Merge pull request #839 from MihailRis/precise-time-in-lua

Precise time in lua

doc/en/scripting/builtins/libtime.md

@@ -1,13 +1,21 @@
-# *time* library
+# *time* Library
 
-```python
-time.uptime() -> float
+```lua
+-- Returns the time since engine startup in seconds and milliseconds.
+time.uptime() -> number
+
+-- Returns the time delta in seconds and milliseconds (time elapsed since the previous frame)
+time.delta() -> number
+
+-- Returns UTC time in seconds
+time.utc_time() -> int
+
+-- Returns local (system) time in seconds
+time.local_time() -> int
+
+-- Returns the local time offset from UTC in seconds
+time.utc_offset() -> int
+
+-- Returns high-precision time in seconds (elapsed since the engine startup).
+time.precise_time() -> number
 ```
-
-Returns time elapsed since the engine started.
-
-```python
-time.delta() -> float
-```
-
-Returns time elapsed since the last frame.

doc/ru/scripting/builtins/libtime.md

@@ -15,4 +15,7 @@ time.local_time() -> int
 
 -- Возвращает смещение локального времени от UTC в секундах
 time.utc_offset() -> int
+
+-- Возвращает время высокой точности в секундах. За точку отсчёта берётся запуск движка.
+time.precise_time() -> number
 ```

src/logic/scripting/lua/libs/libtime.cpp

@@ -62,11 +62,20 @@ static int l_utc_offset(lua::State* L) {
     return lua::pushnumber(L, offset);
 }
 
+static auto start_time = std::chrono::steady_clock::now();
+
+static int l_precise_time(lua::State* L) {
+    auto time = std::chrono::steady_clock::now();
+    std::chrono::duration<double> delta = time - start_time;
+    return lua::pushnumber(L, delta.count());
+}
+
 const luaL_Reg timelib[] = {
     {"uptime", lua::wrap<l_uptime>},
     {"delta", lua::wrap<l_delta>},
     {"utc_time", lua::wrap<l_utc_time>},
     {"utc_offset", lua::wrap<l_utc_offset>},
     {"local_time", lua::wrap<l_local_time>},
+    {"precise_time", lua::wrap<l_precise_time>},
     {nullptr, nullptr}
 };