EnumVisibleObjects problem

[skra]

hi,
i'm currently hooking endscene and trying to use the enum visible objects function. for the moment i'm doing the same as apoc suggested in his guide for making a better objectmanager, hoever everytime the enumvis. funktion is called wow crashes. here is the crashlog

World of WarCraft (build 11403)


This application has encountered a critical error:

ERROR #132 (0x85100084) Fatal Exception

Exception:	0xC0000005 (ACCESS_VIOLATION) at 0023:0047B95F

The instruction at "0x0047B95F" referenced memory at "0x000000AC".
The memory could not be "read".


WoWBuild: 11403

----------------------------------------
    Memory Dump
----------------------------------------

Code: 16 bytes starting at (EIP = 0047B95F)

0047B95F: 8B 40 04 A8  01 57 75 04  85 C0 75 04  33 DB EB 02  [email protected]...


Stack: 1024 bytes starting at (ESP = 1255FA4C)

* = addr                                         **                       *   
1255FA40: 19 00 00 00  00 00 00 00  60 BD 76 15  60 BD 76 15  ........`.v.`.v.
1255FA50: E4 FB 55 12  D4 FA 55 12  EB 42 29 04  52 12 62 04  ..U...U..B).R.b.
1255FA60: 00 00 00 00  94 DF 6C 1B  E8 59 18 6B  FF FF FF FF  ......l..Y.k....
1255FA70: 00 00 00 00  5C FA 55 12  EB 42 29 04  0C 80 BD 22  ....\.U..B)...."
1255FA80: 2C 80 BD 22  00 00 00 00  D4 FA 55 12  00 00 00 00  ,.."......U.....
1255FA90: 44 02 B3 22  60 BD 76 15  00 00 00 80  B4 FA 55 12  D.."`.v.......U.
1255FAA0: 74 FD 26 6B  40 B9 47 00  00 00 00 00  52 12 62 04  t.&[email protected].
1255FAB0: 00 00 00 00  00 00 00 00  00 00 00 00  52 12 62 04  ............R.b.
1255FAC0: 00 00 00 00  52 12 62 04  E4 FB 55 12  18 FB 55 12  ....R.b...U...U.
1255FAD0: 30 FB 55 12  54 FB 55 12  E9 45 29 04  00 00 00 00  0.U.T.U..E).....
1255FAE0: 00 80 BD 22  2C 80 BD 22  00 80 BD 22  88 E5 FD 00  ...",.."..."....
1255FAF0: A8 03 B3 22  10 0C B3 22  00 00 00 00  00 00 00 00  ..."..."........
1255FB00: 00 00 00 00  00 00 00 00  14 00 B3 22  00 00 00 00  ..........."....
1255FB10: 00 00 00 00  00 00 00 00  01 00 00 00  00 00 00 00  ................
1255FB20: 14 00 B3 22  00 00 00 00  01 00 00 00  00 00 00 00  ..."............
1255FB30: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  ................
1255FB40: 00 00 00 00  00 00 80 7F  E4 FB 55 12  48 57 75 15  ..........U.HWu.
1255FB50: 00 9C 2F 01  6C FB 55 12  92 3D 29 04  60 BD 76 15  ../.l.U..=).`.v.
1255FB60: 00 00 00 00  00 00 C0 FF  00 00 00 00  B4 FB 55 12  ..............U.
1255FB70: BA 3C 29 04  C4 FB 55 12  17 A0 63 09  28 FB 55 12  .<)...U...c.(.U.
1255FB80: B8 FB 55 12  D0 8C 6B 6B  FF FF FF FF  08 7D 28 6B  ..U...kk.....}(k
1255FB90: 42 1B 58 77  37 86 48 6B  5F A0 63 09  00 9C 2F 01  B.Xw7.Hk_.c.../.
1255FBA0: 48 57 75 15  00 00 00 00  01 00 00 00  00 00 00 00  HWu.............
1255FBB0: 00 C8 43 13  DC FB 55 12  37 10 62 04  48 09 62 04  ..C...U.7.b.H.b.
1255FBC0: 60 BD 76 15  C4 FF 55 12  02 27 36 6B  FF FF FF FF  `.v...U..'6k....
1255FBD0: 10 FD 55 12  8C 02 25 01  48 57 75 15  10 FC 55 12  ..U...%.HWu...U.
