Begining sphere_area project

active_projects/sphere_area.py

@@ -0,0 +1,73 @@
+from big_ol_pile_of_manim_imports import *
+from active_projects.shadows import *
+
+
+class AskAboutShadowRelation(SpecialThreeDScene):
+    def construct(self):
+        self.show_surface_area()
+        self.show_area_of_shadow()
+        self.show_light_source()
+        self.show_four_circles()
+
+    def show_surface_area(self):
+        sphere = self.get_sphere()
+        sphere.set_fill(BLUE_E, opacity=0.5)
+        sphere.add_updater(
+            lambda s, dt: s.rotate(0.1 * dt, axis=OUT)
+        )
+        pieces = sphere.deepcopy()
+        pieces.space_out_submobjects(1.5)
+        pieces.shift(IN)
+        pieces.set_color(GREEN)
+
+        # radial_line = Line(ORIGIN, sphere.get_right())
+        # R_label = TexMobject("R")
+        # R_label.set_color(BLUE)
+        # R_label.rotate(90 * DEGREES, RIGHT)
+        # R_label.next_to(radial_line, OUT, SMALL_BUFF)
+
+        sa_equation = TexMobject(
+            "\\text{Surface area} = 4\\pi R^2",
+            tex_to_color_map={"R": BLUE}
+        )
+        sa_equation.scale(1.5)
+        sa_equation.to_edge(UP)
+
+        self.set_camera_to_default_position()
+        self.add_fixed_in_frame_mobjects(sa_equation)
+        self.play(
+            Write(sphere, run_time=1),
+            FadeInFromDown(sa_equation),
+            # ShowCreation(radial_line),
+            # FadeInFrom(R_label, IN),
+        )
+        self.play(
+            Transform(
+                sphere, pieces,
+                rate_func=there_and_back_with_pause,
+                run_time=2
+            )
+        )
+        self.play(LaggedStart(
+            UpdateFromAlphaFunc, sphere,
+            lambda mob: (mob, lambda m, a: m.set_fill(
+                color=interpolate_color(BLUE_E, YELLOW, a),
+                opacity=interpolate(0.5, 1, a)
+            )),
+            rate_func=there_and_back,
+            lag_ratio=0.2,
+        ))
+        self.play(self.camera.frame_center.shift, 2 * LEFT)
+        self.wait(2)
+
+        self.sphere = sphere
+        self.sa_equation = sa_equation
+
+    def show_area_of_shadow(self):
+        pass
+
+    def show_light_source(self):
+        pass
+
+    def show_four_circles(self):
+        pass