diff --git a/extras/conf/SRB2-22.cfg b/extras/conf/SRB2-22.cfg
index 3fd4b6ccd..465986542 100644
--- a/extras/conf/SRB2-22.cfg
+++ b/extras/conf/SRB2-22.cfg
@@ -3129,6 +3129,192 @@ linedeftypes
 			title = "Fog Wall";
 			prefix = "(909)";
 		}
+
+		910
+		{
+			title = "100% Additive";
+			prefix = "(910)";
+		}
+
+		911
+		{
+			title = "90% Additive";
+			prefix = "(911)";
+		}
+
+		912
+		{
+			title = "80% Additive";
+			prefix = "(912)";
+		}
+
+		913
+		{
+			title = "70% Additive";
+			prefix = "(913)";
+		}
+
+		914
+		{
+			title = "60% Additive";
+			prefix = "(914)";
+		}
+
+		915
+		{
+			title = "50% Additive";
+			prefix = "(915)";
+		}
+
+		916
+		{
+			title = "40% Additive";
+			prefix = "(916)";
+		}
+
+		917
+		{
+			title = "30% Additive";
+			prefix = "(917)";
+		}
+
+		918
+		{
+			title = "20% Additive";
+			prefix = "(918)";
+		}
+
+		919
+		{
+			title = "10% Additive";
+			prefix = "(919)";
+		}
+
+		920
+		{
+			title = "100% Subtractive";
+			prefix = "(920)";
+		}
+
+		921
+		{
+			title = "90% Subtractive";
+			prefix = "(921)";
+		}
+
+		922
+		{
+			title = "80% Subtractive";
+			prefix = "(922)";
+		}
+
+		923
+		{
+			title = "70% Subtractive";
+			prefix = "(923)";
+		}
+
+		924
+		{
+			title = "60% Subtractive";
+			prefix = "(924)";
+		}
+
+		925
+		{
+			title = "50% Subtractive";
+			prefix = "(925)";
+		}
+
+		926
+		{
+			title = "40% Subtractive";
+			prefix = "(926)";
+		}
+
+		927
+		{
+			title = "30% Subtractive";
+			prefix = "(927)";
+		}
+
+		928
+		{
+			title = "20% Subtractive";
+			prefix = "(928)";
+		}
+
+		929
+		{
+			title = "10% Subtractive";
+			prefix = "(929)";
+		}
+
+		930
+		{
+			title = "100% Reverse Subtractive";
+			prefix = "(930)";
+		}
+
+		931
+		{
+			title = "90% Reverse Subtractive";
+			prefix = "(931)";
+		}
+
+		932
+		{
+			title = "80% Reverse Subtractive";
+			prefix = "(932)";
+		}
+
+		933
+		{
+			title = "70% Reverse Subtractive";
+			prefix = "(933)";
+		}
+
+		934
+		{
+			title = "60% Reverse Subtractive";
+			prefix = "(934)";
+		}
+
+		935
+		{
+			title = "50% Reverse Subtractive";
+			prefix = "(935)";
+		}
+
+		936
+		{
+			title = "40% Reverse Subtractive";
+			prefix = "(936)";
+		}
+
+		937
+		{
+			title = "30% Reverse Subtractive";
+			prefix = "(937)";
+		}
+
+		938
+		{
+			title = "20% Reverse Subtractive";
+			prefix = "(938)";
+		}
+
+		939
+		{
+			title = "10% Reverse Subtractive";
+			prefix = "(939)";
+		}
+
+		940
+		{
+			title = "Modulate";
+			prefix = "(940)";
+		}
 	}
 }
 
diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 92e03aa80..066822e8c 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -1494,11 +1494,11 @@ static void HWR_ProcessSeg(void) // Sort of like GLWall::Process in GZDoom
 					transnum_t transtable = R_GetLinedefTransTable(gl_linedef);
 					if (transtable == NUMTRANSMAPS)
 						transtable = 0;
-					if (gl_linedef->special == 910)
+					if (gl_linedef->special >= 910 && gl_linedef->special <= 919)
 						blend = AST_ADD;
-					else if (gl_linedef->special == 911)
+					else if (gl_linedef->special >= 920 && gl_linedef->special <= 929)
 						blend = AST_SUBTRACT;
-					else if (gl_linedef->special == 912)
+					else if (gl_linedef->special >= 930 && gl_linedef->special <= 939)
 						blend = AST_REVERSESUBTRACT;
 
 					blendmode = HWR_SurfaceBlend(blend, transtable, &Surf);
diff --git a/src/p_setup.c b/src/p_setup.c
index ffa9444b3..0ffc807f5 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -3144,21 +3144,18 @@ static void P_ConvertBinaryMap(void)
 				lines[i].args[1] = tag;
 			lines[i].special = 720;
 			break;
-		case 900: //Translucent wall (10%)
-		case 901: //Translucent wall (20%)
-		case 902: //Translucent wall (30%)
-		case 903: //Translucent wall (40%)
-		case 904: //Translucent wall (50%)
-		case 905: //Translucent wall (60%)
-		case 906: //Translucent wall (70%)
-		case 907: //Translucent wall (80%)
-		case 908: //Translucent wall (90%)
-			lines[i].alpha = ((909 - lines[i].special) << FRACBITS)/10;
-			break;
 		default:
 			break;
 		}
 
+		// Set alpha for translucent walls
+		if (lines[i].special >= 900 && lines[i].special < 909)
+			lines[i].alpha = ((909 - lines[i].special) << FRACBITS)/10;
+
+		// Set alpha for additive/subtractive/reverse subtractive walls
+		if (lines[i].special >= 910 && lines[i].special <= 939)
+			lines[i].alpha = ((10 - lines[i].special % 10) << FRACBITS)/10;
+
 		//Linedef executor delay
 		if (lines[i].special >= 400 && lines[i].special < 500)
 		{
diff --git a/src/r_segs.c b/src/r_segs.c
index 10f445022..209810059 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -162,25 +162,25 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 		return;
 
 	transtable = R_GetLinedefTransTable(ldef);
-	if (ldef->special == 910)
+	if (ldef->special >= 910 && ldef->special <= 919)
 	{
 		if (transtable == NUMTRANSMAPS)
 			transtable = 0;
 		blendmode = AST_ADD;
 	}
-	else if (ldef->special == 911)
+	else if (ldef->special >= 920 && ldef->special <= 929)
 	{
 		if (transtable == NUMTRANSMAPS)
 			transtable = 0;
 		blendmode = AST_SUBTRACT;
 	}
-	else if (ldef->special == 912)
+	else if (ldef->special >= 930 && ldef->special <= 939)
 	{
 		if (transtable == NUMTRANSMAPS)
 			transtable = 0;
 		blendmode = AST_REVERSESUBTRACT;
 	}
-	else if (ldef->special == 913)
+	else if (ldef->special == 940)
 	{
 		transtable = 0;
 		blendmode = AST_MODULATE;