From bbda9089d2115dcfc80608030ffb9d81fe3bd042 Mon Sep 17 00:00:00 2001
From: casperlamboo <casperlamboo@gmail.com>
Date: Wed, 18 Jan 2017 12:05:21 +0100
Subject: [PATCH] don't calculate 1 - alpha twice

---
 src/sliceActions/calculateLayersIntersections.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/sliceActions/calculateLayersIntersections.js b/src/sliceActions/calculateLayersIntersections.js
index 9c7a408..45f15fb 100644
--- a/src/sliceActions/calculateLayersIntersections.js
+++ b/src/sliceActions/calculateLayersIntersections.js
@@ -33,8 +33,9 @@ export default function calculateLayersIntersections(lines, settings) {
           z = line.start.z;
         } else {
           const alpha = (y - line.start.y) / (line.end.y - line.start.y);
-          x = line.end.x * alpha + line.start.x * (1 - alpha);
-          z = line.end.z * alpha + line.start.z * (1 - alpha);
+          const alpha1 = 1 - alpha;
+          x = line.end.x * alpha + line.start.x * alpha1;
+          z = line.end.z * alpha + line.start.z * alpha1;
         }
 
         layerIntersectionPoints[layerIndex][lineIndex] = new THREE.Vector2(z, x);