From 1f489d5dbec73f397023474ca08962e886874bae Mon Sep 17 00:00:00 2001
From: Mitchell Richters <mjr4077au@gmail.com>
Date: Sun, 8 Jan 2023 22:12:50 +1100
Subject: [PATCH] - SW: Don't back up the actor's Z after changing it in
 `KeepActorOnFloor()`.
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* This seems completely wrong and kills Z interpolation on slopes, vators, etc.
* Thanks Graf 😁
* Fixes #844.
* Partially addresses #845.
---
 source/games/sw/src/actor.cpp | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/source/games/sw/src/actor.cpp b/source/games/sw/src/actor.cpp
index 2517730f2..3017a68fb 100644
--- a/source/games/sw/src/actor.cpp
+++ b/source/games/sw/src/actor.cpp
@@ -549,7 +549,6 @@ void KeepActorOnFloor(DSWActor* actor)
                 actor->user.Flags &= ~(SPR_SWIMMING);
                 actor->spr.cstat &= ~(CSTAT_SPRITE_YCENTER);
                 actor->spr.pos.Z = actor->user.oz = actor->user.loz;
-                actor->backupz();
                 return;
             }
 
@@ -560,7 +559,6 @@ void KeepActorOnFloor(DSWActor* actor)
 
             // are swimming
             actor->spr.pos.Z = actor->user.oz = actor->user.loz - depth;
-            actor->backupz();
         }
         else
         {
@@ -569,7 +567,6 @@ void KeepActorOnFloor(DSWActor* actor)
             {
                 NewStateGroup(actor, actor->user.ActorActionSet->Swim);
                 actor->spr.pos.Z = actor->user.oz = actor->user.loz - depth;
-                actor->backupz();
                 actor->user.Flags |= (SPR_SWIMMING);
                 actor->spr.cstat |= (CSTAT_SPRITE_YCENTER);
             }
@@ -578,7 +575,6 @@ void KeepActorOnFloor(DSWActor* actor)
                 actor->user.Flags &= ~(SPR_SWIMMING);
                 actor->spr.cstat &= ~(CSTAT_SPRITE_YCENTER);
                 actor->spr.pos.Z = actor->user.oz = actor->user.loz;
-                actor->backupz();
             }
         }
 
@@ -593,7 +589,6 @@ void KeepActorOnFloor(DSWActor* actor)
     if (actor->user.Flags & (SPR_MOVED))
     {
         actor->spr.pos.Z = actor->user.oz = actor->user.loz;
-        actor->backupz();
     }
     else
     {
@@ -602,7 +597,6 @@ void KeepActorOnFloor(DSWActor* actor)
         FAFgetzrangepoint(actor->spr.pos, actor->sector(),&ceilz, &ctrash, &florz, &ftrash);
 
         actor->spr.pos.Z = actor->user.oz = florz;
-        actor->backupz();
     }
 #endif
 }