MC_CAN_SELECT_CHARACTER (allows preventing starting a run with a character from character selection, including via random)

Added an optional boolean parameter to Isaac.StartNewGame to set Seeds.IsCustomRun
Optionally allow passing a whole Seeds object to Isaac.StartNewGame instead of just the start seed int

Author: ConnorForan

changelog.txt

@@ -29,6 +29,12 @@ Added:
 		Called before Game():BombTearflagEffects(), used when TearFlags-based effects are triggered by an explosion.
 		Return false to cancel, or a table containing changed values for Position, Radius, TearFlags, and/or RadiusMult.
 		Optional param is the EntityType of the Source entity, if one exists (the Source can be nil).
+	- MC_CAN_SELECT_CHARACTER(PlayerType, bool IsBeingSelected)
+		Will only run for characters present in the character select menu that are capable of being selected (IE, not hidden or locked behind an achievement).
+		Return false to prevent the character from being selectable. This has no visual effects.
+		IsBeingSelected is true if the player is actually trying to start a run with the character. Returning false in this case will play the error buzzer sound.
+		Otherwise, this is just a check by some other logic (such as deciding which characters are eligible for random character selection).
+		Optional param: PlayerType
 * Added EntitySaveStateManager class to support persistent, modded save data for entities.
 * EntityLaser:
 	- SetInitSound(SoundEffect sound)
@@ -60,6 +66,10 @@ Added:
 * The "Error" and "Modeling Clay" trinkets now use the sprite of the item they are mimicking when smelted, like how they do in later versions of Repentance+.
 /newline/
 Modified:
+* Isaac:
+	- StartNewGame
+		Added optional param "bool isCustomRun".
+		Added function variant that takes a whole Seeds object instead of a seed integer.
 * EntityPlayer:
 	- SetControllerIndex(integer ControllerIndex, boolean IncludePlayerOwned = false)
 		If IncludePlayerOwned set to true, then sets ControllerIndex for player's subplayer/twinplayer

libzhl/IsaacRepentance_static.cpp

@@ -607,6 +607,27 @@ int HistoryHUD::GetNumVisibleItems() const {
 	return GetNumRows() * GetNumColumns();
 }
 
+int Menu_Character::GetPlayerTypeFromMenuID(int menuID, bool taintedMenu) {
+	if (menuID > 0) {
+		if (menuID < 18) {
+			return __ptr_g_MenuCharacterEntries[taintedMenu ? (menuID + 18) : menuID].playerType;
+		} else if (menuID < (int)g_ModCharacterMap.size() + 18) {
+			const auto& modChar = g_ModCharacterMap[menuID - 18];
+			return taintedMenu ? modChar.tainted : modChar.normal;
+		}
+	}
+	return -1;
+}
+
+int Menu_Character::GetPlayerTypeFromCurrentMenuID(int menuID) {
+	const bool taintedMenu = GetSelectedCharacterMenu() == 1;
+	return Menu_Character::GetPlayerTypeFromMenuID(menuID, taintedMenu);
+}
+
+int Menu_Character::GetSelectedPlayerType() {
+	return GetPlayerTypeFromCurrentMenuID(SelectedCharacterID);
+}
+
 bool Isaac::IsInGame() {
 	return g_Manager->GetState() == 2 && g_Game;
 }

libzhl/functions/ASM.zhl

@@ -5,6 +5,7 @@ asm DisableExitPrompt "8d45??c745??00009643"; //DisableExitPrompt option patch
 asm LeaderboardGoalPatch "83be????????01b807000000"; //LeaderboardGoalPatch
 
 asm HideModdedCharacterByAchievement "80b8????????0075??83b8????????0075??8b08"; //PatchModdedCharacterHiddenByAchievementInMenu
+asm MenuCharacter_PreSelectCharacter "74??a1????????83ec14";
 
 asm RenderCharacterWheel_RenderPositionStackOffset "f30f114c24??f30f58d0f30f115424";  // Offset is one byte @ +0x5
 asm RenderCharacterWheel_GetMenuCharacterIndex "a1????????8b0c??f30f104c";  // 8 bytes, moves a data ptr into EAX, then the value into ECX, using EBX

