Changed the behavior of ObjCanSeeObj_ShootThru_Fix

* now the critter can only see through objects in front of it.

artifacts/ddraw.ini

@@ -562,7 +562,7 @@ InventoryApCost=4
 QuickPocketsApCostReduction=2
 
 ;Set to 1 to fix obj_can_see_obj script function to allow critters to see through other critters and objects with 'ShootThru' flag set
-;Note that enabling this option can cause unexpected NPC behavior in some situations, e.g. able to attack or enter into a dialogue with the player behind some objects
+;Note that enabling this option can cause unexpected NPC behavior in some cases, e.g. initiating combat or dialogue when the player is hiding behind some obstacles
 ObjCanSeeObj_ShootThru_Fix=0
 
 ;Set to 1 to fix the broken obj_can_hear_obj script function

artifacts/scripting/headers/sfall.h

@@ -246,8 +246,8 @@
 
 // returns the corrected tile distance between two objects to the distance variable (return value >= 9996 is an error when getting the distance)
 #define distance_objs(distance, obj1, obj2)             distance := tile_distance_objs(obj1, obj2) - 1;           \
-                                                        if (get_flags(obj1) bwand FLAG_MULTIHEX) distance--; \
-                                                        if (get_flags(obj2) bwand FLAG_MULTIHEX) distance--
+                                                        if (get_flags(obj1) bwand FLAG_MULTIHEX) then distance--; \
+                                                        if (get_flags(obj2) bwand FLAG_MULTIHEX) then distance--
 
 
 /* sfall metalure3 function macros */

sfall/FalloutEngine.cpp

@@ -298,6 +298,7 @@ const DWORD block_for_tocks_ = 0x4C93B8;
 const DWORD buf_to_buf_ = 0x4D36D4;
 const DWORD cai_attempt_w_reload_ = 0x42AECC;
 const DWORD caiHasWeapPrefType_ = 0x42938C;
+const DWORD can_see_ = 0x412BEC;
 const DWORD check_death_ = 0x410814;
 const DWORD check_for_death_ = 0x424EE8;
 const DWORD Check4Keys_ = 0x43F73C;
@@ -541,6 +542,7 @@ const DWORD main_init_system_ = 0x480CC0;
 const DWORD main_menu_hide_ = 0x481A00;
 const DWORD main_menu_loop_ = 0x481AEC;
 const DWORD make_path_func_ = 0x415EFC;
+const DWORD make_straight_path_ = 0x4163AC;
 const DWORD make_straight_path_func_ = 0x4163C8;
 const DWORD map_disable_bk_processes_ = 0x482104;
 const DWORD map_enable_bk_processes_ = 0x4820C0;

sfall/FalloutEngine.h

@@ -575,6 +575,7 @@ extern const DWORD block_for_tocks_;
 extern const DWORD buf_to_buf_;
 extern const DWORD cai_attempt_w_reload_;
 extern const DWORD caiHasWeapPrefType_;
+extern const DWORD can_see_;
 extern const DWORD check_death_;
 extern const DWORD check_for_death_;
 extern const DWORD Check4Keys_;
@@ -824,6 +825,7 @@ extern const DWORD main_menu_loop_;
 // - path is saved in ecx as a sequence of tile directions (0..5) to move on each step,
 // - returns path length
 extern const DWORD make_path_func_;
+extern const DWORD make_straight_path_;
 extern const DWORD make_straight_path_func_; // (TGameObj *aObj<eax>, int aTileFrom<edx>, int a3<ecx>, signed int aTileTo<ebx>, TGameObj **aObjResult, int a5, int (*a6)(void))
 extern const DWORD map_disable_bk_processes_;
 extern const DWORD map_enable_bk_processes_;

sfall/MiscPatches.cpp

@@ -128,16 +128,27 @@ static void __declspec(naked) op_obj_can_see_obj_hook() {
 	using namespace Fields;
 	__asm {
 		mov  edi, [esp + 4]; // buf **ret_objStruct
+		test ebp, ebp;
+		jz   onlyOnce;
+		xor  ebp, ebp;
+		push edx;
+		mov  edx, [edi - 8]; // target
+		push eax;            // source
+		call can_see_;
+		test eax, eax;
+		pop  eax;
+		pop  edx;
+		jz   normal;
+onlyOnce:
 		push obj_shoot_blocking_at_; // check hex objects func pointer
 		push 0x20;                   // flags, 0x20 = check ShootThru
 		push edi;
 		call make_straight_path_func_;
-		// fix: see through critters
-		mov  edx, [esp + 4];
-		mov  ebx, [edx];
+		// see through critter
+		mov  ebx, [edi];
 		test ebx, ebx;
 		jz   skip;
-		cmp  ebx, [edx - 8]; // target
+		cmp  ebx, [edi - 8]; // target
 		jne  noTarget;
 skip:
 		retn 8;
@@ -148,9 +159,14 @@ noTarget:
 		je   isCritter;
 		retn 8;
 isCritter:
-		mov  [edx - 4], ebx;            // replace source
+		mov  [edi - 4], ebx;            // replace source
 		mov  dword ptr [esp], 0x456BAB; // continue
 		retn 8;
+normal: // vanilla behavior
+		push 0x10;
+		push edi;
+		call make_straight_path_;
+		retn 8;
 	}
 }