Emscripten: Reimplement Start and Stop without emscripten_sleep

- emscripten_sleep requires asynchify.
- Final fixes for save and load scene.
- New function for taking a screenshot and downloading it.
- Fix unit tests

CMakeLists.txt

@@ -1124,7 +1124,11 @@ if(${PLAYER_BUILD_EXECUTABLE} AND ${PLAYER_TARGET_PLATFORM} MATCHES "^SDL(1|2)$"
 		set(PLAYER_JS_POSTJS "${CMAKE_CURRENT_SOURCE_DIR}/resources/emscripten/emscripten-post.js")
 		set(PLAYER_JS_SHELL "${CMAKE_CURRENT_SOURCE_DIR}/resources/emscripten/emscripten-shell.html")
 
-		set_property(TARGET ${EXE_NAME} PROPERTY LINK_FLAGS "-s ALLOW_MEMORY_GROWTH -s MINIFY_HTML=0 -s MODULARIZE -s EXIT_RUNTIME -s EXPORT_NAME='createEasyRpgPlayer' --bind --pre-js ${PLAYER_JS_PREJS} --post-js ${PLAYER_JS_POSTJS} -sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE=['$autoResumeAudioContext','$dynCall']")
+		set_property(TARGET ${EXE_NAME} PROPERTY LINK_FLAGS
+			"-sALLOW_MEMORY_GROWTH -sMINIFY_HTML=0 -sMODULARIZE -sEXPORT_NAME=createEasyRpgPlayer \
+			 -sEXIT_RUNTIME --bind --pre-js ${PLAYER_JS_PREJS} --post-js ${PLAYER_JS_POSTJS} \
+			 -sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE=['$autoResumeAudioContext','$dynCall'] \
+			 -sEXPORTED_FUNCTIONS=_main,_malloc,_free")
 		set_source_files_properties("src/platform/sdl/main.cpp" PROPERTIES
 			OBJECT_DEPENDS "${PLAYER_JS_PREJS};${PLAYER_JS_POSTJS};${PLAYER_JS_SHELL}")
 
@@ -1420,7 +1424,10 @@ if(PLAYER_ENABLE_TESTS)
 	if(CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
 		target_compile_definitions(test_runner_player PUBLIC EP_NATIVE_TEST_PATH=\"${CMAKE_CURRENT_SOURCE_DIR}/tests/assets\")
 		target_compile_definitions(test_runner_player PUBLIC EP_TEST_PATH=\"/assets\")
+		target_compile_definitions(test_runner_player PUBLIC DOCTEST_CONFIG_NO_EXCEPTIONS_BUT_WITH_ALL_ASSERTS=1)
+
 		target_link_libraries(test_runner_player "nodefs.js")
+		set_property(TARGET test_runner_player PROPERTY LINK_FLAGS "-sALLOW_MEMORY_GROWTH --bind")
 	else()
 		target_compile_definitions(test_runner_player PUBLIC EP_TEST_PATH=\"${CMAKE_CURRENT_SOURCE_DIR}/tests/assets\")
 	endif()
@@ -1434,10 +1441,6 @@ if(PLAYER_ENABLE_TESTS)
 	endif()
 	add_dependencies(check_player test_runner_player)
 	add_dependencies(check check_player)
-
-	if(CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
-		set_property(TARGET test_runner_player APPEND_STRING PROPERTY LINK_FLAGS "-s ALLOW_MEMORY_GROWTH")
-	endif()
 endif()
 
