Emscripten build integration for WASM version

.gitignore

@@ -34,6 +34,12 @@
 # executable
 /GPMD85emu
 
+# WebAssembly & Emscripten
+*.wasm
+/storage
+/GPMD85emu.js
+/GPMD85emu.data
+
 # autoconf
 /autom4te.cache
 /autoscan.log

GPMD85emu.cpp

@@ -1,5 +1,5 @@
 /*	GPMD85emu.cpp: Initialization and main program loop.
-	Copyright (c) 2011-2024 Martin Borik <mborik@users.sourceforge.net>
+	Copyright (c) 2011-2025 Martin Borik <mborik@users.sourceforge.net>
 
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
@@ -21,6 +21,18 @@
 //-----------------------------------------------------------------------------
 int main(int argc, char** argv)
 {
+#ifdef __EMSCRIPTEN__
+#define PATH_WEBHOME "/home/web_user"
+#define PATH_STORAGE "/storage"
+	PathUserHome = strdup(PATH_WEBHOME);
+	PathApplication = strdup(PATH_STORAGE);
+	PathResources = (char *) malloc(strlen(PATH_STORAGE) + 1);
+	PathAppConfig = (char *) malloc(strlen(PATH_WEBHOME) + 1);
+	strcpy(PathResources, PATH_STORAGE);
+	strcpy(PathAppConfig, PATH_WEBHOME);
+
+	EmResetBlocking();
+#else
 	if (!ParseOptions(&argc, &argv))
 		return EXIT_FAILURE;
 	else if (argv_config.version) {
@@ -36,6 +48,7 @@ int main(int argc, char** argv)
 	PathAppConfig = (char *) malloc(strlen(PathUserHome) + 16);
 	strcpy(PathResources, DIR_RESOURCES);
 	sprintf(PathAppConfig, "%s%c.%s", PathUserHome, DIR_DELIMITER, PACKAGE_TARNAME);
+#endif
 
 	debug("",   "Resource path: %s", PathResources);
 	debug(NULL, "Application path: %s", PathApplication);
@@ -126,7 +139,18 @@ int main(int argc, char** argv)
 	debug("", "Starting main CPU %dHz loop", CPU_FRAMES_PER_SEC);
 
 	while (Emulator->isActive) {
+#ifdef __EMSCRIPTEN__
+	if (!EmCheckBlocking())
+		continue;
+
+	EmRegisterMainLoop([&] {
+		if (!Emulator->isActive) {
+			EmExitMainLoop();
+			return;
+		}
+#else
 		nextTick = SDL_GetTicks() + CPU_TIMER_INTERVAL;
+#endif
 
 		while (SDL_PollEvent(&event)) {
 			switch (event.type) {
@@ -214,8 +238,12 @@ int main(int argc, char** argv)
 
 		Emulator->CpuTimerCallback();
 
+#ifdef __EMSCRIPTEN__
+	});
+#else
 		while (SDL_GetTicks() < nextTick)
 			SDL_Delay(1);
+#endif
 	}
 
 	SDL_GetWindowPosition(gdc.window,

configure.ac

@@ -26,6 +26,16 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
 ]])], [clang=yes], [clang=no])
 AC_MSG_RESULT([$clang])
 
+# Add an additional flag if using Emscripten
+AC_MSG_CHECKING([if compiling with Emscripten])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
+	#ifndef __EMSCRIPTEN__
+		not emscripten
+	#endif
+]])], [emscripten=yes], [emscripten=no])
+AM_CONDITIONAL([EMSCRIPTEN], [test "x$emscripten" = "xyes"])
+AC_MSG_RESULT([$emscripten])
+
 # Check if we have enabled debug mode:
 AC_MSG_CHECKING([gpmd85emu: Debug mode])
 AC_ARG_ENABLE([debug],
@@ -85,8 +95,18 @@ if test "x$softrender" = "xyes"; then
 fi
 AC_MSG_RESULT([${softrender}])
 
-resDir_CFLAGS=" -DDIR_RESOURCES=\"\\\""$\{pkgdatadir}"\\\"\""
-AC_SUBST(resDir_CFLAGS)
+if test "x$emscripten" = "xyes"; then
+AC_MSG_RESULT([override gpmd85emu: Software renderer... yes for Emscripten])
+	CXXFLAGS+=" -DSOFTRENDER -s USE_SDL=2"
+	CFLAGS+=" -DSOFTRENDER -s USE_SDL=2"
+	LDFLAGS+=" -Oz \
+	-s ENVIRONMENT=web \
+	-s ALLOW_MEMORY_GROWTH=1 \
+	-s OFFSCREEN_FRAMEBUFFER=1 \
+	--use-preload-plugins --preload-file ./storage"
+	EXEEXT=".js"
+else
+	resDir_CFLAGS=" -DDIR_RESOURCES=\"\\\""$\{pkgdatadir}"\\\"\""
 
