Merge pull request #64101 from timothyqiu/subsecond

core/os/os.cpp

@@ -86,6 +86,9 @@ uint64_t OS::get_system_time_secs() const {
 uint64_t OS::get_system_time_msecs() const {
 	return 0;
 }
+double OS::get_subsecond_unix_time() const {
+	return 0.0;
+}
 void OS::debug_break(){
 
 	// something

core/os/os.h

@@ -437,6 +437,7 @@ public:
 	virtual uint64_t get_unix_time() const;
 	virtual uint64_t get_system_time_secs() const;
 	virtual uint64_t get_system_time_msecs() const;
+	virtual double get_subsecond_unix_time() const; // For use in Time::get_unix_time().
 
 	virtual void delay_usec(uint32_t p_usec) const = 0;
 	virtual void add_frame_delay(bool p_can_draw);

core/os/time.cpp

@@ -392,7 +392,7 @@ Dictionary Time::get_time_zone_from_system() const {
 }
 
 double Time::get_unix_time_from_system() const {
-	return OS::get_singleton()->get_unix_time();
+	return OS::get_singleton()->get_subsecond_unix_time();
 }
 
 uint64_t Time::get_ticks_msec() const {

doc/classes/OS.xml

@@ -552,6 +552,7 @@
 			<description>
 				Returns the current UNIX epoch timestamp in seconds.
 				[b]Important:[/b] This is the system clock that the user can manually set. [b]Never use[/b] this method for precise time calculation since its results are also subject to automatic adjustments by the operating system. [b]Always use[/b] [method get_ticks_usec] or [method get_ticks_msec] for precise time calculation instead, since they are guaranteed to be monotonic (i.e. never decrease).
+				[b]Note:[/b] To get a floating point timestamp with sub-second precision, use [method Time.get_unix_time_from_system].
 			</description>
 		</method>
 		<method name="get_unix_time_from_datetime" qualifiers="const">

drivers/unix/os_unix.cpp

@@ -172,6 +172,12 @@ uint64_t OS_Unix::get_system_time_msecs() const {
 	return uint64_t(tv_now.tv_sec) * 1000 + uint64_t(tv_now.tv_usec) / 1000;
 }
 
+double OS_Unix::get_subsecond_unix_time() const {
+	struct timeval tv_now;
+	gettimeofday(&tv_now, nullptr);
+	return (double)tv_now.tv_sec + double(tv_now.tv_usec) / 1000000;
+}
+
 OS::Date OS_Unix::get_date(bool utc) const {
 	time_t t = time(nullptr);
 	struct tm lt;

drivers/unix/os_unix.h

@@ -80,6 +80,7 @@ public:
 	virtual uint64_t get_unix_time() const;
 	virtual uint64_t get_system_time_secs() const;
 	virtual uint64_t get_system_time_msecs() const;
+	virtual double get_subsecond_unix_time() const;
 
 	virtual void delay_usec(uint32_t p_usec) const;
 	virtual uint64_t get_ticks_usec() const;

platform/uwp/os_uwp.cpp

@@ -547,6 +547,23 @@ uint64_t OS_UWP::get_unix_time() const {
 	return (*(uint64_t *)&ft - *(uint64_t *)&fep) / 10000000;
 };
 
+double OS_UWP::get_subsecond_unix_time() const {
+	// 1 Windows tick is 100ns
+	const uint64_t WINDOWS_TICKS_PER_SECOND = 10000000;
+	const uint64_t TICKS_TO_UNIX_EPOCH = 116444736000000000LL;
+
+	SYSTEMTIME st;
+	GetSystemTime(&st);
+	FILETIME ft;
+	SystemTimeToFileTime(&st, &ft);
+	uint64_t ticks_time;
+	ticks_time = ft.dwHighDateTime;
+	ticks_time <<= 32;
+	ticks_time |= ft.dwLowDateTime;
+
+	return (double)(ticks_time - TICKS_TO_UNIX_EPOCH) / WINDOWS_TICKS_PER_SECOND;
+}
+
 void OS_UWP::delay_usec(uint32_t p_usec) const {
 	int msec = p_usec < 1000 ? 1 : p_usec / 1000;
 

platform/uwp/os_uwp.h

@@ -193,6 +193,7 @@ public:
 	virtual Time get_time(bool utc) const;
 	virtual TimeZoneInfo get_time_zone_info() const;
 	virtual uint64_t get_unix_time() const;
+	virtual double get_subsecond_unix_time() const;
 
 	virtual bool can_draw() const;
 	virtual Error set_cwd(const String &p_cwd);

platform/windows/os_windows.cpp

@@ -2584,6 +2584,23 @@ uint64_t OS_Windows::get_system_time_msecs() const {
 	return (uint64_t)(ret / WINDOWS_TICK - MSEC_TO_UNIX_EPOCH);
 }
 
+double OS_Windows::get_subsecond_unix_time() const {
+	// 1 Windows tick is 100ns
+	const uint64_t WINDOWS_TICKS_PER_SECOND = 10000000;
+	const uint64_t TICKS_TO_UNIX_EPOCH = 116444736000000000LL;
+
+	SYSTEMTIME st;
+	GetSystemTime(&st);
+	FILETIME ft;
+	SystemTimeToFileTime(&st, &ft);
+	uint64_t ticks_time;
+	ticks_time = ft.dwHighDateTime;
+	ticks_time <<= 32;
+	ticks_time |= ft.dwLowDateTime;
+
+	return (double)(ticks_time - TICKS_TO_UNIX_EPOCH) / WINDOWS_TICKS_PER_SECOND;
+}
+
 void OS_Windows::delay_usec(uint32_t p_usec) const {
 	if (p_usec < 1000)
 		Sleep(1);

platform/windows/os_windows.h

@@ -520,6 +520,7 @@ public:
 	virtual uint64_t get_unix_time() const;
 	virtual uint64_t get_system_time_secs() const;
 	virtual uint64_t get_system_time_msecs() const;
+	virtual double get_subsecond_unix_time() const;
 
 	virtual bool can_draw() const;
 	virtual Error set_cwd(const String &p_cwd);