Detecting multiple key presses - ComputerCraft Forums (archive)

TheOddByte #1

1852 posts

Location Sweden

Posted 31 August 2014 - 03:21 AM

Hello everyone, I've stumbled upon a problem, it's that I don't know how to detect if multiple keys have been pressed. Like you've might have seen in programs that they use CTRL+S or something. Now how would I do this? can someone give me some code example? do I have to modify os.pullEvent/pullEventRaw or something todo this?
I tried doing this in some weird way using timers, problem was I couldn't hold down a key. ( for example hold down shift, then press left. I had to press shift and then press left )
And if you're wondering if I have to code left to show I can tell you right now that the answer is nope. The code got deleted as it was a test-script and it didn't work.

- Thanks in advance, TheOddByte

natedogith1 #2

natedogith1's profile picture

108 posts

Posted 31 August 2014 - 03:42 AM

There's not really a way to do that in CC (though somewhere on the forums I've seen someone jury-rig it). The best bet is just to see if someone's pressed the two keys within some time of each other.

Bomb Bloke #3

Bomb Bloke's profile picture

7083 posts

Location Tasmania (AU)

Posted 31 August 2014 - 04:23 AM

There's one exception (and only one) that comes to mind - holding down Ctrl while pressing characters generates key events for those characters, but not char events.

This means that if you rig your script to queue a custom event whenever a key event is detected, then see whether a char event can be pulled before that custom event, you can tell whether a given character was held in conjunction with Ctrl or not.

TheOddByte #4

1852 posts

Location Sweden

Posted 31 August 2014 - 06:04 PM

Thanks for the help, I gave it a shot and this was the result.

Spoiler


local event, enabled, timeout, key_hold, key = {}
while true do
    local e = { os.pullEvent() }
    if e[1] == "key" then
        if e[2] == 29 or e[2] == 42 then
            enabled = true
            for k, v in pairs( e ) do
                event[k] = v
            end
            timeout = os.startTimer( .8 )

        else

            if enabled then
                if key and e[2] == key then
                    key_hold = true
                else
                    if key == nil then
                        key = e[2]
                        key_hold = true;
                    else
                        key = nil
                        key_hold = false
                    end
                end
                -- Handle multiple keys here later, just print them now for debug
                print( event[2] .. " + " .. e[2] )
            end
        end

    elseif e[1] == "timer" and e[2] == timeout then
        if not key_hold then
            event = {}
            enabled = false;
        end
        key_hold = false;
        timeout = os.startTimer( 0.1 )
    end
end

It's not perfect, but it kinda works :P/>

Edited on 31 August 2014 - 04:08 PM