diff --git a/source/games/duke/src/_polymost.cpp b/source/games/duke/src/_polymost.cpp
index cf7bcf8d2..021ddf42c 100644
--- a/source/games/duke/src/_polymost.cpp
+++ b/source/games/duke/src/_polymost.cpp
@@ -168,16 +168,16 @@ void renderMirror(int cposx, int cposy, int cposz, binangle cang, fixedhoriz cho
 		int dst = 0x7fffffff, i = 0;
 		for (int k = 0; k < mirrorcnt; k++)
 		{
-			int j = abs(wall[mirrorwall[k]].x - cposx) + abs(wall[mirrorwall[k]].y - cposy);
+			int j = abs(mirrorwall[k]->x - cposx) + abs(mirrorwall[k]->y - cposy);
 			if (j < dst) dst = j, i = k;
 		}
 
-		if (wall[mirrorwall[i]].overpicnum == TILE_MIRROR)
+		if (mirrorwall[i]->overpicnum == TILE_MIRROR)
 		{
 			int tposx, tposy;
 			fixed_t tang;
 
-			renderPrepareMirror(cposx, cposy, cposz, cang.asq16(), choriz.asq16(), mirrorwall[i], &tposx, &tposy, &tang);
+			renderPrepareMirror(cposx, cposy, cposz, cang.asq16(), choriz.asq16(), wallnum(mirrorwall[i]), &tposx, &tposy, &tang);
 
 			int j = g_visibility;
 			g_visibility = (j >> 1) + (j >> 2);
diff --git a/source/games/duke/src/global.cpp b/source/games/duke/src/global.cpp
index a7df7869b..bb47058dd 100644
--- a/source/games/duke/src/global.cpp
+++ b/source/games/duke/src/global.cpp
@@ -116,7 +116,7 @@ int numcyclers;								// sector lighting effects
 Cycler cyclers[MAXCYCLERS];
 int mirrorcnt;
 int mirrorsector[64];					// mirrors
-int mirrorwall[64];
+walltype* mirrorwall[64];
 int numplayersprites;						// player management for some SEs.
 player_orig po[MAXPLAYERS];
 unsigned ambientfx;							// used by soundtag and soundtagonce script commands. If exported, export the commands, not the data!
diff --git a/source/games/duke/src/global.h b/source/games/duke/src/global.h
index b87d5019b..f7b5548a2 100644
--- a/source/games/duke/src/global.h
+++ b/source/games/duke/src/global.h
@@ -98,7 +98,7 @@ extern int cloudclock;
 extern DDukeActor *spriteq[1024];
 extern Cycler cyclers[MAXCYCLERS];
 extern int mirrorsector[64];
-extern int mirrorwall[64];
+extern walltype* mirrorwall[64];
 
 extern int wupass;
 extern int chickenplant;
diff --git a/source/games/duke/src/premap_d.cpp b/source/games/duke/src/premap_d.cpp
index 5e6847a4b..7ac35bc34 100644
--- a/source/games/duke/src/premap_d.cpp
+++ b/source/games/duke/src/premap_d.cpp
@@ -389,7 +389,7 @@ void prelevel_d(int g)
 				assert(wallnum(&wal) > 0);
 				sectp->ceilingpicnum = MIRROR;
 				sectp->floorpicnum = MIRROR;
-				mirrorwall[mirrorcnt] = wallnum(&wal);
+				mirrorwall[mirrorcnt] = &wal;
 				mirrorsector[mirrorcnt] = sectnum(sectp);
 				mirrorcnt++;
 				continue;
diff --git a/source/games/duke/src/premap_r.cpp b/source/games/duke/src/premap_r.cpp
index a01e44ef5..b0a3bb3e7 100644
--- a/source/games/duke/src/premap_r.cpp
+++ b/source/games/duke/src/premap_r.cpp
@@ -732,7 +732,7 @@ void prelevel_r(int g)
 			{
 				sector[j].ceilingpicnum = MIRROR;
 				sector[j].floorpicnum = MIRROR;
-				mirrorwall[mirrorcnt] = i;
+				mirrorwall[mirrorcnt] = wal;
 				mirrorsector[mirrorcnt] = j;
 				mirrorcnt++;
 				continue;