From cc4f1f21f96e34dfac3df13c935c98cc25920b8d Mon Sep 17 00:00:00 2001
From: NY00123 <ny00@outlook.com>
Date: Mon, 13 Apr 2020 22:47:19 +0300
Subject: [PATCH] Interpolation fixes for SW:

draw.cpp: Fix the lack of interpolation while walking on a sector
object, like the bus roof or the floor of the train in Seppuku Station.
track.cpp: Make sure the player's location and angle aren't mistakenly
interpolated while standing on a moving sector object as a consequence.
---
 source/sw/src/draw.cpp  | 11 +++++++----
 source/sw/src/track.cpp |  5 ++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/source/sw/src/draw.cpp b/source/sw/src/draw.cpp
index 525d6f4b9..5dff0bd2e 100644
--- a/source/sw/src/draw.cpp
+++ b/source/sw/src/draw.cpp
@@ -2056,10 +2056,13 @@ drawscreen(PLAYERp pp)
 
     if (pp->sop_riding || pp->sop_control)
     {
-        tx = pp->posx;
-        ty = pp->posy;
-        tz = pp->posz;
-        tq16ang = pp->q16ang;
+        if (pp->sop_control)
+        {
+            tx = pp->posx;
+            ty = pp->posy;
+            tz = pp->posz;
+            tq16ang = pp->q16ang;
+        }
         tsectnum = pp->cursectnum;
         updatesectorz(tx, ty, tz, &tsectnum);
     }
diff --git a/source/sw/src/track.cpp b/source/sw/src/track.cpp
index 3fabb3295..429d03d08 100644
--- a/source/sw/src/track.cpp
+++ b/source/sw/src/track.cpp
@@ -1630,6 +1630,8 @@ MovePlayer(PLAYERp pp, SECTOR_OBJECTp sop, int nx, int ny)
     pp->posx += BOUND_4PIX(nx);
     pp->posy += BOUND_4PIX(ny);
 
+    pp->oposx = pp->posx;
+    pp->oposy = pp->posy;
 
     if (TEST(sop->flags, SOBJ_DONT_ROTATE))
     {
@@ -1674,7 +1676,7 @@ MovePlayer(PLAYERp pp, SECTOR_OBJECTp sop, int nx, int ny)
 
     // New angle is formed by taking last known angle and
     // adjusting by the delta angle
-    pp->q16ang = fix16_from_int(NORM_ANGLE(pp->RevolveAng + pp->RevolveDeltaAng));
+    pp->oq16ang = pp->q16ang = fix16_from_int(NORM_ANGLE(pp->RevolveAng + pp->RevolveDeltaAng));
 
     UpdatePlayerSprite(pp);
 }
@@ -1927,6 +1929,7 @@ PlayerPart:
                     pp->SpriteP->z = pp->loz;
                 }
             }
+            pp->oposz = pp->posz;
         }
         else
         {