From 1f73c9cf9954e736c567ffe0bc144ed51b9868e3 Mon Sep 17 00:00:00 2001
From: spherallic <spherallic@gmail.com>
Date: Sun, 11 Sep 2022 16:15:50 +0200
Subject: [PATCH] Add flag to per-sector gravity for overriding MF2_OBJECTFLIP

---
 extras/conf/SRB2-22.cfg | 1 +
 src/p_mobj.c            | 8 ++++++++
 src/p_spec.c            | 3 +++
 src/r_defs.h            | 1 +
 4 files changed, 13 insertions(+)

diff --git a/extras/conf/SRB2-22.cfg b/extras/conf/SRB2-22.cfg
index 006430422..6abf14a35 100644
--- a/extras/conf/SRB2-22.cfg
+++ b/extras/conf/SRB2-22.cfg
@@ -578,6 +578,7 @@ linedeftypes
 			title = "Per-Sector Gravity";
 			prefix = "(1)";
 			flags64text = "[6] Flip in reverse gravity";
+			flags8192text = "[13] Override MF2_OBJECTFLIP";
 		}
 
 		5
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 36253569b..a4f2147e5 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -1464,7 +1464,11 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 			gravityadd = -FixedMul(gravity, gravfactor);
 
 			if ((rover->master->frontsector->flags & MSF_GRAVITYFLIP) && gravityadd > 0)
+			{
+				if (rover->master->frontsector->specialflags & SSF_GRAVITYOVERRIDE)
+					mo->flags2 &= ~MF2_OBJECTFLIP;
 				mo->eflags |= MFE_VERTICALFLIP;
+			}
 
 			no3dfloorgrav = false;
 			break;
@@ -1476,7 +1480,11 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 		gravityadd = -FixedMul(gravity, P_GetSectorGravityFactor(mo->subsector->sector));
 
 		if ((mo->subsector->sector->flags & MSF_GRAVITYFLIP) && gravityadd > 0)
+		{
+			if (mo->subsector->sector->specialflags & SSF_GRAVITYOVERRIDE)
+				mo->flags2 &= ~MF2_OBJECTFLIP;
 			mo->eflags |= MFE_VERTICALFLIP;
+		}
 	}
 
 	// Less gravity underwater.
diff --git a/src/p_spec.c b/src/p_spec.c
index 03ed298e8..4ebf5ccd3 100644
--- a/src/p_spec.c
+++ b/src/p_spec.c
@@ -6283,6 +6283,9 @@ void P_SpawnSpecials(boolean fromnetsave)
 					else
 						sectors[s].flags &= ~MSF_GRAVITYFLIP;
 
+					if (lines[i].flags & ML_EFFECT6)
+						sectors[s].specialflags |= SSF_GRAVITYOVERRIDE;
+
 					CheckForReverseGravity |= (sectors[s].flags & MSF_GRAVITYFLIP);
 				}
 				break;
diff --git a/src/r_defs.h b/src/r_defs.h
index e91f864ac..38c6e25f7 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -315,6 +315,7 @@ typedef enum
 	SSF_FINISHLINE = 1<<17,
 	SSF_ROPEHANG = 1<<18,
 	SSF_JUMPFLIP = 1<<19,
+	SSF_GRAVITYOVERRIDE = 1<<20,
 } sectorspecialflags_t;
 
 typedef enum