 # Checks for libraries (with classic lib/header solution if pkg-config fail):
 PKG_CHECK_MODULES([libSDL], [sdl2],, [
@@ -100,6 +120,15 @@ PKG_CHECK_MODULES([libSDL], [sdl2],, [
 	], AC_MSG_ERROR([SDL2 library not found]))
 ])
 
+# NOTICE: In case of compile error with missing malloc() / realloc() functions,
+#         you can try to set enviroment variables 'ac_cv_func_malloc_0_nonnull'
+#         and 'ac_cv_func_realloc_0_nonnull' to 'yes' and reconfigure.
+AC_FUNC_MALLOC
+AC_FUNC_REALLOC
+AC_FUNC_ERROR_AT_LINE
+fi
+
+AC_SUBST(resDir_CFLAGS)
 AC_SUBST(CXXFLAGS)
 AC_SUBST(CFLAGS)
 AC_SUBST(DEBUG)
@@ -108,7 +137,7 @@ AC_SUBST(DEBUG)
 AC_CHECK_HEADERS([\
 	stdio.h stdarg.h stddef.h stdint.h stdlib.h unistd.h \
 	inttypes.h memory.h string.h strings.h \
-	sys/syslimits.h \
+	sys/syslimits.h sys/stat.h sys/types.h \
 ])
 
 AC_HEADER_STAT
@@ -118,13 +147,6 @@ AC_HEADER_STDBOOL
 AC_C_BIGENDIAN
 AC_C_INLINE
 
-# NOTICE: In case of compile error with missing malloc() / realloc() functions,
-#         you can try to set enviroment variables 'ac_cv_func_malloc_0_nonnull'
-#         and 'ac_cv_func_realloc_0_nonnull' to 'yes' and reconfigure.
-AC_FUNC_MALLOC
-AC_FUNC_REALLOC
-AC_FUNC_ERROR_AT_LINE
-
 # Checks for standard library functions:
 AC_CHECK_FUNCS([memset mkdir strstr strtol strcasecmp strrchr])
 

globals.h

@@ -188,6 +188,25 @@ enum TDebugListSource { MEM, HL, DE, BC, AF, SP, PC };
 // screen offsets of top-left -> bottom-right corner
 typedef struct TDrawRegion { WORD tl, br; } TDrawRegion;
 //-----------------------------------------------------------------------------
+#ifdef __EMSCRIPTEN__
+	// WebAssembly modifications using emscripten
+	#include <emscripten.h>
+	#include <functional>
+	static std::function<void()> EmMainLoopRef;
+	static std::function<bool()> EmCheckBlockingRef;
+	inline void EmMainLoopImpl() { EmMainLoopRef(); }
+	inline bool EmCheckBlocking() { return EmCheckBlockingRef(); }
+	inline void EmResetBlocking() { EmCheckBlockingRef = [] { return true; }; }
+	inline void EmSetBlocking(std::function<bool()> checker) {
+		EmCheckBlockingRef = checker;
+	}
+	inline void EmRegisterMainLoop(std::function<void()> loop) {
+		EmMainLoopRef = loop;
+		emscripten_set_main_loop(EmMainLoopImpl, CPU_TIMER_INTERVAL, true);
+	}
+	inline void EmExitMainLoop() { emscripten_cancel_main_loop(); }
+#endif
+//-----------------------------------------------------------------------------
 static char msgbuffer[1024];
 //-----------------------------------------------------------------------------
 inline void error(const char *ns, const char *msg, ...)

gui/CommonDialog.cpp

@@ -117,8 +117,14 @@ void UserInterface::AboutDialog()
 	DWORD nextTick;
 	SDL_Event event;
 
+#ifdef __EMSCRIPTEN__
+	EmSetBlocking([&] { return (i == 0); });
+	EmExitMainLoop();
+	EmRegisterMainLoop([&] {
+#else
 	while (i) {
 		nextTick = SDL_GetTicks() + CPU_TIMER_INTERVAL;
+#endif
 
 		while (SDL_PollEvent(&event)) {
 			switch (event.type) {
@@ -149,9 +155,13 @@ void UserInterface::AboutDialog()
 			}
 		}
 
