From 3c16a23865255b14b3fa9b98e9570abddca7e339 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Wed, 27 Jan 2016 12:02:43 +0100
Subject: [PATCH] - when rendering mirrors, discard subsectors lying behind
 them.

---
 src/gl/scene/gl_bsp.cpp    | 13 ++++++++-----
 src/gl/scene/gl_portal.cpp | 13 +++++++++++--
 src/gl/scene/gl_portal.h   |  2 ++
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/gl/scene/gl_bsp.cpp b/src/gl/scene/gl_bsp.cpp
index dd6df82876..ef7af4d21e 100644
--- a/src/gl/scene/gl_bsp.cpp
+++ b/src/gl/scene/gl_bsp.cpp
@@ -361,11 +361,6 @@ static void DoSubsector(subsector_t * sub)
 	sector_t * fakesector;
 	sector_t fake;
 	
-	// check for visibility of this entire subsector. This requires GL nodes.
-	// (disabled because it costs more time than it saves.)
-	//if (!clipper.CheckBox(sub->bbox)) return;
-
-
 #ifdef _DEBUG
 	if (sub->sector-sectors==931)
 	{
@@ -387,6 +382,14 @@ static void DoSubsector(subsector_t * sub)
 		UnclipSubsector(sub);
 	}
 
+	if (GLRenderer->mCurrentPortal)
+	{
+		int clipres = GLRenderer->mCurrentPortal->ClipSubsector(sub);
+		if (clipres == GLPortal::PClip_InFront) return;
+	}
+
+
+
 	fakesector=gl_FakeFlat(sector, &fake, false);
 
 	if (sector->validcount != validcount)
diff --git a/src/gl/scene/gl_portal.cpp b/src/gl/scene/gl_portal.cpp
index 5b6c8e27db..a22c25e2d1 100644
--- a/src/gl/scene/gl_portal.cpp
+++ b/src/gl/scene/gl_portal.cpp
@@ -750,7 +750,6 @@ void GLSectorStackPortal::DrawContents()
 	viewx += origin->xDisplacement;
 	viewy += origin->yDisplacement;
 	GLRenderer->mViewActor = NULL;
-	GLRenderer->mCurrentPortal = this;
 
 
 	validcount++;
@@ -937,7 +936,7 @@ void GLMirrorPortal::DrawContents()
 
 int GLMirrorPortal::ClipSeg(seg_t *seg) 
 { 
-	// this seg is completely behind the mirror!
+	// this seg is completely behind the mirror.
 	if (P_PointOnLineSide(seg->v1->x, seg->v1->y, linedef) &&
 		P_PointOnLineSide(seg->v2->x, seg->v2->y, linedef)) 
 	{
@@ -946,6 +945,16 @@ int GLMirrorPortal::ClipSeg(seg_t *seg)
 	return PClip_Inside; 
 }
 
+int GLMirrorPortal::ClipSubsector(subsector_t *sub) 
+{ 
+	// this seg is completely behind the mirror!
+	for(int i=0;i<sub->numlines;i++)
+	{
+		if (P_PointOnLineSide(sub->firstline[i].v1->x, sub->firstline[i].v1->y, linedef) == 0) return PClip_Inside;
+	}
+	return PClip_InFront; 
+}
+
 int GLMirrorPortal::ClipPoint(fixed_t x, fixed_t y) 
 { 
 	if (P_PointOnLineSide(x, y, linedef)) 
diff --git a/src/gl/scene/gl_portal.h b/src/gl/scene/gl_portal.h
index 384a34f7d8..c7c07986be 100644
--- a/src/gl/scene/gl_portal.h
+++ b/src/gl/scene/gl_portal.h
@@ -160,6 +160,7 @@ public:
 	}
 
 	virtual int ClipSeg(seg_t *seg) { return PClip_Inside; }
+	virtual int ClipSubsector(subsector_t *sub) { return PClip_Inside; }
 	virtual int ClipPoint(fixed_t x, fixed_t y) { return PClip_Inside; }
 
 	static void BeginScene();
@@ -189,6 +190,7 @@ public:
 
 	virtual bool NeedCap() { return false; }
 	virtual int ClipSeg(seg_t *seg);
+	virtual int ClipSubsector(subsector_t *sub);
 	virtual int ClipPoint(fixed_t x, fixed_t y);
 };