From 8ae23eafb6389942fd94a5d9193dca18ae8897bb Mon Sep 17 00:00:00 2001
From: Jarrod Doyle <thejarroddoyle@gmail.com>
Date: Sun, 26 Jan 2025 17:20:46 +0000
Subject: [PATCH] Reverse mesh poly winding order

---
 KeepersCompound.Lightmapper/MeshBuilder.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/KeepersCompound.Lightmapper/MeshBuilder.cs b/KeepersCompound.Lightmapper/MeshBuilder.cs
index 658439a..4f4b9f4 100644
--- a/KeepersCompound.Lightmapper/MeshBuilder.cs
+++ b/KeepersCompound.Lightmapper/MeshBuilder.cs
@@ -155,12 +155,13 @@ public class MeshBuilder
         var indexOffset = _vertices.Count;
 
         // Polygons are n-sided, but fortunately they're convex so we can just do a fan triangulation
+        // Embree triangle winding order is reverse of LGS winding order, so we go (0, i+1, i) instead of (0, i+1, i)
         _vertices.AddRange(vertices);
         for (var i = 1; i < vertexCount - 1; i++)
         {
             _indices.Add(indexOffset);
-            _indices.Add(indexOffset + i);
             _indices.Add(indexOffset + i + 1);
+            _indices.Add(indexOffset + i);
             _primSurfaceMap.Add(surfaceType);
             _triangleCount++;
         }