Enable the volume controller dialog on Emscripten

Export volume_dialog_open() so the web shell can open it, and add
modal_run to ASYNCIFY_ADD since it drives an async loop.

src/CMakeLists.txt

@@ -73,8 +73,10 @@ target_sources(xsystem35 PRIVATE
   jpeg.c
   menu.c
   message.c
+  microui/microui.c
   midi.c
   mmap.c
+  modal.c
   msgskip.c
   mt19937-1.c
   music.c
@@ -93,6 +95,7 @@ target_sources(xsystem35 PRIVATE
   system.c
   texthook.c
   variable.c
+  volume.c
   vsp.c
   xsystem35.c
   )
@@ -120,11 +123,6 @@ else()
   endif()
 endif()
 
-if (NOT EMSCRIPTEN)
-  target_sources(xsystem35 PRIVATE
-    modal.c microui/microui.c volume.c)
-endif()
-
 if (HAVE_WEBP)
   target_sources(xsystem35 PRIVATE webp.c)
   target_link_libraries(xsystem35 PRIVATE WebP)
@@ -167,7 +165,7 @@ if (EMSCRIPTEN)
     # Functions that call an asynchronous function via a function pointer must
     # be added to ASYNCIFY_ADD, even if it had a direct call to another
     # asynchronous function, so that the indirect call itself is instrumented.
-    -sASYNCIFY_ADD=commands2F60,nact_main,send_agsevent,cb_waitkey_sprite
+    -sASYNCIFY_ADD=commands2F60,nact_main,send_agsevent,cb_waitkey_sprite,modal_run
     -sALLOW_MEMORY_GROWTH=1
     -sNO_EXIT_RUNTIME=1
     -sEXPORTED_FUNCTIONS=_main,_malloc

src/menu.c

@@ -41,10 +41,6 @@ void menu_init(void) {
 	return;
 }
 
-void menu_render_overlay(void) {
-	return;
-}
-
 EM_JS(void, menu_setSkipState, (bool enabled, bool activated), {
 	xsystem35.shell.setSkipButtonState(enabled, activated);
 });

src/modal.c

@@ -24,6 +24,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <SDL.h>
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
 
 #include "event.h"
 #include "font.h"
@@ -290,6 +293,7 @@ static bool modal_event_trampoline(const SDL_Event *e) {
 	return current_modal->handler(e, current_modal);
 }
 
+EMSCRIPTEN_KEEPALIVE  // Prevent inlining, because this function is listed in ASYNCIFY_ADD
 void modal_run(modal *m) {
 	assert(!ctx);  // modals are not nestable
 	ctx = calloc(1, sizeof(*ctx));

src/volume.c

@@ -24,6 +24,9 @@
 
 #include <stdio.h>
 #include <string.h>
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
 #include "portab.h"
 #include "system.h"
 #include "nact.h"
@@ -215,6 +218,7 @@ static bool volume_build(mu_Context *ctx, modal *modal) {
 	return keep_open;
 }
 
+EMSCRIPTEN_KEEPALIVE
 void volume_dialog_open(void) {
 	struct volume_state st = {
 		.base = { .build = volume_build, .handler = modal_default_handler },

src/xsystem35.c

@@ -40,10 +40,6 @@
 #include <emscripten.h>
 #endif
 
-#ifndef __EMSCRIPTEN__
-#define HAVE_VOLUME_VALANCER 1
-#endif
-
 #include "nact.h"
 #include "debugger.h"
 #include "portab.h"
@@ -503,9 +499,7 @@ int main(int argc, char **argv) {
 	if (integer_scaling)
 		gfx_setIntegerScaling(true);
 
-#ifdef HAVE_VOLUME_VALANCER
 	volume_init();
-#endif
 	menu_init();
 	
 	if (debugger_mode != DEBUGGER_DISABLED) {