From 2317a7d982f68fc3a03c70d857309e6cf938cc87 Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Tue, 9 Jun 2020 21:24:42 -0700
Subject: [PATCH] Torus

---
 manimlib/mobject/three_dimensions.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/manimlib/mobject/three_dimensions.py b/manimlib/mobject/three_dimensions.py
index fed060e1..4093b884 100644
--- a/manimlib/mobject/three_dimensions.py
+++ b/manimlib/mobject/three_dimensions.py
@@ -1,3 +1,5 @@
+import math
+
 from manimlib.constants import *
 from manimlib.mobject.types.surface import ParametricSurface
 from manimlib.mobject.types.surface import SGroup
@@ -93,6 +95,19 @@ class Cylinder(ArglessSurface):
         return [np.cos(u), np.sin(u), v]
 
 
+class Torus(ArglessSurface):
+    CONFIG = {
+        "u_range": (0, TAU),
+        "v_range": (0, TAU),
+        "r1": 3,
+        "r2": 1,
+    }
+
+    def uv_func(self, u, v):
+        P = np.array([math.cos(u), math.sin(u), 0])
+        return (self.r1 - self.r2 * math.cos(v)) * P - math.sin(v) * OUT
+
+
 class Line3D(Cylinder):
     CONFIG = {
         "width": 0.05,