OpenCV

[Charles]

Hello,

I have an Opencv project and an Irrlicht one wich are working well but as soon as I mixed them it doesn't work any more.
There isn't any error at compilation or execution but programm stay indefinitely on OpenCV functions. Moreover, I tried some snippets using Opencv and Irrlicht and the same issue happens

for example :

int main(int argc, char** argv )
{

irr::IrrlichtDevice *device = irr::createDevice( // creation device
irr::video::EDT_OPENGL, // l'API est OpenGL
irr::core::dimension2d<irr::u32>(800,600), // taille de la fenetre 800x600
32, false, true, false, 0);

irr::video::IVideoDriver* driver =
device->getVideoDriver(); // creation driver
irr::scene::ISceneManager *sceneManager =
device->getSceneManager ();

VideoCapture cap(0);

if ( !cap.isOpened() ) // if not success, exit program
{
cout << "Cannot open the web cam" << endl;
return -1;
}

while(device->run())
{
std::cout<<"Step 1 : OpenCv "<<std::endl;
Mat img;
cap.read(img);
driver->beginScene(true,false,SColor(255,100,101,140));
driver->endScene();
std::cout<<"Step 2 : Irrlicht"<<std::endl;

}
device->drop();

return 0;
}


When this code is executed, it never goes throught Step 2. Is there something I am doing wrong ?
Thank you for your advices


Charles

[thanhle]

From what I read, you said that the video capture is in infinite loop.
So, there is no reason it will go to Irrlicht rendering code.

[Charles]

Yes, I want at each loop read a frame, extract some information from it and then use irrlicht to render.
I don't understand what is wrong ? I already use the read() function in loop for opencv application and it works.
Even if I put this function out the loop, my program will stay on this function wherase it works when there is no irrlicht.
I am afraid this issue come from my computer or maybe it is because I am using a virtualbox. I am sure that what I want to do is possible because I found examples but even them I can't make them work.
Of course, I did research on the web and I found a similar issue but no answer

[CuteAlien]

Did you step through with a debugger to see where exactly it hangs?

[Charles]

No,
I havn't many experience with debbuger.
What kind of informations should I search with debbuger ?
Maybe I should try without virtualbox to be sure this isn't the reason of my trouble.


Thank you for your answer.

[CuteAlien]

Get familiar with a debugger, it's easy to learn and worth it! Programmers spend a lot of time in it. And then you can just step through your program line by line and see exactly what your program does. Most IDE's come with a debugger integrated. For example if you are workin in VS you can set a breakpoint in the first line (with F9), run the app in your debugger (F5) and then you can step through your app line-by-line (F10 for each line) and see exactly where it stops (if you use C::B - it works just the same, only using other function keys for the debugger).

[Charles]

Ok.
I'll try it very soon.
When I am using the qtcreator debugger I reveive two error messages :

libv4l2: error got 4 consecutive frame decode errors, last error: VIDIOC_DQBUF: Erreur d'entrée/
and
(Control:2366): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

The app stay at my opencv read function but it seem it would be the same for any opencv function.

[Charles]

It's working with visual Studio 2010.
I suppose the issue came from my virutalbox.
Thank you for your help