# -*- coding: utf-8 -*- from helpers import * from mobject.tex_mobject import TexMobject from mobject import Mobject from mobject.image_mobject import ImageMobject from mobject.vectorized_mobject import * from animation.animation import Animation from animation.transform import * from animation.simple_animations import * from animation.compositions import * from animation.playground import * from animation.continual_animation import * from topics.geometry import * from topics.characters import * from topics.functions import * from topics.fractals import * from topics.number_line import * from topics.combinatorics import * from topics.numerals import * from topics.three_dimensions import * from topics.objects import * from topics.probability import * from topics.complex_numbers import * from scene import Scene from scene.reconfigurable_scene import ReconfigurableScene from scene.zoomed_scene import * from scene.moving_camera_scene import * from camera import * from mobject.svg_mobject import * from mobject.tex_mobject import * from topics.graph_scene import * RESOURCE_DIR = os.path.join(MEDIA_DIR, "3b1b_videos", "π Day 2018", "images") def get_image(name): return ImageMobject(os.path.join(RESOURCE_DIR, name)) def get_circle_drawing_terms(radius = 1, positioning_func = lambda m : m.center()): circle = Circle(color = YELLOW, radius = 1.25) positioning_func(circle) radius = Line(circle.get_center(), circle.points[0]) radius.highlight(WHITE) one = TexMobject("1") one.scale(0.75) one_update = UpdateFromFunc( one, lambda m : m.move_to( radius.get_center() + \ 0.25*rotate_vector(radius.get_vector(), TAU/4) ), ) decimal = DecimalNumber(0, num_decimal_points = 4, show_ellipsis = True) decimal.scale(0.75) def reposition_decimal(decimal): vect = radius.get_vector() unit_vect = vect/np.linalg.norm(vect) angle = radius.get_angle() alpha = (-np.cos(2*angle) + 1)/2 interp_length = interpolate(decimal.get_width(), decimal.get_height(), alpha) buff = interp_length/2 + MED_SMALL_BUFF decimal.move_to(radius.get_end() + buff*unit_vect) decimal.shift(UP*decimal.get_height()/2) return decimal kwargs = {"run_time" : 3, "rate_func" : bezier([0, 0, 1, 1])} changing_decimal = ChangingDecimal( decimal, lambda a : a*TAU, position_update_func = reposition_decimal, **kwargs ) terms = VGroup(circle, radius, one, decimal) generate_anims1 = lambda : [ShowCreation(radius), Write(one)] generate_anims2 = lambda : [ ShowCreation(circle, **kwargs), Rotating(radius, about_point = radius.get_start(), **kwargs), changing_decimal, one_update, ] return terms, generate_anims1, generate_anims2 ## class PiTauDebate(PiCreatureScene): def construct(self): pi, tau = self.pi, self.tau self.add(pi, tau) pi_value = TextMobject("3.1415...!") pi_value.highlight(BLUE) tau_value = TextMobject("6.2831...!") tau_value.highlight(GREEN) self.play(PiCreatureSays( pi, pi_value, target_mode = "angry", look_at_arg = tau.eyes, # bubble_kwargs = {"width" : 3} )) self.play(PiCreatureSays( tau, tau_value, target_mode = "angry", look_at_arg = pi.eyes, bubble_kwargs = {"width" : 3, "height" : 2}, )) self.wait() # Show tau terms, generate_anims1, generate_anims2 = get_circle_drawing_terms( radius = 1.25, positioning_func = lambda m : m.to_edge(RIGHT, buff = 2).to_edge(UP, buff = 1) ) circle, radius, one, decimal = terms self.play( RemovePiCreatureBubble(pi), RemovePiCreatureBubble(tau), *generate_anims1() ) self.play( tau.change, "hooray", pi.change, "sassy", *generate_anims2() ) self.wait() # Show pi circle = Circle(color = RED, radius = 1.25/2) circle.rotate(TAU/4) circle.move_to(pi) circle.to_edge(UP, buff = MED_LARGE_BUFF) diameter = Line(circle.get_left(), circle.get_right()) one = TexMobject("1") one.scale(0.75) one.next_to(diameter, UP, SMALL_BUFF) circum_line = diameter.copy().scale(np.pi) circum_line.match_style(circle) circum_line.next_to(circle, DOWN, buff = MED_LARGE_BUFF) # circum_line.to_edge(LEFT) brace = Brace(circum_line, DOWN, buff = SMALL_BUFF) decimal = DecimalNumber(np.pi, num_decimal_points = 4, show_ellipsis = True) decimal.scale(0.75) decimal.next_to(brace, DOWN, SMALL_BUFF) self.play( FadeIn(VGroup(circle, diameter, one)), tau.change, "confused", pi.change, "hooray" ) self.add(circle.copy().fade(0.5)) self.play( ReplacementTransform(circle, circum_line, run_time = 2) ) self.play(GrowFromCenter(brace), Write(decimal)) self.wait(3) # self.play() def create_pi_creatures(self): pi = self.pi = Randolph() pi.to_edge(DOWN).shift(4*LEFT) tau = self.tau = TauCreature( # mode = "angry", file_name_prefix = "TauCreatures", color = GREEN_E ).flip() tau.to_edge(DOWN).shift(4*RIGHT) return VGroup(pi, tau) class HartlAndPalais(Scene): def construct(self): hartl_rect = ScreenRectangle( color = WHITE, stroke_width = 1, ) hartl_rect.scale_to_fit_width(SPACE_WIDTH - 1) hartl_rect.to_edge(LEFT) palais_rect = hartl_rect.copy() palais_rect.to_edge(RIGHT) tau_words = TextMobject("$\\tau$ ``tau''") tau_words.next_to(hartl_rect, UP) hartl_words = TextMobject("Michael Hartl's \\\\ ``Tau manifesto''") hartl_words.next_to(hartl_rect, DOWN) palais_words = TextMobject("Robert Palais' \\\\ ``Pi is Wrong!''") palais_words.next_to(palais_rect, DOWN) for words in hartl_words, palais_words: words.scale(0.7, about_edge = UP) three_legged_creature = ThreeLeggedPiCreature(height = 1.5) three_legged_creature.next_to(palais_rect, UP) # self.add(hartl_rect, palais_rect) self.add(hartl_words) self.play(Write(tau_words)) self.wait() self.play(FadeIn(palais_words)) self.play(FadeIn(three_legged_creature)) self.play(three_legged_creature.change_mode, "wave") self.play(Blink(three_legged_creature)) self.play(Homotopy( lambda x, y, z, t : (x + 0.1*np.sin(2*TAU*t)*np.exp(-10*(t-0.5 - 0.5*(y-1.85))**2), y, z), three_legged_creature, run_time = 2, )) self.wait() class ManyFormulas(Scene): def construct(self): formulas = VGroup( TexMobject("\\sin(x + \\tau) = \\sin(x)"), TexMobject("e^{\\tau i} = 1"), TexMobject("n! \\approx \\sqrt{\\tau n} \\left(\\frac{n}{e} \\right)^n"), TexMobject("c_n = \\frac{1}{\\tau} \\int_0^\\tau f(x) e^{inx}dx"), ) formulas.arrange_submobjects(DOWN, buff = MED_LARGE_BUFF) formulas.to_edge(LEFT) self.play(LaggedStart(FadeIn, formulas, run_time = 3)) circle = Circle(color = YELLOW, radius = 2) circle.to_edge(RIGHT) radius = Line(circle.get_center(), circle.get_right()) radius.highlight(WHITE) angle_groups = VGroup() for denom in 5, 4, 3, 2: radius_copy = radius.copy() radius_copy.rotate(TAU/denom, about_point = circle.get_center()) arc = Arc( angle = TAU/denom, stroke_color = RED, stroke_width = 4, radius = circle.radius, ) arc.shift(circle.get_center()) mini_arc = arc.copy() mini_arc.set_stroke(WHITE, 2) mini_arc.scale(0.15, about_point = circle.get_center()) tau_tex = TexMobject("\\tau/%d"%denom) point = mini_arc.point_from_proportion(0.5) tau_tex.next_to(point, direction = point - circle.get_center()) angle_group = VGroup(radius_copy, mini_arc, tau_tex, arc) angle_groups.add(angle_group) angle_group = angle_groups[0] self.play(*map(FadeIn, [circle, radius])) self.play( circle.set_stroke, {"width" : 1,}, FadeIn(angle_group), ) self.wait() for group in angle_groups[1:]: self.play(Transform(angle_group, group, path_arc = TAU/8)) self.wait() class HistoryOfOurPeople(TeacherStudentsScene): def construct(self): self.teacher_says( "Today: The history \\\\ of our people.", bubble_kwargs = {"width" : 4, "height" : 3} ) self.change_all_student_modes("hooray") self.wait() self.play(*[ ApplyMethod(pi.change, "happy", self.screen) for pi in self.pi_creatures ]) self.wait(4) class TauFalls(Scene): def construct(self): tau = TauCreature() bottom = np.min(tau.body.points[:,1])*UP angle = -0.15*TAU tau.generate_target() tau.target.change("angry") tau.target.rotate(angle, about_point = bottom) self.play(Rotate(tau, angle, rate_func = rush_into, path_arc = angle, about_point = bottom)) # self.play(MoveToTarget(tau, rate_func = rush_into, path_arc = angle)) self.play(MoveToTarget(tau)) self.wait() class EulerWrites628(Scene): CONFIG = { "camera_config" : { "background_alpha" : 255, } } def construct(self): image = ImageMobject(os.path.join(RESOURCE_DIR, "dalembert_zoom")) image.scale_to_fit_width(2*SPACE_WIDTH - 1) image.to_edge(UP, buff = MED_SMALL_BUFF) image.fade(0.15) rect = Rectangle( width = 12, height = 0.5, stroke_width = 0, fill_opacity = 0.3, fill_color = GREEN, ) rect.insert_n_anchor_points(20) rect.apply_function(lambda p : np.array([p[0], p[1] - 0.005*p[0]**2, p[2]])) rect.rotate(0.012*TAU) rect.move_to(image) rect.shift(0.15*DOWN) words = TextMobject( "``Let", "$\\pi$", "be the", "circumference", "of a circle whose", "radius = 1''", ) words.highlight_by_tex_to_color_map({ "circumference" : YELLOW, "radius" : GREEN, }) words.next_to(image, DOWN) pi = words.get_part_by_tex("\\pi").copy() terms, generate_anims1, generate_anims2 = get_circle_drawing_terms( radius = 1, positioning_func = lambda circ : circ.next_to(words, DOWN, buff = 1.25) ) circle, radius, one, decimal = terms unwrapped_perimeter = Line(ORIGIN, TAU*RIGHT) unwrapped_perimeter.match_style(circle) unwrapped_perimeter.next_to(circle, DOWN) brace = Brace(unwrapped_perimeter, UP, buff = SMALL_BUFF) perimeter = TexMobject( "\\pi\\epsilon\\rho\\iota\\mu\\epsilon\\tau\\rho\\text{o}\\varsigma", "\\text{ (perimeter)}", "=" ) perimeter.next_to(brace, UP, submobject_to_align = perimeter[1], buff = SMALL_BUFF) perimeter[0][0].highlight(GREEN) self.play(FadeInFromDown(image)) self.play( Write(words), GrowFromPoint(rect, rect.point_from_proportion(0.9)) ) self.wait() self.play(*generate_anims1()) self.play(*generate_anims2()) self.play(terms.shift, UP) self.play( pi.scale, 2, pi.shift, DOWN, pi.highlight, GREEN ) self.wait() self.play( GrowFromCenter(brace), circle.set_stroke, YELLOW, 1, ReplacementTransform(circle.copy(), unwrapped_perimeter), decimal.scale, 1.25, decimal.next_to, perimeter[-1].get_right(), RIGHT, ReplacementTransform(pi, perimeter[0][0]), Write(perimeter), ) self.wait() class HeroAndVillain(Scene): CONFIG = { "camera_config" : { "background_alpha" : 255, } } def construct(self): good_euler = get_image("Leonhard_Euler_by_Handmann") bad_euler_pixelated = get_image("Leonard_Euler_pixelated") bad_euler = get_image("Leonard_Euler_revealed") pictures = good_euler, bad_euler_pixelated, bad_euler for mob in pictures: mob.scale_to_fit_height(5) good_euler.move_to(SPACE_WIDTH*LEFT/2) bad_euler.move_to(SPACE_WIDTH*RIGHT/2) bad_euler_pixelated.move_to(bad_euler) good_euler_label = TextMobject("Leonhard Euler") good_euler_label.next_to(good_euler, DOWN) tau_words = TextMobject("Used 6.2831...") tau_words.next_to(good_euler, UP) tau_words.highlight(GREEN) bad_euler_label = TextMobject("Also Euler...") bad_euler_label.next_to(bad_euler, DOWN) pi_words = TextMobject("Used 3.1415...") pi_words.highlight(RED) pi_words.next_to(bad_euler, UP) self.play( FadeInFromDown(good_euler), Write(good_euler_label) ) self.play(LaggedStart(FadeIn, tau_words)) self.wait() self.play(FadeInFromDown(bad_euler_pixelated)) self.play(LaggedStart(FadeIn, pi_words)) self.wait(2) self.play( FadeIn(bad_euler), Write(bad_euler_label), ) self.remove(bad_euler_pixelated) self.wait(2)