diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 15fcfe881..4bc01a697 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -778,6 +778,7 @@ set (PCH_SOURCES
 	build/src/voxmodel.cpp
 
 	core/movie/playmve.cpp
+	core/automap.cpp
 	core/cheats.cpp
 	core/cheathandler.cpp
 	core/mathutil.cpp
diff --git a/source/blood/src/actor.cpp b/source/blood/src/actor.cpp
index 69319a7b7..8d3e193a3 100644
--- a/source/blood/src/actor.cpp
+++ b/source/blood/src/actor.cpp
@@ -26,6 +26,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 
 #include "build.h"
+#include "automap.h"
 #include "pragmas.h"
 #include "mmulti.h"
 #include "common.h"
@@ -6191,7 +6192,7 @@ spritetype * actSpawnThing(int nSector, int x, int y, int z, int nThingType)
         pSprite->xrepeat = pThingInfo->xrepeat;
     if (pThingInfo->yrepeat)
         pSprite->yrepeat = pThingInfo->yrepeat;
-    SetBitString(show2dsprite, pSprite->index);
+    show2dsprite.Set(pSprite->index);
     switch (nThingType) {
     case kThingVoodooHead:
         pXThing->data1 = 0;
@@ -6307,7 +6308,7 @@ spritetype* actFireMissile(spritetype *pSprite, int a2, int a3, int a4, int a5,
     }
     spritetype *pMissile = actSpawnSprite(pSprite->sectnum, x, y, z, 5, 1);
     int nMissile = pMissile->index;
-    SetBitString(show2dsprite, nMissile);
+    show2dsprite.Set(nMissile);
     pMissile->type = nType;
     pMissile->shade = pMissileInfo->shade;
     pMissile->pal = 0;
diff --git a/source/blood/src/blood.cpp b/source/blood/src/blood.cpp
index d2089b917..d8a5d44a4 100644
--- a/source/blood/src/blood.cpp
+++ b/source/blood/src/blood.cpp
@@ -29,6 +29,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "common.h"
 #include "common_game.h"
 #include "g_input.h"
+#include "automap.h"
 
 #include "db.h"
 #include "blood.h"
diff --git a/source/blood/src/db.cpp b/source/blood/src/db.cpp
index 59ddb64c5..20da50cca 100644
--- a/source/blood/src/db.cpp
+++ b/source/blood/src/db.cpp
@@ -29,6 +29,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "zstring.h"
 #include "m_crc32.h"
 #include "md4.h"
+#include "automap.h"
 
 //#include "actor.h"
 #include "globals.h"
diff --git a/source/blood/src/messages.cpp b/source/blood/src/messages.cpp
index 660daac91..b7aa16109 100644
--- a/source/blood/src/messages.cpp
+++ b/source/blood/src/messages.cpp
@@ -39,6 +39,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "cheathandler.h"
 #include "d_protocol.h"
 #include "gamestate.h"
+#include "automap.h"
 
 BEGIN_BLD_NS
 
diff --git a/source/blood/src/player.cpp b/source/blood/src/player.cpp
index 1d1f0623a..8773daaf9 100644
--- a/source/blood/src/player.cpp
+++ b/source/blood/src/player.cpp
@@ -47,6 +47,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "nnexts.h"
 #include "gstrings.h"
 #include "gamestate.h"
+#include "automap.h"
 
 BEGIN_BLD_NS
 
diff --git a/source/blood/src/view.cpp b/source/blood/src/view.cpp
index c65c25e8d..c0b45b1e3 100644
--- a/source/blood/src/view.cpp
+++ b/source/blood/src/view.cpp
@@ -45,6 +45,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "v_video.h"
 #include "v_font.h"
 #include "statusbar.h"
+#include "automap.h"
 #include "glbackend/glbackend.h"
 
 BEGIN_BLD_NS
diff --git a/source/build/include/build.h b/source/build/include/build.h
index 938693037..587a40966 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -435,26 +435,6 @@ EXTERN int16_t headspritesect[MAXSECTORS+1], headspritestat[MAXSTATUS+1];
 EXTERN int16_t prevspritesect[MAXSPRITES], prevspritestat[MAXSPRITES];
 EXTERN int16_t nextspritesect[MAXSPRITES], nextspritestat[MAXSPRITES];
 
