feat: promo items (#347)

Cheat command that force-enables promotion items (pre-order roll cage "helmet", skin, antenna)

---------

Co-authored-by: ThisAMJ <69196954+ThisAMJ@users.noreply.github.com>

Author: KiIoOnline

docs/cvars.md

@@ -514,6 +514,7 @@
 |sar_scrollspeed_y|210|Scroll speed HUD y offset.|
 |sar_seamshot_finder|0|Enables or disables seamshot finder overlay.|
 |sar_session|cmd|sar_session - prints the current tick of the server since it has loaded|
+|sar_set_promo_items_state|cmd|sar_set_promo_items_state \<off\|all\|skins\|helmet\|antenna>... - enables coop promotional items on spawn.|
 |sar_show_entinp|0|Print all entity inputs to console.|
 |sar_skiptodemo|cmd|sar_skiptodemo \<demoname> - skip demos in demo queue to this demo|
 |sar_speedrun_autoreset_clear|cmd|sar_speedrun_autoreset_clear - stop using the autoreset file|

src/Cheats.cpp

@@ -331,6 +331,7 @@ Memory::Patch *g_floorReportalPatch;
 Memory::Patch *g_coopLoadingDotsPatch;
 Memory::Patch *g_autoGrabPatchServer;
 Memory::Patch *g_autoGrabPatchClient;
+Memory::Patch *g_promoFlagsPatch;
 
 void Cheats::Init() {
 	sv_laser_cube_autoaim = Variable("sv_laser_cube_autoaim");
@@ -399,6 +400,14 @@ void Cheats::Init() {
 		g_autoGrabPatchClient->Restore();
 	}
 
+	g_promoFlagsPatch = new Memory::Patch();
+	auto portal2PromoFlags = Memory::Scan(MODULE("server"), Offsets::Portal2PromoFlagsSig, Offsets::Portal2PromoFlagsOff);
+	if (portal2PromoFlags) {
+		unsigned char promoFlagsByte = 0x00;
+		g_promoFlagsPatch->Execute(Memory::Deref<uintptr_t>(portal2PromoFlags), &promoFlagsByte, 1); // Note: Has to be active before map loads.
+		g_promoFlagsPatch->Restore();
+	}
+
 	Variable::RegisterAll();
 	Command::RegisterAll();
 }
@@ -422,6 +431,8 @@ void Cheats::Shutdown() {
 	SAFE_DELETE(g_autoGrabPatchServer);
 	g_autoGrabPatchClient->Restore();
 	SAFE_DELETE(g_autoGrabPatchClient);
+	g_promoFlagsPatch->Restore();
+	SAFE_DELETE(g_promoFlagsPatch);
 }
 
 
@@ -589,3 +600,37 @@ void Cheats::CheckAutoGrab() {
 		g_autoGrabPatchClient->Restore();
 	}
 }
+
+DECL_AUTO_COMMAND_COMPLETION(sar_set_promo_items_state, ({"skins", "helmet", "antenna"})) // TODO: Add support for autofilling multiple args.
+CON_COMMAND_F_COMPLETION(sar_set_promo_items_state, "sar_set_promo_items_state <off|all|skins|helmet|antenna>... - enables coop promotional items on spawn.\n", FCVAR_CHEAT, AUTOCOMPLETION_FUNCTION(sar_set_promo_items_state)) {
+	if (!g_promoFlagsPatch || !g_promoFlagsPatch->IsInit()) {
+		return console->Print("sar_set_promo_items_state is not available.\n");
+	}
+
+	if (args.ArgC() < 2) {
+		return console->Print(sar_set_promo_items_state.ThisPtr()->m_pszHelpString);
+	}
+
+	unsigned char targetFlags = 0;
+	for (int i = 1; i < args.ArgC(); i++) {
+		if (strcasecmp(args[i], "off") == 0) {
+			g_promoFlagsPatch->Restore();
+			return;
+		}
+		if (strcasecmp(args[i], "all") == 0) {
+			targetFlags = 0b111;
+			break;
+		}
+		if (strcasecmp(args[i], "skins") == 0) {;
+			targetFlags |= 0b001;
+		} else if (strcasecmp(args[i], "helmet") == 0) {
+			targetFlags |= 0b010;
+		} else if (strcasecmp(args[i], "antenna") == 0) {
+			targetFlags |= 0b100;
+		} else {
+			return console->Print(sar_set_promo_items_state.ThisPtr()->m_pszHelpString);
+		}
+	}
+	g_promoFlagsPatch->Restore();
+	g_promoFlagsPatch->Execute(&targetFlags, 1);
+}