1255FBE0: 27 01 A2 66  00 C8 43 13  00 9C 2F 01  10 6A A6 66  '..f..C.../..j.f
1255FBF0: 08 4B 75 15  48 57 75 15  00 00 00 00  38 FC 55 12  .Ku.HWu.....8.U.
1255FC00: 08 4B 75 15  48 57 75 15  00 00 00 00  00 00 00 00  .Ku.HWu.........
1255FC10: 4C FC 55 12  5B 0F A2 66  48 57 75 15  00 9C 2F 01  L.U.[..fHWu.../.
1255FC20: 48 57 75 15  3C 6A A2 66  A0 FC 55 12  00 00 00 00  HWu.<j.f..U.....
1255FC30: B8 D0 72 15  48 57 75 15  00 00 00 00  00 00 00 00  ..r.HWu.........
1255FC40: F6 00 00 00  7B 01 00 00  B8 D0 72 15  64 FC 55 12  ....{.....r.d.U.
1255FC50: DD 6A A2 66  08 4B 75 15  1C 23 30 01  8C FC 55 12  .j.f.Ku..#0...U.
1255FC60: 00 00 00 00  2C FD 55 12  D1 B1 A6 66  08 4B 75 15  ....,.U....f.Ku.
1255FC70: 1C 23 30 01  8C FC 55 12  00 00 00 00  00 10 00 00  .#0...U.........
1255FC80: C8 E9 75 15  68 37 6D 15  08 4B 75 15  00 00 00 00  ..u.h7m..Ku.....
1255FC90: 00 00 00 00  00 00 00 00  00 00 76 43  00 80 BD 43  ..........vC...C
1255FCA0: 00 00 00 00  00 00 00 00  A0 DD 73 15  00 00 25 01  ..........s...%.
1255FCB0: 00 00 00 00  02 00 00 00  00 00 00 00  00 01 00 00  ................
1255FCC0: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  ................
1255FCD0: 00 00 00 00  00 01 00 00  EC FC 55 12  04 EE 75 15  ..........U...u.
1255FCE0: 00 83 6D 15  00 00 00 00  01 00 00 00  14 FD 55 12  ..m...........U.
1255FCF0: 41 BE A0 66  00 00 00 00  C8 E9 75 15  00 E9 75 15  A..f......u...u.
1255FD00: 00 00 00 00  00 00 00 00  00 00 00 00  00 EE 75 15  ..............u.
1255FD10: 00 00 00 00  00 00 00 00  18 D1 72 15  02 00 00 00  ..........r.....
1255FD20: 00 00 00 00  00 10 00 00  00 00 00 00  84 FD 55 12  ..............U.
1255FD30: 73 D3 A0 66  B8 D0 72 15  1C 23 30 01  68 FD 55 12  s..f..r..#0.h.U.
1255FD40: 00 00 00 00  C8 E9 75 15  00 00 00 00  50 B8 76 15  ......u.....P.v.
1255FD50: 80 31 FF 00  1C 23 30 01  00 00 00 00  00 00 00 00  .1...#0.........
1255FD60: 00 00 76 43  00 80 BD 43  00 00 00 00  00 00 00 00  ..vC...C........
1255FD70: 00 00 00 00  00 00 76 43  00 80 BD 43  96 2F 7B 09  ......vC...C./{.
1255FD80: C8 E9 75 15  20 FE 55 12  EB D3 A0 66  C8 E9 75 15  ..u. .U....f..u.
1255FD90: 80 31 FF 13  74 FE 55 12  C8 E9 75 15  00 00 00 00  .1..t.U...u.....
1255FDA0: D0 22 30 01  00 FD 55 12  60 FE 55 12  30 FE 55 12  ."0...U.`.U.0.U.
1255FDB0: 4E BD A6 66  00 D1 72 15  00 00 00 00  1C 23 30 01  N..f..r......#0.
1255FDC0: D0 D1 72 15  74 FE 55 12  C8 E9 75 15  00 00 00 00  ..r.t.U...u.....
1255FDD0: 00 00 00 00  00 00 00 00  D4 D0 72 15  C8 E9 75 15  ..........r...u.
1255FDE0: 00 00 00 00  00 00 00 00  00 00 00 00  00 FE 55 12  ..............U.
1255FDF0: 6E 2F A0 66  00 D0 72 15  00 00 00 00  00 00 00 00  n/.f..r.........
1255FE00: 00 00 00 00  00 9C A0 66  00 00 00 00  00 00 00 00  .......f........
1255FE10: 2C FE 55 12  1A 3B A0 66  B4 D0 72 15  FA 2C 7B 09  ,.U..;.f..r..,{.
1255FE20: 8C FE 55 12  6F 94 A0 66  80 31 FF 13  D4 D0 72 15  ..U.o..f.1....r.
1255FE30: 74 FE 55 12  01 00 00 00  00 00 00 00  D0 D1 72 15  t.U...........r.
1255FE40: 00 22 C5 77  60 FE 55 12  00 00 00 00  F0 AC 2F 01  .".w`.U......./.

