects '''
try:
float(x)
float(y)
except ValueError:
debug_output('bad argument to joint: x, y must be float',
self._tw.running_sugar)
# Create the Physics object...
x1 = x + self._tw.canvas.width / 2.
y1 = y + self._tw.canvas.height / 2.
x2 = self._tw.turtles.get_active_turtle().get_x() + \
self._tw.canvas.width / 2.
y2 = self._tw.turtles.get_active_turtle().get_y() + \
self._tw.canvas.height / 2.
self._dict['jointlist'].append(
{'userData': None,
'anchor2': [x1 * self._scale, y1 * self._scale],
'anchor1': [x2 * self._scale, y2 * self._scale],
'collideConnected': True,
'body1': self._id, # A reasonable default?
'body2': 2, # Assume most recent?
'type': 'distance'})
# Search for the body to attach to...
id = self._search((x1 * self._scale, y1 * self._scale))
if id is not None:
# debug_output('found a match for joint body2 (%d)' % (id),
# self._tw.running_sugar)
self._dict['jointlist'][-1]['body2'] = id
id = self._search((x2 * self._scale, y2 * self._scale))
if id is not None:
# debug_output('found a match for joint body1 (%d)' % (id),
# self._tw.running_sugar)
self._dict['jointlist'][-1]['body1'] = id
# ...and draw it on the Turtle canvas
x1, y1 = self._tw.turtles.turtle_to_screen_coordinates((x, y))
x2, y2 = self._tw.turtles.turtle_to_screen_coordinates(
self._tw.turtles.get_active_turtle().get_xy())
self._tw.canvas.canvas.set_source_rgb(0., 0., 0.)
self._tw.canvas.canvas.set_line_width(3.)
self._tw.canvas.canvas.move_to(x1, y1)
self._tw.canvas.canvas.line_to(x2, y2)
self._tw.canvas.canvas.stroke()
self._tw.canvas.canvas.set_line_width(
self._tw.turtles.get_active_turtle().get_pen_size())
self._tw.canvas.inval()
def _prim_save_box2d(self, name):
''' Save bodylist to a Physics project '''
data = json_dump(self._dict)
if not self._tw.running_sugar:
print data
else:
data_path = get_path(self._tw.activity, 'instance')
tmp_file = os.path.join(data_path, 'tmpfile')
fd = open(tmp_file, 'w')
fd.write(data)
fd.close()
dsobject = datastore.create()
dsobject.metadata['title'] = name
dsobject.metadata['icon-color'] = profile.get_color().to_string()
dsobject.metadata['mime_type'] = 'application/x-physics-activity'
dsobject.metadata['activity'] = 'org.laptop.physics'
dsobject.set_file_path(tmp_file)
datastore.write(dsobject)
dsobject.destroy()
os.remove(tmp_file)
def _cross_product_area(self, polygon):
''' Cross-product area is positive for counter-clockwise polygons '''
a = 0.
for i in range(len(polygon)):
if (i + 1) < len(polygon):
a += (polygon[i][0] * polygon[i + 1][1]) - \
(polygon[i + 1][0] * polygon[i][1])
else:
a += (polygon[i][0] * polygon[0][1]) - \
(polygon[0][0] * polygon[i][1])
return a / 2.
