Fix Rare Segfault

docs/CHANGELOG.md

@@ -44,6 +44,7 @@
     * `Improved Classic Title Positioning` (Enabled By Default)
     * `Use Updated Title` (Enabled By Default)
     * `Hide Block Outline When GUI Is Hidden` (Enabled By Default)
+    * `Fix Crash When Generating Certain Seed` (Enabled By Default)
   * Existing Functionality (All Enabled By Default)
     * `Fix Screen Rendering When Hiding HUD`
     * `Sanitize Usernames`

launcher/src/client/available-feature-flags

@@ -106,4 +106,5 @@ TRUE Property Scale Animated Textures
 TRUE Allow High-Resolution Title
 TRUE Improved Classic Title Positioning
 TRUE Use Updated Title
-TRUE Hide Block Outline When GUI Is Hidden
+TRUE Hide Block Outline When GUI Is Hidden
+TRUE Fix Crash When Generating Certain Seed

mods/src/misc/misc.cpp

@@ -434,6 +434,15 @@ static void Player_tick_injection(Player_tick_t original, Player *self) {
     original(self);
 }
 
+// Rare Segfault
+static int Dimension_isValidSpawn_Level_getTopTile_injection(Level *self, int x, int z) {
+    int ret = self->getTopTile(x, z);
+    if (ret == 0) {
+        ret = Tile::invisible_bedrock->id;
+    }
+    return ret;
+}
+
 // Init
 void init_misc() {
     // Sanitize Username
@@ -579,6 +588,11 @@ void init_misc() {
         overwrite_calls(Player_tick, Player_tick_injection);
     }
 
+    // Rare Segfault
+    if (feature_has("Fix Crash When Generating Certain Seed", server_enabled)) {
+        overwrite_call((void *) 0xb198c, (void *) Dimension_isValidSpawn_Level_getTopTile_injection);
+    }
+
     // Init Other Components
     _init_misc_tinting();
     _init_misc_ui();

symbols/src/level/Level.def

@@ -49,6 +49,7 @@ method bool hasDirectSignal(int x, int y, int z) = 0xa5d88;
 method bool getDirectSignal(int x, int y, int z, int direction) = 0xa5d2c;
 method bool canSeeSky(int x, int y, int z) = 0xa39b8;
 method bool isDay() = 0xa3d9c;
+method int getTopTile(int x, int z) = 0xa2cc8;
 
 virtual-method void tick() = 0x28;
 virtual-method void updateSleepingPlayerList() = 0x2c;