From 9b1ec60e3c1e69f26174f82b1b44f6245702a322 Mon Sep 17 00:00:00 2001
From: Roman Fomin <rfomin@gmail.com>
Date: Mon, 12 Jun 2023 14:17:04 +0700
Subject: [PATCH] fix door interpolation in Doom2 MAP19 (#1100)

* fix Boom elevators
---
 src/p_floor.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/p_floor.c b/src/p_floor.c
index 774777f8..f1a800b1 100644
--- a/src/p_floor.c
+++ b/src/p_floor.c
@@ -61,8 +61,13 @@ result_e T_MovePlane
   fixed_t       lastpos;     
   fixed_t       destheight; //jff 02/04/98 used to keep floors/ceilings
                             // from moving thru each other
+  static boolean moved_ceil, moved_floor;
 
-  sector->oldgametic = gametic;
+  if (sector->oldgametic != gametic)
+  {
+    sector->oldgametic = gametic;
+    moved_ceil = moved_floor = false;
+  }
 
   switch(floorOrCeiling)
   {
@@ -70,7 +75,11 @@ result_e T_MovePlane
       // Moving a floor
 
       // [AM] Store old sector heights for interpolation.
-      sector->oldfloorheight = sector->floorheight;
+      if (!moved_floor)
+      {
+        sector->oldfloorheight = sector->floorheight;
+        moved_floor = true;
+      }
 
       switch(direction)
       {
@@ -150,7 +159,11 @@ result_e T_MovePlane
       // moving a ceiling
 
       // [AM] Store old sector heights for interpolation.
-      sector->oldceilingheight = sector->ceilingheight;
+      if (!moved_ceil)
+      {
+        sector->oldceilingheight = sector->ceilingheight;
+        moved_ceil = true;
+      }
 
       switch(direction)
       {