clear() function problems

[gamescoper]

Firstly this is my first attempt at windows programming in c++ (my first attempt at c++ was for dos) anyway i was trying to make a menu and i thought that i should clear the gui objects before drawing in the next menu. Well after going through a few tutorials i got this far and the clear() function doesnt work. Heres the code i will be really grateful for any help i can get

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//includes
#include <irrlicht.h>
//namespaces
using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;
//not sure about this bit
#ifdef _IRR_WINDOWS_
#pragma comment(lib, "Irrlicht.lib")
#endif
//this is need for the gui
IrrlichtDevice *device = 0;
s32 cnt = 0;
IGUIListBox* listbox = 0;
//event reciever
class MyEventReceiver : public IEventReceiver
{
public:
	virtual bool OnEvent(const SEvent& event)
	{
		if (event.EventType == EET_GUI_EVENT)
		{
			s32 id = event.GUIEvent.Caller->getID();
			IGUIEnvironment* guienv = device->getGUIEnvironment();
			switch(event.GUIEvent.EventType)
{
    case EGET_BUTTON_CLICKED:

				if (id == 101)
				{
//problem here
					guienv->clear();
					guienv->addButton(rect<s32>(104, 64, 320, 96), 0, -1, L"Back");
                    guienv->addStaticText(L"Story mode in develpoment", rect<s32>(104, 32, 320, 52), false, false, 0, -1);
					return true;
				}
}
}
}
};
//main bit for drawing
int main()
{
    IrrlichtDevice *device =
		createDevice( video::EDT_SOFTWARE, dimension2d<s32>(640, 480), 32, true, false, false, 0);
    device->setWindowCaption(L"Window");
    IVideoDriver* driver = device->getVideoDriver();
	ISceneManager* smgr = device->getSceneManager();
	IGUIEnvironment* guienv = device->getGUIEnvironment();
	guienv->addButton(rect<s32>(88, 200, 304, 240), 0, 4, L"Exit");
	guienv->addButton(rect<s32>(88, 152, 304, 192), 0, 3, L"Options");
    guienv->addButton(rect<s32>(88, 104, 304, 144), 0, 2, L"Multiplayer");
    guienv->addButton(rect<s32>(88, 56, 304, 96), 0, 101, L"Story Mode");
    guienv->addStaticText(L"Game menu", rect<s32>(88, 16, 304, 36), false, false, 0, -1);

    while(device->run())
	{
		driver->beginScene(true, true, SColor(255,100,101,140));

		smgr->drawAll();
		guienv->drawAll();

		driver->endScene();
	}
}    

sorry about it not being neat and i never compile with the comments so dont worry if there in the way somehow. I have searched around a bit but i havent anything yet

[rogerborg]

No problem, I prefer full runnable source than a commented snippet, because the compiler and debugger are far better at analysing source than my feeble meatbrain.

Just a couple of common snafus.

You need to actually instantiate your event receiver and pass it to the device. Also, you're hiding your global device variable with a local one in your main(). So just change your device instantiation to this:

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    MyEventReceiver receiver;
    device = createDevice( video::EDT_SOFTWARE, dimension2d<s32>(640, 480), 32, true, false, false, &receiver);

Two other things. Your OnEvent() method should return false; at the end, and just before you exit your main() function, call device->drop() to clean up all the memory.

I highly recommend that you learn to use your debugger. Sticking a breakpoint in your OnEvent() method would have shown very quickly that it wasn't being called, and you can work backwards from there.

[gamescoper]

thanks for the help and as a matter of fact this is THE best forum i have been to people here are so nice and comfortable to speak with unless they are shouting at you but thats impossible without VOIP

[ibax]

I have problems, with the clear() function.

when my project reaches the "env->clear();" part of my code, it crashes. I use this clear() function sometimes in my project, and is working, but now it crashes. when I delete it, the program works correctly (but the previously added GUI elements are on the screen, too.

I can't find the solution... once it is working, once not. why is it? if I use for the GUI elements the setVisible(false) method, it is working, but I have lot of GUI elements...

can somebody help me?

[JP]

Possibly your env pointer is invalid, have you got two declarations of it and you're only assigning a value to one?

[ibax]

hmm, it is interesting, what u said, but this function works, but if I remove the comments ( // ), the program crashes...

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void Admin::changeLogin(IGUIEnvironment* env, IVideoDriver* driver, IrrlichtDevice* dev)
{
// env->clear(); 

env->addStaticText(L"New login name",rect<s32>(50,140,250,162),0,0,0,-1,1);
		
env->addStaticText(L"New password",rect<s32>(50,221,250,243),0,0,0,-1,1);
env->addStaticText(L"New password once again",rect<s32>(50,302,250,324),0,0,0,-1,1);
}

[vitek]

Two things... It is very useful if you provide a simple testcase that compiles, runs and illustrates the problem. It is also nice if you create your own thread if your particular issue is different from the original [which it is].

Travis