From 0d191563729f2454a07d1f802f86f1908dbabfd2 Mon Sep 17 00:00:00 2001
From: Kevin Caccamo <kevin@ciinet.org>
Date: Sat, 1 Jun 2019 21:29:30 -0400
Subject: [PATCH] Fix OBJ face normal direction

https://forum.zdoom.org/viewtopic.php?f=2&t=64740
---
 src/r_data/models/models_obj.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/r_data/models/models_obj.cpp b/src/r_data/models/models_obj.cpp
index bbf8e3b5b7..89d2e60cbc 100644
--- a/src/r_data/models/models_obj.cpp
+++ b/src/r_data/models/models_obj.cpp
@@ -388,7 +388,7 @@ void FOBJModel::BuildVertexBuffer(FModelRenderer *renderer)
 					side + j * 3 + // Current surface and previous triangles
 					surfaces[i].vbStart; // Previous surfaces
 
-				OBJFaceSide &curSide = surfaces[i].tris[j].sides[side];
+				OBJFaceSide &curSide = surfaces[i].tris[j].sides[2 - side];
 
 				int vidx = curSide.vertref;
 				int uvidx = (curSide.uvref >= 0 && (unsigned int)curSide.uvref < uvs.Size()) ? curSide.uvref : 0;