src/Cheats.hpp

@@ -50,3 +50,5 @@ extern Variable hide_gun_when_holding;
 extern Variable r_flashlightbrightness;
 
 extern Command sar_togglewait;
+
+extern Memory::Patch *g_promoFlagsPatch;

src/Modules/Server.cpp

@@ -285,6 +285,7 @@ DETOUR(Server::PlayerRunCommand, CUserCmd *cmd, void *moveHelper) {
 
 	Cheats::AutoStrafe(slot, thisptr, cmd);
 	Cheats::CheckFloorReportals();
+	if (!sv_cheats.GetBool()) g_promoFlagsPatch->Restore(); // We only want to check this once per map load, to preserve the intended behavior.
 
 	inputHud.SetInputInfo(slot, cmd->buttons, {cmd->sidemove, cmd->forwardmove, cmd->upmove});
 

src/Offsets/Portal 2 9568.hpp

@@ -537,6 +537,10 @@ SIGSCAN_DEFAULT(FloorReportalBranch, "75 7D 8B 8E C0 04 00 00",
 SIGSCAN_DEFAULT(CPortal_Player__PollForUseEntity_CheckMP, "74 ? ? ? 8B 82 ? ? ? ? FF D0 84 C0 74 ? 8B CE",
                                                           "74 ? 8B 10 83 EC 0C 50 FF 92 88 00 00 00 83 C4 10 84 C0 ? ? ? ? ? ? ? ? ? ? ? ? ? 00 00") // "OnJump" xref -> CPortal_Player:PreThink -> CBasePlayer::PreThink -> CBasePlayer::ItemPreFrame -> CBasePlayer::PlayerUse -> CPortal_Player vtable offset -> CPortal_Player::PlayerUse -> Second function call from disassembly -> CPortal_Player::PollForUseEntity -> jz instruction
 
+SIGSCAN_DEFAULT(Portal2PromoFlagsSig, "F6 05 ? ? ? ? 02 74 ? 8B CE",
+                                      "A1 ? ? ? ? A8 02") // "#P2_WearableType_Flag" xref -> CPortal_Player::GiveDefaultItems -> bitwise & -> portal2 promo flag
+OFFSET_DEFAULT(Portal2PromoFlagsOff, 2, 1)
+
 // VPhysics
 OFFSET_EMPTY(DestroyEnvironment)
 OFFSET_EMPTY(GetActiveEnvironmentByIndex)

src/Utils/Memory.cpp

@@ -245,6 +245,7 @@ Memory::Patch::~Patch() {
 }
 bool Memory::Patch::Execute() {
 	if (this->isPatched) return true; // already executed
+	if (!this->IsInit()) return false;
 	unsigned char *tmpPatch = new unsigned char[this->size];
 	//	We create another patch, because this->patch is gonna be deleted
 	memcpy(tmpPatch, this->patch, this->size);

src/Utils/Memory.hpp

@@ -50,6 +50,13 @@ namespace Memory {
 		bool Execute(uintptr_t location, unsigned char (&bytes)[size]) {
 			return Execute(location, bytes, size);
 		}
+		bool Execute(unsigned char *bytes, size_t size) {
+			return Execute(location, bytes, size);
+		}
+		template <size_t size>
+		bool Execute(unsigned char (&bytes)[size]) {
+			return Execute(location, bytes, size);
+		}
 		bool Restore();
 		bool IsPatched();
 		bool IsInit();