libzhl/functions/MenuCharacter.zhl

@@ -42,9 +42,18 @@ struct Menu_Character depends (ANM2, CompletionWidget) {
 	inline ANM2* GetSeedEntrySprite() { return &this->_SeedEntrySprite; }
 	inline ANM2* GetPageSwapWidgetSprite() { return &this->_PageSwapWidgetSprite; }
 	inline ANM2* GetTaintedBGDecoSprite() { return &this->_TaintedMenuBGDecoSprite; }
-    
-    inline int GetNumCharacters() { return this->_numCharacters; }
+
+	inline int GetNumCharacters() { return this->_numCharacters; }
 	inline int GetSelectedCharacterMenu() { return this->_characterMenuShown; }
+
+	// Given a CharacterMenu ID, returns the corresponding PlayerType in the specified menu (-1 for random).
+	static int LIBZHL_API Menu_Character::GetPlayerTypeFromMenuID(int menuID, bool taintedMenu);
+
+	// Given a CharacterMenu ID, returns the corresponding PlayerType in the current menu (-1 for random).
+	int LIBZHL_API Menu_Character::GetPlayerTypeFromCurrentMenuID(int menuID);
+
+	// Returns the PlayerType of the currently selected character in the wheel (-1 for random).
+	int LIBZHL_API Menu_Character::GetSelectedPlayerType();
 }} 
     int Status : 0x0; //1 seeds screen //4 transitioning to tainted
     bool IsCharacterUnlocked : 0x5;

libzhl/functions/Seeds.zhl

@@ -16,13 +16,16 @@ __thiscall bool Seeds::HasSeedEffect(uint32_t seedEffect);
 "558bec83ec1453568b71":
 __thiscall bool Seeds::AchievementUnlocksDisallowed();
 
-// sorry for the mess, this is a direct ghidra export :(
+// Please note that the constructors for this class allocate 0x14 bytes for SeedEffects.
+// We cannot properly free this memory ourselves at the moment. The proper destructor for this
+// class may have been inlined everywhere. Passing the Seeds to certain functions like
+// StartNewGame will handle the cleanup for us however, just be mindful.
 struct Seeds depends (RNG,ANM2){
     bool _isCustomRun : 0x0;
     unsigned int _gameStartSeed : 0x4;
     RNG _rng : 0x8;
     unsigned int _stageSeeds[14] : 0x18;
     unsigned int _playerInitSeed : 0x50;
-	unsigned int _unkseed : 0x54;
+    // 0x54 is a pointer to some kind of data structure for SeedEffects.
     int _seedEffectsCount : 0x58;
 } : 0x5c;

repentogon/LuaInterfaces/LuaIsaac.cpp

@@ -197,10 +197,18 @@ LUA_FUNCTION(Lua_StartNewGame) {
 	int pltype = (int)luaL_optinteger(L, 1, 0);
 	int challenge = (int)luaL_optinteger(L, 2, 0);
 	unsigned int difficulty = (int)luaL_optinteger(L, 3, 0);
-	unsigned int seed = (int)luaL_optinteger(L, 4, 0);
-	Seeds seedobj;	//am avoiding heap corruption this way
-	seedobj.constructor();	
-	seedobj.set_start_seed(seed);
+	// Note: At the moment we cannot properly free some of the memory allocated by the Seeds constructors ourselves.
+	// However, StartNewGame will handle it for us. Just be aware of this.
+	Seeds seedobj;
+	if (lua_type(L, 4) == LUA_TUSERDATA) {
+		seedobj.construct_from_copy(lua::GetLuabridgeUserdata<Seeds*>(L, 4, lua::Metatables::SEEDS, "Seeds"));
+	} else {
+		unsigned int seed = (unsigned int)luaL_optinteger(L, 4, 0);
+		bool isCustomRun = lua::luaL_optboolean(L, 5, false);
+		seedobj.constructor();
+		seedobj.set_start_seed(seed);
+		seedobj._isCustomRun = isCustomRun;
+	}
 	g_Manager->StartNewGame(pltype, challenge, seedobj, difficulty);
 	return 0;
 }
@@ -784,6 +792,8 @@ LUA_FUNCTION(Lua_StartDailyGame) {
 	const unsigned int date = (unsigned int)luaL_checkinteger(L, 1);
 
 	// defer start to the manager
+	// Note: At the moment we cannot properly free some of the memory allocated by the Seeds constructors by ourselves.
+	// However, StartNewGame will handle it for us. Just be aware of this.
 	Seeds seeds; seeds.constructor();
 	g_Manager->StartNewGame(ePlayerType::PLAYER_ISAAC, eChallenge::CHALLENGE_NULL, seeds, 0);
 

repentogon/LuaInterfaces/Menus/LuaCharacterMenu.cpp

@@ -301,27 +301,14 @@ LUA_FUNCTION(lua_CharMenu_SetSelectedCharacterID)
 	return 0;
 }
 
