From b3b5cb2fa410554edb095fb0515ed6cc17098145 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Thu, 17 Nov 2016 23:13:17 +0100
Subject: [PATCH] - fixed: Lines with both sides in the same sector but an
 active portal may not be discarded early.

---
 src/gl/scene/gl_bsp.cpp | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/gl/scene/gl_bsp.cpp b/src/gl/scene/gl_bsp.cpp
index 7b9830050..f0ddfd642 100644
--- a/src/gl/scene/gl_bsp.cpp
+++ b/src/gl/scene/gl_bsp.cpp
@@ -140,12 +140,15 @@ static void AddLine (seg_t *seg, bool portalclip)
 	{
 		if (currentsector->sectornum == seg->backsector->sectornum)
 		{
-			FTexture * tex = TexMan(seg->sidedef->GetTexture(side_t::mid));
-			if (!tex || tex->UseType==FTexture::TEX_Null) 
+			if (!seg->linedef->isVisualPortal())
 			{
-				// nothing to do here!
-				seg->linedef->validcount=validcount;
-				return;
+				FTexture * tex = TexMan(seg->sidedef->GetTexture(side_t::mid));
+				if (!tex || tex->UseType==FTexture::TEX_Null) 
+				{
+					// nothing to do here!
+					seg->linedef->validcount=validcount;
+					return;
+				}
 			}
 			backsector=currentsector;
 		}