manim: sum of different phase

rhaos68 · Oct 2, 2020 · d5cafc4 · d5cafc4
1 parent 43b9ed4
commit d5cafc4
Showing 1 changed file with 139 additions and 0 deletions.
diff --git a/sum_diff_phase.py b/sum_diff_phase.py
@@ -0,0 +1,139 @@
+from manimlib.imports import *
+
+class PhaseChange(Scene):
+    def construct(self):
+        self.draw_axis()
+        self.draw_grid()
+
+        self.draw_wave()
+        self.wait()
+
+    def get_axis(self, max_y=1):
+        g = VGroup()
+        min_x = -6
+        max_x = 6
+
+        def xy(x, y):
+            return np.array([x, y, 0])
+
+        def tex(str, color=WHITE):
+            return TexMobject(str,color=color).scale(0.6)
+
+        def get_line(s,e):
+            return Line(s,e , color=BLUE, stroke_width=5)
+
+        x_axis = get_line(xy(min_x,0), xy(max_x,0))
+        g.add(x_axis)
+
+        x_labels = [tex("0.5", color=BLUE), tex("1", color=BLUE)]
+
+        # i: 0   1
+        # x: 0   6
+        for i in range(len(x_labels)):
+            x_labels[i].next_to(xy(6*i,0), DOWN)
+            g.add(x_labels[i])
+
+        # max_y: 1 -> 0.5 ~ -0.5
+        #        2 -> 1 ~ -1
+        y_axis = get_line(xy(min_x, max_y/2),xy(min_x,-max_y/2) )
+        g.add(y_axis)
+
+        y_labels = []
+        for i in range(max_y, -max_y-1, -1):
+            y_labels.append(tex(str(i)))
+
+        #i: 0    1   2    or  0   1   2   3   4
+        #y: 0.5  0  -0.5      1  0.5 0 -0.5 -1
+        for i in range(len(y_labels)):
+            y_labels[i].next_to(xy(-6, -0.5*(i-max_y)), LEFT)
+            g.add(y_labels[i])
+
+        self.min_x = min_x
+        self.max_x = max_x
+        return g
+
+    def draw_grid(self):
+        def get_s_line(x1, y1, x2, y2):  # small grid
+            return Line(np.array([x1, y1, 0]), np.array([x2, y2, 0]), stroke_color=BLUE_D, stroke_width=1,
+                        stroke_opacity=0.7)
+        y1, y2 = 2.5, -2.5
+        sv_lines = [get_s_line(x, y1, x, y2) for x in np.arange(self.min_x , self.max_x+1, 1)]
+
+        self.add(*sv_lines)
+
+    def draw_axis(self):
+        def tex(str):
+            return TexMobject(str, ).scale(0.8)
+
+        eq1 = tex(r"y_1=\sin 2\pi \cdot 2 \cdot t")
+        eq2 = tex(r"y_1=\sin (2\pi \cdot 2 \cdot t - \phi), \phi = ")
+        eq3 = tex(r"y = y_1 + y_2")
+
+        phi_num = Integer(0, color=RED)
+
+        axis1 = self.get_axis(1)
+        axis1.shift(UP*2)
+        eq1.next_to(axis1,UP,aligned_edge=LEFT, buff=0).shift(RIGHT*0.8+DOWN*0.1)
+
+
+        axis2 = self.get_axis(1)
+        axis2.shift(UP*0.5)
+        eq2.next_to(axis2, UP, aligned_edge=LEFT, buff=0).shift(RIGHT * 0.8+DOWN*0.1)
+        phi_num.next_to(eq2, RIGHT)
+
+        axis3 = self.get_axis(2)
+        axis3.shift(DOWN*1.5)
+        eq3.next_to(axis3, UP, aligned_edge=LEFT, buff=0).shift(RIGHT * 0.8+DOWN*0.1)
+
+        self.add(axis1, axis2, axis3)
+        self.add(eq1, eq2, phi_num, eq3)
+
+        self.phi_num = phi_num
+
+    def draw_wave(self):
+        vt = ValueTracker(0)
+
+        def get_wave(A=1, f=2, phi=0):  # phi: degree
+            # x: -6 ...  0 ... 6
+            # t: 0  ..  0.5 .. 1
+            # t = x/12 + 0.5
+            return FunctionGraph(
+                lambda x: A/2*np.sin(2 * PI * f * (x / 12 + 0.5) - phi * PI / 180),
+                # lambda t : np.sin(t),
+                x_min=self.min_x,
+                x_max=self.max_x,
+            )
+
+        def get_sum_cal(A=1,f=2):
+            phi = vt.get_value()
+            return FunctionGraph(
+                lambda x: (A / 2 * np.sin(2 * PI * f * (x / 12 + 0.5))) +
+                          (A / 2 * np.sin(2 * PI * f * (x / 12 + 0.5)-(phi * PI / 180))),
+                # lambda t : np.sin(t),
+                x_min=self.min_x,
+                x_max=self.max_x,
+            )
+
+        wave1 = get_wave(1, 2, 0).shift(UP * 2)
+        wave2 = get_wave(1, 2, 0).shift(UP * 0.5)
+        wave3 = get_sum_cal(1, 2).shift(DOWN * 1.5)
+        self.add(wave1, wave2, wave3)
+
+        #ani
+        def update_wave2(mob):
+            new_wave = get_wave(phi=vt.get_value()).shift(UP * 0.5)
+            mob.become(new_wave)
+
+        def update_wave3(mob):
+            new_wave = get_sum_cal(1, 2).shift(DOWN * 1.5)
+            mob.become(new_wave)
+
+        def update_phi(mob):
+            mob.set_value(vt.get_value())
+
+        wave2.add_updater(update_wave2)
+        wave3.add_updater(update_wave3)
+        self.phi_num.add_updater(update_phi)
+
+        self.play(vt.set_value, 360, rate_func=linear, run_time=10)
+        self.wait()