diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index 73893734d..de077520c 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -2606,28 +2606,29 @@ void polymost_completeMirror()
 
 static inline int32_t polymost_findwall(tspritetype const * const tspr, vec2_t const * const tsiz, int32_t * rd)
 {
-    int32_t dist = 4, closest = -1;
+    int32_t dist = 4;
     auto const sect = tspr->sector();
     vec2_t n;
+    walltype* closest = nullptr;
 
-    for (intptr_t i=sect->wallptr; i<sect->wallptr + sect->wallnum; i++)
+    for(auto& wal : wallsofsector(sect))
     {
-        if ((wall[i].nextsector == -1 || ((sector[wall[i].nextsector].ceilingz > (tspr->z - ((tsiz->y * tspr->yrepeat) << 2))) ||
-             sector[wall[i].nextsector].floorz < tspr->z)) && !polymost_getclosestpointonwall((const vec2_t *) tspr, i, &n))
+        if ((!wal.twoSided() || ((wal.nextSector()->ceilingz > (tspr->z - ((tsiz->y * tspr->yrepeat) << 2))) ||
+             wal.nextSector()->floorz < tspr->z)) && !polymost_getclosestpointonwall((const vec2_t *) tspr, wallnum(&wal), &n))
         {
             int const dst = abs(tspr->x - n.x) + abs(tspr->y - n.y);
 
             if (dst <= dist)
             {
                 dist = dst;
-                closest = i;
+                closest = &wal;
             }
         }
     }
 
     *rd = dist;
 
-    return closest;
+    return closest? wallnum(closest) : -1;
 }
 
 static int32_t polymost_lintersect(int32_t x1, int32_t y1, int32_t x2, int32_t y2,
diff --git a/source/core/automap.cpp b/source/core/automap.cpp
index e0fbed31e..0165e5f69 100644
--- a/source/core/automap.cpp
+++ b/source/core/automap.cpp
@@ -419,33 +419,26 @@ void drawredlines(int cposx, int cposy, int czoom, int cang)
 	{
 		if (!gFullMap && !show2dsector[i]) continue;
 
-		int startwall = sector[i].wallptr;
-		int endwall = sector[i].wallptr + sector[i].wallnum;
-
 		int z1 = sector[i].ceilingz;
 		int z2 = sector[i].floorz;
-		walltype* wal;
-		int j;
 
-		for (j = startwall, wal = &wall[startwall]; j < endwall; j++, wal++)
+		for (auto& wal : wallsofsector(i))
 		{
-			int k = wal->nextwall;
-			if (k < 0 || k >= numwalls) continue;
+			if (!wal.twoSided()) continue;
 
-			int s = wal->nextsector;
-			if (s < 0 || s >= numsectors) continue;
+			auto osec = wal.nextSector();
 
-			if (sector[s].ceilingz == z1 && sector[s].floorz == z2)
-				if (((wal->cstat | wal->nextWall()->cstat) & (16 + 32)) == 0) continue;
+			if (osec->ceilingz == z1 && osec->floorz == z2)
+				if (((wal.cstat | wal.nextWall()->cstat) & (16 + 32)) == 0) continue;
 
-			if (ShowRedLine(j, i))
+			if (ShowRedLine(wallnum(&wal), i))
 			{
-				int ox = wal->x - cposx;
-				int oy = wal->y - cposy;
+				int ox = wal.x - cposx;
+				int oy = wal.y - cposy;
 				int x1 = DMulScale(ox, xvect, -oy, yvect, 16) + (width << 11);
 				int y1 = DMulScale(oy, xvect, ox, yvect, 16) + (height << 11);
 
-				auto wal2 = wal->point2Wall();
+				auto wal2 = wal.point2Wall();
 				ox = wal2->x - cposx;
 				oy = wal2->y - cposy;
 				int x2 = DMulScale(ox, xvect, -oy, yvect, 16) + (width << 11);
@@ -474,26 +467,20 @@ static void drawwhitelines(int cposx, int cposy, int czoom, int cang)
 	{
 		if (!gFullMap && !show2dsector[i] && !isSWALL()) continue;
 