-// Given a CharacterMenu character ID, returns the corresponding PlayerType.
-int GetPlayerTypeFromCharacterMenuID(const int charID, const bool taintedMenu) {
-	if (charID > 0) {
-		if (charID < 18) {
-			return __ptr_g_MenuCharacterEntries[taintedMenu ? (charID + 18) : charID].playerType;
-		} else if (charID < (int)g_ModCharacterMap.size() + 18) {
-			const auto& modChar = g_ModCharacterMap[charID - 18];
-			return taintedMenu ? modChar.tainted : modChar.normal;
-		}
-	}
-	return -1;
-}
-
 LUA_FUNCTION(lua_CharMenu_GetPlayerTypeFromCharacterMenuID)
 {
 	lua::LuaCheckMainMenuExists(L, lua::metatables::CharacterMenuMT);
 	Menu_Character* menu = g_MenuManager->GetMenuCharacter();
 
 	const int charID = (int)luaL_checkinteger(L, 1);
 	const bool taintedMenu = lua::luaL_optboolean(L, 2, menu->GetSelectedCharacterMenu() == 1);
-	const int playerType = GetPlayerTypeFromCharacterMenuID(charID, taintedMenu);
+	const int playerType = Menu_Character::GetPlayerTypeFromMenuID(charID, taintedMenu);
 
 	if (playerType < 0) {
 		lua_pushnil(L);
@@ -337,8 +324,7 @@ LUA_FUNCTION(lua_CharMenu_GetSelectedCharacterPlayerType)
 	lua::LuaCheckMainMenuExists(L, lua::metatables::CharacterMenuMT);
 	Menu_Character* menu = g_MenuManager->GetMenuCharacter();
 
-	const bool taintedMenu = menu->GetSelectedCharacterMenu() == 1;
-	const int playerType = GetPlayerTypeFromCharacterMenuID(menu->SelectedCharacterID, taintedMenu);
+	const int playerType = menu->GetSelectedPlayerType();
 
 	if (playerType < 0) {
 		lua_pushnil(L);

repentogon/Patches/ASMPatches/ASMCallbacks.cpp

@@ -1518,9 +1518,8 @@ void RunRenderCharacterWheelCallbacks(ANM2* sprite, Vector* pos, const int playe
 
 void __stdcall RenderVanillaCharacterWheelTrampoline(const int menuid, Vector* pos) {
 	ANM2* sprite = &g_MenuManager->GetMenuCharacter()->_CharacterPortraitsSprite;
-	const bool taintedMenu = g_MenuManager->GetMenuCharacter()->GetSelectedCharacterMenu() == 1;
-	if (menuid >= 0 && menuid < 18) {
-		const int playerType = (menuid == 0) ? -1 : __ptr_g_MenuCharacterEntries[taintedMenu ? (menuid + 18) : menuid].playerType;
+	const int playerType = g_MenuManager->GetMenuCharacter()->GetPlayerTypeFromCurrentMenuID(menuid);
+	if (playerType < NUM_PLAYER_TYPES) {
 		RunRenderCharacterWheelCallbacks(sprite, pos, playerType);
 	} else {
 		// Failsafe
@@ -1637,13 +1636,11 @@ void RunPostRenderCharacterMenuCallback(const int playerType, Vector* pos, ANM2*
 static bool _skipEdenTokensRender = false;
 
 void __stdcall RenderVanillaCharacterMenuTrampoline(Vector* pos) {
-	int menuid = g_MenuManager->GetMenuCharacter()->SelectedCharacterID;
 	ANM2* vanillaSprite = g_MenuManager->GetMenuCharacter()->GetBigCharPageSprite();
 	Vector zeroVector(0, 0);
 	_skipEdenTokensRender = false;
-	if (menuid >= 0 && menuid < 18) {
-		const bool taintedMenu = g_MenuManager->GetMenuCharacter()->GetSelectedCharacterMenu() == 1;
-		const int playerType = (menuid == 0) ? -1 : __ptr_g_MenuCharacterEntries[taintedMenu ? (menuid + 18) : menuid].playerType;
+	const int playerType = g_MenuManager->GetMenuCharacter()->GetSelectedPlayerType();
+	if (playerType < NUM_PLAYER_TYPES) {
 		if (RunPreRenderCharacterMenuCallback(playerType, pos, vanillaSprite, nullptr, false)) {
 			vanillaSprite->Render(pos, &zeroVector, &zeroVector);
 			RunPostRenderCharacterMenuCallback(playerType, pos, vanillaSprite, nullptr, false, false);
@@ -1742,6 +1739,49 @@ void ASMPatchRenderCustomCharacterMenu_Default() {
 	sASMPatcher.PatchAt(patchAddr, &patch);
 }
 
