Keep the path solve's target room check on 1.14d

[ResurrectedTrader]

D2Common_10142 (the path solve) only checks tPathInfo.pTargetRoom under D2_VERSION_113C. A 1.14d build therefore goes on solving toward a target subtile that lies in no active room, where the game gives up.

1.14d

PATH_CalculatePath (Game.exe 0x649970) fails when either room is missing, before the PATH_IsTargetDestinationAllowed / bAllowInTown test:

00649A90  sub     eax, ebx
00649A92  mov     ebx, ecx
00649A94  sub     ecx, esi
00649A96  cmp     eax, 64h                          ; |dx| <= 100
00649A99  jg      loc_649C7B
00649A9F  neg     eax
00649AA1  cmp     eax, 64h
00649AA4  jg      loc_649C7B
00649AAA  cmp     ecx, 64h                          ; |dy| <= 100
00649AAD  jg      loc_649C7B
00649AB3  neg     ecx
00649AB5  cmp     ecx, 64h
00649AB8  jg      loc_649C7B
00649ABE  mov     ecx, [edi+1Ch]                    ; start room
00649AC1  push    ebx
00649AC2  mov     [ebp+var_2C], ecx
00649AC5  call    DRLGROOM_FindBetterNearbyRoom     ; target room (COLLISION_GetRoomBySubTileCoordinates)
00649ACA  cmp     [ebp+var_2C], 0                   ; start room
00649ACE  mov     [ebp+var_28], eax
00649AD1  jz      loc_649C7B                        ; -> no path
00649AD7  test    eax, eax                          ; <== target room
00649AD9  jz      loc_649C7B                        ; <== -> no path
00649ADF  mov     ecx, [ebp+arg_4]
00649AE2  lea     esi, [ebp+var_34]
00649AE5  call    PATH_CanMonsterPathInArea         ; PATH_IsTargetDestinationAllowed
00649AEA  test    eax, eax
00649AEC  jnz     short loc_649AF7
00649AEE  cmp     [ebp+arg_8], eax                  ; bAllowInTown
00649AF1  jz      loc_649C7B

1.10f

1.10f does not have the check, which is why it stays version-gated. D2Common.0x6FDA8600 (#10142) only asserts the start room (tPathInfo.hRoomStart). It accepts a NULL target room and, for the in-town test, falls back to the room halfway between start and target:

