From 1237cef4a0c33b0700a8b3a4a046bfef871fe459 Mon Sep 17 00:00:00 2001
From: Val Erastov <xibyte@gmail.com>
Date: Tue, 8 Dec 2015 20:17:37 -0800
Subject: [PATCH] fix normales planes

---
 web/app/engine.js | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/web/app/engine.js b/web/app/engine.js
index 1bf3ac9a..a32a4e18 100644
--- a/web/app/engine.js
+++ b/web/app/engine.js
@@ -537,20 +537,24 @@ TCAD.geom.extrude = function(source, sourceNormal, target, expansionFactor) {
     poly.push(face);
   }
 
+  var bottomNormal, topNormal;
   if (negate) {
     lid.reverse();
+    bottomNormal = sourceNormal;
+    topNormal = sourceNormal.negate();
   } else {
     source = source.slice(0);
     source.reverse();
+    bottomNormal = sourceNormal.negate();
+    topNormal = sourceNormal;
   }
 
   function vecToVertex(v) {
     return new CSG.Vertex(TCAD.utils.csgVec(v));
   }
 
-  var negateNormal = sourceNormal.negate();
-  var sourcePlane = new CSG.Plane(negateNormal.csg(), negateNormal.dot(source[0]));
-  var lidPlane = new CSG.Plane(sourceNormal.csg(), sourceNormal.dot(lid[0]));
+  var sourcePlane = new CSG.Plane(bottomNormal.csg(), bottomNormal.dot(source[0]));
+  var lidPlane = new CSG.Plane(topNormal.csg(), topNormal.dot(lid[0]));
 
   poly[0] = new CSG.Polygon(source.map(vecToVertex), TCAD.utils.createShared(), sourcePlane);
   poly[1] = new CSG.Polygon(lid.map(vecToVertex), TCAD.utils.createShared(), lidPlane);