-
-    //These variables are for auto-mapping with the draw2dscreen function.
-    //When you load a new board, these bits are all set to 0 - since
-    //you haven't mapped out anything yet.  Note that these arrays are
-    //bit-mapped.
-    //If you want draw2dscreen() to show sprite #54 then you say:
-    //   spritenum = 54;
-    //   show2dsprite[spritenum>>3] |= (1<<(spritenum&7));
-    //And if you want draw2dscreen() to not show sprite #54 then you say:
-    //   spritenum = 54;
-    //   show2dsprite[spritenum>>3] &= ~(1<<(spritenum&7));
-
-EXTERN int automapping;
-EXTERN FixedBitArray<MAXSECTORS> show2dsector;
-EXTERN bool gFullMap;
-
-EXTERN char show2dwall[(MAXWALLS+7)>>3];
-EXTERN char show2dsprite[(MAXSPRITES+7)>>3];
-
-
 EXTERN uint8_t gotpic[(MAXTILES+7)>>3];
 EXTERN char gotsector[(MAXSECTORS+7)>>3];
 
diff --git a/source/build/include/cstat.h b/source/build/include/cstat.h
index 92b98d5b7..51aa9b135 100644
--- a/source/build/include/cstat.h
+++ b/source/build/include/cstat.h
@@ -1,3 +1,4 @@
+#pragma once
 // nobody uses these. What's so cool about naked numbers? :(
 
 // system defines for status bits
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 89fba4f17..8f138dbbf 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -10,6 +10,7 @@
 
 #include "gl_load.h"
 #include "build.h"
+#include "automap.h"
 
 #include "imagehelpers.h"
 #include "common.h"
diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index bb6633fb1..507e2792c 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -6,6 +6,7 @@ Ken Silverman's official web site: http://www.advsys.net/ken
 
 
 #include "build.h"
+#include "automap.h"
 #include "common.h"
 #include "engine_priv.h"
 #include "mdsprite.h"
@@ -2633,7 +2634,7 @@ void polymost_drawrooms()
         if (automapping)
         {
             for (int z=bunchfirst[closest]; z>=0; z=bunchp2[z])
-                show2dwall[thewall[z]>>3] |= pow2char[thewall[z]&7];
+                show2dwall.Set(thewall[z]);
         }
 
         numbunches--;
@@ -3626,7 +3627,7 @@ void polymost_drawsprite(int32_t snum)
     }
 
     if (automapping == 1 && (unsigned)spritenum < MAXSPRITES)
-        show2dsprite[spritenum>>3] |= pow2char[spritenum&7];
+        show2dsprite.Set(spritenum);
 
 _drawsprite_return:
     ;
diff --git a/source/core/automap.cpp b/source/core/automap.cpp
new file mode 100644
index 000000000..c554e8ca1
--- /dev/null
+++ b/source/core/automap.cpp
@@ -0,0 +1,105 @@
+//-------------------------------------------------------------------------
+/*
+Copyright (C) 1996, 2003 - 3D Realms Entertainment
+Copyright (C) 2020 - Christoph Oelckers
+
+This file is part of Duke Nukem 3D version 1.5 - Atomic Edition
+
+Duke Nukem 3D is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+Original Source: 1996 - Todd Replogle
+Prepared for public release: 03/21/2003 - Charlie Wiederhold, 3D Realms
+Modifications for JonoF's port by Jonathon Fowler (jf@jonof.id.au)
+*/
+//------------------------------------------------------------------------- 
+
+#include "automap.h"
+#include "cstat.h"
+#include "c_dispatch.h"
+#include "c_cvars.h"
+#include "gstrings.h"
+#include "printf.h"
+
+
+bool automapping;
+bool gFullMap;
+FixedBitArray<MAXSECTORS> show2dsector;
+FixedBitArray<MAXWALLS> show2dwall;
+FixedBitArray<MAXSPRITES> show2dsprite;
+
+//---------------------------------------------------------------------------
+//
+//
+//
+//---------------------------------------------------------------------------
+
+CCMD(allmap)
+{
+	if (!CheckCheatmode(true, false))
+	{
+		gFullMap = !gFullMap;
+		Printf("%s\n", GStrings(gFullMap ? "SHOW MAP: ON" : "SHOW MAP: OFF"));
+	}
+}
+
+//---------------------------------------------------------------------------
+//
+//
+//
+//---------------------------------------------------------------------------
+
+void ClearAutomap()
+{
+    show2dsector.Zero();
+    show2dwall.Zero();
+    show2dsprite.Zero();
+}
+
+//---------------------------------------------------------------------------
+//
+//
+//
+//---------------------------------------------------------------------------
+
+void MarkSectorSeen(int i)
+{
+	if (i >= 0) 
+	{
+		show2dsector.Set(i);
+		auto wal = &wall[sector[i].wallptr];
+		for (int j = sector[i].wallnum; j > 0; j--, wal++)
+		{
+			i = wal->nextsector;
+			if (i < 0) continue;
+			if (wal->cstat & 0x0071) continue;
+			if (wall[wal->nextwall].cstat & 0x0071) continue;
+			if (sector[i].lotag == 32767) continue;
+			if (sector[i].ceilingz >= sector[i].floorz) continue;
+			show2dsector.Set(i);
+		}
+	}
+}
+
+//---------------------------------------------------------------------------
+//
+//
+//
+//---------------------------------------------------------------------------
+
+void DrawOverheadMap(int pl_x, int pl_y, int pl_angle)
+{
+}
+
diff --git a/source/core/automap.h b/source/core/automap.h
new file mode 100644
index 000000000..0d14a7998
--- /dev/null
+++ b/source/core/automap.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "tarray.h"
+#include "build.h"
+
+extern bool automapping;
+extern bool gFullMap;
+extern FixedBitArray<MAXSECTORS> show2dsector;
+extern FixedBitArray<MAXWALLS> show2dwall;
+extern FixedBitArray<MAXSPRITES> show2dsprite;
+
+
+void ClearAutomap();
+void MarkSectorSeen(int sect);
+void DrawOverheadMap(int x, int y, int ang);
+
diff --git a/source/core/cheats.cpp b/source/core/cheats.cpp
index 2c63150bc..ade259f82 100644
--- a/source/core/cheats.cpp
+++ b/source/core/cheats.cpp
@@ -150,15 +150,6 @@ CCMD(noclip)
 	}
 }
 
