System conditions

This section describes all the conditions in the built-in System object in Construct 2. They are listed in the order they appear in the Add Condition dialog.

General

Compare two values
Compare any two expressions (which can either numbers or text) with each other. They can be compared as Equal, Not equal, Less, Less or equal, Greater or Greater or equal.

Every tick
A condition which is always true. Used on its own, this has the same effect as running every time it is checked, which is once per tick, hence the name "Every tick". This is about 60 times a second on most computers; see how events work for more information. Adding Every tick to an event with other conditions is redundant and has no effect at all.

Is between values
Test if a number is between two values (greater or equal to a lower value and less or equal to a higher value).

Is group active
Test if a group of events is active or inactive. The name of the group is used to identify it.

Global & local variables

Compare variable
Compare the value of a event variable (a global variable or local variable in scope). Event variables can store both numbers and text. The comparison can be made Equal, Not equal, Less, Less or equal, Greater or Greater or equal.

Layers

Compare opacity
Compare the opacity (or semitransparency) of a layer, from 0 (transparent) to 100 (opaque). A layer's opacity cannot be outside this range.

Layer is visible
Test if a layer is currently visible or not.

Loops

Loops can be stopped with the Stop Loop system action.

For
Repeat the event a number of times, using an index variable over a range of values. The index can be retrieved with the LoopIndex system expression and passing the name of the loop.

For Each
For Each (ordered)
Repeat the event once per picked instance. This only repeats for instances that have been picked by prior conditions. See how events work for more information on picking. For Each is commonly mis-used or used redundantly - actions already apply for each instance picked by conditions, so it often is simply not needed. However, if you fully understand how the event system works, it can be used to force the event to apply once per instance where the event system would not normally do that. The 'ordered' variant allows the order that the instances are iterated in to be defined by an expression. For example, ordering by Sprite.Y ascending will iterate the top instances on the screen first, moving downwards.

Repeat
Simply repeat the event a given number of times. This tests any conditions following it on every repeat, and if those conditions are met also runs the actions and any sub-events on every repeat.

While
Repeat the event until one of the other conditions in the event becomes false or a Stop loop action is used. Be careful not to create infinite loops which will cause the game to hang.

Pick instances

Pick all
Reset the picked objects back to all of them. Subsequent conditions will pick from all instances again instead of filtering from only those meeting all the conditions so far. See How events work for more information on how instances are picked in events. Useful in subevents to start affecting different instances again.

Pick Nth instance
Pick the instance at a given place in the internal list of picked objects. This is most useful used in sub-events to act on separate instances. For example, in a "Sprite collided with Sprite" event, Pick 0th instance and Pick 1st instance can be used to act on each instance involved in the collision separately.

If all objects are currently picked, this condition can also be used to pick an object by its index ID (IID). For more information, see common features.

Pick random instance
Pick a random instance from the currently picked objects. In other words, if Pick random instance follows another condition, it will pick a random instance from the instances meeting the prior condition. Otherwise it picks a random instance from all the instances.

Special conditions

Else
Run if the previous event did not run. Note that this condition does not pick any objects: if it follows an event that picks objects, in the Else event all instances revert to picked again. Else can only follow normal (non-triggered) events. It can also follow another Else event with other conditions to make an "if - else if - else" chain.

Is in preview
True when running the project from a preview in Construct 2, and false when running after being exported. Useful to add debug or diagnostic features for previewing only.

Is on mobile device
Tries to detect whether the current device viewing the project is a mobile (e.g. phone or tablet). It is very difficult to accurately detect this so detection may not be perfect: there may be some mobile systems for which Is on mobile is not true, and (although less likely) desktop systems for which Is on mobile returns true. The condition always returns true when packaged via the PhoneGap or AppMobi containers, and always returns true for iOS or Android based devices. Beyond that Construct 2 will test a few other common mobile manufacturers. Otherwise, it will return true if the current system is not a desktop system, since there are relatively few desktop OSs; the desktop systems it checks for are Windows, Linux, OS 9, OS X, Solaris and BSD.

Trigger once while true
Turn an ordinary event (which is tested every tick) in to a trigger. For example, if an event plays a sound when lives equals 0, normally this event runs every tick. This plays about 60 sounds a second and would sound pretty bad. Adding Trigger once while true after the other conditions makes the event run just once when it first becomes true. This makes the previous example only play a sound once the first time your lives reaches 0. It must be the last condition in an event.

Start & end

On end of layout
Triggered when the layout is ending. This can happen when the project goes to a different layout or when the project closes.

On start of layout
Triggered when the layout begins.

Time

Compare time
Compare the time, in seconds, since the game began. For example, events can be set up to run when the time reaches (equals) 10 seconds.

Every X seconds
Run the event regularly at a given time interval in seconds. This can also be used beneath other conditions to only run the event at a given time interval while the other conditions are true, e.g. "Player is holding spacebar AND every 0.5 seconds: fire laser".