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from manimlib.imports import *
t_offset = 0
c_t = 0
class cycloid(Scene):
def construct(self):
cycl = ParametricFunction(
lambda t: np.array([
t - np.sin(t),
1 - np.cos(t),
0
]), t_min = -2.75*np.pi, t_max = 3*np.pi, color = BLUE
).shift(0.73*RIGHT)
wheel_radius = 1
wheel_function_path = lambda x : 0 + wheel_radius
line = FunctionGraph(lambda x : 0, color = BLACK)
wheel_path = FunctionGraph(wheel_function_path)
velocity_factor = 0.25
frame_rate = self.camera.frame_rate
self.dt = 1 / frame_rate
wheel = Circle(color = BLACK, radius = 1)
dot = Dot(radius = 0.16, color = RED)
#dot.move_to(wheel.get_arc_center() + np.array([0,2,0]))
def update_dot(mob,dt):
global t_offset,c_t
if dt == 0 and c_t == 0:
rate= - velocity_factor * self.dt
c_t += 1
else:
rate = - dt*velocity_factor
if dt > 0:
c_t = 0
mob.move_to(wheel.point_from_proportion(((t_offset + rate))%1))
t_offset += rate
#self.add(mob.copy())
#dot.move_to(wheel.get_arc_center() + np.array([0,2,0]))
dot.add_updater(update_dot)
self.add(wheel,dot, line, cycl)
self.play(MoveAlongPath(wheel, wheel_path, run_time = 9, rate_func = linear))
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