Can't run OpenCV-App because of runtime error missing Qt5OpenGL.dll and Qt5Test.dll - opencv

Question

I want to build an application using the OpenCV library built with cmake.
First I downloaded the sources for opencv4.5.5. I created in that folder a subfolder mingwbuild and from there I can the command "cmake ../ -G "MinGW Makefiles"
Then I ran the command "mingw32-make install" and it took 2 hours to compile.
I then used cmake again to build a project, like described in the first answer here:
Configuring an c++ OpenCV project with Cmake
When I then ran the generated .exe, it would give me a runtime error "Qt5OpenGl.dll and Qt5Test.dll could not be found"
So I downloaded QtOpenGl.dll with MSYS2 from here https://packages.msys2.org/package/mingw-w64-x86_64-qt5-base
with the command "pacman -S mingw-w64-x86_64-qt5-base"
When I then run my opencvtest.exe , it says that it could not find the entry point of some method in QtOpenGl.dll . So the version or something must be wrong?
When searching for the package in the MSYS2 terminal, it says there are 10 packages I can download and install. The first four are:
$ pacman -Ss qt5-base
mingw32/mingw-w64-i686-qt5-base 5.15.3+kde+r174-2 (mingw-w64-i686-qt5)
A cross-platform application and UI framework (mingw-w64)
mingw32/mingw-w64-i686-qt5-base-debug 5.15.3+kde+r174-2 (mingw-w64-i686-qt5-debug)
A cross-platform application and UI framework (mingw-w64)
mingw64/mingw-w64-x86_64-qt5-base 5.15.3+kde+r174-2 (mingw-w64-x86_64-qt5) [installed]
A cross-platform application and UI framework (mingw-w64)
mingw64/mingw-w64-x86_64-qt5-base-debug 5.15.3+kde+r174-2 (mingw-w64-x86_64-qt5-debug)
Maybe if I choose the release package, I also have to set the option -DCMAKE_BUILD_TYPE=Release when invoking cmake?
Option x86 means 64-bit package and without x86, it means 32-bit packages. How can I figure out which of these I do need?
Any help is appreciated.

Answer 1

I finally managed to compile my OpenCVApp
The key was to work only in the MSYS2 MinGW x64 shell.
First I needed to install cmake like so:
pacman -S mingw-w64-x86_64-cmake
Then I had to install opencv with pacman like so:
pacman -S /mingw-w64-x86_64-opencv
The Qt5, I had to install like so:
pacman -S mingw-w64-x86_64-qt5-base
Then I created a new directory with src/main.cpp and CMakeLists.txt inside it like so:
Here CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT (opencvtest)
find_package(OpenCV REQUIRED )
set( NAME_SRC
src/main.cpp
)
set( NAME_HEADERS
include/header.h
)
INCLUDE_DIRECTORIES( ${CMAKE_CURRENT_SOURCE_DIR}/include )
link_directories( ${CMAKE_BINARY_DIR}/bin)
set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR}/bin)
add_executable( opencvtest ${NAME_SRC} ${NAME_HEADERS} )
target_link_libraries( opencvtest ${OpenCV_LIBS} )
Here main.cpp
#include <iostream>
#include <sstream>
#include <string>
#include <fstream>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace std;
const cv::Vec3b color_azure{ 255, 129, 0 };
const cv::Vec3b color_violet{ 255, 0, 127 };
const cv::Vec3b color_black {0,0,0};
int main() {
cout << "App started" << endl;
cv::Mat image = cv::Mat(cv::Size(800, 600), CV_8UC3, color_black);
std::vector<cv::Point> vs(5);
vs[0] = cv::Point(200, 450);
vs[1] = cv::Point(600, 250);
vs[2] = cv::Point(400, 50);
vs[3] = cv::Point(200, 250);
vs[4] = cv::Point(600, 450);
std::vector<int> nk(9);
nk[0] = 0;
nk[1] = 1;
nk[2] = 2;
nk[3] = 3;
nk[4] = 4;
nk[5] = 0;
nk[6] = 3;
nk[7] = 1;
nk[8] = 4;
std::stringstream ss("Das-ist-das-Haus-vom-Ni-ko-laus");
std::vector<std::string> silben(9);
int j = 0;
while (ss.good())
{
std::string substr;
getline(ss, substr, '-');
silben[j++] = substr + "-";
}
for (int i = 0; i < 8; i++) {
cv::line(image, vs[nk[i]], vs[nk[i + 1]], color_azure, 5);
cv::putText(image, silben[i], cv::Point(i*60, 475),
cv::FONT_HERSHEY_PLAIN, 1, color_violet, 2);
cv::imshow("Image", image);
cv::waitKey();
}
cv::imshow("Image", image);
cv::waitKey(0);
return 0;
}
Then compiling and running worked fine:
mkdir buildmingw
cd buildmingw
cmake .. -G "MinGW Makefiles"
mingw32-make
bin/opencvtest.exe