+#ifdef __EMSCRIPTEN__
+	});
+#else
 		while (SDL_GetTicks() < nextTick)
 			SDL_Delay(1);
 	}
+#endif
 
 	defaultSurface = LockSurface(defaultTexture);
 
@@ -168,6 +178,10 @@ void UserInterface::AboutDialog()
 
 	SDL_Delay(GPU_TIMER_INTERVAL);
 	needRelease = true;
+
+#ifdef __EMSCRIPTEN__
+	EmResetBlocking();
+#endif
 }
 //-----------------------------------------------------------------------------
 BYTE UserInterface::QueryDialog(const char *title, bool save)

gui/UserInterfaceData.h

@@ -218,7 +218,9 @@ static GUI_MENU_ENTRY gui_view_size_menu[] = {
 	{ MI_RADIO, "\a300%", "3", SDL_SCANCODE_3, NULL, ccb_view_size, dcb_view_size_state, true, false, DM_TRIPLESIZE },
 	{ MI_RADIO, "\a400%", "4", SDL_SCANCODE_4, NULL, ccb_view_size, dcb_view_size_state, true, false, DM_QUADRUPLESIZE },
 	{ MI_RADIO, "\a500%", "5", SDL_SCANCODE_5, NULL, ccb_view_size, dcb_view_size_state, true, false, DM_QUINTUPLESIZE },
+#ifndef __EMSCRIPTEN__
 	{ MI_RADIO, "\aFULLSCREEN", "F", SDL_SCANCODE_F, NULL, ccb_view_size, dcb_view_size_state, true, false, DM_FULLSCREEN },
+#endif
 	{ MENU_END }
 };
 static GUI_MENU_ENTRY gui_view_cmode_menu[] = {
@@ -421,7 +423,9 @@ static GUI_MENU_ENTRY UNUSED_VARIABLE gui_main_menu[] = {
 	{ MI_DIALOG, "P\aOKE", NULL, SDL_SCANCODE_O, NULL, NULL, NULL, false },
 	{ MI_SEPARATOR },
 	{ MI_DIALOG, "\aABOUT", "^F1", SDL_SCANCODE_A, NULL, ccb_about, NULL, true },
+#ifndef __EMSCRIPTEN__
 	{ MI_STANDARD, "E\aXIT", "F4", SDL_SCANCODE_X, NULL, ccb_exit, NULL, true },
+#endif
 	{ MENU_END }
 };
 //-----------------------------------------------------------------------------

res/Makefile.am

@@ -8,6 +8,15 @@ RES = \
 	icon.bmp \
 	statusbar.bmp
 
+if EMSCRIPTEN
+bin_SCRIPTS = .emcpy
+CLEANFILES = $(bin_SCRIPTS)
+.emcpy:
+	@echo "Copying resource files to WASM storage"
+	@cp $(RES) ../storage
+	@touch $@
+endif
+
 pkgdata_DATA = $(RES)
 
 EXTRA_DIST = $(RES)

rom/Makefile.am

@@ -36,6 +36,16 @@ ROM = \
 	sach1.rmm \
 	wurmi.rmm
 
+if EMSCRIPTEN
+bin_SCRIPTS = .emcpy
+CLEANFILES = $(bin_SCRIPTS)
+.emcpy:
+	@echo "Copying ROM files to WASM storage/rom/"
+	@mkdir -p ../storage/rom
+	@cp $(ROM) ../storage/rom/
+	@touch $@
+endif
+
 pkgdata_DATA = $(ROM)
 
 EXTRA_DIST = $(ROM) README.md

src/Emulator.cpp

@@ -699,13 +699,15 @@ bool TEmulator::TestHotkeys()
 				Settings->Screen->halfPass = HP_OFF;
 				break;
 
+#ifndef __EMSCRIPTEN__
 			case SDL_SCANCODE_F:	// FULL-SCREEN
 			case SDL_SCANCODE_RETURN:
 				if (Settings->Screen->size == DM_FULLSCREEN)
 					ActionSizeChange((int) Settings->Screen->realsize);
 				else
 					ActionSizeChange(0);
 				return true;
+#endif
 
 			case SDL_SCANCODE_M:	// MONO/STANDARD MODES
 				if (video->GetColorProfile() == CP_STANDARD) {
@@ -760,9 +762,11 @@ bool TEmulator::TestHotkeys()
 					ActionPlayPause();
 				break;
 
+#ifndef __EMSCRIPTEN__
 			case SDL_SCANCODE_F4:	// EXIT
 				ActionExit();
 				break;
+#endif
 
 			case SDL_SCANCODE_F5:	// RESET
 				if (key & KM_SHIFT)