Modloader GUI classes/structs missing

[GamerGuy 3]

I found @V3ct0r's pkodev modloader quite a while back and had no idea what I was doing at the time but after some playing around and creating a few "test" mods, I absolutely think this is the best thing to happen to precompiled ToP binaries in forever, however I started a new project fixing and adding new forms ingame when I hit a roadblock.

While most of the classes used in ToP are easily found with Ida I could not find CTextButton and a few others at all only the address for their procedures, I would think the class would've been recoverable as a struct that I could recreate and have functions get called when it's clicked et cetera.

 

Would I just need to recreate the class from source?(but then with vtables?) I'm a bit lost at the moment and any help is appreciated!

///
	gui::CForm* frmTest = gui::CUIInterface::Instance().FindForm("frmTest");
    if (frmTest != nullptr) {
        CTextButton* btnTest = frmTest->Find<CTextButton>("btnTest");
        if (btnTest != nullptr) {
          btnTest.evtMouseClick = ClickTestButton;
        }
    }
///

void ClickTestButton(CGuiData* sender,int x, int y, MouseClickState key){
//Do whatever
}

I suppose this question is more pointed to @V3ct0r but I'm happy for a response from anyone with the knowledge

[V3ct0r 2,117]

Hello @GamerGuy,

 

You should write address of ClickTestButton() function into btnTest + 0x94 address.

 

For example:

class CTextButton {
public:
	typedef void(__cdecl* OnMouseClickHandler__Ptr)(CTextButton*, int, int, unsigned int);
	
	CTextButton() = delete;
	~CTextButton() = default;
	inline void OnMouseClick(OnMouseClickHandler__Ptr handler) { m_evtMouseClick = handler; }
private:
	char m_nop[0x94];
	OnMouseClickHandler__Ptr m_evtMouseClick;
};

and:

CTextButton* btnTest = frmTest->Find<CTextButton>("btnTest");
if (btnTest != nullptr) {
	btnTest->OnMouseClick(&ClickTestButton);
}

 

or another way:

void ClickTestButton(void* sender, int x, int y, unsigned int key);


void* btnTest = frmTest->Find<void>("btnTest");
if (btnTest != nullptr) {
	*reinterpret_cast<unsigned int*>(reinterpret_cast<unsigned int>(btnTest) + 0x94) = reinterpret_cast<unsigned int>(&ClickTestButton);
}


void ClickTestButton(void* sender, int x, int y, unsigned int key) {
    //Do whatever
}

 

[GamerGuy 3]

2 hours ago, V3ct0r said:

Hello @GamerGuy,

 

You should write address of ClickTestButton() function into btnTest + 0x94 address.

 

For example:

class CTextButton {
public:
	typedef void(__cdecl* OnMouseClickHandler__Ptr)(CTextButton*, int, int, unsigned int);
	
	CTextButton() = delete;
	~CTextButton() = default;
	inline void OnMouseClick(OnMouseClickHandler__Ptr handler) { m_evtMouseClick = handler; }
private:
	char m_nop[0x94];
	OnMouseClickHandler__Ptr m_evtMouseClick;
};

and:

CTextButton* btnTest = frmTest->Find<CTextButton>("btnTest");
if (btnTest != nullptr) {
	btnTest->OnMouseClick(&ClickTestButton);
}

 

or another way:

void ClickTestButton(void* sender, int x, int y, unsigned int key);


void* btnTest = frmTest->Find<void>("btnTest");
if (btnTest != nullptr) {
	*reinterpret_cast<unsigned int*>(reinterpret_cast<unsigned int>(btnTest) + 0x94) = reinterpret_cast<unsigned int>(&ClickTestButton);
}


void ClickTestButton(void* sender, int x, int y, unsigned int key) {
    //Do whatever
}

 

Thanks alot for the fast reply! 

May I ask how you came upon this address?
I've been using ida for looking for the addresses but I can't seem to find it

(I am mostly a noob with reverse engineering tho)

[GamerGuy 3]

Aha! I think I might have found out myself!

So I started looking for a place that sets the function to call inside the binary and came across this

loc_46FAB2:
mov     dword ptr [eax+94h], offset loc_46F770 //eax must be the offset for the CTextButton object and thus eax + 0x94 must be the offset for function
mov     this, [esi+4]
mov     eax, [this]
push    offset aBtnlefthair ; "btnLeftHair"
call    dword ptr [eax+48h]
test    eax, eax
jnz     short loc_46FB01

I'm thinking this is right but otherwise feel free to correct me

[V3ct0r 2,117]

@GamerGuy,

 

Exactly!