diff --git a/src/p_setup.c b/src/p_setup.c
index ab4c87f99..268d90690 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -2705,13 +2705,13 @@ static void P_ConvertBinaryMap(void)
 			boolean frontceil = (lines[i].special == 701 || lines[i].special == 702 || lines[i].special == 713);
 			boolean backceil = (lines[i].special == 711 || lines[i].special == 712 || lines[i].special == 703);
 
-			lines[i].args[0] = backfloor ? 2 : (frontfloor ? 1 : 0);
-			lines[i].args[1] = backceil ? 2 : (frontceil ? 1 : 0);
+			lines[i].args[0] = backfloor ? TMS_BACK : (frontfloor ? TMS_FRONT : TMS_NONE);
+			lines[i].args[1] = backceil ? TMS_BACK : (frontceil ? TMS_FRONT : TMS_NONE);
 
 			if (lines[i].flags & ML_NETONLY)
-				lines[i].args[2] |= SL_NOPHYSICS;
+				lines[i].args[2] |= TMSL_NOPHYSICS;
 			if (lines[i].flags & ML_NONET)
-				lines[i].args[2] |= SL_DYNAMIC;
+				lines[i].args[2] |= TMSL_DYNAMIC;
 
 			lines[i].special = 700;
 			break;
@@ -2722,13 +2722,13 @@ static void P_ConvertBinaryMap(void)
 		case 715: //Slope back sector ceiling  by 3 tagged vertices
 		{
 			if (lines[i].special == 704)
-				lines[i].args[0] = 0;
+				lines[i].args[0] = TMSP_FRONTFLOOR;
 			else if (lines[i].special == 705)
-				lines[i].args[0] = 1;
+				lines[i].args[0] = TMSP_FRONTCEILING;
 			else if (lines[i].special == 714)
-				lines[i].args[0] = 2;
+				lines[i].args[0] = TMSP_BACKFLOOR;
 			else if (lines[i].special == 715)
-				lines[i].args[0] = 3;
+				lines[i].args[0] = TMSP_BACKCEILING;
 
 			lines[i].args[1] = lines[i].tag;
 
@@ -2751,9 +2751,9 @@ static void P_ConvertBinaryMap(void)
 			}
 
 			if (lines[i].flags & ML_NETONLY)
-				lines[i].args[4] |= SL_NOPHYSICS;
+				lines[i].args[4] |= TMSL_NOPHYSICS;
 			if (lines[i].flags & ML_NONET)
-				lines[i].args[4] |= SL_DYNAMIC;
+				lines[i].args[4] |= TMSL_DYNAMIC;
 
 			lines[i].special = 704;
 			break;
diff --git a/src/p_slopes.c b/src/p_slopes.c
index c4ef28666..9f18fe111 100644
--- a/src/p_slopes.c
+++ b/src/p_slopes.c
@@ -250,14 +250,14 @@ static void line_SpawnViaLine(const int linenum, const boolean spawnthinker)
 	vector2_t direction;
 	fixed_t nx, ny, dz, extent;
 
-	boolean frontfloor = line->args[0] == 1;
-	boolean backfloor = line->args[0] == 2;
-	boolean frontceil = line->args[1] == 1;
-	boolean backceil = line->args[1] == 2;
+	boolean frontfloor = line->args[0] == TMS_FRONT;
+	boolean backfloor = line->args[0] == TMS_BACK;
+	boolean frontceil = line->args[1] == TMS_FRONT;
+	boolean backceil = line->args[1] == TMS_BACK;
 	UINT8 flags = 0; // Slope flags
-	if (line->args[2] & 1)
+	if (line->args[2] & TMSL_NOPHYSICS)
 		flags |= SL_NOPHYSICS;
-	if (line->args[2] & 2)
+	if (line->args[2] & TMSL_DYNAMIC)
 		flags |= SL_DYNAMIC;
 
 	if(!frontfloor && !backfloor && !frontceil && !backceil)
@@ -464,26 +464,26 @@ static void line_SpawnViaMapthingVertexes(const int linenum, const boolean spawn
 	UINT16 tag2 = line->args[2];
 	UINT16 tag3 = line->args[3];
 	UINT8 flags = 0; // Slope flags
-	if (line->args[4] & 1)
+	if (line->args[4] & TMSL_NOPHYSICS)
 		flags |= SL_NOPHYSICS;
-	if (line->args[4] & 2)
+	if (line->args[4] & TMSL_DYNAMIC)
 		flags |= SL_DYNAMIC;
 
 	switch(line->args[0])
 	{
-	case 0:
+	case TMSP_FRONTFLOOR:
 		slopetoset = &line->frontsector->f_slope;
 		side = &sides[line->sidenum[0]];
 		break;
-	case 1:
+	case TMSP_FRONTCEILING:
 		slopetoset = &line->frontsector->c_slope;
 		side = &sides[line->sidenum[0]];
 		break;
-	case 2:
+	case TMSP_BACKFLOOR:
 		slopetoset = &line->backsector->f_slope;
 		side = &sides[line->sidenum[1]];
 		break;
-	case 3:
+	case TMSP_BACKCEILING:
 		slopetoset = &line->backsector->c_slope;
 		side = &sides[line->sidenum[1]];
 	default:
@@ -605,13 +605,13 @@ void P_CopySectorSlope(line_t *line)
 		setback |= P_SetSlopeFromTag(bsec, line->args[2], false);
 		setback |= P_SetSlopeFromTag(bsec, line->args[3], true);
 
-		if (line->args[4] & 1)
+		if (line->args[4] & TMSC_FRONTTOBACKFLOOR)
 			setback |= P_CopySlope(&bsec->f_slope, fsec->f_slope);
-		if (line->args[4] & 2)
+		if (line->args[4] & TMSC_BACKTOFRONTFLOOR)
 			setfront |= P_CopySlope(&fsec->f_slope, bsec->f_slope);
-		if (line->args[4] & 4)
+		if (line->args[4] & TMSC_FRONTTOBACKCEILING)
 			setback |= P_CopySlope(&bsec->c_slope, fsec->c_slope);
-		if (line->args[4] & 8)
+		if (line->args[4] & TMSC_BACKTOFRONTCEILING)
 			setfront |= P_CopySlope(&fsec->c_slope, bsec->c_slope);
 	}
 
diff --git a/src/p_slopes.h b/src/p_slopes.h
index e7c850ab8..17c885fb2 100644
--- a/src/p_slopes.h
+++ b/src/p_slopes.h
@@ -18,6 +18,35 @@
 extern pslope_t *slopelist;
 extern UINT16 slopecount;
 
+typedef enum
+{
+	TMSP_FRONTFLOOR,
+	TMSP_FRONTCEILING,
+	TMSP_BACKFLOOR,
+	TMSP_BACKCEILING,
+} textmapslopeplane_t;
+
+typedef enum
+{
+	TMSC_FRONTTOBACKFLOOR   = 1,
+	TMSC_BACKTOFRONTFLOOR   = 1<<1,
+	TMSC_FRONTTOBACKCEILING = 1<<2,
+	TMSC_BACKTOFRONTCEILING = 1<<3,
+} textmapslopecopy_t;
+
+typedef enum
+{
+	TMS_NONE,
+	TMS_FRONT,
+	TMS_BACK,
+} textmapside_t;
+
+typedef enum
+{
+	TMSL_NOPHYSICS = 1,
+	TMSL_DYNAMIC = 2,
+} textmapslopeflags_t;
+
 void P_LinkSlopeThinkers (void);
 
 void P_CalculateSlopeNormal(pslope_t *slope);