UnrealEngineUWP/Engine/Source/Runtime/Launch/Private/HTML5/LaunchHTML5.cpp

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#include "CoreMinimal.h"
#include "Misc/App.h"
#include "Misc/OutputDeviceError.h"
#include "HTML5/HTML5PlatformMisc.h"
#include "Templates/ScopedPointer.h"
#include "LaunchEngineLoop.h"
#include "EngineAnalytics.h"
#include "Interfaces/IAnalyticsProvider.h"
THIRD_PARTY_INCLUDES_START
	#ifdef HTML5_USE_SDL2
		#include <SDL.h>
	#endif
	#include <emscripten/emscripten.h>
	#include <emscripten/trace.h>
	#include <emscripten/html5.h>
THIRD_PARTY_INCLUDES_END

DEFINE_LOG_CATEGORY_STATIC(LogHTML5Launch, Log, All);

#include <string.h>
#include <locale.h>

FEngineLoop	GEngineLoop;
TCHAR GCmdLine[2048];

void HTML5_Tick()
{
//	UE_LOG(LogTemp,Display,TEXT("HTML5_Tick"));
	static uint32 FrameCount = 1;
	char Buf[128];
	sprintf(Buf, "Frame %u", FrameCount);
	emscripten_trace_record_frame_start();
	emscripten_trace_enter_context(Buf);
	GEngineLoop.Tick();
	emscripten_trace_exit_context();
	emscripten_trace_record_frame_end();

	// Assuming 60fps, log out the memory report. This isn't important to be
	// exactly every second, it just needs done periodically
	if (FrameCount % 60 == 0)
	{
		emscripten_trace_report_memory_layout();
	}

	++FrameCount;
}

const char *beforeunload_callback(int eventType, const void *reserved, void *userData)
{
	if (FEngineAnalytics::IsAvailable())
	{
		FEngineAnalytics::GetProvider().EndSession();
	}
	return ""; // don't show a confirmation dialog to not block
}

void HTML5_Init ()
{
	UE_LOG(LogTemp,Display,TEXT("HTML5_Init"));
	emscripten_trace_record_frame_start();

	// initialize the engine
	UE_LOG(LogTemp,Display,TEXT("PreInit Start"));
	emscripten_trace_enter_context("PreInit");
	GEngineLoop.PreInit(0, NULL, GCmdLine);
	emscripten_trace_exit_context();
	UE_LOG(LogHTML5Launch,Display,TEXT("PreInit Complete"));

	UE_LOG(LogHTML5Launch,Display,TEXT("Init Start"));
	emscripten_trace_enter_context("Init");
	GEngineLoop.Init();
	emscripten_set_beforeunload_callback(0, beforeunload_callback);
	emscripten_trace_exit_context();
	UE_LOG(LogHTML5Launch,Display,TEXT("Init Complete"));
	
	emscripten_trace_record_frame_end();

	// main loop
	emscripten_set_main_loop(HTML5_Tick, 0, true);
//	emscripten_set_main_loop(HTML5_Tick, 0, false);
//	emscripten_set_main_loop_timing(EM_TIMING_SETIMMEDIATE, 0);
	EM_ASM(throw 'SimulateInfiniteLoop');
}

class FHTML5Exec : private FSelfRegisteringExec
{
public:

	FHTML5Exec()
		{}

	/** Console commands **/
	virtual bool Exec( UWorld* InWorld, const TCHAR* Cmd, FOutputDevice& Ar ) override
	{
		if (FParse::Command(&Cmd, TEXT("em_trace_close")))
		{
			emscripten_trace_exit_context();//"main");
			emscripten_trace_close();
			return true;
		}
		return false;
	}
};
static TUniquePtr<FHTML5Exec> GHTML5Exec;

/*
#if HTML5_ENABLE_RENDERER_THREAD
// Keep the HTML5 Canvas on the main thread to receive proxied WebGL events to.
#define EMSCRIPTEN_PTHREAD_TRANSFERRED_CANVASES ""
#else
// Transfer the canvas to the main UE4 application thread so that OffscreenCanvas
// can be used on it. Using OffscreenCanvas ties the WebGL context to being only
// accessible from a single thread, so UE4 multithreaded rendering cannot be
// enabled at the same time this is used.
#define EMSCRIPTEN_PTHREAD_TRANSFERRED_CANVASES "#canvas"
#endif
*/

int main(int argc, char** argv)
{
	// Specify the application wide locale to be UTF-8 aware. Without this,
	// wprintf family of functions will fail on not being able to handle
	// non-ASCII characters such as Scandinavian <20>, <20> and <20>. Even more,
	// current UE_LOG() handling is not able to cope with these kind of
	// failures, and would crash.
	setlocale(LC_ALL, "C.UTF-8");

	UE_LOG(LogHTML5Launch,Display,TEXT("Starting UE4 ... %s\n"), GCmdLine);

	// TODO: configure this via the command line?
	emscripten_trace_configure("http://127.0.0.1:5000/", "UE4Game");
	GHTML5Exec = MakeUnique<FHTML5Exec>();

	emscripten_trace_enter_context("main");

#ifdef HTML5_USE_SDL2
	EM_ASM({console.log("SDL_Init")});
	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE);
#endif
	GCmdLine[0] = 0;
	// to-do use Platform Str functions.
	FCString::Strcpy(GCmdLine, TEXT(" "));

	for (int Option = 1; Option < argc; Option++)
	{
		FCString::Strcat(GCmdLine, TEXT("  "));
		FCString::Strcat(GCmdLine, ANSI_TO_TCHAR(argv[Option]));
	}

	UE_LOG(LogHTML5Launch,Display,TEXT("Command line: %s\n"), GCmdLine);

	HTML5_Init();

	return 0;
}


void EmptyLinkFunctionForStaticInitializationHTML5Win32(void) {}