Add cutscene skipping to L4D quick reset

Also done with quite a lot of RE help from bill - thanks again!

1 files changed, 201 insertions, 14 deletions

diff --git a/src/l4dreset.c b/src/l4dreset.c
index 2245a16..2477b8b 100644
--- a/src/l4dreset.c
+++ b/src/l4dreset.c
@@ -21,12 +21,16 @@
 #include "engineapi.h"
 #include "ent.h"
 #include "errmsg.h"
+#include "event.h"
+#include "fastfwd.h"
 #include "feature.h"
 #include "gamedata.h"
 #include "gametype.h"
+#include "hook.h"
 #include "intdefs.h"
 #include "l4dmm.h"
 #include "mem.h"
+#include "sst.h"
 #include "vcall.h"
 #include "x86.h"
 #include "x86util.h"
@@ -37,12 +41,19 @@
 
 FEATURE("Left 4 Dead quick resetting")
 REQUIRE(ent)
+REQUIRE(fastfwd)
 REQUIRE(l4dmm)
+REQUIRE_GLOBAL(srvdll)
+REQUIRE_GAMEDATA(vtidx_GameFrame) // note: for L4D1 only, always defined anyway
+REQUIRE_GAMEDATA(vtidx_GameShutdown)
+REQUIRE_GAMEDATA(vtidx_OnGameplayStart)
 
 static void **votecontroller;
 static int off_callerrecords = -1;
 static int off_voteissues;
 
+static void *director; // "TheDirector" server global
+
 // Note: the vote callers vector contains these as elements. We don't currently
 // do anything with the structure, but we're keeping it here for reference.
 /*struct CallerRecord {
@@ -74,7 +85,7 @@ static struct CVoteIssue *getissue(const char *textkey) {
 	}
 }
 
-static void reset(void) {
+static inline void reset(void) {
 	// reset the vote cooldowns if possible (will skip L4D1). only necessary on
 	// versions >2045 and on map 1, but it's easiest to do unconditionally
 	if (off_callerrecords != -1) {
@@ -84,16 +95,90 @@ static void reset(void) {
 				off_callerrecords);
 		recordvector->sz = 0;
 	}
-	struct CVoteIssue *issue = getissue("#L4D_vote_restart_game");
-	ExecuteCommand(issue);
+	ExecuteCommand(getissue("#L4D_vote_restart_game"));
 }
 
-static void change(const char *missionid) {
+static inline void change(const char *missionid) {
 	struct CVoteIssue *issue = getissue("#L4D_vote_mission_change");
 	SetIssueDetails(issue, missionid); // will just nop if invalid
 	ExecuteCommand(issue);
 }
 
