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joystick

Reads data from a Linux joystick controller

Plugin opcode in joystick.

Syntax

kres joystick kdevice, ktab

Performance

📝 Note

Please note that this opcode is currently only supported on GNU/Linux.

kdevice -- the index of the joystick device, either /dev/js_N_ or /dev/input/js_N_.

ktab -- A table to hold input results, should be at least enough elements to store one value for each stick axis and one for each button + 2. The first two elements of the table are initialized with the number of axes and the number of buttons, respectively, when a joystick is opened. If a joystick is unplugged during performance, the opcode will repeatedly attempt to reopen the device with a delay between attempts.

Examples

Here is an example of the joystick opcode. It uses the file joystick.csd.

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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac      ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o joystick.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
;0dbfs  = 1

instr 1 ; gives information about your joystick in real time

kmask    joystick   0, 1
kidx     =  2
kaxes    tab 0, 1 ; number of axes has been stored in position 0
kbuttons tab 1, 1 ; number of buttons has been stored in position 1
         printf "this joystick has %d axes, %d buttons\n", kidx, kaxes, kbuttons
kuniq    init 0

reportaxis: ; first we see if we have any x/y input
        kcheck    =  kmask & (1<<kidx)
        if kcheck == 0 kgoto nexta
        kres      tab       kidx, 1
        kuniq     =  kuniq + 1 ; to be sure to make the printf print
                  printf    "axis %d, value %6d\n", kuniq, kidx-2, kres
nexta:
        kidx      =  kidx+1
        if kidx < (kaxes+2) kgoto reportaxis

reportbutton: ; now we check for any buttons pressed
        kcheck    =  kmask & 1<<kidx
        if kcheck == 0 kgoto nextb
        kres      tab       kidx, 1 ; a button has been pressed, get from table
                  printf    "button %d, pushed\n", kidx*kres, (kidx-(kaxes+2))
                  printf    "button %d, released\n", kidx*(1-kres), (kidx-(kaxes+2))

nextb:
        kidx      =  kidx+1
        if kidx < (kaxes+kbuttons+2) kgoto reportbutton

endin
</CsInstruments>
<CsScore>

f1  0 32    7     0     7     0         ; will hold the joystick data

i1  0  60000

e
</CsScore>
</CsoundSynthesizer>

Here is another example of the joystick opcode. It uses the file joystick-2.csd.

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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac    ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o joystick-2.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
;0dbfs  = 1

instr 1

kmask   joystick   0, 1
kaxes    init 0
kbuttons init 0
kx0      init 0 ; first two entries are # of axes and # of buttons, 
ky0      init 0 ; then axes, then buttons                           
         vtabk 0, 1, kaxes, kbuttons, kx0, ky0
kidx     =  2+kaxes 

buttons:
  kcheck =  kmask & 1<<kidx   ; if the button was just now pressed and...
  kres   tab       kidx, 1    ; if button value is one, start a note
         schedkwhen  kres*kcheck, 1, 20, 2, 0, 60000, kidx, kx0, ky0
  kidx   =  kidx+1
if kidx < (kaxes+kbuttons+2) kgoto buttons

endin

instr 2 ; play a tone until the button is released

kstop   tab  p4, 1 ; when this button is released, we fade out
ihz     init cpsoct(((p5+32767)/9362)+5) ; ~ 30 hz to 4khz
print ihz
ito     init ampdb(((p6+32767)/2184)+60) ; ~ 60 - 90 db
kenv    init 0
kdelta  init ito/(kr*10)
if kstop == 1 kgoto output
if kdelta < 0 kgoto output
kdelta    =  kdelta*-1

output:
  kenv =  kenv+kdelta
  kenv limit kenv, 0, ito
  aout oscils 1, ihz, 0
  aout =  kenv*aout
       outs aout, aout
if kenv != 0 kgoto noexit
if kdelta > 0 kgoto noexit
turnoff
noexit:

endin
</CsInstruments>
<CsScore>
f1  0 32    7     0     7     0         ; will hold the joystick data

i1  0  60000

e
</CsScore>
</CsoundSynthesizer>

See also

Sensing and Control: Keyboard and mouse sensing

non-MIDI devices

Credits

Author: Justin Glenn Smith
2010

New in version 5.17.12