def _reverse_order(self, polygon):
''' Turn a clockwise polygon into a counter-clockwise polygon '''
n = len(polygon)
for i in range(n / 2):
tmp = polygon[i][:]
polygon[i] = polygon[n - 1 - i][:]
polygon[n - 1 - i] = tmp[:]
return polygon
def _rotate_polygon(self, cx, cy, angle):
''' Rotate the polygon points around cx,cy '''
for p in self._polygon:
h = sqrt((cx - p[0]) * (cx - p[0]) + (cy - p[1]) * (cy - p[1]))
a = atan2(cx - p[0], cy - p[1])
p[0] = cx + h * cos(a + angle)
p[1] = cy + h * sin(a + angle)
def _near(self, p1, p2, threshold=THRESHOLD):
''' Is point 1 near point 2? '''
if sqrt((p1[0] - p2[0]) * (p1[0] - p2[0]) + \
(p1[1] - p2[1]) * (p1[1] - p2[1])) < threshold:
return True
return False
def _search(self, point):
''' Return object id of object under point '''
n = len(self._dict['bodylist'])
for i in range(n):
j = n - i - 1 # search in reverse order
if self._hit(self._dict['bodylist'][j]['shapes'],
self._dict['bodylist'][j]['position'], point):
return self._dict['bodylist'][j]['userData']['saveid']
return None
def _hit(self, shapes, position, point):
''' Is xy in shape? '''
for s in shapes:
if s['type'] == 'circle':
if self._near((s['localPosition'][0] + position[0],
s['localPosition'][1] + position[1]),
point, threshold=s['radius']):
return True
else: # polygon
if self._point_in_polygon((point[0] - position[0],
point[1] - position[1]),
s['vertices']):
return True
return False
def _point_in_polygon(self, point, polygon):
'''Ray-casting method of determing if point is in polygon '''
inside = False
p1x, p1y = polygon[0]
for i in range(len(polygon) + 1):
p2x, p2y = polygon[i % len(polygon)]
if point[1] > min(p1y, p2y):
if point[1] <= max(p1y, p2y):
if point[0] <= max(p1x, p2x):
if p1y != p2y:
xinters = (point[1] - p1y) * (p2x - p1x) \
/ (p2y - p1y) + p1x
if p1x == p2x or point[0] <= xinters:
inside = not inside
p1x, p1y = p2x, p2y
return inside
def _point_in_triangle(self, triangle, point):
''' Is the point in the triangle? '''
return \
self._cross_product_area(
(triangle[0], triangle[1], point)) >= 0 and \
self._cross_product_area(
(triangle[1], triangle[2], point)) >= 0 and \
self._cross_product_area(
(triangle[2], triangle[0], point)) >= 0
def _triangulate(self, polygon):
''' Convert a polygon into triangles '''
# Variation of an ear-cutting algorithm
# Based on an algorithm by Gregor Lingl on python.org
triangles = []
while len(polygon) > 2:
found_a_triangle = False
count = 0
while not found_a_triangle and count < len(polygon):
count += 1
triangle = polygon[:3]
if self._cross_product_area(triangle) >= 0:
for point in polygon[3:]:
if self._point_in_triangle(triangle, point):
break
else:
triangles.append(triangle)
polygon.remove(triangle[1])
found_a_triangle = True
polygon.append(polygon.pop(0))
if count == len(polygon):
return None
return triangles
def _gear(self, tooth_count):
''' Draw a gear '''
points = []
x = 0
y = 0
heading = 0
for i in range(tooth_count):
tooth, heading = self._gear_tooth(x, y, heading)
for p in tooth:
points.append(p)
x, y = tooth[-1][0], tooth[-1][1]
heading -= 2. * pi / tooth_count
minx = 1000
miny = 1000
maxx = -1000
maxy = -1000
for p in points:
if p[0] < minx:
minx = p[0]
if p[0] > maxx:
maxx = p[0]
if p[1] < miny:
miny = p[1]
if p[1] > maxy:
maxy = p[1]
# Recenter on 0, 0
cx = (maxx + minx) / 2.
cy = (maxy + miny) / 2.
for p in points:
p[0] -= cx
p[1] -= cy
return points
def _gear_tooth(self, x, y, heading):
''' Draw one tooth of a gear '''
points = []
half = self.TOOTH_SCALE / 2.
top = 1.5 * self.TOOTH_SCALE - \
(cos(self.TOOTH_ANGLE) * self.TOOTH_SCALE * 2.)
points.append([half * cos(heading) + x,
half * sin(heading) + y])
heading += self.TOOTH_ANGLE
points.append([self.TOOTH_SCALE * cos(heading) + points[0][0],
self.TOOTH_SCALE * sin(heading) + points[0][1]])
heading -= self.TOOTH_ANGLE
points.append([top * cos(heading) + points[1][0],
top * sin(heading) + points[1][1]])
heading -= self.TOOTH_ANGLE
points.append([self.TOOTH_SCALE * cos(heading) + points[2][0],
self.TOOTH_SCALE * sin(heading) + points[2][1]])
heading += self.TOOTH_ANGLE
points.append([half * cos(heading) + points[3][0],
half * sin(heading) + points[3][1]])
return points, heading
def _get_rgb(self):
''' For backward compatibility '''
if hasattr(self._tw.canvas, 'get_rgb'):
return self._tw.canvas.get_rgb()
else:
return self._tw.canvas._fgrgb
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