+static short ffdelay = 0, ffamt;
+static bool mapchanging = false;
+
+HANDLE_EVENT(Tick, bool simulating) {
+	if (!mapchanging && ffdelay && !--ffdelay) fastfwd(ffamt, 30);
+}
+
+typedef void (*VCALLCONV OnGameplayStart_func)(void *this);
+static OnGameplayStart_func orig_OnGameplayStart;
+static void VCALLCONV hook_OnGameplayStart(void *this) {
+	orig_OnGameplayStart(this);
+	if (mapchanging) reset(); // prevent bots walking around. note ffdelay is 45
+	mapchanging = false; // resume countdown!
+}
+// Simply reuse the above for L4D1, since the calling ABI is the exact same!
+#define UnfreezeTeam_func OnGameplayStart_func
+#define UnfreezeTeam OnGameplayStart
+#define orig_UnfreezeTeam orig_OnGameplayStart
+#define hook_UnfreezeTeam hook_OnGameplayStart
+
+static inline int getffamt(const char *campaign) {
+	// TODO(compat): add popular custom campaigns too:
+	// - dark blood 2
+	// - grey scale
+	// - left 4 mario
+	// - ravenholm
+	// - warcelona
+	// - tour of terror
+	// - dam it
+	// - carried off
+	if (GAMETYPE_MATCHES(L4D1)) {
+		if (!strcmp(campaign, "Hospital")) return 9; // No Mercy
+		if (!strcmp(campaign, "SmallTown")) return 12; // Death Toll
+		if (!strcmp(campaign, "Airport")) return 12; // Dead Air
+		if (!strcmp(campaign, "Farm")) return 15; // Blood Harvest
+		if (!strcmp(campaign, "River")) return 15; // The Sacrifice
+		if (!strcmp(campaign, "Garage")) return 8; // Crash Course
+	}
+	else /* L4D2 */ {
+		if (!strncmp(campaign, "L4D2C", 5)) {
+			int ret;
+			switch (campaign[5]) {
+				case '1':
+					switch (campaign[6]) {
+						case '\0': return 13; // Dead Center
+						case '0': ret = 12; break; // Death Toll
+						case '1': ret = 13; break; // Dead Air
+						case '2': ret = 16; break; // Blood Harvest
+						case '3': ret = 18; break; // Cold Stream
+						case '4': ret = 16; break; // The Last Stand
+						default: return 0;
+					}
+					if (campaign[7]) return 0;
+					return ret;
+				case '2': ret = 12; break; // Dark Carnival
+				case '3': ret = 19; break; // Swamp Fever
+				case '4': ret = 8; break; // Hard Rain
+				case '5': ret = 13; break; // The Parish
+				case '6': ret = 10; break; // The Passing
+				case '7': ret = 15; break; // The Sacrifice
+				case '8': ret = 9; break; // No Mercy
+				case '9': ret = 8; break; // Crash Course
+				default: return 0;
+			}
+			if (campaign[6]) return 0;
+			return ret;
+		}
+	}
+	return 0; // if unknown, just don't skip, I guess.
+}
+
+DEF_CVAR_UNREG(sst_l4d_quickreset_fastfwd,
+		"Fast-forward through cutscenes when quick-resetting", 1,
+		CON_ARCHIVE | CON_HIDDEN)
+
 DEF_CCMD_HERE_UNREG(sst_l4d_quickreset,
 		"Reset (or switch) campaign and clear all vote cooldowns", 0) {
 	if (cmd->argc > 2) {
@@ -104,17 +189,29 @@ DEF_CCMD_HERE_UNREG(sst_l4d_quickreset,
 		con_warn("not hosting a server\n");
 		return;
 	}
-	if (cmd->argc == 2) {
-		const char *cur = l4dmm_curcampaign();
-		if (!cur || strcasecmp(cur, cmd->argv[1])) {
-			change(cmd->argv[1]);
-			return;
-		}
+	const char *campaign = l4dmm_curcampaign();
+	if (cmd->argc == 2 && (!campaign || strcasecmp(campaign, cmd->argv[1]))) {
+		change(cmd->argv[1]);
+		campaign = cmd->argv[1];
+		mapchanging = true;
+	}
+	else {
+		reset();
+		// same-map reset is delayed by about a second - save that time here
+		// also, set mapchanging back to false in case it got stuck somehow
+		if (!(mapchanging = !l4dmm_firstmap())) fastfwd(0.8, 10);
+	}
+	if (campaign && con_getvari(sst_l4d_quickreset_fastfwd) &&
+			(ffamt = getffamt(campaign))) {
+		ffdelay = 45; // 1.5s
 	}
-	reset();
 }
 
-PREINIT { return GAMETYPE_MATCHES(L4D); }
+PREINIT {
+	if (!GAMETYPE_MATCHES(L4D)) return false;
+	con_reg(sst_l4d_quickreset_fastfwd);
+	return true;
+}
 
 // Note: this returns a pointer to subsequent bytes for find_voteissues() below
 static inline const uchar *find_votecontroller(con_cmdcbv1 listissues_cb) {
@@ -191,6 +288,52 @@ static inline bool find_votecallers(void *votectrlspawn) {
 	return false;
 }
 