my EnumObjDelegate looks like this:

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumObjectsCallbackDelegate(int lowGuid, int highGuid, uint filter);

because afaik the guid is passed via 2 ints (but that seems to be wrong or it wouldn't crash) what leads me to my next question. is

             ulong hGuid = (ulong)highGuid;
            ulong temp_hguid = hGuid << 32;
            ulong lGuid = (ulong)lowGuid;
            ulong guid = temp_hguid | lGuid;
            IntPtr objPtr = InternalGetObjectByGuid(guid);

the right aproach to put the guid back together?

[Apoc]

        #region Nested type: EnumObjectsCallback

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumObjectsCallback(ulong guid, int filter);

        #endregion

        #region Nested type: EnumVisibleObjectsDelegate

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumVisibleObjectsDelegate(IntPtr callback, int filter);

        #endregion

[skra]

well that is what i did before, but it didn't work either. it produces the same error. so i guess the error comes from somewhere else, but i can' figure out from where. if i vomment out the "EnumObj(CallbackPointer, 0)" call it runs without crashing, and it can't be anithing in the callbackhandler because i'm not doing anithing in there yet. i'm just returning 1

[Apoc]

I'd check your addresses then. Make sure they're correct.

[skra]

i checked them again just now and they seem to be correct =/
i'm using

        EnumVisibleObjects = 0x0047B940, 
        ClntObjMgrGetActivePlayer = 0x0047A5C0,
        ClntObjMgrObjectPtr = 0x0047BBC0

[adaephon]

Are you sure you're calling the right functions? From your post it sounds like you are calling EnumVisibleObjects (0x0047B940) with the delegate taking a GUID and filter. This isn't correct - EnumVisibleObjects takes a pointer to a callback function and a filter - internally it then calls your callback function, which takes a GUID and a filter.

[skra]

Are you sure you're calling the right functions? From your post it sounds like you are calling EnumVisibleObjects (0x0047B940) with the delegate taking a GUID and filter. This isn't correct - EnumVisibleObjects takes a pointer to a callback function and a filter - internally it then calls your callback function, which takes a GUID and a filter.

yes i am sure

initialisation
            Callback = EnumObjectsCallbackHandler;
            CallbackPtr = Marshal.GetFunctionPointerForDelegate(Callback);
in pulse
            EnumObjs(CallbackPtr, 0);

             private static int EnumObjectsCallbackHandler(ulong guid, int filter)
        {return 1;}

does anyone have an idea what could be wrong?

