58 lines
1.9 KiB
Text
58 lines
1.9 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{(env-gen rate gate levelScale levelBias timeScale doneAction envelope)}
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A segment based envelope generator. Note that the SC3 language
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reorders the inputs to this UGen so that the envelope is the first
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argument.
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There are utilities for contructing the envelope argument.
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The arguments for levelScale, levelBias, and timeScale are polled
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when the env-gen is triggered and remain constant for the duration
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of the envelope.
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envelope - an breakpoint set
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gate - this triggers the envelope and holds it open while > 0. If
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the Env is fixed-length (e.g. Env.linen, Env.perc), the gate
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argument is used as a simple trigger. If it is an sustaining
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envelope (e.g. Env.adsr, Env.asr), the envelope is held open
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until the gate becomes 0, at which point is released.
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levelScale - scales the levels of the breakpoints.
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levelBias - offsets the levels of the breakpoints.
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timeScale - scales the durations of the segments.
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doneAction - an integer representing an action to be executed when
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the env is finished playing. This can be used to free
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the enclosing synth, etc.
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(import (rhs) (rsc3))
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Percussive envelope
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(let* ((d (env-perc 0.01 1 1 (list -4 -4)))
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(e (env-gen kr 1 0.1 0 1 remove-synth d)))
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(audition (out 0 (mul e (sin-osc ar 440 0)))))
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The break-point assistant makes a static envelope from a
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co-ordinate list. There is a duration and amplitude scalar.
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(let* ((d (env-coord (list (cons 0 0)
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(cons 0.75 1)
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(cons 1 0))
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1 1 (replicate 3 "linear")))
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(e (env-gen kr 1 0.1 0 1 remove-synth d)))
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(audition (out 0 (mul e (sin-osc ar 440 0)))))
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Trapezoidal
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(let* ((d (env-trapezoid 0 0.25 2 0.1))
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(e (env-gen kr 1 0.1 0 1 remove-synth d)))
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(audition (out 0 (mul e (sin-osc ar 440 0)))))
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0.0 3 -1 -1 0.1 0.5 1.0 0.0 0.1 0.0 1.0 0.0 0.0 1.5 1.0 0.0
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(env-trapezoid 0 0.25 2 0.1)
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