From aa12772e079f37cb48cba3602eaeacb2cabbc3c8 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Wed, 20 Apr 2016 13:18:53 +0200
Subject: [PATCH] - crash fix and minor optimization.

---
 src/gl/scene/gl_bsp.cpp | 8 +++++---
 src/r_defs.h            | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/gl/scene/gl_bsp.cpp b/src/gl/scene/gl_bsp.cpp
index 4377f68f1..725ea8663 100644
--- a/src/gl/scene/gl_bsp.cpp
+++ b/src/gl/scene/gl_bsp.cpp
@@ -141,11 +141,13 @@ static void AddLine (seg_t *seg, bool portalclip)
 	}
 	currentsubsector->flags |= SSECF_DRAWN;
 
+	BYTE ispoly = BYTE(seg->sidedef->Flags & WALLF_POLYOBJ);
+
 	if (!seg->backsector)
 	{
 		clipper.SafeAddClipRange(startAngle, endAngle);
 	}
-	else if (!(seg->sidedef->Flags & WALLF_POLYOBJ))	// Two-sided polyobjects never obstruct the view
+	else if (!ispoly)	// Two-sided polyobjects never obstruct the view
 	{
 		if (currentsector->sectornum == seg->backsector->sectornum)
 		{
@@ -179,9 +181,9 @@ static void AddLine (seg_t *seg, bool portalclip)
 
 	seg->linedef->flags |= ML_MAPPED;
 
-	if ((seg->sidedef->Flags & WALLF_POLYOBJ) || seg->linedef->validcount!=validcount) 
+	if (ispoly || seg->linedef->validcount!=validcount) 
 	{
-		if (!(seg->sidedef->Flags & WALLF_POLYOBJ)) seg->linedef->validcount=validcount;
+		if (!ispoly) seg->linedef->validcount=validcount;
 
 		if (gl_render_walls)
 		{
diff --git a/src/r_defs.h b/src/r_defs.h
index 1f2f35621..2260dbf1d 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -1001,7 +1001,7 @@ public:
 
 	int GetPortalType(int plane)
 	{
-		return SkyBoxes[plane]->special1;
+		return SkyBoxes[plane] == nullptr? -1 : SkyBoxes[plane]->special1;
 	}
 
 	int GetOppositePortalGroup(int plane)