1 files changed, 99 insertions, 13 deletions

diff --git a/platform/javascript/javascript_main.cpp b/platform/javascript/javascript_main.cpp
index 815bc7e456..a30d84a52c 100644
--- a/platform/javascript/javascript_main.cpp
+++ b/platform/javascript/javascript_main.cpp
@@ -30,42 +30,128 @@
 
 #include "core/io/resource_loader.h"
 #include "main/main.h"
-#include "os_javascript.h"
+#include "platform/javascript/display_server_javascript.h"
+#include "platform/javascript/os_javascript.h"
 
 #include <emscripten/emscripten.h>
+#include <stdlib.h>
 
-extern "C" EMSCRIPTEN_KEEPALIVE void main_after_fs_sync(char *p_idbfs_err) {
+static OS_JavaScript *os = nullptr;
+static uint64_t target_ticks = 0;
+
+void exit_callback() {
+	emscripten_cancel_main_loop(); // After this, we can exit!
+	Main::cleanup();
+	int exit_code = OS_JavaScript::get_singleton()->get_exit_code();
+	memdelete(os);
+	os = nullptr;
+	emscripten_force_exit(exit_code); // No matter that we call cancel_main_loop, regular "exit" will not work, forcing.
+}
+
+void main_loop_callback() {
+	uint64_t current_ticks = os->get_ticks_usec();
+
+	bool force_draw = DisplayServerJavaScript::get_singleton()->check_size_force_redraw();
+	if (force_draw) {
+		Main::force_redraw();
+	} else if (current_ticks < target_ticks) {
+		return; // Skip frame.
+	}
+
+	int target_fps = Engine::get_singleton()->get_target_fps();
+	if (target_fps > 0) {
+		target_ticks += (uint64_t)(1000000 / target_fps);
+	}
+	if (os->main_loop_iterate()) {
+		emscripten_cancel_main_loop(); // Cancel current loop and wait for finalize_async.
+		/* clang-format off */
+		EM_ASM({
+			// This will contain the list of operations that need to complete before cleanup.
+			Module.async_finish = [
+				// Always contains at least one async promise, to avoid firing immediately if nothing is added.
+				new Promise(function(accept, reject) {
+					setTimeout(accept, 0);
+				})
+			];
+		});
+		/* clang-format on */
+		os->get_main_loop()->finish();
+		os->finalize_async(); // Will add all the async finish functions.
+		EM_ASM({
+			Promise.all(Module.async_finish).then(function() {
+				Module.async_finish = [];
+				ccall("cleanup_after_sync", null, []);
+			});
+		});
+	}
+}
 
+extern "C" EMSCRIPTEN_KEEPALIVE void cleanup_after_sync() {
+	emscripten_set_main_loop(exit_callback, -1, false);
+}
+
+extern "C" EMSCRIPTEN_KEEPALIVE void main_after_fs_sync(char *p_idbfs_err) {
 	String idbfs_err = String::utf8(p_idbfs_err);
 	if (!idbfs_err.empty()) {
 		print_line("IndexedDB not available: " + idbfs_err);
 	}
-	OS_JavaScript *os = OS_JavaScript::get_singleton();
 	os->set_idb_available(idbfs_err.empty());
+	// TODO: Check error return value.
+	Main::setup2(); // Manual second phase.
 	// Ease up compatibility.
 	ResourceLoader::set_abort_on_missing_resources(false);
 	Main::start();
-	os->run_async();
+	os->get_main_loop()->init();
+	// Immediately run the first iteration.
+	// We are inside an animation frame, we want to immediately draw on the newly setup canvas.
+	main_loop_callback();
+	emscripten_resume_main_loop();
 }
 
 int main(int argc, char *argv[]) {
+	// Create and mount userfs immediately.
+	EM_ASM({
+		FS.mkdir('/userfs');
+		FS.mount(IDBFS, {}, '/userfs');
+	});
+
+	// Configure locale.
+	char locale_ptr[16];
+	/* clang-format off */
+	EM_ASM({
+		stringToUTF8(Module['locale'], $0, 16);
+	}, locale_ptr);
+	/* clang-format on */
+	setenv("LANG", locale_ptr, true);
+
+	// Ensure the canvas ID.
+	/* clang-format off */
+	EM_ASM({
+		stringToUTF8("#" + Module['canvas'].id, $0, 255);
+	}, DisplayServerJavaScript::canvas_id);
+	/* clang-format on */
+
+	os = new OS_JavaScript();
+
+	// We must override main when testing is enabled
+	TEST_MAIN_OVERRIDE
+
+	Main::setup(argv[0], argc - 1, &argv[1], false);
+	emscripten_set_main_loop(main_loop_callback, -1, false);
+	emscripten_pause_main_loop(); // Will need to wait for FS sync.
 
 	// Sync from persistent state into memory and then
 	// run the 'main_after_fs_sync' function.
 	/* clang-format off */
-	EM_ASM(
-		FS.mkdir('/userfs');
-		FS.mount(IDBFS, {}, '/userfs');
+	EM_ASM({
 		FS.syncfs(true, function(err) {
-			ccall('main_after_fs_sync', null, ['string'], [err ? err.message : ""])
+			requestAnimationFrame(function() {
+				ccall('main_after_fs_sync', null, ['string'], [err ? err.message : ""]);
+			});
 		});
-	);
+	});
 	/* clang-format on */
 
-	new OS_JavaScript(argc, argv);
-	// TODO: Check error return value.
-	Main::setup(argv[0], argc - 1, &argv[1]);
-
 	return 0;
 	// Continued async in main_after_fs_sync() from the syncfs() callback.
 }