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return

Returns a value from an instrument at i-time.

The value of a global instrument (instrument 0) can be retrieved after compilation by the evalstr opcode. The retrieval of values returned by other instruments is not yet implemented.

Syntax

return(ival)

return ival

Initialization

ival -- a value to be returned by instrument.

Examples

Here is a short example of return with evalstr.

ival evalstr "return 2 + 2"
print ival

The complete example plays a bell arpeggio over a bass line, with stereo echoes and reverb. It builds on tjingboem's example from issue #315.

Instrument 2 builds a code string for each note. In that string, return supplies a frequency to evalstr, which assigns it to iFreq. The console prints each returned frequency as the melody plays. The code in the string runs in the global space, even though instrument 2 calls evalstr.

Change the offsets in iNotes to make a new melody, or change the roots in score field p4 to try a different chord sequence. Score field p5 raises the melody by octaves on the second pass.

It uses the file return.csd.

A bell arpeggio using return and evalstr.
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<CsoundSynthesizer>
<CsOptions>
-odac
</CsOptions>
<CsInstruments>
sr = 48000
ksmps = 32
nchnls = 2
0dbfs = 1

; Based on tjingboem's return/evalstr example in manual issue #315.
; Expanded here into a bell arpeggio with bass and stereo echoes.
gaLeft init 0
gaRight init 0

instr 1
  ; Each score event starts eight notes and a bass note.
  ; p4 sets the MIDI root. p5 shifts the melody up by octaves.
  schedule 3, 0, 1.9, p4 - 12
  iStep = 0
  while iStep < 8 do
    schedule 2, iStep * 0.25, 1.5, p4 + 12 * p5, iStep
    iStep += 1
  od
endin

instr 2
  ; sprintf inserts the root and step into the code string.
  ; evalstr runs this code in the global space (instrument 0).
  Scode sprintf {{
iNotes[] fillarray 0, 7, 12, 14, 19, 14, 12, 7
return cpsmidinn(%d + iNotes[%d])
}}, p4, p5
  iFreq evalstr Scode
  ; iFreq holds the value supplied by return, in Hz.
  printf_i "step %d, returned frequency %.2f Hz\n", 1, p5, iFreq

  aBodyEnv transeg 0, 0.003, 0, 0.13, p3 - 0.003, -7, 0
  aBrightEnv transeg 0, 0.002, 0, 0.055, p3 - 0.002, -12, 0
  aBody poscil aBodyEnv, iFreq
  aBright poscil aBrightEnv, iFreq * 2.01
  aLeft, aRight pan2 aBody + aBright, 0.15 + 0.1 * p5
  gaLeft += aLeft
  gaRight += aRight
endin

instr 3
  aEnv linseg 0, 0.015, 0.16, p3 - 0.215, 0.12, 0.2, 0
  aBass poscil aEnv, cpsmidinn(p4)
  gaLeft += aBass * 0.7
  gaRight += aBass * 0.7
endin

instr 99
  ; Cross the echoes between the speakers, then add reverb.
  aEchoLeft delay gaRight, 0.375
  aEchoRight delay gaLeft, 0.625
  aLeft = gaLeft + 0.4 * aEchoLeft
  aRight = gaRight + 0.4 * aEchoRight
  aRevLeft, aRevRight reverbsc aLeft, aRight, 0.82, 7000
  ; Fade the last second so the reverb ends smoothly.
  aFade linseg 1, p3 - 1, 1, 1, 0
  outs (aLeft + 0.25 * aRevLeft) * aFade, (aRight + 0.25 * aRevRight) * aFade
  clear gaLeft, gaRight
endin
</CsInstruments>
<CsScore>
; The second pass raises the melody by an octave.
i 1  0 0.01 48 0
i 1  2 0.01 44 0
i 1  4 0.01 41 0
i 1  6 0.01 43 0
i 1  8 0.01 48 1
i 1 10 0.01 44 1
i 1 12 0.01 41 1
i 1 14 0.01 43 1
; Let the last notes and reverb ring out.
i 99 0 22
e
</CsScore>
</CsoundSynthesizer>

See Also

evalstr, String Manipulation Opcodes

Credits

Author: Victor Lazzarini, 2013