[YetiHunter]

I've got the same problem at the moment. Does someone have a solution for this?

[TOM_RUS]

        #region Nested type: EnumObjectsCallback

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumObjectsCallback(ulong guid, int filter);

        #endregion

        #region Nested type: EnumVisibleObjectsDelegate

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumVisibleObjectsDelegate(IntPtr callback, int filter);

        #endregion

Your filter isn't filter actually. It's pointer, which than passed to callback for use...

[skra]

umm so you mean it should be something like this

EnumObjs(CallbackPtr, (int*)0);

[UnnamedFunctionPointer(CallingConvention.Cdecl)]
private delegate int EnumVisObjDelegate(IntPtr callback, int* filter);

[flo8464]

Are you ingame when you call it?
Else exactly that access violation will occur.

[skra]

Yes of cause i'm ingame^^ and my endscene hook is working aswell ( at least i think so because my pulse method is allways called =P )

[Robske]

Are you ingame when you call it?
Else exactly that access violation will occur.

Wrong

EnumVisibleObjects will not throw any exceptions when not 'in-game'. It will do what it's supposed to do, enumerate all visible objects. (0)

[ostapus]

here is what i am using, function definition wise.

static int _FastEnumObjectsCallback(WGUID guid, DWORD dwParams)
{
}


typedef void (*pEnumVisibleObjects) (CallBack *callBack, UINT type) ;
pEnumVisibleObjects EnumVisibleObjects ;
GetPointer(EnumVisibleObjects, pEnumVisibleObjects, fptrEnumVisibleObjects) ;
EnumVisibleObjects(_FastEnumObjectsCallback, (DWORD) &params) ;

[swayenvoy]

I think i had the same problem, here are my definitions:

        /// <summary>
        /// This function allows you to enumerate over WoW's list of objects, an also
        /// base that enumeration around a filter.
        /// </summary>
        /// <param name="callback">
        /// A callback to be used to let WoW know when to stop,
        /// or continue to call your callback with objects.
        /// </param>
        /// <param name="filter">
        /// A filter of WoWObjectType. Basically to narrow down the search to specific
        /// types of objects.
        /// </param>
        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumVisibleObjectsDelegate(IntPtr callback, int filter);
        /// <summary>
        /// Acts as the callback from WoW. This function will be called for each object
        /// during the enumeration. A GUID will be passed back that you can then use in the
        /// ClntObjMgrGetObjectPtr function to get the actual pointer.
        /// </summary>
        /// <param name="guid">A GUID to use.</param>
        /// <param name="filter">A filter for the object type.</param>
        /// <returns>
        /// Returns 0 when the enumeration should be stopped or
        /// 1 when the enumeration should continue.
        /// </returns>
        /// <remarks>
        /// If no objects are left to enumerate, the function will no longer be called.
        /// </remarks>
        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int EnumObjectsCallbackDelegate(WGUID guid, int filter);
        private readonly EnumObjectsCallbackDelegate _Callback;
        private readonly IntPtr _CallbackPtr;

        _Callback = EnumObjectsCallbackHandler;
        _CallbackPtr = Marshal.GetFunctionPointerForDelegate(_Callback);

       private int EnumObjectsCallbackHandler(WGUID guid, int filter) {...}
      
       EnumObjects(_CallbackPtr, 0);

       [StructLayout(LayoutKind.Sequential)]
    public struct WGUID
    {
        public int lowGuid;
        public int highGuid;

        public static implicit operator ulong(WGUID obj)
        {
            List<byte> tmp = new List<byte>();
            tmp.AddRange(BitConverter.GetBytes(obj.lowGuid));
            tmp.AddRange(BitConverter.GetBytes(obj.highGuid));
            return BitConverter.ToUInt64(tmp.ToArray(), 0);
        }
    }

Maybe it's not the freakiest way of doing this but for me it worked.

WARNING: Not tested with the latest patch.