From 5556756d43c98e1d2df71e5b702084bfd4cb5739 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 13 Jun 2021 09:32:30 +0200
Subject: [PATCH] - map fix for Hickston Swamp (RR mod) E1L3:

Wall sprite is placed in the wrong sector which makes the new renderer's far stricter checks to reduce sprite flicker fail to position it correctly.
---
 source/core/gamefuncs.h                           | 15 +++++++++++++++
 source/core/maphack.cpp                           | 10 ++++++++++
 .../35ffa2f17ab074263f0963449dc7d463.mhk          |  2 ++
 3 files changed, 27 insertions(+)
 create mode 100644 wadsrc/static/engine/compatibility/35ffa2f17ab074263f0963449dc7d463.mhk

diff --git a/source/core/gamefuncs.h b/source/core/gamefuncs.h
index dd3191a79..bc11f3428 100644
--- a/source/core/gamefuncs.h
+++ b/source/core/gamefuncs.h
@@ -77,16 +77,31 @@ inline DVector2 WallDelta(const walltype* wallnum)
     return WallEnd(wallnum) - WallStart(wallnum);
 }
 
+inline double SpriteX(spritetype* spr)
+{
+    return spr->x * (1 / 16.);
+}
+
 inline double SpriteX(int wallnum)
 {
     return sprite[wallnum].x * (1 / 16.);
 }
 
+inline double SpriteY(spritetype* spr)
+{
+    return spr->y * (1 / -16.);
+}
+
 inline double SpriteY(int wallnum)
 {
     return sprite[wallnum].y * (1 / -16.);
 }
 
+inline DVector2 SpritePos(spritetype* spr)
+{
+    return { SpriteX(spr), SpriteY(spr) };
+}
+
 inline double PointOnLineSide(double x, double y, double linex, double liney, double deltax, double deltay)
 {
     return (x - linex) * deltay - (y - liney) * deltax;
diff --git a/source/core/maphack.cpp b/source/core/maphack.cpp
index e2749c281..70f5a37df 100644
--- a/source/core/maphack.cpp
+++ b/source/core/maphack.cpp
@@ -146,6 +146,16 @@ static int32_t LoadMapHack(const char *filename)
                 blockingpairs[currentwall].Push(sc.Number);
             }
         }
+        else if (sc.Compare("sector"))
+        {
+            if (sc.CheckNumber())
+            {
+                if (currentsprite != -1 && validateSprite())
+                {
+                    sprite[currentsprite].sectnum = sc.Number;
+                }
+            }
+        }
         else if (sc.Compare("picnum"))
         {
             if (sc.CheckNumber())
diff --git a/wadsrc/static/engine/compatibility/35ffa2f17ab074263f0963449dc7d463.mhk b/wadsrc/static/engine/compatibility/35ffa2f17ab074263f0963449dc7d463.mhk
new file mode 100644
index 000000000..8e7c73da6
--- /dev/null
+++ b/wadsrc/static/engine/compatibility/35ffa2f17ab074263f0963449dc7d463.mhk
@@ -0,0 +1,2 @@
+// Hickston Swamp E1L3 (RR mod) wall sprite in wrong sector flickers with new renderer
+sprite 225 sector 565