Creating Timers and Delayed Events

Sometimes you want something to start on a delay or run some script at a time in the future. To do this, we can use a timer. Timers are created via the global Animator's 'createTimer()' function.

Here's a simple example of calling a function a few moments after an event fires:

function Trigger:onEnter(obj)
	getAnimator():createTimer(self, self.onTimeOut, seconds(2))
end

function Trigger:onTimeOut()
	print("Time's up!")
end

In this example, when an object passes through the Trigger and causes the 'onEnter()' event to fire, a timer is created that will wait 2 seconds, then call the Trigger's own 'onTimeOut()' function that, in this case, prints a message. Notice that for the second argument of 'createTimer()' we pass in a function as an object, hence the '.' (i.e. self.onTimeOut) and not ':' (i.e. self:onTimeOut). The ':' would signify to call the 'onTimeOut()' function, which is not what we want here.

Here's another example of creating a Trigger that creates a timer when the player enters it that requires you to reach a different Trigger in a set amount of time or else the object is deactivated. Here's the code for Trigger 1:

-- To store our object during the timer wait time
Trigger.objToRemove = nil

-- Function to stop the timer. Called by the other Trigger if
-- our object makes it there in time
function Trigger:stopTimer()

	-- Verify we are running a timer
	if (not self.objToRemove) then
		return
	end

	-- Clear out our variable stored in the object
	self.objToRemove.startTrigger = nil
	-- Stop the timer so it doesnt call our onTimeOut() function
	getAnimator():stopTimer(self, self.onTimeOut)
	-- Reactivate us so we can pass another object through
	self.active = true
	-- Clear state
	self.objToRemove = nil
end

-- Called when an object enters the trigger
function Trigger:onEnter(obj)
	-- Deactivate us so this Trigger can't be re-triggered until the timer is stopped
	self.active = false
	-- Store our object so we can refer to it in our onTimeOut function
	self.objToRemove = obj
	-- Store this trigger inside the object so the other trigger can find us and stop
	-- the timer when the object enters it
	obj.startTrigger = self
	-- Create our timer. After 2 seconds, it will call our onTimeOut() function
	getAnimator():createTimer(self, self.onTimeOut, seconds(2))
end

-- Function called when the timer's timeout is reached
function Trigger:onTimeOut()
	-- Remove the object from the space
	self.objToRemove:fadeOutAndOrphan()
	-- Reactivate us so we can handle another object
	self.active = true
end

Here's the code for Trigger 2:

function Trigger:onEnter(obj)
	-- Check to see if the object passing in has our start timer object
	-- which means the timer is currently active
	if (exists(obj.startTrigger)) then
		obj.startTrigger:stopTimer()
	end
end

The main part of the example is the Animator's 'createTimer()' and 'stopTimer()' functions. With these functions, we can have the Animator call a function in the future. In the above example our future called function removes the object from the space if it isn't stopped in time.

Made It In Time

Did Not Make It In Time