Added a new hook: HOOK_ROLLCHECK

artifacts/scripting/headers/sfall.h

@@ -71,6 +71,7 @@
 #define HOOK_ENCOUNTER        (43)
 #define HOOK_ADJUSTPOISON     (44)
 #define HOOK_ADJUSTRADS       (45)
+#define HOOK_ROLLCHECK        (46)
 
 //Valid arguments to list_begin
 #define LIST_CRITTERS    (0)

artifacts/scripting/hookscripts.txt

@@ -718,3 +718,26 @@ Critter arg0 - the critter (usually dude_obj)
 int     arg1 - the amount of radiation being added/removed
 
 int     ret0 - the new amount of radiation being added/removed
+
+-------------------------------------------
+
+HOOK_ROLLCHECK (hs_rollcheck.int)
+
+Runs when a game event performs a random roll to check the chance of success or failure.
+
+int     arg0 - event type:
+               1 - checks the chance of an attack hitting the target
+               2 - checks the chance of a bullet from a burst hitting the target (for burst attacks)
+               3 - checks the chance when using skills (not listed below)
+               4 - check the chance of using Repair skill
+               5 - check the chance of using Doctor skill
+               6 - check the chance of using Steal skill for the thief
+               7 - the second Steal skill chance check for the target to catch the thief, in which the target's failure is the thief's success result
+int     arg1 - the value of roll result (see ROLL_* constants), which is calculated as:
+               for ROLL_CRITICAL_SUCCESS: random(1, 100) <= (random_chance / 10) + bonus
+               for ROLL_CRITICAL_FAILURE: random(1, 100) <= -random_chance / 10
+int     arg2 - the chance value
+int     arg3 - the bonus value, used when checking critical success
+int     arg4 - random chance (calculated as: chance - random(1, 100)), where a negative value is a failure check (ROLL_FAILURE)
+
+int     ret0 - overrides the roll result

sfall/Modules/CritterPoison.cpp

@@ -116,7 +116,7 @@ static void __declspec(naked) critter_check_rads_hack() {
 }
 
 void CritterPoison::init() {
-	// Allow changing the poison level for critters
+	// Allow changing the poison level for NPCs
 	MakeCall(0x42D226, critter_adjust_poison_hack);
 	SafeWrite8(0x42D22C, 0xDA); // jmp 0x42D30A
 

sfall/Modules/HookScripts.cpp

@@ -107,10 +107,11 @@ static HooksInjectInfo injectHooks[] = {
 	{HOOK_ENCOUNTER,        Inject_EncounterHook,        0},
 	{HOOK_ADJUSTPOISON,     Inject_AdjustPoisonHook,     0},
 	{HOOK_ADJUSTRADS,       Inject_AdjustRadsHook,       1},  // always embedded for party control fix
+	{HOOK_ROLLCHECK,        Inject_RollCheckHook,        0},
 };
 
 void HookScripts::InjectingHook(int hookId) {
-	if (!IsInjectHook(hookId) && injectHooks[hookId].id == hookId) {
+	if (IsInjectHook(hookId) == false && injectHooks[hookId].id == hookId) {
 		injectHooks[hookId].injectState = 2;
 		injectHooks[hookId].inject();
 		devlog_f("Inject hook ID: %d\n", DL_INIT, hookId);

sfall/Modules/HookScripts.h

@@ -72,6 +72,7 @@ enum HookType
 	HOOK_ENCOUNTER        = 43,
 	HOOK_ADJUSTPOISON     = 44,
 	HOOK_ADJUSTRADS       = 45,
+	HOOK_ROLLCHECK        = 46,
 	HOOK_COUNT
 };
 

sfall/Modules/HookScripts/MiscHs.cpp

@@ -631,6 +631,57 @@ cancelEnc:
 	}
 }
 
+static long __stdcall RollCheckHook_Script(long roll, long chance, long bonus, long randomChance, long calledFrom) {
+	long hookType;
+	switch (calledFrom - 5) {
+		case 0x42388E: // compute_attack_
+		// compute_spray_
+		case 0x4234D1: hookType = 1; break; // single and burst attack hit event
+		// compute_spray_
+		case 0x42356C: hookType = 2; break; // burst attack bullet hit event
+		// skill_result_
+		case 0x4AAB29: hookType = 3; break; // common skill check event
+		// skill_use_
+		case 0x4AB3B6: hookType = 4; break; // SKILL_REPAIR
+		case 0x4AB8B5: hookType = 5; break; // SKILL_DOCTOR
+		// skill_check_stealing_            // SKILL_STEAL
+		case 0x4ABC9F: hookType = 6; break; // source stealing check event
+		case 0x4ABCE6: hookType = 7; break; // target stealing check event (fail for success stealing)
+	default:
+		return roll; // unsupported hook
+	}
+
+	BeginHook();
+	argCount = 5;
+
+	args[0] = hookType;
+	args[1] = roll;
+	args[2] = chance;
+	args[3] = bonus;
+	args[4] = randomChance;
+
+	RunHookScript(HOOK_ROLLCHECK);
+	if (cRet) roll = rets[0];
+
+	EndHook();
+	return roll;
+}
+
+static void __declspec(naked) roll_check_hook() {
+	__asm {
+		push ecx;
+		push [esp + 0xC + 8]; // calledFrom
+		push ebx; // random chance value
+		push esi; // bonus
+		push edi; // chance value
+		call fo::funcoffs::roll_check_critical_;
+		push eax; // roll result
+		call RollCheckHook_Script;
+		pop  ecx;
+		retn;
+	}
+}
+
 void Inject_BarterPriceHook() {
 	HookCalls(BarterPriceHook, {
 		0x474D4C, // barter_attempt_transaction_ (offers button)
@@ -698,6 +749,10 @@ void Inject_EncounterHook() {
 	HookCall(0x4C095C, wmRndEncounterOccurred_hook);
 }
 
+void Inject_RollCheckHook() {
+	HookCall(0x4A3020, roll_check_hook);
+}
+
 void InitMiscHookScripts() {
 	HookScripts::LoadHookScript("hs_barterprice", HOOK_BARTERPRICE);
 	HookScripts::LoadHookScript("hs_useskillon", HOOK_USESKILLON);
@@ -710,6 +765,7 @@ void InitMiscHookScripts() {
 	HookScripts::LoadHookScript("hs_resttimer", HOOK_RESTTIMER);
 	HookScripts::LoadHookScript("hs_explosivetimer", HOOK_EXPLOSIVETIMER);
 	HookScripts::LoadHookScript("hs_encounter", HOOK_ENCOUNTER);
+	HookScripts::LoadHookScript("hs_rollcheck", HOOK_ROLLCHECK);
 }
 
 }

sfall/Modules/HookScripts/MiscHs.h

@@ -16,6 +16,7 @@ namespace sfall
 	void Inject_RestTimerHook();
 	void Inject_ExplosiveTimerHook();
 	void Inject_EncounterHook();
+	void Inject_RollCheckHook();
 
 	// Implementation of is_within_perception_ engine function with the hook
 	long __fastcall sf_is_within_perception(fo::GameObject* watcher, fo::GameObject* target);