 # Instrumentation framework

resources/emscripten/emscripten-post.js

@@ -14,14 +14,11 @@ if (Module.saveFs === undefined) {
 }
 
 Module.initApi = function() {
-  Module.api_private.downloadSavegame_js = function(buffer, size, index) {
+  Module.api_private.download_js = function(buffer, size, filename) {
     const blob = new Blob([Module.HEAPU8.slice(buffer, buffer + size)]);
     const link = document.createElement('a');
     link.href = window.URL.createObjectURL(blob);
-    if (index < 10) {
-      index = "0" + index;
-    }
-    link.download = "Save" + index + ".lsd";
+    link.download = UTF8ToString(filename);
     link.click();
     link.remove();
   }

resources/emscripten/emscripten-pre.js

@@ -42,7 +42,7 @@ Module = { ...Module,
     Module.totalDependencies = Math.max(Module.totalDependencies, left);
     Module.setStatus(left ? `Preparing... (${Module.totalDependencies - left}/${Module.totalDependencies})` : 'Downloading game data...');
   }
-});
+};
 
 /**
  * Parses the current location query to setup a specific game

src/bitmap.cpp

@@ -173,7 +173,7 @@ Bitmap::Bitmap(Bitmap const& source, Rect const& src_rect, bool transparent) {
 	Blit(0, 0, source, src_rect, Opacity::Opaque());
 }
 
-bool Bitmap::WritePNG(Filesystem_Stream::OutputStream& os) const {
+bool Bitmap::WritePNG(std::ostream& os) const {
 	size_t const width = GetWidth(), height = GetHeight();
 	size_t const stride = width * 4;
 

src/bitmap.h

@@ -198,7 +198,7 @@ class Bitmap {
 	 * @param os output stream that PNG will be output.
 	 * @return true if success, otherwise false.
 	 */
-	bool WritePNG(Filesystem_Stream::OutputStream&) const;
+	bool WritePNG(std::ostream& os) const;
 
 	/**
 	 * Gets the background color

src/image_png.cpp

@@ -21,6 +21,7 @@
 #include <cstring>
 #include <csetjmp>
 #include <vector>
+#include <fstream>
 
 #include "output.h"
 #include "image_png.h"
@@ -250,7 +251,7 @@ static void flush_stream(png_structp out_ptr) {
 	reinterpret_cast<Filesystem_Stream::OutputStream*>(png_get_io_ptr(out_ptr))->flush();
 }
 
-bool ImagePNG::WritePNG(Filesystem_Stream::OutputStream& os, uint32_t width, uint32_t height, uint32_t* data) {
+bool ImagePNG::WritePNG(std::ostream& os, uint32_t width, uint32_t height, uint32_t* data) {
 	png_structp write = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 	if (!write) {
 		Output::Warning("Bitmap::WritePNG: error in png_create_write");

src/image_png.h

@@ -24,7 +24,7 @@
 namespace ImagePNG {
 	bool ReadPNG(const void* buffer, bool transparent, int& width, int& height, void*& pixels);
 	bool ReadPNG(Filesystem_Stream::InputStream& is, bool transparent, int& width, int& height, void*& pixels);
-	bool WritePNG(Filesystem_Stream::OutputStream& os, uint32_t width, uint32_t height, uint32_t* data);
+	bool WritePNG(std::ostream& os, uint32_t width, uint32_t height, uint32_t* data);
 }
 
 #endif

src/output.cpp

@@ -28,6 +28,7 @@
 #  include <android/log.h>
 #elif defined(EMSCRIPTEN)
 #  include <emscripten.h>
+#  include "platform/emscripten/interface.h"
 #elif defined(__vita__)
 #  include <psp2/kernel/processmgr.h>
 #endif
@@ -275,12 +276,17 @@ void Output::Quit() {
 }
 
 bool Output::TakeScreenshot() {
+#ifdef EMSCRIPTEN
+	Emscripten_Interface::TakeScreenshot();
+	return true;
+#else
 	int index = 0;
 	std::string p;
 	do {
 		p = "screenshot_" + std::to_string(index++) + ".png";
 	} while(FileFinder::Save().Exists(p));
 	return TakeScreenshot(p);
+#endif
 }
 
 bool Output::TakeScreenshot(StringView file) {
@@ -293,7 +299,7 @@ bool Output::TakeScreenshot(StringView file) {
 	return false;
 }
 
