EMSCRIPTEN: Merging parts of scummvm/scummvm#3686 for fullscreen support, disabling exit buttons (openURL has been fixed in libsdl-org/SDL@15ebad6e7d and is not needed anymore)

backends/platform/sdl/emscripten/emscripten-main.cpp

@@ -0,0 +1,50 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "common/scummsys.h"
+
+#if defined(__EMSCRIPTEN__) 
+#include "backends/platform/sdl/emscripten/emscripten.h"
+#include "backends/plugins/sdl/sdl-provider.h"
+#include "base/main.h"
+
+int main(int argc, char *argv[]) {
+
+	// Create our OSystem instance
+	g_system = new OSystem_Emscripten();
+	assert(g_system);
+
+	// Pre initialize the backend
+	g_system->init();
+
+#ifdef DYNAMIC_MODULES
+	PluginManager::instance().addPluginProvider(new SDLPluginProvider());
+#endif
+
+	// Invoke the actual ScummVM main entry point:
+	int res = scummvm_main(argc, argv);
+
+	// Free OSystem
+	g_system->destroy();
+
+	return res;
+}
+#endif

backends/platform/sdl/emscripten/emscripten.cpp

@@ -0,0 +1,71 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifdef __EMSCRIPTEN__
+
+
+#define FORBIDDEN_SYMBOL_EXCEPTION_FILE
+#include <emscripten.h>
+
+#include "backends/platform/sdl/emscripten/emscripten.h"
+
+// Inline JavaScript, see https://emscripten.org/docs/api_reference/emscripten.h.html#inline-assembly-javascript for details
+EM_JS(bool, isFullscreen, (), {
+	return !!document.fullscreenElement;
+});
+
+EM_JS(void, toggleFullscreen, (bool enable), {
+	let canvas = document.getElementById('canvas');
+	if (enable && !document.fullscreenElement) {
+		canvas.requestFullscreen();
+	}
+	if (!enable && document.fullscreenElement) {
+		document.exitFullscreen();
+	}
+});
+
+
+// Overridden functions
+bool OSystem_Emscripten::hasFeature(Feature f) {
+	if (f == kFeatureFullscreenMode)
+		return true;
+	if (f == kFeatureNoQuit)
+		return true;
+	return OSystem_POSIX::hasFeature(f);
+}
+
+bool OSystem_Emscripten::getFeatureState(Feature f) {
+	if (f == kFeatureFullscreenMode) {
+		return isFullscreen();
+	} else {
+		return OSystem_POSIX::getFeatureState(f);
+	}
+}
+
+void OSystem_Emscripten::setFeatureState(Feature f, bool enable) {
+	if (f == kFeatureFullscreenMode) {
+		toggleFullscreen(enable);
+	} else {
+		OSystem_POSIX::setFeatureState(f, enable);
+	}
+}
+
+#endif

backends/platform/sdl/emscripten/emscripten.h

@@ -0,0 +1,35 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef PLATFORM_SDL_EMSCRIPTEN_H
+#define PLATFORM_SDL_EMSCRIPTEN_H
+
+#include "backends/platform/sdl/posix/posix.h"
+
+class OSystem_Emscripten : public OSystem_POSIX {
+public:
+	bool hasFeature(Feature f) override;
+	void setFeatureState(Feature f, bool enable) override;
+	bool getFeatureState(Feature f) override;
+
+};
+
+#endif

backends/platform/sdl/module.mk

@@ -72,6 +72,12 @@ MODULE_OBJS += \
 	switch/switch.o
 endif
 
+ifdef EMSCRIPTEN
+MODULE_OBJS += \
+	emscripten/emscripten-main.o \
+	emscripten/emscripten.o
+endif
+
 # We don't use rules.mk but rather manually update OBJS and MODULE_DIRS.
 MODULE_OBJS := $(addprefix $(MODULE)/, $(MODULE_OBJS))
 OBJS := $(MODULE_OBJS) $(OBJS)

backends/platform/sdl/posix/posix-main.cpp

@@ -21,7 +21,7 @@
 
 #include "common/scummsys.h"
 
-#if defined(POSIX) && !defined(MACOSX) && !defined(SAMSUNGTV) && !defined(MAEMO) && !defined(GPH_DEVICE) && !defined(GP2X) && !defined(DINGUX) && !defined(OPENPANDORA) && !defined(PLAYSTATION3) && !defined(PSP2) && !defined(NINTENDO_SWITCH)
+#if defined(POSIX) && !defined(MACOSX) && !defined(SAMSUNGTV) && !defined(MAEMO) && !defined(GPH_DEVICE) && !defined(GP2X) && !defined(DINGUX) && !defined(OPENPANDORA) && !defined(PLAYSTATION3) && !defined(PSP2) && !defined(NINTENDO_SWITCH)  && !defined(__EMSCRIPTEN__)
 
 #include "backends/platform/sdl/posix/posix.h"
 #include "backends/plugins/sdl/sdl-provider.h"

configure

@@ -2900,6 +2900,10 @@ EOF
 		_freetype_found="true"
 		if test "$_debug_build" = no; then
 			_optimization_level=-O3 -g4
+	
+		append_var DEFINES "-DEMSCRIPTEN"
+		add_line_to_config_mk 'EMSCRIPTEN = 1'
+
 		else
 			_optimization_level=-O2
 		fi