3b1b-manim/topics/fractals.py
2017-01-05 11:57:30 -08:00

383 lines
10 KiB
Python

# from mobject import Mobject, Point, Mobject1D
from mobject.vectorized_mobject import VMobject, VGroup, VectorizedPoint
from scene import Scene
from animation.transform import Transform
from animation.simple_animations import ShowCreation
from topics.geometry import Line
from helpers import *
def rotate(points, angle = np.pi, axis = OUT):
if axis is None:
return points
matrix = rotation_matrix(angle, axis)
points = np.dot(points, np.transpose(matrix))
return points
class SpaceFillingCurve(VMobject):
CONFIG = {
"radius" : 3,
"order" : 5,
"colors" : [RED, GREEN],
}
def generate_points(self):
points = self.get_anchor_points()
for triplet in zip(points, points[1:], points[2:]):
corner = VMobject()
corner.set_points_as_corners(triplet)
self.add(corner)
self.gradient_highlight(*self.colors)
def get_anchor_points(self):
raise Exception("Not implemented")
class LindenmayerCurve(SpaceFillingCurve):
CONFIG = {
"axiom" : "A",
"rule" : {},
"scale_factor" : 2,
"radius" : 3,
"start_step" : RIGHT,
"angle" : np.pi/2,
}
def expand_command_string(self, command):
result = ""
for letter in command:
if letter in self.rule:
result += self.rule[letter]
else:
result += letter
return result
def get_command_string(self):
result = self.axiom
for x in range(self.order):
result = self.expand_command_string(result)
return result
def get_anchor_points(self):
step = float(self.radius) * self.start_step
step /= (self.scale_factor**self.order)
curr = np.zeros(3)
result = [curr]
for letter in self.get_command_string():
if letter is "+":
step = rotate(step, self.angle)
elif letter is "-":
step = rotate(step, -self.angle)
else:
curr = curr + step
result.append(curr)
return np.array(result) - center_of_mass(result)
class SelfSimilarSpaceFillingCurve(SpaceFillingCurve):
CONFIG = {
"offsets" : [],
#keys must awkwardly be in string form...
"offset_to_rotation_axis" : {},
"scale_factor" : 2,
"radius_scale_factor" : 0.5,
}
def transform(self, points, offset):
"""
How to transform the copy of points shifted by
offset. Generally meant to be extended in subclasses
"""
copy = np.array(points)
if str(offset) in self.offset_to_rotation_axis:
copy = rotate(
copy,
axis = self.offset_to_rotation_axis[str(offset)]
)
copy /= self.scale_factor,
copy += offset*self.radius*self.radius_scale_factor
return copy
def refine_into_subparts(self, points):
transformed_copies = [
self.transform(points, offset)
for offset in self.offsets
]
return reduce(
lambda a, b : np.append(a, b, axis = 0),
transformed_copies
)
def get_anchor_points(self):
points = np.zeros((1, 3))
for count in range(self.order):
points = self.refine_into_subparts(points)
return points
def generate_grid(self):
raise Exception("Not implemented")
class HilbertCurve(SelfSimilarSpaceFillingCurve):
CONFIG = {
"offsets" : [
LEFT+DOWN,
LEFT+UP,
RIGHT+UP,
RIGHT+DOWN,
],
"offset_to_rotation_axis" : {
str(LEFT+DOWN) : RIGHT+UP,
str(RIGHT+DOWN) : RIGHT+DOWN,
},
}
class HilbertCurve3D(SelfSimilarSpaceFillingCurve):
CONFIG = {
"offsets" : [
LEFT+DOWN+OUT,
LEFT+UP+OUT,
LEFT+UP+IN,
LEFT+DOWN+IN,
RIGHT+DOWN+IN,
RIGHT+UP+IN,
RIGHT+UP+OUT,
RIGHT+DOWN+OUT,
],
"offset_to_rotation_axis" : {}#TODO
}
class PeanoCurve(SelfSimilarSpaceFillingCurve):
CONFIG = {
"colors" : [PURPLE, TEAL],
"offsets" : [
LEFT+DOWN,
LEFT,
LEFT+UP,
UP,
ORIGIN,
DOWN,
RIGHT+DOWN,
RIGHT,
RIGHT+UP,
],
"offset_to_rotation_axis" : {
str(LEFT) : UP,
str(UP) : RIGHT,
str(ORIGIN) : LEFT+UP,
str(DOWN) : RIGHT,
str(RIGHT) : UP,
},
"scale_factor" : 3,
"radius_scale_factor" : 2.0/3,
}
class TriangleFillingCurve(SelfSimilarSpaceFillingCurve):
CONFIG = {
"colors" : [MAROON, YELLOW],
"offsets" : [
LEFT/4.+DOWN/6.,
ORIGIN,
RIGHT/4.+DOWN/6.,
UP/3.,
],
"offset_to_rotation_axis" : {
str(ORIGIN): RIGHT,
str(UP/3.) : UP,
},
"scale_factor" : 2,
