From 12b97752902aa60cf7d542071f82fe1446a1a5a8 Mon Sep 17 00:00:00 2001
From: Lach <lachsrb2@gmail.com>
Date: Sat, 6 Sep 2025 15:43:00 +1000
Subject: [PATCH] Position checkpoint parts correctly in reverse gravity

---
 src/objects/checkpoint.cpp | 15 +++++++++++++++
 src/p_mobj.c               |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/src/objects/checkpoint.cpp b/src/objects/checkpoint.cpp
index c0a9dfe83..507d23aa1 100644
--- a/src/objects/checkpoint.cpp
+++ b/src/objects/checkpoint.cpp
@@ -323,6 +323,11 @@ private:
 
 		arm()->angle = angle - ANGLE_90;
 		arm()->rollangle = -(ANGLE_90) + pivot();
+
+		if (arm()->eflags & MFE_VERTICALFLIP)
+		{
+			arm()->rollangle = InvAngle(arm()->rollangle);
+		}
 	}
 
 	void pull()
@@ -337,8 +342,18 @@ private:
 			P_GetMobjHead(this) + (FixedMul(r, FSIN(pivot())) * P_MobjFlip(this))
 		);
 
+		if (orb()->eflags & MFE_VERTICALFLIP)
+		{
+			orb()->z -= orb()->height;
+		}
+
 		P_MoveOrigin(arm(), orb()->x, orb()->y, orb()->z);
 
+		if (arm()->eflags & MFE_VERTICALFLIP)
+		{
+			arm()->z += orb()->height - arm()->height;
+		}
+
 		if (speed())
 		{
 			orb()->afterimages();
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 8abc77242..f3cabf1ee 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -14582,6 +14582,11 @@ static boolean P_SetupSpawnedMapThing(mapthing_t *mthing, mobj_t *mobj)
 	}
 	case MT_CHECKPOINT_END:
 	{
+		if (mthing->options & MTF_OBJECTFLIP)
+		{
+			mobj->eflags |= MFE_VERTICALFLIP;
+			mobj->flags2 |= MF2_OBJECTFLIP;
+		}
 		Obj_LinkCheckpoint(mobj);
 		break;
 	}