Use Windows API instead of QT to load the library, because QLibrary will not...

Use Windows API instead of QT to load the library, because QLibrary will not search in the folder of the lib for dependencies

src/driver.cpp

@@ -6,6 +6,9 @@
 #include "dmxchannelfilter.h"
 #include <QDir>
 #include <cstring>
+#ifdef Q_OS_WIN
+#include <windows.h>
+#endif
 
 HardwareInterface * driver = nullptr;
 
@@ -27,7 +30,29 @@ namespace Driver {
     bool loadDriver(QString path){
 #if defined(Q_OS_WIN)
     typedef HardwareInterface * (*getDriverFunc)();
-    getDriverFunc getDriver =  reinterpret_cast<getDriverFunc>(QLibrary::resolve(path,"getDriver"));
+    // we have to load the library with the Windows API to handle dependecies in the same folder, see https://bugreports.qt.io/projects/QTBUG/issues/QTBUG-74001
+    path.replace("/","\\");
+    auto pathC = path.toStdString();
+    auto handle = LoadLibraryExA(pathC.c_str(),nullptr, LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR|LOAD_LIBRARY_SEARCH_DEFAULT_DIRS);
+    if(handle == nullptr){
+        auto errorCode = GetLastError();
+        qDebug() << "Loading of lib failed, error code: "<<errorCode;
+        if(errorCode == 126)
+            ErrorNotifier::get()->newError("Fehler beim laden der DLL, Abhängigkeiten zu anderen DLLs konnten nicht geladen werden.");
+        else{
+            ErrorNotifier::get()->newError("Fehler beim laden der DLL. Error code: " + QString::number(errorCode));
+        }
+        return false;
+    }
+    auto func = GetProcAddress(handle,"getDriver");
+    if(func == nullptr){
+        auto errorCode = GetLastError();
+        qDebug() << "Loading of lib failed, error code: "<<errorCode;
+        ErrorNotifier::get()->newError("Fehler beim laden der Funktion \"getDriver\" aus der DLL, Fehlercode: " + QString::number(errorCode));
+        return false;
+    }
+    getDriverFunc getDriver = reinterpret_cast<getDriverFunc>(func);
+    //getDriverFunc getDriver =  reinterpret_cast<getDriverFunc>(QLibrary::resolve(path,"getDriver"));
     if(getDriver!=nullptr){
         HardwareInterface * inter = getDriver();
         if(inter != nullptr){