OnMapChangeHook

README.md

@@ -375,6 +375,21 @@ Called when a gets off a ladder -> Direct bind to `CFuncLadder::PlayerGotOff`<br
 Called when the movetype is about to change.<br>
 If you call `Entity:SetMoveType` on the current entity inside this hook, it would have no effect.<br>
 
+#### HolyLib:OnMapChange(string levelName, string landmarkName)
+> [!NOTE]
+> This currently works only `LINUX32`
+
+Called right before a level transition occurs, this hook allows you to react to map changes initiated via changelevel.
+- string levelName — The name of the level we are changing to.
+- string levelLandmark — The name of the landmark (if any) otherwise, an empty string.
+Example usage:
+```lua
+hook.Add("HolyLib:OnMapChange", "HelloThere", function(levelName, landmarkName)
+    print("Next level name: " .. levelName)
+    print("Using landmark: " .. landmarkName) 
+end)
+```
+
 ## gameevent
 This module contains additional functions for the gameevent library.<br>
 With the Add/Get/RemoveClient* functions you can control the gameevents that are networked to a client which can be useful.<br>
@@ -4514,4 +4529,4 @@ PrintTable(fileTable)
 ## Usage with vphysics jolt
 Currently there might be bugs when combining holylib with VPhysics-Jolt.<br>
 This mainly affects the `physenv` module and most other modules should be completely fine.<br>
-Only VPhysics-Jolt builds from https://github.com/RaphaelIT7/VPhysics-Jolt will be suppored for now due to holylib requiring extented functionality.<br>
+Only VPhysics-Jolt builds from https://github.com/RaphaelIT7/VPhysics-Jolt will be suppored for now due to holylib requiring extented functionality.<br>

gluatests/lua/autorun/gmod_tests_init.lua

@@ -1,10 +1,18 @@
 include( "gmod_tests/sh_init.lua" )
 
+hook.Add("HolyLib:OnMapChange", "HookOnMapChangeTest", function(levelName, levelLandmark)
+	local currentMap = game.GetMap()
+
+	if not file.Exists("HookOnMapChangeData.txt", "DATA") then
+		file.Write("HookOnMapChangeData.txt", currentMap .. "\n" .. levelName .. "\n" .. levelLandmark)
+	end
+end)
+
 -- We change the level once and run everything again as in rare cases a crash might only ocurr after a map change.
 hook.Add("GLuaTest_Finished", "ChangeLevel", function()
 	if not file.Exists("waschanged.txt", "DATA") then
 		file.Write("waschanged.txt", "yes")
 
 		RunConsoleCommand("changelevel", game.GetMap())
 	end
-end)
+end)

gluatests/lua/tests/modules/holylib/OnMapChange.lua

@@ -0,0 +1,22 @@
+return {
+    groupName = "HolyLib:OnMapChange",
+    cases = {
+        {
+            name = "Hook is called with correct map name",
+            when = file.Exists("HookOnMapChangeData.txt", "DATA"),
+            func = function(state)
+                local data = file.Read("HookOnMapChangeData.txt", "DATA")
+                expect(data).to.exist()
+
+                local lines = string.Explode("\n", data)
+                expect(#lines).to.beGreaterThan(1)
+
+                local oldLevel = lines[1]
+                local levelName = lines[2]
+
+                expect(levelName).to.beA("string")
+                expect(levelName).to.equal(oldLevel)
+            end,
+        },
+    }
+}

source/modules/holylib.cpp

@@ -12,6 +12,7 @@
 #include "sourcesdk/baseclient.h"
 #include "hl2/hl2_player.h"
 #include "unordered_set"
+#include "host_state.h"
 
 // memdbgon must be the last include file in a .cpp file!!!
 #include "tier0/memdbgon.h"
@@ -22,6 +23,7 @@ class CHolyLibModule : public IModule
 	virtual void LuaInit(GarrysMod::Lua::ILuaInterface* pLua, bool bServerInit) OVERRIDE;
 	virtual void LuaShutdown(GarrysMod::Lua::ILuaInterface* pLua) OVERRIDE;
 	virtual void InitDetour(bool bPreServer) OVERRIDE;
+	virtual void LevelShutdown() OVERRIDE;
 	virtual const char* Name() { return "holylib"; };
 	virtual int Compatibility() { return LINUX32 | LINUX64; };
 	virtual bool SupportsMultipleLuaStates() { return true; };
@@ -373,6 +375,42 @@ LUA_FUNCTION_STATIC(ReceiveClientMessage)
 	return 0;
 }
 
