From 1a9edc400f4ad0d217200b7694bf5383cce6543d Mon Sep 17 00:00:00 2001
From: Ruben Weituschewitz <weituschewitz@gmail.com>
Date: Wed, 1 Apr 2020 18:33:28 +0200
Subject: [PATCH] Recalculate normals on import

---
 Assets/Scripts/Services/ImportFolder.cs |  2 ++
 Assets/Scripts/Util/Stl/StlImporter.cs  | 12 +++++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Assets/Scripts/Services/ImportFolder.cs b/Assets/Scripts/Services/ImportFolder.cs
index b157707..e759c80 100644
--- a/Assets/Scripts/Services/ImportFolder.cs
+++ b/Assets/Scripts/Services/ImportFolder.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -16,6 +17,7 @@
 
 namespace StlVault.Services
 {
+    [DebuggerDisplay("{" + nameof(DisplayName) + "}")]
     internal sealed class ImportFolder : FileSourceBase, IImportFolder
     {
         private readonly Dictionary<string, IFileInfo> _knownFiles = new Dictionary<string, IFileInfo>();
diff --git a/Assets/Scripts/Util/Stl/StlImporter.cs b/Assets/Scripts/Util/Stl/StlImporter.cs
index 534350b..e175441 100644
--- a/Assets/Scripts/Util/Stl/StlImporter.cs
+++ b/Assets/Scripts/Util/Stl/StlImporter.cs
@@ -117,11 +117,13 @@ void WriteFacet(int currentFacet)
                 ref var face = ref facets[currentFacet];
 
                 // Invert indices because .stl files are right-handed
-                vertices[index0] = new Vector3(-face.vert_1.y, face.vert_1.z, face.vert_1.x);
-                vertices[index1] = new Vector3(-face.vert_2.y, face.vert_2.z, face.vert_2.x);
-                vertices[index2] = new Vector3(-face.vert_3.y, face.vert_3.z, face.vert_3.x);
-                var normal = new Vector3(-face.normal.y, face.normal.z, face.normal.x);
-
+                var a = new Vector3(-face.vert_1.y, face.vert_1.z, face.vert_1.x);
+                var b = new Vector3(-face.vert_2.y, face.vert_2.z, face.vert_2.x);
+                var c = new Vector3(-face.vert_3.y, face.vert_3.z, face.vert_3.x);
+                vertices[index0] = a; vertices[index1] = b; vertices[index2] = c;
+                
+                // Recompute normal vector
+                var normal = Vector3.Cross(a - b, c - a).normalized;
                 normals[index0] = normal;
                 normals[index1] = normal;
                 normals[index2] = normal;