SHIP:Node:timer

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Animations and delayed events or pauses require periodic or one-shot timers. The timer node fills this need in Template:SHIP.

The timer node is a 0.1s resolution event timer which can be set up to be free running or one-shot, with an auto-reload capability.

Parent Nodes

The following nodes are permitted to hold this node:

• box
• display
• group
• text
• page
• variable

Child Nodes

The following nodes are permitted to exist within this node:

• constant
• listener
• variable

Properties

Property	Data Type	Description
SHIP:Property:timer:name
enabled	Boolean	If true (default if unset) this timer is enabled.
alarm*	Boolean	Set to true at run-time when a timer's count value transitions from 1 to 0.
autoreload	Boolean	Determines whether or not period will be loaded into value automatically after it expires.
oneshot	Boolean	If set, the timer will stop when the count value is zero and self-set the enabled property to false
period	Integer	Value used by a timer to reload the countdown value after the timer has expired.
value	Integer	Remaining count-down value, in 10ths of a second, of the timer

*available at SHIPEngine run time only and cannot be set in SHIPTide. Use a Sail script at shiplaunch time if this property needs to be set when the GUI starts to run.

**available only in SHIPTide; cannot be accessed from Sail scripts at run-time.

Operation

The timer is a 0.1s resolution event timer which can be set up to be free-running or one-shot, with an auto-reload capability. The timer's value property represents the current remaining time on the given timer, in tenths of a seconds. For example, if the timer.value is 34, there are 3.4 seconds left on the timer before it hits 0.

When enabled is set to true and the timer.value property is non-zero, the timer begins to count down, with the value property decrementing ever 0.1Hz. On a count value transition from 1 to 0 (the timer expires), the alarm property is set to true. The alarm must be manually reset (set to false) by a Sail script.

In the majority of designs, a listener is attached to the alarm. When the alarm goes Template:Reference the associated script action is taken, often including restarting the timer.

The oneshot and autoreload Properties

A "one shot" timer stops when it has completed its count. The opposite of a one shot timer is a "free running" timer which, when it competes its count, automatically restarts counting in a "free running" mode. The timer node supports both types of operation based on the oneshot value.

When a timer expires and the oneshot property is true, the timer.enabled property is set to false, stopping the timer. Hence the term "one shot", since the timer is now halted and must be re-configured and re-started manually from a Sail script.

However when a timer expires and all the following conditions are true:

• oneshot is set to false (expressing a desire to be a free-running timer)
• autoreload is set to true
• the reload period is set to a value greater than zero

then

• enabled is kept unchanged (true)
• value will be automatically reloaded from period
• and the timer will restart counting down.

This is the free-running mode of the timer.

In both one-shot and free-running modes, care must be taken to clear the alarm property in a Sail script before the next alarm or the next alarm event may be missed.

Examples

Animation Timers

Here is a complete example of a timer, including an associated listener and script which increment a variable every 0.3 seconds:

In this example, the timer is set up as a oneshot with a 0.3 second period. Each time the alarm goes true, the listener awakes and runs the script. The script increments a Short variable named animationCounter.

animationCounter can now be the foundation for numerous listeners throughout the GUI. They will wake up every time animationCounter increments (once every 0.3 seconds) and can use the value to determine which animation image needs to be displayed. For example, if a given animation is composed of 3 cycling images, (animationCounter % 3) could be used in a switch statement to select and display the correct image in the cycle.