+#ifdef _WIN32
+static inline bool find_TheDirector(void *GameShutdown) {
+	// in 2045, literally the first instruction of this function is loading
+	// TheDirector into ECX. although, do the usual search in case moves a bit.
+	const uchar *insns = (const uchar *)GameShutdown;
+	for (const uchar *p = insns; p - insns < 24;) {
+		if (p[0] == X86_MOVRMW && p[1] == X86_MODRM(0, 1, 5)) {
+			void **indirect = mem_loadptr(p + 2);
+			director = *indirect;
+			return true;
+		}
+		NEXT_INSN(p, "load of TheDirector");
+	}
+	return false;
+}
+#endif
+
+static inline bool find_UnfreezeTeam(void *GameFrame) { // note: L4D1 only
+	// CServerGameDLL::GameFrame() loads TheDirector into ECX and then calls
+	// Director::Update()
+	const uchar *insns = (const uchar *)GameFrame, *p = insns;
+	while (p - insns < 192) {
+		if (p[0] == X86_MOVRMW && p[1] == X86_MODRM(0, 1, 5) &&
+				mem_loadptr(mem_loadptr(p + 2)) == director &&
+				p[6] == X86_CALL) {
+			p += 11 + mem_loadoffset(p + 7);
+			insns = p;
+			goto ok;
+		}
+		NEXT_INSN(p, "Director::Update call");
+	}
+	return false;
+ok: // Director::Update calls UnfreezeTeam after the first jmp instruction
+	while (p - insns < 96) {
+		// jz XXX; mov ecx, <reg>; call Director::UnfreezeTeam
+		if (p[0] == X86_JZ && p[2] == X86_MOVRMW && (p[3] & 0xF8) == 0xC8 &&
+				p[4] == X86_CALL) {
+			p += 9 + mem_loadoffset(p + 5);
+			orig_UnfreezeTeam = (UnfreezeTeam_func)p;
+			return true;
+		}
+		NEXT_INSN(p, "Director::UnfreezeTeam call");
+	}
+	return false;
+ }
+
 INIT {
 	struct con_cmd *cmd_listissues = con_findcmd("listissues");
 	if (!cmd_listissues) {
@@ -207,8 +350,41 @@ INIT {
 		errmsg_errorx("couldn't find vote issues list offset\n");
 		return false;
 	}
+	void **vtable;
+#ifdef _WIN32
+	void *GameShutdown = (*(void ***)srvdll)[vtidx_GameShutdown];
+	if (!find_TheDirector(GameShutdown)) {
+		errmsg_errorx("couldn't find TheDirector variable");
+		return false;
+	}
+#else
+#warning TODO(linux): should be able to just dlsym(server, "TheDirector")
+	return false;
+#endif
+#ifdef _WIN32 // L4D1 has no Linux build, no need to check whether L4D2
+	if (GAMETYPE_MATCHES(L4D2)) {
+#endif
+		vtable = mem_loadptr(director);
+		if (!os_mprot(vtable + vtidx_OnGameplayStart, sizeof(*vtable),
+				PAGE_READWRITE)) {
+			errmsg_errorsys("couldn't make virtual table writable");
+			return false;
+		}
+		orig_OnGameplayStart = (OnGameplayStart_func)hook_vtable(vtable,
+				vtidx_OnGameplayStart, (void *)&hook_OnGameplayStart);
+#ifdef _WIN32 // L4D1 has no Linux build!
+	}
+	else /* L4D1 */ {
+		void *GameFrame = (*(void ***)srvdll)[vtidx_GameFrame];
+		if (!find_UnfreezeTeam(GameFrame)) {
+			errmsg_errorx("couldn't find UnfreezeTeam function");
+			return false;
+		}
+		orig_UnfreezeTeam = (UnfreezeTeam_func)hook_inline(
+				(void *)orig_UnfreezeTeam, (void *)&hook_UnfreezeTeam);
+	}
+#endif
 	// Only try cooldown stuff for L4D2, since L4D1 always had unlimited votes.
-	// NOTE: assuming L4D2 always has Spawn in gamedata (why wouldn't it?)
 	if (GAMETYPE_MATCHES(L4D2)) {
 		// g_voteController is invalid if not running a server so get the
 		// vtable by inspecting the ent factory code instead
@@ -217,7 +393,7 @@ INIT {
 			errmsg_errorx("couldn't find vote controller entity factory");
 			goto nocd;
 		}
-		void **vtable = ent_findvtable(factory, "CVoteController");
+		vtable = ent_findvtable(factory, "CVoteController");
 		if (!vtable) {
 			errmsg_errorx("couldn't find CVoteController vtable");
 			goto nocd;
@@ -228,7 +404,18 @@ nocd:		errmsg_note("resetting a first map will not clear vote cooldowns");
 		}
 	}
 	con_reg(sst_l4d_quickreset);
+	sst_l4d_quickreset_fastfwd->base.flags &= ~CON_HIDDEN;
 	return true;
 }
 
+END {
+	if (GAMETYPE_MATCHES(L4D2)) {
+		unhook_vtable(mem_loadptr(director), vtidx_OnGameplayStart,
+				(void *)orig_OnGameplayStart);
+	}
+	else {
+		unhook_inline((void *)orig_UnfreezeTeam);
+	}
+}
+
 // vi: sw=4 ts=4 noet tw=80 cc=80