OpenCV setting resolution results failing in reading frames

Question

I've tried to change the resolution on raspicam v2 with my raspberry pi 4 b, but this code gives me false every time I try to read frame... Is there anything I am missing? I can easily read frames without setting those parameters, but then it gives me really poor resolution.

#include "opencv2/opencv.hpp"
using namespace cv;
int main(int argc, char **argv)
{
    VideoCapture cap;
    if (!cap.open(0))
        return 0;
     cap.set(CAP_PROP_FRAME_WIDTH, 1920);
     cap.set(CAP_PROP_FRAME_HEIGHT, 1080);
     cap.set(CAP_PROP_FPS, 1);
    for (;;)
    {
        Mat frame;   
        if(cap.read(frame))
        {
            std::cout << "I'm trying out" << std::endl;
            imwrite("test.jpg",frame);
            return 0;
        } else{
            std::cout << "doesn't went as planned" << std::endl;
        }
    }
    return 0;
}

Answer 1

The problem was in raspi-config, I thought I've enabled the camera through config.txt, but I've not. so when I've got into the interfaces tab and enabled the camera, everything worked perfectly. Thank you guys for help :)