From 86ddec3f76a6f19b45f61b6b48859bca7effcf49 Mon Sep 17 00:00:00 2001
From: smallmodel <15067410+smallmodel@users.noreply.github.com>
Date: Sun, 8 Sep 2024 00:56:03 +0200
Subject: [PATCH] Clear the world to prevent crashes

---
 code/renderer/tr_bsp.c             | 24 ++++++++++++++++++++++++
 code/renderer/tr_init.c            |  7 +++++++
 code/renderer/tr_local.h           |  1 +
 code/renderer/tr_marks_permanent.c | 10 ++++------
 4 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/code/renderer/tr_bsp.c b/code/renderer/tr_bsp.c
index 7d01b47a..7362269d 100644
--- a/code/renderer/tr_bsp.c
+++ b/code/renderer/tr_bsp.c
@@ -2432,11 +2432,23 @@ void RE_LoadWorldMap( const char *name ) {
     UI_LoadResource("*116");
 }
 
+/*
+=================
+RE_MapVersion
+
+=================
+*/
 int RE_MapVersion(void)
 {
 	return map_version;
 }
 
+/*
+=================
+RE_PrintBSPFileSizes
+
+=================
+*/
 void RE_PrintBSPFileSizes(void)
 {
   ri.Printf(PRINT_ALL, "%s: %i\n", s_worldData.name, map_length);
@@ -2466,3 +2478,15 @@ void RE_PrintBSPFileSizes(void)
   ri.Printf(PRINT_ALL, "%6i   static models defs    %7i\n", g_nStaticModels, 164 * g_nStaticModels);
   ri.Printf(PRINT_ALL, "         static model indexes  %7i\n", g_nStaticModelIndices);
 }
+
+/*
+=================
+R_ClearWorld
+
+Set the world to NULL to prevent anyone from accessing
+freed world data
+=================
+*/
+void R_ClearWorld(void) {
+    tr.world = NULL;
+}
diff --git a/code/renderer/tr_init.c b/code/renderer/tr_init.c
index d9f5d235..4b5d7b0a 100644
--- a/code/renderer/tr_init.c
+++ b/code/renderer/tr_init.c
@@ -1583,6 +1583,13 @@ void RE_BeginRegistration(glconfig_t* glconfigOut) {
     tr.viewCluster = -1;		// force markleafs to regenerate
     R_ClearFlares();
     RE_ClearScene();
+
+    // Added in OPM
+    //  Clear the world because some components
+    //  like the mark system access the world object
+    //  to free allocated marks
+    R_ClearWorld();
+
     R_SetupShaders();
     R_InitLensFlare();
     R_LevelMarksInit();
diff --git a/code/renderer/tr_local.h b/code/renderer/tr_local.h
index 210f5f51..2654a61d 100644
--- a/code/renderer/tr_local.h
+++ b/code/renderer/tr_local.h
@@ -1757,6 +1757,7 @@ void		RE_SetWorldVisData( const byte *vis );
 qhandle_t	RE_RegisterModel( const char *name );
 qhandle_t	RE_RegisterSkin( const char *name );
 void		RE_Shutdown( qboolean destroyWindow );
+void        R_ClearWorld(void);
 
 qboolean	R_GetEntityToken( char *buffer, int size );
 
diff --git a/code/renderer/tr_marks_permanent.c b/code/renderer/tr_marks_permanent.c
index 256ba4c2..d2f1ad2d 100644
--- a/code/renderer/tr_marks_permanent.c
+++ b/code/renderer/tr_marks_permanent.c
@@ -1593,12 +1593,10 @@ void R_LevelMarksFree()
         for (i = tr.world->numDecisionNodes; i < tr.world->numnodes; i++) {
             mnode_t *pLeaf = &tr.world->nodes[i];
 
-            if (pLeaf->iNumMarkFragment) {
-                if (pLeaf->pFirstMarkFragment) {
-                    ri.Free(pLeaf->pFirstMarkFragment);
-                    pLeaf->pFirstMarkFragment = NULL;
-                    pLeaf->iNumMarkFragment   = 0;
-                }
+            if (pLeaf->iNumMarkFragment && pLeaf->pFirstMarkFragment) {
+                ri.Free(pLeaf->pFirstMarkFragment);
+                pLeaf->pFirstMarkFragment = NULL;
+                pLeaf->iNumMarkFragment   = 0;
             }
         }
     }