Qt: Support Qt 6

src/duckstation-qt/main.cpp

@@ -63,10 +63,12 @@ int main(int argc, char* argv[])
   qRegisterMetaType<std::optional<bool>>();
   qRegisterMetaType<std::function<void()>>();
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
   QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
   QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
 #if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
   QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+#endif
 #endif
 
   QApplication app(argc, argv);
@@ -114,3 +116,45 @@ int main(int argc, char* argv[])
   host_interface->Shutdown();
   return result;
 }
+
+#ifdef _WIN32
+
+// Apparently Qt6 got rid of this?
+#include "common/windows_headers.h"
+#include <shellapi.h>
+
+/*
+  WinMain() - Initializes Windows and calls user's startup function main().
+  NOTE: WinMain() won't be called if the application was linked as a "console"
+  application.
+*/
+
+// Convert a wchar_t to char string, equivalent to QString::toLocal8Bit()
+// when passed CP_ACP.
+static inline char* wideToMulti(unsigned int codePage, const wchar_t* aw)
+{
+  const int required = WideCharToMultiByte(codePage, 0, aw, -1, nullptr, 0, nullptr, nullptr);
+  char* result = new char[required];
+  WideCharToMultiByte(codePage, 0, aw, -1, result, required, nullptr, nullptr);
+  return result;
+}
+
+extern "C" int APIENTRY WinMain(HINSTANCE, HINSTANCE, LPSTR /*cmdParamarg*/, int /* cmdShow */)
+{
+  int argc = 0;
+  wchar_t** argvW = CommandLineToArgvW(GetCommandLineW(), &argc);
+  if (argvW == nullptr)
+    return -1;
+  char** argv = new char* [argc + 1];
+  for (int i = 0; i != argc; ++i)
+    argv[i] = wideToMulti(CP_ACP, argvW[i]);
+  argv[argc] = nullptr;
+  LocalFree(argvW);
+  const int exitCode = main(argc, argv);
+  for (int i = 0; (i != argc) && (argv[i] != nullptr); ++i)
+    delete[] argv[i];
+  delete[] argv;
+  return exitCode;
+}
+
+#endif