3b1b-manim/brachistochrone/misc.py

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2016-03-07 19:07:00 -08:00
import numpy as np
import itertools as it
from helpers import *
from mobject.tex_mobject import TexMobject, TextMobject, Brace
from mobject import Mobject
from mobject.image_mobject import ImageMobject
from topics.three_dimensions import Stars
from animation import Animation
from animation.transform import \
Transform, CounterclockwiseTransform, ApplyPointwiseFunction,\
FadeIn, FadeOut, GrowFromCenter, ApplyFunction, ApplyMethod, \
ShimmerIn
from animation.simple_animations import \
ShowCreation, Homotopy, PhaseFlow, ApplyToCenters, DelayByOrder, \
ShowPassingFlash
from animation.playground import TurnInsideOut, Vibrate
from topics.geometry import \
Line, Circle, Square, Grid, Rectangle, Arrow, Dot, Point, \
Arc, FilledRectangle
from topics.characters import Randolph, Mathematician
from topics.functions import ParametricFunction, FunctionGraph
from topics.number_line import NumberLine, NumberPlane
from mobject.region import Region, region_from_polygon_vertices
from scene import Scene
class PhysicalIntuition(Scene):
def construct(self):
n_terms = 4
def func((x, y, ignore)):
z = complex(x, y)
if (np.abs(x%1 - 0.5)<0.01 and y < 0.01) or np.abs(z)<0.01:
return ORIGIN
out_z = 1./(2*np.tan(np.pi*z)*(z**2))
return out_z.real*RIGHT - out_z.imag*UP
arrows = Mobject(*[
Arrow(ORIGIN, np.sqrt(2)*point)
for point in compass_directions(4, RIGHT+UP)
])
arrows.highlight(YELLOW)
arrows.ingest_sub_mobjects()
all_arrows = Mobject(*[
arrows.copy().scale(0.3/(x)).shift(x*RIGHT)
for x in range(1, n_terms+2)
])
terms = TexMobject([
"\\dfrac{1}{%d^2} + "%(x+1)
for x in range(n_terms)
]+["\\cdots"])
terms.shift(2*UP)
plane = NumberPlane(color = BLUE_E)
axes = Mobject(NumberLine(), NumberLine().rotate(np.pi/2))
axes.highlight(WHITE)
for term in terms.split():
self.play(ShimmerIn(term, run_time = 0.5))
self.dither()
self.play(ShowCreation(plane), ShowCreation(axes))
self.play(*[
Transform(*pair)
for pair in zip(terms.split(), all_arrows.split())
])
self.play(PhaseFlow(
func, plane,
run_time = 5,
virtual_time = 8
))