linenv

Abstract

A triggerable linear envelope with sustain segment

Description

linenv is similar to linsegr with an additional gate argument, allowing to retrigger it at will. One of the values can be defined as a sustain point, meaning that as long as the gate is held, the envelope enters a sustain state when reaching this point. When the gate is set to 0, the envelope traverses the rest of the defined points.

If the gate is closed before reaching the sustain segment, the envelope slides to the release section skipping any segments in between.

Syntax

xout linenv kgate, isustindex, kval0, [ktime1, kval1, ktime2, kval2, ...]

Arguments

• kgate: whenever this switches from 0 to 1 a new envelope starts. If a sustain segment was defined, when closing the gate (transition from 1 to 0) the envelope jumps to the sustain segment. Otherwise it just continues until it reaches the last segment (a "oneshot" envelope)
• isustindex: the index of the sustain point. For example, if isustindex is 2, then when the envelope reaches kval2 (after ktime0+ktime1), it enters a sustain phase, where its value remains unmodified until the gate is set to 0. If no sustain point is desired, set isustindex to 0. NB: negative values count from end. To imitate the behaviour of linsegr, use -1 as sustain index.
• kval0, ktime1, ...: a linear envelope, similar to linsegr. The release part can have as many segments as desired. ktime_n values are defined as time interval between two values, not as absolute timestamps

Output

• xout: value of the envelope (k- or a- rate)

Execution Time

• Performance

Examples

<CsoundSynthesizer>

<CsOptions>
-odac
</CsOptions>

<CsInstruments>

/*
    This is the example file for opcode "linenv"

    linenv is a triggerable envelope with a sustain segment

    aout linenv kgate, isustidx, kval0, ktime1, kval1, ..., ktimen, kvaln

    NB: use xtratim if necessary to allow for release segment 

*/


sr = 44100
ksmps  = 64
nchnls = 2
0dbfs  = 1
gkgate init 0

FLpanel "linenv", 240, 100, 100, 100
    gkgate, gih1 FLbutton " Gate", 1, 0, 2, 80, 40, 10, 10, -1  
FLpanelEnd
FLrun

instr 1
    kgate = trighold:k(metro(1/2), 0.5)
    kenv linenv kgate, 1, 0, 0.15, 1, 0.1, 0
    printf "t: %f,  kenv: %f \n", timeinstk(), timeinsts(), kenv

    kenv *= 0.2
    asig = pinker() * interp(kenv)
    outs asig, asig
endin

instr 2
    iperiod = 2
    igatedur = 1
    kgate = trighold:k(metro(1/iperiod), igatedur)
    aenv linenv kgate, -2, 0, 0.05, 1, 0.2, 0.5, 0.2, 1, 0.4, 0
    asig = oscili:a(0.2, 1000) * aenv
    FLsetVal changed(kgate), kgate, gih1
    outs asig, asig
endin

instr 3
    asig pinker
    aenv linenv gkgate, 2, 0, 0.05, 1, 0.1, 0.2, 0.5, 0
    asig *= aenv
    outs asig, asig
endin

instr 4
    ; no sustain ("one shot")
    asig pinker
    aenv linenv gkgate, 0, 0, 0.05, 1, 0.1, 0.2, 0.5, 0
    asig *= aenv
    outs asig, asig
endin

</CsInstruments>

<CsScore>

; i1 0 10
; i2 0 10
i3 0 100
; i4 0 100
</CsScore>
</CsoundSynthesizer>

See also

• ramptrig
• bisect
• interp1d
• bpf
• linsegr

Credits

Eduardo Moguillansky, 2019

(idea based on pd/else's envgen and supercollider's envgen)