How to determine button states?

sys64738

If we do

Loop
C = controls (0) 
If c.b then
// this triggers once per millisecond 
endif
Repeat

Is there a way to just know when the button is down or up. It currently acts like "autofire" like if you wanted to shoot a red laser once on press and then shoot a single blue laser on button up? Kind of used of having key.down key.up in my previous language.

Is there a simple solution to accomplish this with Boolean flags?

Nisse5

Wait for the up afterwards.

Or save the previous state of the button, so you only act on the "down" if the previous state was "up".

sys64738

@Nisse5 I have spent an hour or so trying to do that. If there is a simple solution I am not thinking clearly enough today to find it.

Tratax

The code below should perform a logical check of 3 button "states" and then perform the appropriate action per state, hope this helps!

buttonState = 0

loop
c = controls(0)

if c.b == 1 and buttonState != 2 then
buttonState = 1
endif

if  buttonState == 1 then
ink(red)
print("red!")
buttonState = 2
endif

if buttonState == 2 and c.b == 0 then
ink(blue)
print("blue")
buttonState = 0
endif

update()
repeat

Update: Corrected syntax and print debug test output, works well now!

MikeDX

@Tratax don't forget to check for double equals!

= isn't the same as ==

if c = 1 then // <- this will always return true!

Nisse5

@sys64738 To wait for the up afterwards:

while controls(0).a loop repeat

Or, this version would do the same, but would probably save much more battery:

while controls(0).a loop update() repeat

To track the previous state, something like:

prevstate = true // To make sure that an up exist before the first down
loop
   c = controls(0)
   if c.a and !prevstate then
      // Do something
   endif
   prevstate = c.a
   update()
repeat

sys64738

Have made a new project and tried tratax suggestion with == and c = controls(0) sorted

It triggers red laser every loop while button is held down. Instead of once as needed.

Does while take all the programs focus. In my intended program it needs to still run the main loop at 60 fps

Nisse5

@sys64738 said in How to determine button states?:

Does while take all the programs focus. In my intended program it needs to still run the main loop at 60 fps

Is there any reason why you don't check the controls in the main loop? To me, streamlining control states + drawing + frame updates in the main loop seems like the most efficient use of FUZE.

sys64738

Nisse5 your prevstate example fires a single red laser per press as requested. But how do I tell when button is released

sys64738

@Nisse5 I am checking in main loop

sys64738

Adding this to your code seems to have done it

Thank you tratax and nisse5


If c.a == 0 and prevstate == 1 then
//blue laser
End if

Prevstate = c.a
Update()
Repeat

Tratax

@MikeDX Thanks Mike, this was written on the train without my switch handy.. no excuse for leaving it at home I guess haha

Tratax

Have rewritten the above suggestion for anyone else who needs this solution

Martin

I tackle this differently (there's always more than one way to do stuff)

I maintain a 'debounce' struct. In the main loop I look for c.a == 1 and increment debounce.a. In the else (ie, the button is no longer pressed) I say if debounce.a > 0 then do whatever it was I wanted to do and also reset debounce.a to 0 ready for detecting the next keypress.

For me this solves the problem of only doing something once per press. If instead of performing an action on keyup you really do want keydown then you can say if debounce.a == 1 (or 2 or 3 or 10 or whatever you want). If you want auto repeat you can use debounce.a % 50 or something like that.