ftgen
Prev | Orchestra Opcodes and Operators | Next

## 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
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
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 332. 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 333. 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

Prev | Up | Next
ftfree | Home | ftgenonce