wkUseDesktopWindow, failed attempt at writing to vtable

main.cpp:

#include "main.h"
#include "MinHook.h"
#include <madCHook - dynamic.h>

PVOID GetInterfaceMethod(PVOID intf, DWORD methodIndex)
{
  return *(PVOID*)(*(DWORD*)intf + methodIndex * 4);
}

HRESULT (WINAPI *SCLNext)(void *ptr, HWND hwnd, DWORD dwFlags) = NULL;

HRESULT WINAPI SCLCallback(void *ptr, HWND hwnd, DWORD dwFlags)
{
    printf("The co-operative. Good with Desktops.\n");
    return SCLNext(ptr, GetDesktopWindow(), dwFlags);
}

HRESULT (WINAPI *DDrawCreateNext)(GUID FAR *lpGUID, LPDIRECTDRAW FAR *lplpDD, IUnknown FAR *pUnkOuter);

HRESULT WINAPI DDrawCreateHook(GUID FAR *lpGUID, LPDIRECTDRAW FAR *lplpDD, IUnknown FAR *pUnkOuter)
{
    HRESULT reslt = DDrawCreateNext(lpGUID, lplpDD, pUnkOuter);
    if(SCLNext == NULL)
    {
        printf("Hooking SCL in 3... 2... 1...\n");
        printf("%i\n",MH_Initialize());
        *reinterpret_cast<void**>(&SCLNext) = GetInterfaceMethod(*lplpDD, 20);
        memcpy((void *)((DWORD*)*lplpDD + 20 * 4), (void *)&SCLCallback, 4);
        printf("hookcode %i %i %i %i\n",*lplpDD, &((*lplpDD)->SetCooperativeLevel), MH_CreateHook(GetInterfaceMethod(*lplpDD, 20), (void *)SCLCallback, (PVOID*)&SCLNext), MH_OK);
        //printf("enable %i\n", MH_EnableHook(GetInterfaceMethod(*lplpDD, 20)));
    }
    return reslt;
}

BOOL APIENTRY DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    printf("Hello!\n");
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            InitializeMadCHook();
            printf("You're going MAD!\n");
            HookAPI("DDRAW.dll", "DirectDrawCreate", (void *)DDrawCreateHook, (PVOID *) &DDrawCreateNext);

            // attach to process
            // return FALSE to fail DLL load
            break;

        case DLL_PROCESS_DETACH:
            // detach from process
            break;

        case DLL_THREAD_ATTACH:
            // attach to thread
            break;

        case DLL_THREAD_DETACH:
            // detach from thread
            break;
    }
    return TRUE; // succesful
}






main.h:

#ifndef __MAIN_H__
#define __MAIN_H__

#include <iostream>
#include <fstream>
#include <windows.h>
#include <Ddraw.h>

/*  To use this exported function of dll, include this header
 *  in your project.
 */

#ifdef BUILD_DLL
    #define DLL_EXPORT __declspec(dllexport)
#else
    #define DLL_EXPORT __declspec(dllimport)
#endif


#ifdef __cplusplus
extern "C"
{
#endif

DLL_EXPORT BOOL APIENTRY DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved);
DLL_EXPORT HRESULT WINAPI DDrawCreateHook(GUID FAR *lpGUID, LPDIRECTDRAW FAR *lplpDD, IUnknown FAR *pUnkOuter);
DLL_EXPORT HRESULT WINAPI SCLCallback(void *ptr, HWND hwnd, DWORD dwFlags);
DLL_EXPORT PVOID GetInterfaceMethod(PVOID intf, DWORD methodIndex);

#ifdef __cplusplus
}
#endif

#endif // __MAIN_H__