From 0c6d9a4d85dccabaa7d3614562f9fd0c9f2d9fab Mon Sep 17 00:00:00 2001
From: Nils Dagsson Moskopp <nils@dieweltistgarnichtso.net>
Date: Mon, 16 Oct 2023 19:08:14 +0200
Subject: [PATCH] Partially slice 3D rendered donut along its torodial
 direction

---
 donut.lua | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/donut.lua b/donut.lua
index a07792a3e..96afe0b2c 100644
--- a/donut.lua
+++ b/donut.lua
@@ -43,7 +43,13 @@ function render_frame(A, B)
    local sinB = math.sin(B)
 
    -- theta goas around the cross-sectional circle of a torus
-   for theta=0, 2*math.pi, theta_spacing do
+   local theta = 0
+   while theta <= 2*math.pi do
+      if ( theta < 2*math.pi * 1/8 ) or ( theta > 2*math.pi * 7/8 ) then
+         theta = theta + (theta_spacing * 16)
+      else
+         theta = theta + theta_spacing
+      end
       -- precompute sines and cosines of theta
       local costheta = math.cos(theta)
       local sintheta = math.sin(theta)