-bool Output::TakeScreenshot(Filesystem_Stream::OutputStream& os) {
+bool Output::TakeScreenshot(std::ostream& os) {
 	return DisplayUi->GetDisplaySurface()->WritePNG(os);
 }
 

src/output.h

@@ -78,7 +78,7 @@ namespace Output {
 	 * @param os output stream that PNG will be stored.
 	 * @return true if success, otherwise false.
 	 */
-	bool TakeScreenshot(Filesystem_Stream::OutputStream& os);
+	bool TakeScreenshot(std::ostream& os);
 
 	/**
 	 * Shows/Hides the output log overlay.

src/platform/emscripten/interface.cpp

@@ -20,7 +20,9 @@
 #include <emscripten.h>
 #include <emscripten/bind.h>
 #include <lcf/lsd/reader.h>
+#include <sstream>
 
+#include "async_handler.h"
 #include "filefinder.h"
 #include "player.h"
 #include "scene_save.h"
@@ -38,9 +40,10 @@ bool Emscripten_Interface::DownloadSavegame(int slot) {
 		return false;
 	}
 	auto save_buffer = Utils::ReadStream(is);
+	std::string filename = std::get<1>(FileFinder::GetPathAndFilename(name));
 	EM_ASM_ARGS({
-		Module.api_private.downloadSavegame_js($0, $1, $2);
-	}, save_buffer.data(), save_buffer.size(), slot);
+		Module.api_private.download_js($0, $1, $2);
+	}, save_buffer.data(), save_buffer.size(), filename.c_str());
 	return true;
 }
 
@@ -54,6 +57,17 @@ void Emscripten_Interface::RefreshScene() {
 	Scene::instance->Refresh();
 }
 
+void Emscripten_Interface::TakeScreenshot() {
+	static int index = 0;
+	std::ostringstream os;
+	Output::TakeScreenshot(os);
+	std::string screenshot = os.str();
+	std::string filename = "screenshot_" + std::to_string(index++) + ".png";
+	EM_ASM_ARGS({
+		Module.api_private.download_js($0, $1, $2);
+	}, screenshot.data(), screenshot.size(), filename.c_str());
+}
+
 bool Emscripten_Interface_Private::UploadSavegameStep2(int slot, int buffer_addr, int size) {
 	auto fs = FileFinder::Save();
 	std::string name = Scene_Save::GetSaveFilename(fs, slot);
@@ -72,10 +86,7 @@ bool Emscripten_Interface_Private::UploadSavegameStep2(int slot, int buffer_addr
 		os.write(reinterpret_cast<char*>(buffer_addr), size);
 	}
 
-	// Save changed file system
-	EM_ASM({
-		FS.syncfs(function(err) {});
-	});
+	AsyncHandler::SaveFilesystem();
 
 	return true;
 }
@@ -87,6 +98,7 @@ EMSCRIPTEN_BINDINGS(player_interface) {
 		.class_function("downloadSavegame", &Emscripten_Interface::DownloadSavegame)
 		.class_function("uploadSavegame", &Emscripten_Interface::UploadSavegame)
 		.class_function("refreshScene", &Emscripten_Interface::RefreshScene)
+		.class_function("takeScreenshot", &Emscripten_Interface::TakeScreenshot)
 	;
 
 	emscripten::class_<Emscripten_Interface_Private>("api_private")

src/platform/emscripten/interface.h

@@ -23,6 +23,7 @@ class Emscripten_Interface {
 	static bool DownloadSavegame(int slot);
 	static void UploadSavegame(int slot);
 	static void RefreshScene();
+	static void TakeScreenshot();
 	static void Reset();
 };
 

src/platform/emscripten/main.cpp

@@ -19,28 +19,46 @@
 #include <string>
 #include <vector>
 #include <emscripten.h>
+#include "baseui.h"
 #include "output.h"
 #include "player.h"
 