+// MC_CAN_SELECT_CHARACTER
+bool RunCanSelectCharacterCallback(const int playerType, const bool isBeingSelected) {
+	const int callbackid = 1328;
+	if (CallbackState.test(callbackid - 1000)) {
+		lua_State* L = g_LuaEngine->_state;
+		lua::LuaStackProtector protector(L);
+
+		lua_rawgeti(L, LUA_REGISTRYINDEX, g_LuaEngine->runCallbackRegistry->key);
+
+		lua::LuaResults result = lua::LuaCaller(L).push(callbackid)
+			.push(playerType)
+			.push(playerType)
+			.push(isBeingSelected)
+			.call(1);
+
+		if (!result && lua_isboolean(L, -1) && !lua_toboolean(L, -1)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool __stdcall CharacterMenuPreSelectCharacterTrampoline() {
+	const int playerType = g_MenuManager->GetMenuCharacter()->GetSelectedPlayerType();
+	return RunCanSelectCharacterCallback(playerType, true);
+}
+void ASMPatchCharacterMenuPreSelectCharacter() {
+	void* patchAddr = (char*)sASMDefinitionHolder->GetDefinition(&AsmDefinitions::MenuCharacter_PreSelectCharacter) + 0x2;
+	const int8_t jump = *(int8_t*)((char*)patchAddr - 0x1);
+
+	ASMPatch::SavedRegisters reg(ASMPatch::SavedRegisters::GP_REGISTERS_STACKLESS, true);
+	ASMPatch patch;
+	patch.PreserveRegisters(reg)
+		.AddInternalCall(CharacterMenuPreSelectCharacterTrampoline)
+		.AddBytes("\x84\xC0")  // TEST AL, AL
+		.RestoreRegisters(reg)
+		.AddConditionalRelativeJump(ASMPatcher::CondJumps::JZ, (char*)patchAddr + jump)  // Jump for false
+		.AddBytes(ByteBuffer().AddAny((char*)patchAddr, 0x5))  // Restore the push we overwrote
+		.AddRelativeJump((char*)patchAddr + 0x5);  // Continue for true
+	sASMPatcher.PatchAt(patchAddr, &patch);
+}
+
 // Historically, MC_PRE_MOD_UNLOAD also runs during game shutdown, when the LuaEngine is being destroyed.
 // However, this happens late into the shutdown process, after Game and Manager are already destroyed,
 // so any code running on this callback at this time is very likely to crash the game.
@@ -2262,4 +2302,5 @@ void ASMCallbacks::detail::ApplyPatches()
 	ASMPatchRenderVanillaCharacterMenu_EdenTokens();
 	ASMPatchRenderCustomCharacterMenu_Custom();
 	ASMPatchRenderCustomCharacterMenu_Default();
+	ASMPatchCharacterMenuPreSelectCharacter();
 }

repentogon/Patches/ASMPatches/ASMCallbacks.h

@@ -4,6 +4,7 @@
 
 bool __stdcall RunPreLaserCollisionCallback(Entity_Laser* laser, Entity* entity);
 void RunRenderCharacterWheelCallbacks(ANM2* sprite, Vector* pos, int playerType);
+bool RunCanSelectCharacterCallback(int playerType, bool isBeingSelected);
 
 void PatchPreSampleLaserCollision();
 void PatchPreLaserCollision();

repentogon/Patches/CompletionTracker.cpp

@@ -947,12 +947,8 @@ HOOK_METHOD(PauseScreen, Render, () -> void) {
 HOOK_METHOD(Menu_Character, Render, () -> void) {
 	super();
 	CompletionWidget* cmpl = this->GetCompletionWidget();
-	int menucharid = this->SelectedCharacterID;
-	if (menucharid > 17 && menucharid < (int)g_ModCharacterMap.size() + 18) {
-		const auto& menuchar = g_ModCharacterMap[menucharid - 18];
-		const bool taintedmenu = g_MenuManager->GetMenuCharacter()->GetSelectedCharacterMenu() == 1;
-		const int playertype = taintedmenu ? menuchar.tainted : menuchar.normal;
-
+	const int playertype = g_MenuManager->GetMenuCharacter()->GetSelectedPlayerType();
+	if (playertype >= NUM_PLAYER_TYPES) {
 		Vector* ref = &g_MenuManager->_ViewPosition;
 //		Vector* cpos = new Vector(ref->x - 80, ref->y + 894);	//goes unused
 		ANM2* anm = cmpl->GetANM2();