From 14f4a9e835f4f8b57f6141fb8896de69880d9167 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Mon, 29 Nov 2010 12:43:52 +0000
Subject: [PATCH] - added some fudging to make sectors that are neighboring a
 portal plane but share the same texture properties actual parts of the
 portal. This is only done when portals are defined with portal things. This
 was necessary to preserve an effect that depended on incomplete checks in the
 renderer that could not be preserved with the implementation of linedef based
 portals.

SVN r3012 (trunk)
---
 src/p_spec.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/src/p_spec.cpp b/src/p_spec.cpp
index 0ba2f01d8..bdd6820f4 100644
--- a/src/p_spec.cpp
+++ b/src/p_spec.cpp
@@ -888,6 +888,72 @@ static void SetupCeilingPortal (AStackPoint *point)
 	}
 }
 
+static bool SpreadCeilingPortal(AStackPoint *pt, fixed_t alpha, sector_t *sector)
+{
+	bool fail = false;
+	sector->validcount = validcount;
+	for(int i=0; i<sector->linecount; i++)
+	{
+		line_t *line = sector->lines[i];
+		sector_t *backsector = sector == line->frontsector? line->backsector : line->frontsector;
+		if (line->backsector == line->frontsector) continue;
+		if (backsector == NULL) { fail = true; continue; }
+		if (backsector->validcount == validcount) continue;
+		if (backsector->CeilingSkyBox == pt) continue;
+
+		// Check if the backside would map to the same visplane
+		if (backsector->CeilingSkyBox != NULL) { fail = true; continue; }
+		if (backsector->ceilingplane != sector->ceilingplane) { fail = true; continue; }
+		if (backsector->lightlevel != sector->lightlevel) { fail = true; continue; }
+		if (backsector->GetTexture(sector_t::ceiling)		!= sector->GetTexture(sector_t::ceiling)) { fail = true; continue; }
+		if (backsector->GetXOffset(sector_t::ceiling)		!= sector->GetXOffset(sector_t::ceiling)) { fail = true; continue; }
+		if (backsector->GetYOffset(sector_t::ceiling)		!= sector->GetYOffset(sector_t::ceiling)) { fail = true; continue; }
+		if (backsector->GetXScale(sector_t::ceiling)		!= sector->GetXScale(sector_t::ceiling)) { fail = true; continue; }
+		if (backsector->GetYScale(sector_t::ceiling)		!= sector->GetYScale(sector_t::ceiling)) { fail = true; continue; }
+		if (backsector->GetAngle(sector_t::ceiling)		!= sector->GetAngle(sector_t::ceiling)) { fail = true; continue; }
+		if (SpreadCeilingPortal(pt, alpha, backsector)) { fail = true; continue; }
+	}
+	if (!fail) 
+	{
+		sector->CeilingSkyBox = pt;
+		sector->SetAlpha(sector_t::ceiling, alpha);
+	}
+	return fail;
+}
+
+static bool SpreadFloorPortal(AStackPoint *pt, fixed_t alpha, sector_t *sector)
+{
+	bool fail = false;
+	sector->validcount = validcount;
+	for(int i=0; i<sector->linecount; i++)
+	{
+		line_t *line = sector->lines[i];
+		sector_t *backsector = sector == line->frontsector? line->backsector : line->frontsector;
+		if (line->backsector == line->frontsector) continue;
+		if (backsector == NULL) { fail = true; continue; }
+		if (backsector->validcount == validcount) continue;
+		if (backsector->FloorSkyBox == pt) continue;
+
+		// Check if the backside would map to the same visplane
+		if (backsector->FloorSkyBox != NULL) { fail = true; continue; }
+		if (backsector->floorplane != sector->ceilingplane) { fail = true; continue; }
+		if (backsector->lightlevel != sector->lightlevel) { fail = true; continue; }
+		if (backsector->GetTexture(sector_t::floor)		!= sector->GetTexture(sector_t::floor)) { fail = true; continue; }
+		if (backsector->GetXOffset(sector_t::floor)		!= sector->GetXOffset(sector_t::floor)) { fail = true; continue; }
+		if (backsector->GetYOffset(sector_t::floor)		!= sector->GetYOffset(sector_t::floor)) { fail = true; continue; }
+		if (backsector->GetXScale(sector_t::floor)		!= sector->GetXScale(sector_t::floor)) { fail = true; continue; }
+		if (backsector->GetYScale(sector_t::floor)		!= sector->GetYScale(sector_t::floor)) { fail = true; continue; }
+		if (backsector->GetAngle(sector_t::floor)		!= sector->GetAngle(sector_t::floor)) { fail = true; continue; }
+		if (SpreadFloorPortal(pt, alpha, backsector)) { fail = true; continue; }
+	}
+	if (!fail) 
+	{
+		sector->FloorSkyBox = pt;
+		sector->SetAlpha(sector_t::floor, alpha);
+	}
+	return fail;
+}
+
 void P_SetupPortals()
 {
 	TThinkerIterator<AStackPoint> it;
@@ -936,6 +1002,20 @@ void P_SetupPortals()
 			}
 		}
 	}
+	validcount++;
+	// Some fudging to preserve an unintended 'portal bleeding' effect caused by incomplete checks in the rendering code.
+	// Due to the addition of linedef-based portals this effect no longer works.
+	for(int i=0;i<numsectors; i++)
+	{
+		if (sectors[i].CeilingSkyBox != NULL && sectors[i].CeilingSkyBox->bAlways && sectors[i].validcount != validcount)
+		{
+			SpreadCeilingPortal(barrier_cast<AStackPoint*>(sectors[i].CeilingSkyBox), sectors[i].GetAlpha(sector_t::ceiling), &sectors[i]);
+		}
+		if (sectors[i].FloorSkyBox != NULL && sectors[i].FloorSkyBox->bAlways && sectors[i].validcount != validcount)
+		{
+			SpreadFloorPortal(barrier_cast<AStackPoint*>(sectors[i].FloorSkyBox), sectors[i].GetAlpha(sector_t::floor), &sectors[i]);
+		}
+	}
 }
 
 inline void SetPortal(sector_t *sector, int plane, AStackPoint *portal, fixed_t alpha)