C/C++ Beispielprogramme mit USB Cam und openCV?

[HaWe]

hey, nein, schon richtig: für den Pi, also für Linux.

Habe es so gemacht, USB cam eingestöpselt, und das allererste Programm versucht zu erstellen,

#include "opencv2/opencv.hpp"
using namespace cv;
int main(int argc, char** argv)
{
    VideoCapture cap;
    // open the default camera, use something different from 0 otherwise;
    // Check VideoCapture documentation.
    if(!cap.open(0))
        return 0;
    for(;;)
    {
          Mat frame;
          cap >> frame;
          if( frame.empty() ) break; // end of video stream
          imshow("this is you, smile! :)", frame);
          if( waitKey(10) == 27 ) break; // stop capturing by pressing ESC 
    }
    // the camera will be closed automatically upon exit
    // cap.close();
    return 0;
}

per Geany compile/build settings wie hier angegeben, aber tonnenweise errors:

g++ -Wall -pthread -I/opt/vc/include -I/opt/vc/include/interface/vmcs_host/linux -I/opt/vc/include/interface/vcos/pthreads -o "camtest" "camtest.c" -lshapes -L/opt/vc/lib -lOpenVG -lEGL -lwiringPi -lrt -lpigpio -lArduiPi_OLED  (im Verzeichnis: /home/pi/programs/cam)

/tmp/ccQSKrEJ.o: In function `main':
camtest.c:(.text+0x68): undefined reference to `cv::VideoCapture::VideoCapture()'
camtest.c:(.text+0x78): undefined reference to `cv::VideoCapture::open(int)'
camtest.c:(.text+0x110): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
camtest.c:(.text+0x124): undefined reference to `cv::imshow(std::string const&, cv::_InputArray const&)'
camtest.c:(.text+0x144): undefined reference to `cv::waitKey(int)'
camtest.c:(.text+0x198): undefined reference to `cv::VideoCapture::~VideoCapture()'
camtest.c:(.text+0x1dc): undefined reference to `cv::VideoCapture::~VideoCapture()'
camtest.c:(.text+0x1f0): undefined reference to `cv::VideoCapture::operator>>(cv::Mat&)'
/tmp/ccQSKrEJ.o: In function `cv::Mat::~Mat()':
camtest.c:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x3c): undefined reference to `cv::fastFree(void*)'
/tmp/ccQSKrEJ.o: In function `cv::Mat::release()':
camtest.c:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x58): undefined reference to `cv::Mat::deallocate()'
collect2: error: ld returned 1 exit status
Kompilierung fehlgeschlagen.

wo soll man jetzt anfangen?
Sicher fehlen schon mal eine ganze Menge compile/build parameter.
Aber welche?