ftgen

ftgen — Generate a score function table from within the orchestra.

Description

Generate a score function table from within the orchestra.

Syntax

gir ftgen ifn, itime, isize, igen, iarga [, iargb ] [...]

Initialization

gir -- either a requested or automatically assigned table number above 100.

ifn -- requested table number If ifn is zero, the number is assigned automatically and the value placed in gir. Any other value is used as the table number

itime -- is ignored, but otherwise corresponds to p2 in the score f statement.

isize -- table size. Corresponds to p3 of the score f statement.

igen -- function table GEN routine. Corresponds to p4 of the score f statement.

iarga, iargb, ... -- function table arguments. Correspond to p5 through pn of the score f statement.

Performance

This is equivalent to table generation in the score with the f statement.

[Note] Note

Csound was originally designed to support tables with power of two sizes only. Though this has changed in recent versions (you can use any size by using a negative number), many opcodes will not accept them.

[Warning] Warning

Although Csound will not protest if ftgen is used inside instr-endin statements, this is not the intended or supported use, and must be handled with care as it has global effects. (In particular, a different size usually leads to relocation of the table, which may cause a crash or otherwise erratic behaviour.

Examples

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

Example 319. Example of the ftgen opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

<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 ftgen.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

gisine   ftgen 1, 0, 16384, 10, 1	;sine wave
gisquare ftgen 2, 0, 16384, 10, 1, 0 , .33, 0, .2 , 0, .14, 0 , .11, 0, .09 ;odd harmonics
gisaw    ftgen 3, 0, 16384, 10, 0, .2, 0, .4, 0, .6, 0, .8, 0, 1, 0, .8, 0, .6, 0, .4, 0,.2 ;even harmonics

instr 1

ifn = p4
asig poscil .6, 200, ifn
     outs asig, asig

endin
</CsInstruments>
<CsScore>

i 1 0 2 1 ;sine wave
i 1 3 2 2 ;odd harmonics
i 1 6 2 3 ;even harmonics
e
</CsScore>
</CsoundSynthesizer>


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

Example 320. Example of the ftgen opcode.

This example queries a file for it length to create an f-table of the appropriate size.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in
-odac           -iadc    ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o ftgen-2.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

  sr	    =  48000
  ksmps	    =  16
  nchnls    =  2

;Example by Jonathan Murphy 2007

  0dbfs	    =  1

    instr 1

  Sfile	    =    "beats.wav"

  ilen	    filelen   Sfile  ; Find length
  isr	    filesr    Sfile  ; Find sample rate

  isamps    =  ilen * isr  ; Total number of samples
  isize	    init      1

loop:
  isize	    =  isize * 2
; Loop until isize is greater than number of samples
if (isize < isamps) igoto loop

  itab	    ftgen     0, 0, isize, 1, Sfile, 0, 0, 0
	    print     isize
	    print     isamps

  turnoff
    endin

</CsInstruments>
<CsScore>
i1 0 10
e
</CsScore>
</CsoundSynthesizer>


See also

GEN routine overview, ftgentmp

Credits

Author: Barry L. Vercoe
M.I.T., Cambridge, Mass
1997

Added warning April 2002 by Rasmus Ekman