From 65190afe73b72bc76e591c0bafb9689dd368464d Mon Sep 17 00:00:00 2001
From: TheBrokenRail <connor24nolan@live.com>
Date: Mon, 23 Sep 2024 21:22:43 -0400
Subject: [PATCH] Fix Rare Segfault

---
 docs/CHANGELOG.md                           |  1 +
 launcher/src/client/available-feature-flags |  3 ++-
 mods/src/misc/misc.cpp                      | 14 ++++++++++++++
 symbols/src/level/Level.def                 |  1 +
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index d2fa489f5a..073570429a 100644
--- a/docs/CHANGELOG.md
+++ b/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`
diff --git a/launcher/src/client/available-feature-flags b/launcher/src/client/available-feature-flags
index 8e5c0db08e..f100b2cf08 100644
--- a/launcher/src/client/available-feature-flags
+++ b/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
\ No newline at end of file
+TRUE Hide Block Outline When GUI Is Hidden
+TRUE Fix Crash When Generating Certain Seed
\ No newline at end of file
diff --git a/mods/src/misc/misc.cpp b/mods/src/misc/misc.cpp
index fe7afdd97d..783b13e540 100644
--- a/mods/src/misc/misc.cpp
+++ b/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();
diff --git a/symbols/src/level/Level.def b/symbols/src/level/Level.def
index e80d72ab2c..c5cde735fe 100644
--- a/symbols/src/level/Level.def
+++ b/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;