+namespace {
+	std::vector<std::string> args;
+	int counter = 0;
+}
+
+void main_loop() {
+	if (counter < 5) {
+		++counter;
+	}
+
+	if (counter == 5) {
+		// Yield on start to ensure async operations (e.g. "mounting" of filesystems) can finish
+		Player::Init(std::move(args));
+		Player::Run();
+		++counter;
+	} else if (counter == 6) {
+		Player::MainLoop();
+		if (!DisplayUi.get()) {
+			// Yield on shutdown to ensure async operations (e.g. IDBFS saving) can finish
+			counter = -5;
+		}
+	} else if (counter == -1) {
+		emscripten_cancel_main_loop();
+	}
+}
+
 /**
  * If the main function ever needs to change, be sure to update the `main()`
  * functions of the other platforms as well.
  */
 extern "C" int main(int argc, char* argv[]) {
-	// Yield on start to ensure async operations (e.g. "mounting" of filesystems) can finish
-	// 10ms appears to work already but to be on the safe side better use 100ms
-	emscripten_sleep(100);
-
-	std::vector<std::string> args;
 	args.assign(argv, argv + argc);
 
 	Output::IgnorePause(true);
 
-	Player::Init(std::move(args));
-	Player::Run();
-
-	// Yield on shutdown to ensure async operations (e.g. IDBFS saving) can finish
-	emscripten_sleep(100);
+	emscripten_set_main_loop(main_loop, 0, 0);
 
 	return EXIT_SUCCESS;
 }

src/player.cpp

@@ -214,9 +214,8 @@ void Player::Run() {
 	Game_Clock::ResetFrame(Game_Clock::now());
 
 	// Main loop
-#ifdef EMSCRIPTEN
-	emscripten_set_main_loop(Player::MainLoop, 0, 0);
-#elif defined(USE_LIBRETRO)
+#if defined(USE_LIBRETRO) || defined(EMSCRIPTEN)
+	// emscripten implemented in main.cpp
 	// libretro invokes the MainLoop through a retro_run-callback
 #else
 	while (Transition::instance().IsActive() || (Scene::instance && Scene::instance->type != Scene::Null)) {
@@ -394,8 +393,6 @@ void Player::Exit() {
 
 	Graphics::UpdateSceneCallback();
 #ifdef EMSCRIPTEN
-	emscripten_cancel_main_loop();
-
 	BitmapRef surface = DisplayUi->GetDisplaySurface();
 	std::string message = "It's now safe to turn off\n      your browser.";
 	DisplayUi->CleanDisplay();

src/scene_file.cpp

@@ -204,7 +204,7 @@ void Scene_File::vUpdate() {
 #ifdef EMSCRIPTEN
 		extra_commands_window->SetX(SCREEN_TARGET_WIDTH - extra_commands_window->GetWidth() - 8);
 		extra_commands_window->SetY(file_windows[index]->GetY() + 8);
-		extra_commands_window->SetItemEnabled(0, file_windows[index]->IsValid());
+		extra_commands_window->SetItemEnabled(0, file_windows[index]->IsValid() && file_windows[index]->HasParty());
 		extra_commands_window->SetVisible(true);
 		return;
 #endif

src/window_savefile.cpp

@@ -82,10 +82,14 @@ void Window_SaveFile::SetCorrupted(bool corrupted) {
 	this->corrupted = corrupted;
 }
 
-bool Window_SaveFile::IsValid() {
+bool Window_SaveFile::IsValid() const {
 	return has_save && !corrupted;
 }
 
+bool Window_SaveFile::HasParty() const {
+	return has_party;
+}
+
 void Window_SaveFile::SetHasSave(bool valid) {
 	this->has_save = valid;
 }

src/window_savefile.h

@@ -67,7 +67,12 @@ class Window_SaveFile :	public Window_Base {
 	 *
 	 * @return Whether save is valid
 	 */
-	bool IsValid();
+	bool IsValid() const;
+
+	/**
+	 * @return Whether the save slot contains party information from a save file.
+	 */
+	bool HasParty() const;
 
 	/**
 	 * Sets if there is a savegame in the slot.