Ive been working on this problem for a few days now and nothing ive searched on the net seems to be working
im using gt creator and latest versions for opencv and mingw

 #include "mainwindow.h"
    #include "opencv2/highgui.hpp"
    #include <QApplication>
    #include "opencv2/core/core.hpp"
    #include "opencv2/opencv.hpp"
    #include <QDebug>
    #include <QImage>
    #include <QPixmap>
    #include <QtGlobal>
    #include "opencv2/imgproc/imgproc.hpp"
    #include "opencv2/imgproc/types_c.h"
    #include <opencv2/gapi/own/mat.hpp>
    #include <opencv2/core/mat.hpp>





    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv);
        MainWindow w;
        w.show();
        cv::Mat img;
        cv::gapi::own::Mat img2;

        return a.exec();
    }

in this cv::gapi::own::Mat does not show an error while cv::Mat shows an error
im using qmake
also my .pro file is this

    win32:CONFIG(release, debug|release): LIBS += -     L$$PWD/../../../../../../../cpp/YouTube/opencv/build/x64/vc16/lib/ -lopencv_world4100
    else:win32:CONFIG(debug, debug|release): LIBS += -   L$$PWD/../../../../../../../cpp/YouTube/opencv/build/x64/vc16/lib/ -lopencv_world4100
    INCLUDEPATH += $$PWD/../../../../../../../cpp/YouTube/opencv/build/include
    DEPENDPATH += $$PWD/../../../../../../../cpp/YouTube/opencv/build/include

I tried to run opencv cv::mat and videocapture but not working but some features of opencv are
also opencv_world4100.dll and all have been put into the link as u can see
also i think im using mingw compiler for c++ in qt
as its creating folders named mingw_debug and mingw_profile
ive put the two opencv_world4100 dll and another one in almost every folder
is there something im missing?
also