UE5 源码启动剖析

1一切的起点WinMain函数

对于Windows控制台，程序的入口是main函数

对于Windows窗口，程序的入口是WinMain函数

Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp

int32 WINAPI WinMain(_In_ HINSTANCE hInInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ char* pCmdLine, _In_ int32 nCmdShow)
{
	int32 Result = LaunchWindowsStartup(hInInstance, hPrevInstance, pCmdLine, nCmdShow, nullptr);
	LaunchWindowsShutdown();
	return Result;
}

LAUNCH_API int32 LaunchWindowsStartup( HINSTANCE hInInstance, HINSTANCE hPrevInstance, char*, int32 nCmdShow, const TCHAR* CmdLine )
{
  ...
  ErrorLevel = GuardedMain( CmdLine );
  ...
}

事件分发器

static void WinPumpMessages()
{
	TRACE_CPUPROFILER_EVENT_SCOPE(WinPumpMessages);
	{
		MSG Msg;
		while( PeekMessage(&Msg,NULL,0,0,PM_REMOVE) )
		{
			TranslateMessage( &Msg );
			DispatchMessage( &Msg );
		}
	}
}

事件循环

 	UnrealEditor-Slate.dll!SWindowTitleBar::MinimizeButton_OnClicked() 行 646	C++
 	[内联框架] UnrealEditor-Slate.dll!Invoke(FReply(SWindowTitleBar::*)()) 行 66	C++
 	[内联框架] UnrealEditor-Slate.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int>>::ApplyAfter(FReply(SWindowTitleBar::*)() &) 行 327	C++
 	UnrealEditor-Slate.dll!TBaseSPMethodDelegateInstance<0,SWindowTitleBar,1,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() 行 295	C++
 	[内联框架] UnrealEditor-Slate.dll!TDelegate<FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() 行 620	C++
 	UnrealEditor-Slate.dll!SButton::ExecuteOnClick() 行 465	C++
 	UnrealEditor-Slate.dll!SButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) 行 390	C++
 	UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent::__l8::<lambda>(const FArrangedWidget & TargetWidget, const FPointerEvent & Event) 行 5046	C++
 	UnrealEditor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,FReply <lambda>(const FArrangedWidget &, const FPointerEvent &)>(FSlateApplication * ThisApplication, FEventRouter::FToLeafmostPolicy RoutingPolicy, FPointerEvent EventCopy, const FSlateApplication::RoutePointerUpEvent::__l8::FReply <lambda>(const FArrangedWidget &, const FPointerEvent &) & Lambda, ESlateDebuggingInputEvent DebuggingInputEvent) 行 412	C++
 	UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent(const FWidgetPath & WidgetsUnderPointer, const FPointerEvent & PointerEvent) 行 5032	C++
 	UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent(const FPointerEvent & MouseEvent) 行 5601	C++
 	UnrealEditor-Slate.dll!FSlateApplication::OnMouseUp(const EMouseButtons::Type Button, const UE::Math::TVector2<double> CursorPos) 行 5566	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) 行 2219	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage(TSharedPtr<FWindowsWindow,1> & NativeWindow, HWND__ * InHWnd, unsigned int InMessage, unsigned __int64 InWParam, __int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) 行 2726	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) 行 1895	C++
 	[内联框架] UnrealEditor-ApplicationCore.dll!WindowsApplication_WndProc(HWND__ *) 行 919	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) 行 925	C++
 	[外部代码]	
 	[内联框架] UnrealEditor-ApplicationCore.dll!WinPumpMessages() 行 113	C++
>	UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages(bool bFromMainLoop) 行 142	C++
 	UnrealEditor.exe!FEngineLoop::Tick() 行 5293	C++
 	[内联框架] UnrealEditor.exe!EngineTick() 行 66	C++
 	UnrealEditor.exe!GuardedMain(const wchar_t * CmdLine) 行 202	C++
 	UnrealEditor.exe!LaunchWindowsStartup(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) 行 233	C++
 	UnrealEditor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) 行 282	C++
 	[外部代码]