diff --git a/src/r_defs.h b/src/r_defs.h
index 2d1dc5ca97..27c578e568 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -832,11 +832,11 @@ struct side_t
 
 	void SetTextureXScale(int which, fixed_t scale)
 	{
-		textures[which].xscale = scale <= 0? FRACUNIT : scale;
+		textures[which].xscale = scale == 0 ? FRACUNIT : scale;
 	}
 	void SetTextureXScale(fixed_t scale)
 	{
-		textures[top].xscale = textures[mid].xscale = textures[bottom].xscale = scale <= 0? FRACUNIT : scale;
+		textures[top].xscale = textures[mid].xscale = textures[bottom].xscale = scale == 0 ? FRACUNIT : scale;
 	}
 	fixed_t GetTextureXScale(int which) const
 	{
diff --git a/src/r_segs.cpp b/src/r_segs.cpp
index a40a2ce351..bfeab506ae 100644
--- a/src/r_segs.cpp
+++ b/src/r_segs.cpp
@@ -2769,6 +2769,7 @@ int WallMost (short *mostbuf, const secplane_t &plane)
 static void PrepWallRoundFix(fixed_t *lwall, fixed_t walxrepeat)
 {
 	// fix for rounding errors
+	walxrepeat = abs(walxrepeat);
 	fixed_t fix = (MirrorFlags & RF_XFLIP) ? walxrepeat-1 : 0;
 	int x;
 
@@ -2803,7 +2804,7 @@ static void PrepWallRoundFix(fixed_t *lwall, fixed_t walxrepeat)
 void PrepWall (fixed_t *swall, fixed_t *lwall, fixed_t walxrepeat)
 { // swall = scale, lwall = texturecolumn
 	double top, bot, i;
-	double xrepeat = walxrepeat;
+	double xrepeat = fabs((double)walxrepeat);
 
 	i = WallSX1 - centerx;
 	top = WallUoverZorg + WallUoverZstep * i;
@@ -2812,7 +2813,14 @@ void PrepWall (fixed_t *swall, fixed_t *lwall, fixed_t walxrepeat)
 	for (int x = WallSX1; x < WallSX2; x++)
 	{
 		double frac = top / bot;
-		lwall[x] = xs_RoundToInt(frac * xrepeat);
+		if (walxrepeat < 0)
+		{
+			lwall[x] = xs_RoundToInt(xrepeat - frac * xrepeat);
+		}
+		else
+		{
+			lwall[x] = xs_RoundToInt(frac * xrepeat);
+		}
 		swall[x] = xs_RoundToInt(frac * WallDepthScale + WallDepthOrg);
 		top += WallUoverZstep;
 		bot += WallInvZstep;
@@ -2823,7 +2831,7 @@ void PrepWall (fixed_t *swall, fixed_t *lwall, fixed_t walxrepeat)
 void PrepLWall (fixed_t *lwall, fixed_t walxrepeat)
 { // lwall = texturecolumn
 	double top, bot, i;
-	double xrepeat = walxrepeat;
+	double xrepeat = fabs((double)walxrepeat);
 	double topstep;
 
 	i = WallSX1 - centerx;
@@ -2835,7 +2843,14 @@ void PrepLWall (fixed_t *lwall, fixed_t walxrepeat)
 
 	for (int x = WallSX1; x < WallSX2; x++)
 	{
-		lwall[x] = xs_RoundToInt(top / bot);
+		if (walxrepeat < 0)
+		{
+			lwall[x] = xs_RoundToInt(xrepeat - top / bot);
+		}
+		else
+		{
+			lwall[x] = xs_RoundToInt(top / bot);
+		}
 		top += topstep;
 		bot += WallInvZstep;
 	}