-CCMD(allmap)
-{
-	if (!CheckCheatmode(true, false))
-	{
-		gFullMap = !gFullMap;
-		Printf("%s\n", GStrings(gFullMap ? "SHOW MAP: ON" : "SHOW MAP: OFF"));
-	}
-}
-
 //---------------------------------------------------------------------------
 //
 //
diff --git a/source/core/gamecontrol.h b/source/core/gamecontrol.h
index 5748649c5..c4215d732 100644
--- a/source/core/gamecontrol.h
+++ b/source/core/gamecontrol.h
@@ -57,12 +57,6 @@ void CONFIG_ReadCombatMacros();
 int GameMain();
 int GetAutomapZoom(int gZoom);
 
-// transitional helper inlines to define the interface before rewriting the code.
-inline void ClearAutomap() {}
-inline void MarkSectorSeen(int sect) {}
-inline void DrawOverheadMap(int x, int y, int ang) {} 
-
-
 void DrawCrosshair(int deftile, int health, double xdelta, double scale, PalEntry color = 0xffffffff);
 void updatePauseStatus();
 void DeferedStartGame(MapRecord* map, int skill);
diff --git a/source/core/savegamehelp.cpp b/source/core/savegamehelp.cpp
index 4e9f0b66a..965553c68 100644
--- a/source/core/savegamehelp.cpp
+++ b/source/core/savegamehelp.cpp
@@ -474,7 +474,6 @@ void SaveEngineState()
 	fw->Write(connectpoint2, sizeof(connectpoint2));
 	fw->Write(&randomseed, sizeof(randomseed));
 	fw->Write(&numshades, sizeof(numshades));
-	fw->Write(&automapping, sizeof(automapping));
 	fw->Write(&showinvisibility, sizeof(showinvisibility));
 	WriteMagic(fw);
 
@@ -532,7 +531,6 @@ void LoadEngineState()
 		fr.Read(connectpoint2, sizeof(connectpoint2));
 		fr.Read(&randomseed, sizeof(randomseed));
 		fr.Read(&numshades, sizeof(numshades));
-		fr.Read(&automapping, sizeof(automapping));
 		fr.Read(&showinvisibility, sizeof(showinvisibility));
 		CheckMagic(fr);
 
