From 51e5de9ad13e970b77974e8cd161877cdc99b144 Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Fri, 1 Jan 2021 21:11:27 -0800
Subject: [PATCH] Add MoveCar

---
 custom/drawings.py | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/custom/drawings.py b/custom/drawings.py
index abd1f90..f00e7b5 100644
--- a/custom/drawings.py
+++ b/custom/drawings.py
@@ -92,6 +92,42 @@ class Car(SVGMobject):
         return self[1][4]
 
 
+class MoveCar(ApplyMethod):
+    CONFIG = {
+        "moving_forward": True,
+        "run_time": 5,
+    }
+
+    def __init__(self, car, target_point, **kwargs):
+        self.check_if_input_is_car(car)
+        self.target_point = target_point
+        super().__init__(car.move_to, target_point, **kwargs)
+
+    def check_if_input_is_car(self, car):
+        if not isinstance(car, Car):
+            raise Exception("MoveCar must take in Car object")
+
+    def begin(self):
+        super().begin()
+        car = self.mobject
+        distance = get_norm(op.sub(
+            self.target_mobject.get_right(),
+            self.starting_mobject.get_right(),
+        ))
+        if not self.moving_forward:
+            distance *= -1
+        tire_radius = car.get_tires()[0].get_width() / 2
+        self.total_tire_radians = -distance / tire_radius
+
+    def interpolate_mobject(self, alpha):
+        ApplyMethod.interpolate_mobject(self, alpha)
+        if alpha == 0:
+            return
+        radians = alpha * self.total_tire_radians
+        for tire in self.mobject.get_tires():
+            tire.rotate_in_place(radians)
+
+
 class PartyHat(SVGMobject):
     CONFIG = {
         "file_name": "party_hat",