GEN17
GEN17 — Creates a step function from given x-y pairs.
Initialization
size -- number of points in the table. Must be a power of 2 or a power-of-2 plus 1 (see f statement). The normal value is power-of-2 plus 1.
x1, x2, x3, etc. -- x-ordinate values, in ascending order, 0 first.
a, b, c, etc. -- y-values at those x-ordinates, held until the next x-ordinate.
![[Note]](images/note.png)
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This subroutine creates a step function of x-y pairs whose y-values are held to the right. The right-most y-value is then held to the end of the table. The function is useful for mapping one set of data values onto another, such as MIDI note numbers onto sampled sound ftable numbers ( see loscil). |
Examples
f 1 0 128 -17 0 1 12 2 24 3 36 4 48 5 60 6 72 7 84 8
This describes a step function with 8 successively increasing levels, each 12 locations wide except the last which extends its value to the end of the table. Rescaling is inhibited. Indexing into this table with a MIDI note-number would retrieve a different value every octave up to the eighth, above which the value returned would remain the same.
Here is a complete example of the GEN17 routine. It uses the files gen17.csd.
Example 1282. An example of the GEN17 routine.
<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 gen17.wav -W ;;; for file output any platform ; By Stefano Cucchi & Menno Knevel - 2021 </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 instr 1 gisqre ftgen 2, 0, 16384, 10, 1, 0 , .33, 0, .2 , 0, .14, 0 , .11, 0, .09 ;odd harmonics knoteleft oscil 1, 0.5, 10 ; index to table 10 - gen 17 - every 2 seconds reads all the values in the table n. 10 printks2 "note left = %d\n", knoteleft knoteright oscil 1, 1, 10 ; index to table 10 - gen 17 - every second reads all the values in the table n. 10 printks2 "note right = %d\n", knoteright ixmode = 1 ixoff = 0 iwrap = 1 aphasor1 phasor knoteleft ; the values in table 10 become the frequency of the oscillator asig1 tablei aphasor1, gisqre, ixmode, ixoff, iwrap ; oscillator generating sound in the left channel (table 10 every 2 seconds) aphasor2 phasor knoteright ; the values in table 10 become the frequency of the oscillator asig2 tablei aphasor2, gisqre, ixmode, ixoff, iwrap ; oscillator generating sound in the right channel (table 10 every second) kgenenv linseg 0, 0.3, 0.4, p3-0.6, 0.4, 0.3, 0 ; envelope outs asig1 * kgenenv, asig2 * kgenenv endin </CsInstruments> <CsScore> ; table with gen17 - At point 0 pitch 300 Hz, at point 12 pitch 350 Hz, etc... f 10 0 128 -17 0 300 12 350 20 400 41 434 48 563 67 589 72 632 79 678 100 712 120 789 i1 0 10 e </CsScore> </CsoundSynthesizer>