Fixed the functions of the engine op_obj_can_see_obj_/op_obj_can_hear_obj_ (#189)

Added one additional argument for the hook HOOK_WITHINPERCEPTION.

artifacts/example_mods/WithinPerception/hs_withinperception.ssl

@@ -0,0 +1,58 @@
+/*
+   Example engine algorithm.
+
+   * The AllowUnsafeScripting option must be enabled.
+*/
+
+#include "define_lite.h"
+#include "command.h"
+
+#include "sfall.h"
+#include "define_extra.h"
+
+
+#define can_see_(source, target)    call_offset_r2(0x412BEC, source, target)
+#define obj_dist_(target, source)   call_offset_r2(0x48BBD4, target, source)
+
+procedure start;
+
+procedure start begin
+   if not(init_hook) then begin
+
+      variable source := get_sfall_arg,
+               target := get_sfall_arg,
+               original := get_sfall_arg,
+               type   := get_sfall_arg,  /* new arg */
+               result := 0,
+               distance;
+
+      if target then begin
+         distance := get_critter_stat(source, STAT_pe);
+
+         if can_see_(source, target) then begin
+            distance *= 5;
+            if (get_flags(target) bwand FLAG_TRANSGLASS) then distance /= 2;
+         end
+         else if combat_is_initialized then distance *= 2;
+
+         if target == dude_obj then begin
+            if sneak_success then begin
+               distance /= 4;
+               if has_skill(target, SKILL_SNEAK) > 120 then distance -= 1;
+            end
+            else if dude_is_sneaking then distance := distance * 2 / 3;
+         end
+
+         if obj_dist_(target, source) <= distance then result := 1;
+
+         // example
+         if (result) then begin
+            display_msg("hs_withinperception: " + obj_name(source) + " does he see > " + obj_name(target) + " [original: " + original + " script: " + result + "]");
+         end else begin
+            display_msg("hs_withinperception: " + obj_name(source) + " he does not see > " + obj_name(target) + " [original: " + original + " script: " + result + "]");
+         end
+      end
+
+      //set_sfall_return(result);
+   end
+end

artifacts/scripting/hookscripts.txt

@@ -401,6 +401,7 @@ This is fired after the default calculation is made.
 Critter arg1 - Watcher object
 Obj     arg2 - Target object
 int     arg3 - Result of vanilla function: 1 - within perception range, 0 - otherwise
+int     arg4 - The type of the called hook: 1 - from the script function obj_can_see_obj, 2 - from the script function obj_can_hear_obj (need option CanHearObjFix enabled), 0 for all other cases
 
 int     ret1 - overrides the returned result of the function: 0 - not in range (can't see), 1 - in range (will see if not blocked), 2 - forced detection (will see regardless, only used in obj_can_see_obj scripting function which is called by every critter in the game)
 

sfall/Modules/BugFixes.cpp

@@ -1292,6 +1292,30 @@ skip:
 	}
 }
 
+static void __declspec(naked) op_obj_can_see_obj_hack() {
+	__asm {
+		mov  eax, [esp + 0x2C - 0x28 + 4];  // source
+		mov  ecx, [eax + tile];             // source.tile
+		cmp  ecx, -1;
+		jz   end;
+		mov  eax, [eax + elevation];
+		mov  edi, [edx + elevation];    // target.elev
+		cmp  eax, edi;                  // check source.elev == target.elev
+		retn;
+end:
+		dec  ecx;  // reset ZF
+		retn;
+	}
+}
+
+static void __declspec(naked) op_obj_can_hear_obj_hack() {
+	__asm {
+		mov eax, [esp + 0x28 - 0x28 + 4];  // target
+		mov edx, [esp + 0x28 - 0x24 + 4];  // source
+		retn;
+	}
+}
+
 
 void BugFixes::init()
 {
@@ -1648,6 +1672,20 @@ void BugFixes::init()
 		HookCall(0x4C0AEB, wmRndEncounterOccurred_hook);
 		dlogr(" Done", DL_INIT);
 	}
+
+	// Fix op_obj_can_see_obj_
+	MakeCall(0x456B63, op_obj_can_see_obj_hack);
+	SafeWrite16(0x456B76, 0x23EB);  // jz > jmp (skip unused engine code)
+
+	//Fix broken op_obj_can_hear_obj_ (enable a function)
+	if (GetConfigInt("Misc", "CanHearObjFix", 0) != 0) {
+		dlog("Applying obj_can_hear_obj opcode fix.", DL_INIT);
+		SafeWrite8(0x4583D8, 0x3B); // change jz offset
+		SafeWrite8(0x4583DE, 0x74); // jnz > jz
+		MakeCall(0x4583E0, op_obj_can_hear_obj_hack);
+		SafeWrite8(0x4583E5, 0x90);
+		dlogr(" Done", DL_INIT);
+	}
 }
 
 }

sfall/Modules/HookScripts/MiscHs.cpp

@@ -139,39 +139,62 @@ defaultHandler:
 	}
 }
 
-static void __declspec(naked) PerceptionRangeHook() {
+static void __stdcall PerceptionRangeHook_Script(int type) {
 	__asm {
 		HookBegin;
 		mov  args[0], eax; // watcher
 		mov  args[4], edx; // target
 		call fo::funcoffs::is_within_perception_;
 		mov  args[8], eax; // check result
-		pushad;
+		push eax;
 	}
 
-	argCount = 3;
+	args[3] = type;
+
+	argCount = 4;
 	RunHookScript(HOOK_WITHINPERCEPTION);
 	EndHook();
 
 	__asm {
-		popad;
+		pop eax;
 		cmp cRet, 1;
 		cmovnb eax, rets[0];
+	}
+}
+
+static void __declspec(naked) PerceptionRangeHook() {
+	__asm {
+		push ecx;
+		push 0;
+		call PerceptionRangeHook_Script;
+		pop  ecx;
 		retn;
 	}
 }
 
-static const DWORD PerceptionRangeBonusHack_back = 0x456BA7;
-static const DWORD PerceptionRangeBonusHack_skip = 0x456BDC;
-static void __declspec(naked) PerceptionRangeBonusHack() {
+static void __declspec(naked) PerceptionRangeSeeHook() {
 	__asm {
-		call PerceptionRangeHook;
+		push ecx;
+		push 1;
+		call PerceptionRangeHook_Script;
+		pop  ecx;
 		cmp  eax, 2;
-		jne  nevermind; // return
-		mov  dword ptr[esp + 16], 1;
-		jmp  PerceptionRangeBonusHack_skip; // skip blocking check
+		jne  nevermind; // normal return
+		dec  eax;
+		mov  dword ptr[esp + 0x2C - 0x1C + 4], eax; // set 1, skip blocking check
+		dec  eax;
 nevermind:
-		jmp  PerceptionRangeBonusHack_back;
+		retn;
+	}
+}
+
+static void __declspec(naked) PerceptionRangeHearHook() {
+	__asm {
+		push ecx;
+		push 2;
+		call PerceptionRangeHook_Script;
+		pop  ecx;
+		retn;
 	}
 }
 
@@ -396,9 +419,9 @@ void Inject_WithinPerceptionHook() {
 		0x42BC87,
 		0x42BC9F,
 		0x42BD04,
-		0x458403
 	});
-	MakeJump(0x456BA2, PerceptionRangeBonusHack);
+	HookCall(0x456BA2, PerceptionRangeSeeHook);
+	HookCall(0x458403, PerceptionRangeHearHook);
 }
 
 void Inject_CarTravelHook() {