System

The System` class provides essential utilities for managing time, performance metrics, browser information, and interpolation logic within a Lua environment, facilitating tasks such as accurately track gameplay duration, manage asynchronous operations, smoothly transition values over time, and adapt behaviors based on the device the game is running on.

Usage

To use this module, add the following require at the top of your script:

local System = require 'engine/system'

Reference

system.getPerformanceNow()

Returns a high precision timestamp in milliseconds

Returns:

Time in milliseconds

Return type:

number

system.getTime()

Returns the amount of milliseconds passed since start of playback

Returns:

Player time in milliseconds

Return type:

number

system.getDeltaTime()

Returns the current player delta time between frames in milliseconds

Returns:

Player delta time in milliseconds

Return type:

number

system.getGameTime()

Returns the current game time. This will usually be identical to getTime() except if there were pauses in the game, then the game time will be a smaller number

Returns:

Player delta time in milliseconds

Return type:

number

system.getDeltaGameTime()

Returns the current game delta time between frames in milliseconds

Returns:

Game delta time in milliseconds

Return type:

number

system.sleep(ms)

Waits for a given time in milliseconds

Parameters:

ms (number) – time in milliseconds

Returns:

Returns a promise that will fulfill after the time has passed

Return type:

Promise

system.interpolate(startValue, endValue, duration, callback, doneCallback)

Interpolates between startValue and endValue for duration seconds and will call the callback function

Parameters:

  • startValue (number) – the start value to interpolate from

  • endValue (number) – the end value to interpolate to

  • duration (number) – the amount of seconds to take to interpolate

  • callback (function) – the function to call. the only parameter this gets is the interpolated value

  • doneCallback (function) – the function to call when interpolation is done. this param is optional

system.getUserAgentString()

Returns the full user agent string of the browser.

Returns:

The full user agent string.

Return type:

str

Usage:

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local uaString = System.getUserAgentString()
print("User Agent:", uaString)
system.getUserAgentName()

Returns the name of the browser being used.

Possible return values: “Firefox” “Chrome” “Safari” “Edge” “Opera” “Internet Explorer” “Unknown”

Returns:

The name of the browser.

Return type:

str

Usage:

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local browser = System.getUserAgentName()
print("Browser Name:", browser)
system.isMobileDevice()

Determines if the current device is a mobile device.

Returns:

true if the device is a mobile phone or tablet, otherwise false.

Return type:

boolean

Usage:

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if System.isMobileDevice() then
    print("Running on a mobile device")
else
    print("Running on a desktop device")
end
system.isTouchDevice()

Determines if the current device supports touch input.

This is useful for games that need to handle touch events differently from mouse events.

Returns:

true if the device supports touch input, otherwise false.

Return type:

boolean

Usage:

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if System.isTouchDevice() then
    print("Touch input available")
end
system.getDeviceType()

Returns the type of device the user is running on.

Possible return values: “Mobile” (Phones, tablets, etc.) “Desktop” (Laptops, PCs)

Returns:

“Mobile” or “Desktop”, based on device detection.

Return type:

str

Usage:

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print("Device Type:", System.getDeviceType())

Examples

Retrieve playtime
local System = require 'engine/system'
local Console = require 'engine/console'

local time = System.getTime()
Console.log(time)
Sleep for a while
local System = require 'engine/system'
local Console = require 'engine/console'

Console.log("Going to sleep for a second...")
System.sleep(1000):next(function()
    Console.log("Hello again!")
end)
Block lifecycle hook until promise is resolved
local System = require 'engine/system'
local Console = require 'engine/console'

function init()
    Console.log("Going to sleep for a second...")

    -- Mark this promise as blocking, so init() is not returned from unless this promise is also fulfilled.
    -- This can be either done through System.markPromiseAsBlocking() or on the promise itself with :markAsBlocking()
    System.sleep(1000):next(function()
        Console.log("Hello again!")
    end):markAsBlocking()
end

function render()
    -- This will not execute until the sleep promise has fulfilled
end