diff --git a/source/exhumed/src/cheats.cpp b/source/exhumed/src/cheats.cpp
index 06cb41dda..8f7258d36 100644
--- a/source/exhumed/src/cheats.cpp
+++ b/source/exhumed/src/cheats.cpp
@@ -16,6 +16,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 //-------------------------------------------------------------------------
 #include "ns.h"
+#include "automap.h"
 #include "compat.h"
 #include "common.h"
 #include "engine.h"
diff --git a/source/exhumed/src/init.cpp b/source/exhumed/src/init.cpp
index 5912407bf..8383366b6 100644
--- a/source/exhumed/src/init.cpp
+++ b/source/exhumed/src/init.cpp
@@ -16,6 +16,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 //-------------------------------------------------------------------------
 #include "ns.h"
+#include "automap.h"
 #include "compat.h"
 #include "aistuff.h"
 #include "player.h"
diff --git a/source/exhumed/src/map.cpp b/source/exhumed/src/map.cpp
index 3594b4c68..086debc6e 100644
--- a/source/exhumed/src/map.cpp
+++ b/source/exhumed/src/map.cpp
@@ -22,6 +22,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "exhumed.h"
 #include "view.h"
 #include "v_2ddrawer.h"
+#include "automap.h"
 
 BEGIN_PS_NS
 
diff --git a/source/games/duke/src/cheats.cpp b/source/games/duke/src/cheats.cpp
index 7c31f80e1..f02768441 100644
--- a/source/games/duke/src/cheats.cpp
+++ b/source/games/duke/src/cheats.cpp
@@ -40,6 +40,7 @@ source as it is released.
 #include "cheathandler.h"
 #include "c_dispatch.h"
 #include "gamestate.h"
+#include "automap.h"
 
 EXTERN_CVAR(Int, developer)
 EXTERN_CVAR(Bool, sv_cheats)
diff --git a/source/games/duke/src/game_misc.cpp b/source/games/duke/src/game_misc.cpp
index ddd5b4f44..cb4afe101 100644
--- a/source/games/duke/src/game_misc.cpp
+++ b/source/games/duke/src/game_misc.cpp
@@ -31,6 +31,7 @@ Modifications for JonoF's port by Jonathon Fowler (jf@jonof.id.au)
 
 #include "ns.h"	// Must come before everything else!
 
+#include "automap.h"
 #include "duke3d.h"
 #include "m_argv.h"
 #include "mapinfo.h"
diff --git a/source/games/duke/src/premap.cpp b/source/games/duke/src/premap.cpp
index a54d49ddf..d3fbc24f1 100644
--- a/source/games/duke/src/premap.cpp
+++ b/source/games/duke/src/premap.cpp
@@ -33,6 +33,7 @@ Prepared for public release: 03/21/2003 - Charlie Wiederhold, 3D Realms
 #include "statistics.h"
 #include "gamestate.h"
 #include "sbar.h"
+#include "automap.h"
 
 BEGIN_DUKE_NS  
 
diff --git a/source/games/duke/src/spawn.cpp b/source/games/duke/src/spawn.cpp
index efeb59152..defe73320 100644
--- a/source/games/duke/src/spawn.cpp
+++ b/source/games/duke/src/spawn.cpp
@@ -36,6 +36,7 @@ source as it is released.
 #include "ns.h"
 #include "global.h"
 #include "sounds.h"
+#include "automap.h"
 
 BEGIN_DUKE_NS
 
@@ -115,8 +116,8 @@ short EGS(short whatsect, int s_x, int s_y, int s_z, short s_pn, signed char s_s
 		s->hitag = 0;
 	}
 
-	if (show2dsector[s->sectnum]) show2dsprite[i >> 3] |= (1 << (i & 7));
-	else show2dsprite[i >> 3] &= ~(1 << (i & 7));
+	if (show2dsector[s->sectnum]) show2dsprite.Set(i);
+	else show2dsprite.Clear(i);
 
 	spriteext[i] = {};
 	spritesmooth[i] = {};
diff --git a/source/sw/src/draw.cpp b/source/sw/src/draw.cpp
index e694925be..64ee08af6 100644
--- a/source/sw/src/draw.cpp
+++ b/source/sw/src/draw.cpp
@@ -27,6 +27,7 @@ Prepared for public release: 03/28/2005 - Charlie Wiederhold, 3D Realms
 
 #define QUIET
 #include "build.h"
+#include "automap.h"
 #include "pragmas.h"
 
 
diff --git a/source/sw/src/game.cpp b/source/sw/src/game.cpp
index f6bf7063a..5a3bd88f8 100644
--- a/source/sw/src/game.cpp
+++ b/source/sw/src/game.cpp
@@ -42,6 +42,7 @@ Prepared for public release: 03/28/2005 - Charlie Wiederhold, 3D Realms
 #include "lists.h"
 #include "network.h"
 #include "pal.h"
+#include "automap.h"
 
 
 #include "mytypes.h"