From 8bcdb263d3914838ca713c895d4838d931766a24 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sat, 7 May 2022 17:20:59 +0800
Subject: [PATCH] refactor

---
 src/_impl/_catmull_rom_spline.scad | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/_impl/_catmull_rom_spline.scad b/src/_impl/_catmull_rom_spline.scad
index 9b11b154..eed77e05 100644
--- a/src/_impl/_catmull_rom_spline.scad
+++ b/src/_impl/_catmull_rom_spline.scad
@@ -2,11 +2,15 @@ use <../bezier_curve.scad>;
 
 function _catmull_rom_spline_4pts(t_step, points, tightness) = 
     let(
-        p1x_0tightness = (points[2] - points[0]) / 4 + points[1],
-        v_p1x = points[1] - p1x_0tightness,
-        p1x = p1x_0tightness + v_p1x * tightness,
-        p2x_0tightness = (points[1] - points[3]) / 4 + points[2],
-        v_p2x = points[2] - p2x_0tightness,
-        p2x = p2x_0tightness + v_p2x * tightness
+        p1 = points[1],
+        p2 = points[2],
+        t = (tightness - 1) / 4
     )
-    bezier_curve(t_step, [points[1], p1x, p2x, points[2]]);
+    bezier_curve(t_step, 
+        [
+            p1, 
+            (points[0] - p2) * t + p1, 
+            (points[3] - p1) * t + p2, 
+            p2
+        ]
+    );