+static char pLevelName[256], pLandmarkName[256] = {0};
+static Detouring::Hook detour_CHostState_State_ChangeLevelMP;
+static void hook_CHostState_State_ChangeLevelMP(const char* levelName, const char* landmarkName)
+{
+	if (levelName) 
+	{
+		V_strncpy(pLevelName, levelName, sizeof(pLevelName));
+	}
+
+	if (landmarkName)
+	{
+		V_strncpy(pLandmarkName, landmarkName, sizeof(pLandmarkName));
+	} else {
+		pLandmarkName[0] = '\0';
+	}
+
+	detour_CHostState_State_ChangeLevelMP.GetTrampoline<Symbols::CHostState_State_ChangeLevelMP>()(levelName, landmarkName);
+}
+
+void CHolyLibModule::LevelShutdown()
+{
+	if (*pLevelName == '\0') {
+		return;
+	}
+
+	if (Lua::PushHook("HolyLib:OnMapChange"))
+	{
+		g_Lua->PushString(pLevelName);
+		g_Lua->PushString(pLandmarkName);
+		g_Lua->CallFunctionProtected(3, 0, true);
+	}
+
+	pLevelName[0] = '\0';
+	pLandmarkName[0] = '\0';
+}
+
 void CHolyLibModule::LuaInit(GarrysMod::Lua::ILuaInterface* pLua, bool bServerInit)
 {
 	if (!bServerInit)
@@ -455,6 +493,12 @@ void CHolyLibModule::InitDetour(bool bPreServer)
 		(void*)hook_GetGModServerTags, m_pID
 	);
 
+	Detour::Create(
+		&detour_CHostState_State_ChangeLevelMP, "CHostState_State_ChangeLevelMP",
+		engine_loader.GetModule(), Symbols::CHostState_State_ChangeLevelMPSym,
+		(void*)hook_CHostState_State_ChangeLevelMP, m_pID
+	);
+
 	func_CBaseAnimating_InvalidateBoneCache = (Symbols::CBaseAnimating_InvalidateBoneCache)Detour::GetFunction(server_loader.GetModule(), Symbols::CBaseAnimating_InvalidateBoneCacheSym);
 	Detour::CheckFunction((void*)func_CBaseAnimating_InvalidateBoneCache, "CBaseAnimating::InvalidateBoneCache");
 

source/symbols.cpp

@@ -131,6 +131,13 @@ namespace Symbols
 		NULL_SIGNATURE, // ToDo
 	};
 
+	const std::vector<Symbol> CHostState_State_ChangeLevelMPSym = {
+		Symbol::FromName("_Z23HostState_ChangeLevelMPPKcS0_"),
+		NULL_SIGNATURE,
+		NULL_SIGNATURE,
+		NULL_SIGNATURE,
+	};
+
 	//---------------------------------------------------------------------------------
 	// Purpose: gameevent Symbols
 	//---------------------------------------------------------------------------------

source/symbols.h

@@ -63,6 +63,7 @@ struct edict_t;
 struct PackWork_t;
 class CBaseViewModel;
 class CBaseCombatCharacter;
+class CHostState;
 
 class	CGameTrace;
 typedef	CGameTrace trace_t;
@@ -172,6 +173,9 @@ namespace Symbols
 	typedef void (GMCOMMON_CALLING_CONVENTION* CBaseEntity_SetMoveType)(void* ent, int, int);
 	extern const std::vector<Symbol> CBaseEntity_SetMoveTypeSym;
 
+	typedef void (GMCOMMON_CALLING_CONVENTION* CHostState_State_ChangeLevelMP)(const char* levelName, const char* LandmarkName);
+	extern const std::vector<Symbol> CHostState_State_ChangeLevelMPSym;
+
 	//---------------------------------------------------------------------------------
 	// Purpose: gameevent Symbols
 	//---------------------------------------------------------------------------------