Workerized emscripten retroarch (WIP) (#17484)

* workerized RA

* Workerized (non-async) web player, using OPFS

This patch eliminates the need for asyncify and uses modern filesystem
APIs instead of the deprecated, unmaintained BrowserFS.

This is a WIP patch because it won't fully work until these two
Emscripten PRs land and are released:

emscripten-core/emscripten#23518
emscripten-core/emscripten#23021

The former fixes an offscreen canvas context recreation bug, and the
latter adds an equivalent to BrowserFS's XHR filesystem (but without
the hazardous running-XHR-on-the-main-thread problem).

The biggest issue is that local storage of users who were using the
old version of the webplayer will be gone when they switch to the new
webplayer.  I don't have a good story for converting the old BrowserFS
IDBFS contents into the new OPFS filesystem (the move is worth doing
because OPFS supports seeking and reading only bits of a file, and
because BrowserFS is dead).

I've kept around the old libretro webplayer under
pkg/emscripten/libretro-classic, and with these make flags you can
build a non-workerized RA that uses asyncify to sleep as before:

make -f Makefile.emscripten libretro=$CORE HAVE_WORKER=0 HAVE_WASMFS=0 PTHREAD=0 HAVE_AL=1

I also moved the default directory for core content on emscripten to
not be a subdirectory of the local filesystem mount, because it's
confusing to have a subdirectory that's lazily fetched and not
mirrored to the local storage.  I think it won't impact existing users
of the classic web player because they already have a retroarch.cfg in
place.

* Get fetchfs working without manifest support

* makefile fixes

Author: JoeOsborn

Makefile.common

@@ -1526,7 +1526,10 @@ ifeq ($(HAVE_GL_CONTEXT), 1)
    endif
 
    ifeq ($(HAVE_EMSCRIPTEN), 1)
-      OBJ += gfx/drivers_context/emscriptenegl_ctx.o
+      ifeq ($(HAVE_EGL), 1)
+        OBJ += gfx/drivers_context/emscriptenegl_ctx.o
+      endif
+      OBJ += gfx/drivers_context/emscriptenwebgl_ctx.o
    endif
 
    ifeq ($(HAVE_MALI_FBDEV), 1)

Makefile.emscripten

@@ -24,7 +24,8 @@ HAVE_SCREENSHOTS = 1
 HAVE_REWIND = 1
 HAVE_AUDIOMIXER = 1
 HAVE_CC_RESAMPLER = 1
-HAVE_EGL    = 1
+HAVE_EGL    ?= 0
+HAVE_OPENGLES = 1
 HAVE_RJPEG  = 0
 HAVE_RPNG   = 1
 HAVE_EMSCRIPTEN = 1
@@ -48,6 +49,8 @@ HAVE_7ZIP = 1
 HAVE_BSV_MOVIE = 1
 HAVE_AL = 1
 HAVE_CHD ?= 0
+HAVE_WASMFS ?= 1
+HAVE_WORKER ?= 1
 
 # WARNING -- READ BEFORE ENABLING
 # The rwebaudio driver is known to have several audio bugs, such as
@@ -68,7 +71,7 @@ HAVE_OPENGLES3 ?= 0
 
 ASYNC ?= 0
 LTO ?= 0
-PTHREAD ?= 0
+PTHREAD ?= 4
 
 STACK_SIZE ?= 4194304
 INITIAL_HEAP ?= 134217728
@@ -92,11 +95,52 @@ _cmd_toggle_menu,_cmd_reload_config,_cmd_toggle_grab_mouse,_cmd_toggle_game_focu
 _cmd_set_volume,_cmd_set_shader,_cmd_cheat_set_code,_cmd_cheat_get_code,_cmd_cheat_toggle_index,_cmd_cheat_get_code_state,_cmd_cheat_realloc,\
 _cmd_cheat_get_size,_cmd_cheat_apply_cheats
 