"radius_scale_factor" : 1.5,
}
# class HexagonFillingCurve(SelfSimilarSpaceFillingCurve):
# CONFIG = {
# "start_color" : WHITE,
# "end_color" : BLUE_D,
# "axis_offset_pairs" : [
# (None, 1.5*DOWN + 0.5*np.sqrt(3)*LEFT),
# (UP+np.sqrt(3)*RIGHT, 1.5*DOWN + 0.5*np.sqrt(3)*RIGHT),
# (np.sqrt(3)*UP+RIGHT, ORIGIN),
# ((UP, RIGHT), np.sqrt(3)*LEFT),
# (None, 1.5*UP + 0.5*np.sqrt(3)*LEFT),
# (None, 1.5*UP + 0.5*np.sqrt(3)*RIGHT),
# (RIGHT, np.sqrt(3)*RIGHT),
# ],
# "scale_factor" : 3,
# "radius_scale_factor" : 2/(3*np.sqrt(3)),
# }
# def refine_into_subparts(self, points):
# return SelfSimilarSpaceFillingCurve.refine_into_subparts(
# self,
# rotate(points, np.pi/6, IN)
# )
class UtahFillingCurve(SelfSimilarSpaceFillingCurve):
CONFIG = {
"colors" : [WHITE, BLUE_D],
"axis_offset_pairs" : [
],
"scale_factor" : 3,
"radius_scale_factor" : 2/(3*np.sqrt(3)),
}
class FlowSnake(LindenmayerCurve):
CONFIG = {
"colors" : [YELLOW, GREEN],
"axiom" : "A",
"rule" : {
"A" : "A-B--B+A++AA+B-",
"B" : "+A-BB--B-A++A+B",
},
"radius" : 6, #TODO, this is innaccurate
"scale_factor" : np.sqrt(7),
"start_step" : RIGHT,
"angle" : -np.pi/3,
}
def __init__(self, **kwargs):
LindenmayerCurve.__init__(self, **kwargs)
self.rotate(-self.order*np.pi/9)
class Sierpinski(LindenmayerCurve):
CONFIG = {
"start_color" : RED,
"end_color" : WHITE,
"axiom" : "A",
"rule" : {
"A" : "+B-A-B+",
"B" : "-A+B+A-",
},
"radius" : 6, #TODO, this is innaccurate
"scale_factor" : 2,
"start_step" : RIGHT,
"angle" : -np.pi/3,
}
class KochCurve(LindenmayerCurve):
CONFIG = {
"start_color" : BLUE_D,
"end_color" : WHITE,
"axiom" : "A--A--A--",
"rule" : {
"A" : "A+A--A+A"
},
"radius" : 4,
"scale_factor" : 3,
"start_step" : RIGHT,
"angle" : np.pi/3
}
def __init__(self, **kwargs):
digest_config(self, kwargs)
self.scale_factor = 2*(1+np.cos(self.angle))
LindenmayerCurve.__init__(self, **kwargs)
class StellarCurve(LindenmayerCurve):
CONFIG = {
"start_color" : RED,
"end_color" : BLUE_E,
"rule" : {
"A" : "+B-A-B+A-B+",
"B" : "-A+B+A-B+A-",
},
"scale_factor" : 3,
"angle" : 2*np.pi/5,
}
class SnakeCurve(SpaceFillingCurve):
CONFIG = {
"start_color" : BLUE,
"end_color" : YELLOW,
}
def get_anchor_points(self):
result = []
resolution = 2**self.order
step = 2.0*self.radius / resolution
lower_left = ORIGIN + \
LEFT*(self.radius - step/2) + \
DOWN*(self.radius - step/2)
for y in range(resolution):
x_range = range(resolution)
if y%2 == 0:
x_range.reverse()
for x in x_range:
result.append(
lower_left + x*step*RIGHT + y*step*UP
)
return result
class SpaceFillingCurveScene(Scene):
@staticmethod
def args_to_string(CurveClass, order):
return CurveClass.__name__ + "Order" + str(order)
@staticmethod
def string_to_args(arg_str):
curve_class_name, order_str = arg_str.split()
space_filling_curves = dict([
(Class.__name__, Class)
for Class in get_all_descendent_classes(SpaceFillingCurve)
])
if curve_class_name not in space_filling_curves:
raise Exception(
"%s is not a space filling curve"%curve_class_name
)
CurveClass = space_filling_curves[curve_class_name]
return CurveClass, int(order_str)
class TransformOverIncreasingOrders(SpaceFillingCurveScene):
def setup(self, CurveClass):
sample = CurveClass(order = 1)
self.curve = Line(3*LEFT, 3*RIGHT)
self.curve.gradient_highlight(
sample.start_color,
sample.end_color
)
self.CurveClass = CurveClass
self.order = 0
def construct(self, CurveClass, max_order):
self.setup(CurveClass)
while self.order < max_order:
self.increase_order()
self.dither()
def increase_order(self, *other_anims):
self.order += 1
new_curve = self.CurveClass(order = self.order)
self.play(
Transform(self.curve, new_curve),
*other_anims,
run_time = 3/np.sqrt(self.order)
)
class DrawSpaceFillingCurve(SpaceFillingCurveScene):
def construct(self, CurveClass, order):
curve = CurveClass(order = order)
self.play(ShowCreation(curve), run_time = 10)
self.dither()