Properly implement OS.alert() from script, and use xmessage on X11

core/bind/core_bind.cpp

@@ -732,6 +732,11 @@ int _OS::find_scancode_from_string(const String& p_code) const {
 	return find_keycode(p_code);
 }
 
+void _OS::alert(const String& p_alert,const String& p_title) {
+
+	OS::get_singleton()->alert(p_alert,p_title);
+}
+
 _OS *_OS::singleton=NULL;
 
 void _OS::_bind_methods() {
@@ -859,6 +864,7 @@ void _OS::_bind_methods() {
 
 	ObjectTypeDB::bind_method(_MD("set_use_file_access_save_and_swap","enabled"),&_OS::set_use_file_access_save_and_swap);
 
+	ObjectTypeDB::bind_method(_MD("alert","text","title"),&_OS::alert,DEFVAL("Alert!"));
 
 
 	BIND_CONSTANT( DAY_SUNDAY );

core/bind/core_bind.h

@@ -256,6 +256,9 @@ public:
 
 	String get_data_dir() const;
 
+	void alert(const String& p_alert,const String& p_title="ALERT!");
+
+
 	void set_screen_orientation(ScreenOrientation p_orientation);
 	ScreenOrientation get_screen_orientation() const;
 

platform/x11/os_x11.cpp

@@ -1866,6 +1866,16 @@ void OS_X11::swap_buffers() {
 	context_gl->swap_buffers();
 }
 
+void OS_X11::alert(const String& p_alert,const String& p_title) {
+
+	List<String> args;
+	args.push_back("-center");
+	args.push_back("-title");
+	args.push_back(p_title);
+	args.push_back(p_alert);
+
+	execute("/usr/bin/xmessage",args,true);
+}
 
 void OS_X11::set_icon(const Image& p_icon) {
 	if (!p_icon.empty()) {

platform/x11/os_x11.h

@@ -243,7 +243,7 @@ public:
 	virtual bool is_window_maximized() const;
 
 	virtual void move_window_to_foreground();
-
+	virtual void alert(const String& p_alert,const String& p_title="ALERT!");
 	void run();
 
 	OS_X11();