[R81] Keyboard "On Pressed" odd execution order

Note: This has been a problem for a while. R81 just indicates that it's still a problem in the current build.

A couple others and myself have been playing with Construct 2 a bit and ran into a bit of an odd behavior with events that may or may not be classified as a bug... but regardless it's less than desirable for what we are trying to do.

Suppose we have a sprite object with variables to track control in the following manner:

sprite.up = 0

sprite.up_pressed = 0

And then we have an event at the beginning of the frame as follows:

System.Every Tick
    sprite.set(up = 0)
    sprite.set(up_pressed = 0)

Keyboard.Up arrow is down
    sprite.set(up = 1)

Keyboard.Up arrow pressed
    sprite.set(up_pressed = 1)

That's not a bug.

That's the difference between a Trigger and a non-Trigger event.

Trigger event (those with the green arrow on the left) are events outside the game loop. They are usually triggered before the next game loop to respond fast to the player input.

The order of event is kept inside triggers though.

if you do a

Keyboard: On any key pressed
[ul]
	[li]> set Right_Pressed to 0[/li]
[/ul]Keyboard: On Right arrow pressed
[ul]
	[li]> set Right_Pressed to 1[/li]
[/ul]Keyboard: On any key pressed
Right_Pressed = 1
[ul]
	[li]> Play sound[/li]
	[li]> set Right_Pressed to 0

Keyboard: On any key pressed
[ul]
	[li]> set Right_Pressed to 0[/li]
[/ul]Keyboard: On any key pressed
Right_Pressed = 1
[ul]
	[li]> Play sound[/li]
	[li]> set Right_Pressed to 0[/li]
[/ul]Keyboard: On Right arrow pressed
[ul]
	[li]> set Right_Pressed to 1

Yann is right, it's by design - triggers aren't checked in the top-to-bottom running of the event sheet, they fire whenever the event happens, and most events happen before or after the event sheet runs. If you want a flag set to 1 for the one tick an event fires, make sure you clear the flag at the end of the event sheet. However I would recommend doing everything inside the trigger event if possible.

I've updated the documentation on how events work to clarify this.

Thanks for the expedient response and useful information.

Congrats Ashley, I like the infos and the editing of the manual entry.

Thanks.