-		int startwall = sector[i].wallptr;
-		int endwall = sector[i].wallptr + sector[i].wallnum;
-
-		walltype* wal;
-		int j;
-
-		for (j = startwall, wal = &wall[startwall]; j < endwall; j++, wal++)
+		for (auto& wal : wallsofsector(i))
 		{
-			if (wal->nextwall >= 0) continue;
-			if (!gFullMap && !tileGetTexture(wal->picnum)->isValid()) continue;
+			if (wal.nextwall >= 0) continue;
+			if (!gFullMap && !tileGetTexture(wal.picnum)->isValid()) continue;
 
-			if (isSWALL() && !gFullMap && !show2dwall[j])
+			if (isSWALL() && !gFullMap && !show2dwall[wallnum(&wal)])
 				continue;
 
-			int ox = wal->x - cposx;
-			int oy = wal->y - cposy;
+			int ox = wal.x - cposx;
+			int oy = wal.y - cposy;
 			int x1 = DMulScale(ox, xvect, -oy, yvect, 16) + (width << 11);
 			int y1 = DMulScale(oy, xvect, ox, yvect, 16) + (height << 11);
 
-			int k = wal->point2;
+			int k = wal.point2;
 			auto wal2 = &wall[k];
 			ox = wal2->x - cposx;
 			oy = wal2->y - cposy;
diff --git a/source/core/rendering/hw_sections.h b/source/core/rendering/hw_sections.h
index 4a8b73f0d..bc361f664 100644
--- a/source/core/rendering/hw_sections.h
+++ b/source/core/rendering/hw_sections.h
@@ -4,13 +4,13 @@
 
 struct SectionLine
 {
-	int16_t section;
-	int16_t partnersection;
-	int16_t startpoint;
-	int16_t endpoint;
-	int16_t wall;
-	int16_t partner;
-	int16_t point2index;
+	int section;
+	int partnersection;
+	int startpoint;
+	int endpoint;
+	int wall;
+	int partner;
+	int point2index;
 };
 
 struct Section
diff --git a/source/core/rendering/scene/hw_portal.cpp b/source/core/rendering/scene/hw_portal.cpp
index 4d218a3cf..c8b2baaed 100644
--- a/source/core/rendering/scene/hw_portal.cpp
+++ b/source/core/rendering/scene/hw_portal.cpp
@@ -481,7 +481,7 @@ int HWLinePortal::ClipSector(sectortype *sub)
 	// this seg is completely behind the mirror
 	for (int i = 0; i<sub->wallnum; i++)
 	{
-		if (PointOnLineSide(WallStart(&wall[sub->wallptr]), line) == 0) return PClip_Inside;
+		if (PointOnLineSide(WallStart(sub->firstWall()), line) == 0) return PClip_Inside;
 	}
 	return PClip_InFront;
 }
diff --git a/source/core/rendering/scene/hw_walls.cpp b/source/core/rendering/scene/hw_walls.cpp
index c9374d2c4..a037df233 100644
--- a/source/core/rendering/scene/hw_walls.cpp
+++ b/source/core/rendering/scene/hw_walls.cpp
@@ -109,27 +109,27 @@ static int GetClosestPointOnWall(tspritetype* spr, walltype* wal, vec2_t* const
 
 static int IsOnWall(tspritetype* tspr, int height)
 {
-	int dist = 3, closest = -1;
+	int dist = 3;
 	auto sect = tspr->sector();
 	vec2_t n;
+	walltype* closest = nullptr;
 
 	int topz = (tspr->z - ((height * tspr->yrepeat) << 2));
-	for (int i = sect->wallptr; i < sect->wallptr + sect->wallnum; i++)
+	for(auto& wal : wallsofsector(sect))
 	{
-		auto wal = &wall[i];
-		if ((wal->nextsector == -1 || ((wal->nextSector()->ceilingz > topz) ||
-			wal->nextSector()->floorz < tspr->z)) && !GetClosestPointOnWall(tspr, wal, &n))
+		if ((wal.nextsector == -1 || ((wal.nextSector()->ceilingz > topz) ||
+			wal.nextSector()->floorz < tspr->z)) && !GetClosestPointOnWall(tspr, &wal, &n))
 		{
 			int const dst = abs(tspr->x - n.x) + abs(tspr->y - n.y);
 
 			if (dst <= dist)
 			{
 				dist = dst;
-				closest = i;
+				closest = &wal;
 			}
 		}
 	}
-	return closest == -1? -1 : dist;
+	return closest == nullptr? -1 : dist;
 }
 
 //==========================================================================