diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 7d0e7e490..793050aa2 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -580,9 +580,10 @@ static void HWR_RenderPlane(sector_t *sector, extrasubsector_t *xsub, boolean is
 	if (nrPlaneVerts < 3)   //not even a triangle ?
 		return;
 
-	if (nrPlaneVerts > UINT16_MAX) // FIXME: exceeds plVerts size
+	// This check is so inconsistent between functions, it hurts.
+	if (nrPlaneVerts > INT16_MAX) // FIXME: exceeds plVerts size
 	{
-		CONS_Debug(DBG_RENDER, "polygon size of %d exceeds max value of %d vertices\n", nrPlaneVerts, UINT16_MAX);
+		CONS_Debug(DBG_RENDER, "polygon size of %d exceeds max value of %d vertices\n", nrPlaneVerts, INT16_MAX);
 		return;
 	}
 
diff --git a/src/p_setup.h b/src/p_setup.h
index 6f54bceae..eda6066d3 100644
--- a/src/p_setup.h
+++ b/src/p_setup.h
@@ -47,7 +47,7 @@ typedef struct
 	UINT8 *flatpatch;
 	UINT16 width, height;
 	fixed_t topoffset, leftoffset;
-	size_t texturenum;
+	INT32 texturenum;
 
 #ifdef ESLOPE
 	UINT8 *resizedflat;
diff --git a/src/r_data.c b/src/r_data.c
index 8ceb59dd4..00d8de629 100644
--- a/src/r_data.c
+++ b/src/r_data.c
@@ -1656,7 +1656,7 @@ boolean R_CheckIfPatch(lumpnum_t lump)
 	width = SHORT(patch->width);
 	height = SHORT(patch->height);
 
-	result = (height > 0 && height <= 16384 && width > 0 && width <= 16384 && width < size / 4);
+	result = (height > 0 && height <= 16384 && width > 0 && width <= 16384 && width < (INT16)(size / 4));
 
 	if (result)
 	{
@@ -1769,10 +1769,35 @@ void R_FlatTexture(size_t tex, UINT8 *flat)
 	}
 }
 
-void R_CropFlat(UINT8 *origflat, UINT8 *cropflat, UINT16 origwidth, UINT16 origheight, UINT16 cropwidth, UINT16 cropheight)
+void R_CropFlat(UINT8 *srcflat, UINT8 *destflat,
+				UINT16 srcwidth, UINT16 srcheight,
+				UINT16 resizewidth, UINT16 resizeheight,
+				UINT16 destwidth, UINT16 destheight)
 {
-	UINT16 x, y;
-	for (y = 0; y < cropheight; y++)
-		for (x = 0; x < cropwidth; x++)
-			cropflat[(y * cropwidth) + x] = origflat[(y * origwidth) + x];
+	UINT16 y;
+	UINT16 position = 0;
+	for (y = 0; y < destheight; y++)
+	{
+		if (position > (srcwidth * srcheight))
+			break;
+		if (srcwidth != resizewidth)
+		{
+			if (resizewidth > srcwidth)
+			{
+				UINT8 *pos2 = srcflat+position;
+				UINT8 lastpixel = *(pos2-1);
+				M_Memcpy(destflat, srcflat+position, destwidth);
+				memset(pos2, lastpixel, resizewidth-srcwidth);
+			}
+			else
+				M_Memcpy(destflat, srcflat+position, resizewidth);
+		}
+		else
+			M_Memcpy(destflat, srcflat+position, destwidth);
+		destflat += destwidth;
+		position += srcwidth;
+	}
+
+	while (y++ < min(resizeheight, srcheight))
+		memset(destflat + (y * destwidth), *(destflat - 1), destwidth);
 }
diff --git a/src/r_data.h b/src/r_data.h
index a1e7cd127..8cb41cd2f 100644
--- a/src/r_data.h
+++ b/src/r_data.h
@@ -97,7 +97,10 @@ boolean R_CheckIfPatch(lumpnum_t lump);
 // Lactozilla
 void R_FlatPatch(patch_t *patch, UINT8 *flat);
 void R_FlatTexture(size_t tex, UINT8 *flat);
-void R_CropFlat(UINT8 *origflat, UINT8 *cropflat, UINT16 origwidth, UINT16 origheight, UINT16 cropwidth, UINT16 cropheight);
+void R_CropFlat(UINT8 *srcflat, UINT8 *destflat,
+				UINT16 srcwidth, UINT16 srcheight,
+				UINT16 resizewidth, UINT16 resizeheight,
+				UINT16 destwidth, UINT16 destheight);
 
 extern INT32 numtextures;
 
diff --git a/src/r_plane.c b/src/r_plane.c
index 39f1d220a..91b4f5f2c 100644
--- a/src/r_plane.c
+++ b/src/r_plane.c
@@ -662,6 +662,7 @@ static void R_GetPatchFlat(levelflat_t *levelflat, boolean leveltexture)
 	{
 #ifdef ESLOPE
 		INT32 resizewidth, resizeheight, newresize;
+		INT32 checkresizewidth, checkresizeheight;
 #endif // ESLOPE
 
 		if (!leveltexture)
@@ -700,21 +701,48 @@ static void R_GetPatchFlat(levelflat_t *levelflat, boolean leveltexture)
 			resizewidth <<= 1;
 		while (resizeheight < levelflat->height)
 			resizeheight <<= 1;
+
 		// Scale down to fit in 2048x2048
 		if (resizewidth > 2048)
 			resizewidth = 2048;
 		if (resizeheight > 2048)
 			resizeheight = 2048;
-		// Then scale down to fit the actual flat dimensions
-		while (resizewidth > levelflat->width)
-			resizewidth >>= 1;
-		while (resizeheight > levelflat->height)
-			resizeheight >>= 1;
+
+		// A single pixel difference is negligible.
+		checkresizewidth = levelflat->width - 1;
+		if (checkresizewidth & (checkresizewidth - 1))
+		{
+			checkresizewidth += 2;
+			if (checkresizewidth & (checkresizewidth - 1))
+			{
+				while (resizewidth > levelflat->width)
+					resizewidth >>= 1;
+			}
+			else
+				resizewidth = checkresizewidth;
+		}
+		else
+			resizewidth = checkresizewidth;
+
+		checkresizeheight = levelflat->height - 1;
+		if (checkresizeheight & (checkresizeheight - 1))
+		{
+			checkresizeheight += 2;
+			if (checkresizeheight & (checkresizeheight - 1))
+			{
+				while (resizeheight > levelflat->height)
+					resizeheight >>= 1;
+			}
+			else
+				resizeheight = checkresizeheight;
+		}
+		else
+			resizeheight = checkresizeheight;
 
 		levelflat->resizedwidth = levelflat->resizedheight = (newresize = min(resizewidth, resizeheight));
 		levelflat->resizedflat = Z_Malloc(newresize * newresize, PU_LEVEL, NULL);
 		memset(levelflat->resizedflat, TRANSPARENTPIXEL, newresize * newresize);
-		R_CropFlat(levelflat->flatpatch, levelflat->resizedflat, levelflat->width, levelflat->height, newresize, newresize);
+		R_CropFlat(levelflat->flatpatch, levelflat->resizedflat, levelflat->width, levelflat->height, min(resizewidth, newresize), min(resizeheight, newresize), newresize, newresize);
 #endif // ESLOPE
 	}
 	else