+EXPORTS := callMain,FS,PATH,ERRNO_CODES,stringToNewUTF8,UTF8ToString
+
 LIBS    := -s USE_ZLIB=1
+
+ifeq ($(HAVE_WASMFS), 1)
+   LIBS += -s WASMFS -s FORCE_FILESYSTEM=1 -lfetchfs.js -lopfs.js
+   EXPORTS := $(EXPORTS),FETCHFS,OPFS
+endif
+
+ifeq ($(HAVE_WORKER), 1)
+   LIBS += -s PROXY_TO_PTHREAD -s USE_ES6_IMPORT_META=0 -sENVIRONMENT=worker,web
+else 
+   ifeq ($(HAVE_AL), 1)
+     override ASYNC = 1
+   endif
+endif
+
+ifeq ($(HAVE_OPENGLES), 1)
+   ifeq ($(HAVE_OPENGLES3), 1)
+      LDFLAGS += -s FULL_ES3=1 -s MIN_WEBGL_VERSION=2 -s MAX_WEBGL_VERSION=2
+   else
+      LDFLAGS += -s FULL_ES2=1
+   endif
+endif
+
+ifeq ($(GL_DEBUG), 1)
+   LDFLAGS += -s GL_ASSERTIONS=1 -s GL_DEBUG=1
+endif
+
+ifeq ($(FS_DEBUG), 1)
+   LDFLAGS += -s FS_DEBUG=1
+endif
+
+ifeq ($(HAVE_SDL2), 1)
+   LIBS += -s USE_SDL=2
+   DEFINES += -DHAVE_SDL2
+endif
+
+
 LDFLAGS := -L. --no-heap-copy -s $(LIBS) -s STACK_SIZE=$(STACK_SIZE) -s INITIAL_MEMORY=$(INITIAL_HEAP) \
-           -s EXPORTED_RUNTIME_METHODS=callMain,FS,PATH,ERRNO_CODES,stringToNewUTF8,UTF8ToString \
+           -s EXPORTED_RUNTIME_METHODS=$(EXPORTS) \
            -s ALLOW_MEMORY_GROWTH=1 -s EXPORTED_FUNCTIONS="$(EXPORTED_FUNCTIONS)" \
            -s MODULARIZE=1 -s EXPORT_ES6=1 -s EXPORT_NAME="libretro_$(subst -,_,$(LIBRETRO))" \
+           -s DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR=0 \
+           -s OFFSCREENCANVAS_SUPPORT \
+           -s OFFSCREEN_FRAMEBUFFER \
            --extern-pre-js emscripten/pre.js \
            --js-library emscripten/library_rwebcam.js \
            --js-library emscripten/library_platform_emscripten.js
@@ -105,48 +149,29 @@ ifeq ($(HAVE_RWEBAUDIO), 1)
    LDFLAGS += --js-library emscripten/library_rwebaudio.js
    DEFINES += -DHAVE_RWEBAUDIO
 endif
+
 ifeq ($(HAVE_AL), 1)
    LDFLAGS += -lopenal
    DEFINES += -DHAVE_AL
-   override ASYNC = 1
 endif
 
 ifneq ($(PTHREAD), 0)
-   LDFLAGS += -s MAXIMUM_MEMORY=1073741824 -pthread -s PTHREAD_POOL_SIZE=$(PTHREAD)
-   CFLAGS += -pthread
+   LDFLAGS += -s WASM_MEM_MAX=1073741824 -pthread -s PTHREAD_POOL_SIZE=$(PTHREAD)
+   CFLAGS += -pthread -s SHARED_MEMORY
    HAVE_THREADS=1
 else
    HAVE_THREADS=0
 endif
 
+
 ifeq ($(ASYNC), 1)
+   DEFINES += -DEMSCRIPTEN_ASYNCIFY
    LDFLAGS += -s ASYNCIFY=$(ASYNC) -s ASYNCIFY_STACK_SIZE=8192 
    ifeq ($(DEBUG), 1)
       LDFLAGS += -s ASYNCIFY_DEBUG=1 # -s ASYNCIFY_ADVISE
    endif
 endif
 