6FDA88E7  mov     eax, [esi+1Ch]                    ; start room
6FDA88EA  cmp     eax, ebp
6FDA88EC  mov     [esp+78h+var_2C], eax
6FDA88F0  jz      short loc_6FDA8969
6FDA88F2  mov     ecx, [eax]
6FDA88F4  cmp     edi, ecx
6FDA88F6  jl      short loc_6FDA8911
6FDA88F8  mov     edx, [eax+8]
6FDA88FB  add     edx, ecx
6FDA88FD  cmp     edi, edx
6FDA88FF  jge     short loc_6FDA8911
6FDA8901  mov     ecx, [eax+4]
6FDA8904  cmp     ebx, ecx
6FDA8906  jl      short loc_6FDA8911
6FDA8908  mov     edx, [eax+0Ch]
6FDA890B  add     edx, ecx
6FDA890D  cmp     ebx, edx
6FDA890F  jl      short loc_6FDA896B
6FDA8911  lea     ecx, [esp+78h+arg_0]
6FDA8915  lea     edx, [esp+78h+var_68]
6FDA8919  push    ecx
6FDA891A  push    edx
6FDA891B  push    eax
6FDA891C  mov     [esp+84h+var_68], ebp
6FDA8920  mov     [esp+84h+arg_0], ebp
6FDA8927  call    DUNGEON_GetAdjacentRoomsListFromRoom ; target room: search the adjacent rooms
6FDA892C  xor     edx, edx
6FDA892E  cmp     [esp+78h+arg_0], ebp
6FDA8932  jbe     short loc_6FDA8969
6FDA8934  mov     eax, [esp+78h+var_68]
6FDA8938  mov     eax, [eax+edx*4]
6FDA893B  cmp     eax, ebp
6FDA893D  jz      short loc_6FDA895E
6FDA893F  mov     ecx, [eax]
6FDA8941  cmp     edi, ecx
6FDA8943  jl      short loc_6FDA895E
6FDA8945  mov     ebp, [eax+8]
6FDA8948  add     ebp, ecx
6FDA894A  cmp     edi, ebp
6FDA894C  jge     short loc_6FDA895E
6FDA894E  mov     ecx, [eax+4]
6FDA8951  cmp     ebx, ecx
6FDA8953  jl      short loc_6FDA895E
6FDA8955  mov     eax, [eax+0Ch]
6FDA8958  add     eax, ecx
6FDA895A  cmp     ebx, eax
6FDA895C  jl      short loc_6FDA8997
6FDA895E  mov     eax, [esp+78h+arg_0]
6FDA8962  inc     edx
6FDA8963  xor     ebp, ebp
6FDA8965  cmp     edx, eax
6FDA8967  jb      short loc_6FDA8934
6FDA8969  xor     eax, eax                          ; not found: target room = NULL, no bail-out
6FDA896B  mov     [esp+78h+var_28], eax             ; target room
6FDA896F  mov     eax, [esp+78h+var_2C]
6FDA8973  xor     ebp, ebp
6FDA8975  cmp     eax, ebp
6FDA8977  jnz     short loc_6FDA89A0                ; start room: assert only
6FDA8979  push    327h
6FDA897E  push    6FDE51B4h
6FDA8983  push    6FDE5170h
6FDA8988  call    6FDC4352h
6FDA898D  add     esp, 0Ch
6FDA8990  push    0FFFFFFFFh
6FDA8992  call    6FDC446Fh
6FDA8997  mov     ecx, [esp+78h+var_68]
6FDA899B  mov     eax, [ecx+edx*4]
6FDA899E  jmp     short loc_6FDA896B
6FDA89A0  mov     ebx, [esp+78h+arg_4]
6FDA89A7  cmp     ebx, ebp
6FDA89A9  jz      loc_6FDA8A3F
6FDA89AF  cmp     dword ptr [ebx], 1
6FDA89B2  jnz     loc_6FDA8A3F
6FDA89B8  mov     ecx, ebx
6FDA89BA  call    sub_6FDA56C0
6FDA89BF  test    eax, eax
6FDA89C1  jnz     short loc_6FDA8A3F
6FDA89C3  mov     eax, [esp+78h+var_28]             ; target room NULL?
6FDA89C7  cmp     eax, ebp
6FDA89C9  jnz     short loc_6FDA8A1F                ; -> use the midpoint's room instead
6FDA89CB  mov     edi, [esp+78h+var_30+2]
6FDA89CF  mov     ecx, [esp+78h+var_34+2]
6FDA89D3  and     edi, 0FFFFh
6FDA89D9  and     ecx, 0FFFFh
6FDA89DF  mov     eax, edi
6FDA89E1  mov     ebx, [esp+78h+var_30]
6FDA89E5  sub     eax, ecx
6FDA89E7  mov     ebp, [esp+78h+var_34]
6FDA89EB  cdq
6FDA89EC  sub     eax, edx
6FDA89EE  and     ebx, 0FFFFh
6FDA89F4  sar     eax, 1
6FDA89F6  add     eax, ecx
6FDA89F8  and     ebp, 0FFFFh
6FDA89FE  push    eax
6FDA89FF  mov     eax, ebx
6FDA8A01  sub     eax, ebp
6FDA8A03  mov     ecx, [esp+7Ch+var_2C]
6FDA8A07  cdq
6FDA8A08  sub     eax, edx
6FDA8A0A  mov     edx, eax
6FDA8A0C  sar     edx, 1
6FDA8A0E  add     edx, ebp
6FDA8A10  call    sub_6FD46620
6FDA8A15  push    edi
6FDA8A16  mov     edx, ebx
6FDA8A18  mov     ecx, eax
6FDA8A1A  call    sub_6FD46620
6FDA8A1F  push    eax
6FDA8A20  call    DUNGEON_IsRoomInTown              ; in-town test
6FDA8A25  xor     ebp, ebp
6FDA8A27  test    eax, eax
6FDA8A29  jz      short loc_6FDA8A38
6FDA8A2B  cmp     [esp+78h+arg_8], ebp              ; bAllowInTown
6FDA8A32  jz      loc_6FDA8DFE
6FDA8A38  mov     ebx, [esp+78h+arg_4]
6FDA8A3F  mov     edx, [esi+3Ch]
6FDA8A42  mov     edi, [esi+58h]

Change

Keep the check for D2_VERSION_113C and for 1.14 or later:

#if defined(D2_VERSION_113C) || (D2_VERSION_MAJOR >= 1 && D2_VERSION_MINOR >= 14)

This uses the same D2_VERSION_MAJOR / D2_VERSION_MINOR test as MOO's other version gates. I have not checked 1.11 / 1.12 / 1.13d, so they keep the current behaviour.

🤖 Generated with Claude Code