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#
# Code under the MIT license by Alexander Pruss
#
# L-system with turtle graphics
#
import collections
import random
import mcpi.settings
from mcturtle import *
def playProgram(s, dictionary):
for c in s:
if c in dictionary:
dictionary[c]()
def transform(c, t):
if isinstance(t, basestring):
return t
else:
r = random.random()
for p,out in t:
if r<p:
return out
r -= p
return c
def evolveGenerator(axiom,rules):
for c in axiom:
if c in rules:
yield transform(c, rules[c])
else:
yield c
def evolve(axiom, rules, levelCount):
for i in range(levelCount):
axiom = ''.join(evolveGenerator(axiom,rules))
return axiom
def lsystem(axiom, rules, dictionary, levelCount):
out = evolve(axiom, rules, levelCount)
playProgram(out, dictionary)
if __name__ == "__main__":
t = Turtle()
t.pendelay(0)
t.penup()
t.turtle(None)
t.go(10)
t.verticalangle(90)
t.pendown()
t.penblock(WOOD)
# a fairly simple example with rules from http://www.nbb.cornell.edu/neurobio/land/OldStudentProjects/cs490-94to95/hwchen/
# rules = {'F':'F[-&<F][<++&F]||F[--&>F][+&F]'}
#
# angle = 22.5
#
# dictionary = {
# '[': t.push,
# ']': t.pop,
# 'F': lambda: t.go(5),
# '-': lambda: t.yaw(-angle),
# '+': lambda: t.yaw(angle),
# '&': lambda: t.pitch(angle),
# '^': lambda: t.pitch(-angle),
# '<': lambda: t.roll(-angle),
# '>': lambda: t.roll(angle),
# '|': lambda: t.pitch(180)
# }
#
# lsystem('F', rules, dictionary, 3)
#
# A more complex example with
# rules based on http://www.geekyblogger.com/2008/04/tree-and-l-system.html
#
rules = {'A': '^f[^^f>>>>>>A]>>>[^^f>>>>>>A]>>>>>[^^f>>>>>>A]'}
#randomized version:
# rules = {'A': [(0.75,'^f[^^f>>>>>>A]>>>[^^f>>>>>>A]>>>>>[^^f>>>>>>A]'),
# (0.25,'^f>>[^^f>>>>>>A]>>>[^^f>>>>>>A]')]}
axiom = 'fA'
angle = 15
thickness = 8
length = 10 if mcpi.settings.isPE else 15;
material = WOOD
t.penwidth(thickness)
t.penblock(material)
stack = []
def push():
global length
global thickness
stack.append((length,thickness))
t.push()
thickness = thickness * 0.6
length = length * 0.75
if thickness < 1:
thickness = 1
if length <= 1:
t.penblock(LEAVES_OAK_PERMANENT)
t.penwidth(thickness)
def pop():
global length
global thickness
length,thickness = stack.pop()
t.pop()
dictionary = {
'[': push,
']': pop,
'^': lambda: t.pitch(angle),
'>': lambda: t.roll(angle),
'f': lambda: t.go(length)
}
lsystem(axiom, rules, dictionary, 9 if mcpi.settings.isPE else 11)
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