-ifeq ($(HAVE_OPENGLES), 1)
-   ifeq ($(HAVE_OPENGLES3), 1)
-      LDFLAGS += -s FULL_ES3=1 -s MIN_WEBGL_VERSION=2 -s MAX_WEBGL_VERSION=2
-   else
-      LDFLAGS += -s FULL_ES2=1
-   endif
-endif
-
-ifeq ($(GL_DEBUG), 1)
-   LDFLAGS += -s GL_ASSERTIONS=1 -s GL_DEBUG=1
-endif
-
-ifeq ($(FS_DEBUG), 1)
-   LDFLAGS += -s FS_DEBUG=1
-endif
-
-ifeq ($(HAVE_SDL2), 1)
-   LIBS += -s USE_SDL=2
-   DEFINES += -DHAVE_SDL2
-endif
-
 include Makefile.common
 
 CFLAGS += $(DEF_FLAGS) -Ideps -Ideps/stb
@@ -183,8 +208,10 @@ RARCH_OBJ := $(addprefix $(OBJDIR)/,$(OBJ))
 
 all: $(TARGET)
 
-$(TARGET): $(RARCH_OBJ) $(libretro)
-	@$(if $(libretro), mv -f $(libretro) $(libretro_new),)
+$(libretro_new) : $(libretro)
+	mv -f $(libretro) $(libretro_new)
+
+$(TARGET): $(RARCH_OBJ) $(libretro_new)
 	@$(if $(Q), $(shell echo echo "LD $@ \<obj\> $(libretro_new) $(LIBS) $(LDFLAGS)"),)
 	$(Q)$(LD) -o $@ $(RARCH_OBJ) $(libretro_new) $(LIBS) $(LDFLAGS)
 

frontend/drivers/platform_emscripten.c

@@ -235,8 +235,8 @@ static void frontend_emscripten_get_env(int *argc, char *argv[],
          "config", sizeof(g_defaults.dirs[DEFAULT_DIR_MENU_CONFIG]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_MENU_CONTENT], user_path,
          "content", sizeof(g_defaults.dirs[DEFAULT_DIR_MENU_CONTENT]));
-   fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS], user_path,
-         "content/downloads", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS]));
+   fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS], base_path,
+         "downloads", sizeof(g_defaults.dirs[DEFAULT_DIR_CORE_ASSETS]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_PLAYLIST], user_path,
          "playlists", sizeof(g_defaults.dirs[DEFAULT_DIR_PLAYLIST]));
    fill_pathname_join(g_defaults.dirs[DEFAULT_DIR_REMAP], g_defaults.dirs[DEFAULT_DIR_MENU_CONFIG],
@@ -308,7 +308,10 @@ int main(int argc, char *argv[])
       specialHTMLTargets["!canvas"] = Module.canvas;
    });
 
+   emscripten_set_canvas_element_size("!canvas", 800, 600);
+   emscripten_set_element_css_size("!canvas", 800.0, 600.0);
    emscripten_set_main_loop(emscripten_mainloop, 0, 0);
+   emscripten_set_main_loop_timing(EM_TIMING_RAF, 1);
    rarch_main(argc, argv, NULL);
 
    return 0;

gfx/drivers_context/emscriptenegl_ctx.c

@@ -124,11 +124,9 @@ static void gfx_ctx_emscripten_destroy(void *data)
 
    if (!emscripten)
       return;
-
 #ifdef HAVE_EGL
    egl_destroy(&emscripten->egl);
 #endif
-
    free(data);
 }
 
@@ -191,7 +189,6 @@ static void *gfx_ctx_emscripten_init(void *video_driver)
 #endif
 
    return emscripten;
-
 error:
    gfx_ctx_emscripten_destroy(video_driver);
    return NULL;