From b480f78c96a4e6c19fcd81a1d9fbdf71e64201f2 Mon Sep 17 00:00:00 2001
From: Lactozilla <jp6781615@gmail.com>
Date: Tue, 4 Jun 2024 18:34:38 -0300
Subject: [PATCH] Implement support for ZDoom GL2 nodes

---
 src/p_setup.c | 71 ++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 21 deletions(-)

diff --git a/src/p_setup.c b/src/p_setup.c
index c4b4a35b3..3e327a549 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -3419,13 +3419,13 @@ typedef enum {
 } nodetype_t;
 
 // Find out the BSP format.
-static nodetype_t P_GetNodetype(const virtres_t *virt, UINT8 **nodedata)
+static nodetype_t P_GetNodetype(const virtres_t *virt, UINT8 **nodedata, char signature[4 + 1])
 {
 	boolean supported[NUMNODETYPES] = {0};
 	nodetype_t nodetype = NT_UNSUPPORTED;
-	char signature[4 + 1];
 
 	*nodedata = NULL;
+	signature[0] = signature[4] = '\0';
 
 	if (udmf)
 	{
@@ -3434,7 +3434,7 @@ static nodetype_t P_GetNodetype(const virtres_t *virt, UINT8 **nodedata)
 		if (virtznodes && virtznodes->size)
 		{
 			*nodedata = virtznodes->data;
-			supported[NT_XGLN] = supported[NT_XGL3] = true;
+			supported[NT_XGLN] = supported[NT_XGL2] = supported[NT_XGL3] = true;
 		}
 	}
 	else
@@ -3456,9 +3456,9 @@ static nodetype_t P_GetNodetype(const virtres_t *virt, UINT8 **nodedata)
 			virtssectors = vres_Find(virt, "SSECTORS");
 
 			if (virtssectors && virtssectors->size)
-			{ // Possibly GL nodes: NODES ignored, SSECTORS takes precedence as nodes lump, (It is confusing yeah) and has a signature.
+			{ // Possibly GL nodes: NODES ignored, SSECTORS takes precedence as nodes lump (it is confusing, yeah), and has a signature.
 				*nodedata = virtssectors->data;
-				supported[NT_XGLN] = supported[NT_ZGLN] = supported[NT_XGL3] = true;
+				supported[NT_XGLN] = supported[NT_ZGLN] = supported[NT_XGL2] = supported[NT_XGL3] = true;
 			}
 			else
 			{ // Possibly ZDoom extended nodes: SSECTORS is empty, NODES has a signature.
@@ -3478,19 +3478,42 @@ static nodetype_t P_GetNodetype(const virtres_t *virt, UINT8 **nodedata)
 	}
 
 	M_Memcpy(signature, *nodedata, 4);
-	signature[4] = '\0';
 	(*nodedata) += 4;
 
-	if (!strcmp(signature, "XNOD"))
-		nodetype = NT_XNOD;
-	else if (!strcmp(signature, "ZNOD"))
-		nodetype = NT_ZNOD;
-	else if (!strcmp(signature, "XGLN"))
-		nodetype = NT_XGLN;
-	else if (!strcmp(signature, "ZGLN"))
-		nodetype = NT_ZGLN;
-	else if (!strcmp(signature, "XGL3"))
-		nodetype = NT_XGL3;
+	// Identify node format from its starting signature.
+	if (memcmp(&signature[1], "NOD", 3) == 0) // ZDoom extended nodes
+	{
+		if (signature[0] == 'X')
+		{
+			nodetype = NT_XNOD; // Uncompressed
+		}
+		else if (signature[0] == 'Z')
+		{
+			nodetype = NT_ZNOD; // Compressed
+		}
+	}
+	else if (memcmp(&signature[1], "GL", 2) == 0) // GL nodes
+	{
+		switch (signature[0])
+		{
+		case 'X': // Uncompressed
+			switch (signature[3])
+			{
+			case 'N': nodetype = NT_XGLN; break; // GL nodes
+			case '2': nodetype = NT_XGL2; break; // Version 2 GL nodes
+			case '3': nodetype = NT_XGL3; break; // Version 3 GL nodes
+			}
+			break;
+		case 'Z': // Compressed
+			switch (signature[3])
+			{
+			case 'N': nodetype = NT_ZGLN; break; // GL nodes (compressed)
+			case '2': nodetype = NT_ZGL2; break; // Version 2 GL nodes (compressed)
+			case '3': nodetype = NT_ZGL3; break; // Version 3 GL nodes (compressed)
+			}
+			break;
+		}
+	}
 
 	return supported[nodetype] ? nodetype : NT_UNSUPPORTED;
 }
@@ -3560,6 +3583,7 @@ static boolean P_LoadExtendedSubsectorsAndSegs(UINT8 **data, nodetype_t nodetype
 		switch (nodetype)
 		{
 		case NT_XGLN:
+		case NT_XGL2:
 		case NT_XGL3:
 			for (m = 0; m < (size_t)subsectors[i].numlines; m++, k++)
 			{
@@ -3571,7 +3595,7 @@ static boolean P_LoadExtendedSubsectorsAndSegs(UINT8 **data, nodetype_t nodetype
 
 				READUINT32((*data)); // partner, can be ignored by software renderer
 
-				if (nodetype == NT_XGL3)
+				if (nodetype != NT_XGLN)
 				{
 					UINT32 linenum = READUINT32((*data));
 					if (linenum != 0xFFFFFFFF && linenum >= numlines)
@@ -3682,8 +3706,9 @@ static void P_LoadExtendedNodes(UINT8 **data, nodetype_t nodetype)
 
 static void P_LoadMapBSP(const virtres_t *virt)
 {
+	char signature[4 + 1];
 	UINT8 *nodedata = NULL;
-	nodetype_t nodetype = P_GetNodetype(virt, &nodedata);
+	nodetype_t nodetype = P_GetNodetype(virt, &nodedata, signature);
 
 	switch (nodetype)
 	{
@@ -3715,6 +3740,7 @@ static void P_LoadMapBSP(const virtres_t *virt)
 	}
 	case NT_XNOD:
 	case NT_XGLN:
+	case NT_XGL2:
 	case NT_XGL3:
 		if (!P_LoadExtraVertices(&nodedata))
 			return;
@@ -3723,10 +3749,13 @@ static void P_LoadMapBSP(const virtres_t *virt)
 		P_LoadExtendedNodes(&nodedata, nodetype);
 		break;
 	default:
-		CONS_Alert(CONS_WARNING, "Unsupported BSP format detected.\n");
-		return;
+		if (isprint(signature[0]) && isprint(signature[1]) && isprint(signature[2]) && isprint(signature[3]))
+		{
+			I_Error("Unsupported BSP format '%s' detected!\n", signature);
+			return;
+		}
+		I_Error("Unknown BSP format detected!\n");
 	}
-	return;
 }
 
 // Split from P_LoadBlockMap for convenience