From 7105a87a1e5472a77b3f71109017eb15409d87a3 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Sat, 6 Feb 2016 19:19:18 +0100
Subject: [PATCH] - fixed retrieval of mapsection for polyportals. - render
 wall portals on one sided lines.

---
 src/gl/scene/gl_portal.cpp |  7 ++++++-
 src/gl/scene/gl_sky.cpp    |  9 +--------
 src/gl/scene/gl_walls.cpp  | 19 ++++++++++++++++---
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/gl/scene/gl_portal.cpp b/src/gl/scene/gl_portal.cpp
index 2d74af820d..5ce683f571 100644
--- a/src/gl/scene/gl_portal.cpp
+++ b/src/gl/scene/gl_portal.cpp
@@ -1050,7 +1050,12 @@ void GLLineToLinePortal::DrawContents()
 
 	for (unsigned i = 0; i < lines.Size(); i++)
 	{
-		int mapsection = lines[i].seg->linedef->getPortalDestination()->frontsector->subsectors[0]->mapsection;
+		line_t *line = lines[i].seg->linedef->getPortalDestination();
+		subsector_t *sub;
+		if (line->sidedef[0]->Flags & WALLF_POLYOBJ) 
+			sub = R_PointInSubsector(line->v1->x, line->v1->y);
+		else sub = line->frontsector->subsectors[0];
+		int mapsection = sub->mapsection;
 		currentmapsection[mapsection >> 3] |= 1 << (mapsection & 7);
 	}
 
diff --git a/src/gl/scene/gl_sky.cpp b/src/gl/scene/gl_sky.cpp
index c882674dd0..5a5a10a265 100644
--- a/src/gl/scene/gl_sky.cpp
+++ b/src/gl/scene/gl_sky.cpp
@@ -193,19 +193,12 @@ void GLWall::SkyLine(sector_t *fs, line_t *line)
 {
 	ASkyViewpoint * skyboxx = line->skybox;
 	GLSkyInfo skyinfo;
-	GLLineToLineInfo llinfo;
 	int ptype;
 
 	// JUSTHIT is used as an indicator that a skybox is in use.
 	// This is to avoid recursion
 
-	if (line->isVisualPortal())
-	{
-		ptype = PORTALTYPE_LINETOLINE;
-		llinfo.init(line);
-		l2l = UniqueLineToLines.Get(&llinfo);
-	}
-	else if (!gl_noskyboxes && skyboxx && GLRenderer->mViewActor != skyboxx && !(skyboxx->flags&MF_JUSTHIT))
+	if (!gl_noskyboxes && skyboxx && GLRenderer->mViewActor != skyboxx && !(skyboxx->flags&MF_JUSTHIT))
 	{
 		ptype = PORTALTYPE_SKYBOX;
 		skybox = skyboxx;
diff --git a/src/gl/scene/gl_walls.cpp b/src/gl/scene/gl_walls.cpp
index c8430986f4..5d33670ce9 100644
--- a/src/gl/scene/gl_walls.cpp
+++ b/src/gl/scene/gl_walls.cpp
@@ -1475,7 +1475,18 @@ void GLWall::Process(seg_t *seg, sector_t * frontsector, sector_t * backsector)
 		// sector's sky
 		SkyNormal(frontsector, v1, v2);
 
-		if (seg->linedef->skybox == NULL)
+		if (seg->linedef->isVisualPortal())
+		{
+			GLLineToLineInfo llinfo;
+			ztop[0] = zceil[0];
+			ztop[1] = zceil[1];
+			zbottom[0] = zfloor[0];
+			zbottom[1] = zfloor[1];
+			llinfo.init(seg->linedef);
+			l2l = UniqueLineToLines.Get(&llinfo);
+			PutPortal(PORTALTYPE_LINETOLINE);
+		}
+		else if (seg->linedef->skybox == NULL && !seg->linedef->isVisualPortal())
 		{
 			// normal texture
 			gltexture = FMaterial::ValidateTexture(seg->sidedef->GetTexture(side_t::mid), false, true);
@@ -1590,12 +1601,14 @@ void GLWall::Process(seg_t *seg, sector_t * frontsector, sector_t * backsector)
 
 		if (seg->linedef->isVisualPortal() && seg->sidedef == seg->linedef->sidedef[0])
 		{
+			GLLineToLineInfo llinfo;
 			ztop[0] = FIXED2FLOAT(bch1);
 			ztop[1] = FIXED2FLOAT(bch2);
 			zbottom[0] = FIXED2FLOAT(bfh1);
 			zbottom[1] = FIXED2FLOAT(bfh2);
-
-			SkyLine(frontsector, seg->linedef);
+			llinfo.init(seg->linedef);
+			l2l = UniqueLineToLines.Get(&llinfo);
+			PutPortal(PORTALTYPE_LINETOLINE);
 		}
 		else if (backsector->e->XFloor.ffloors.Size() || frontsector->e->XFloor.ffloors.Size())
 		{