;; (env-gen rate gate levelScale levelBias timeScale doneAction envelope)

;; A segment based envelope generator.  Note that the SC3 language
;; reorders the inputs to this UGen so that the envelope is the first
;; argument.

;; There are utilities for contructing the envelope argument.

;; The arguments for levelScale, levelBias, and timeScale are polled
;; when the env-gen is triggered and remain constant for the duration
;; of the envelope.

;; envelope - an breakpoint set

;; gate - this triggers the envelope and holds it open while > 0. If
;;        the Env is fixed-length (e.g. Env.linen, Env.perc), the gate
;;        argument is used as a simple trigger. If it is an sustaining
;;        envelope (e.g. Env.adsr, Env.asr), the envelope is held open
;;        until the gate becomes 0, at which point is released.

;; levelScale - scales the levels of the breakpoints.

;; levelBias - offsets the levels of the breakpoints.

;; timeScale - scales the durations of the segments.

;; doneAction - an integer representing an action to be executed when
;;              the env is finished playing. This can be used to free
;;              the enclosing synth, etc.

(import (rhs) (rsc3))

;; Percussive envelope
(let* ((d (env-perc 0.01 1 1 (list -4 -4)))
       (e (env-gen kr 1 0.1 0 1 remove-synth d)))
  (audition (out 0 (mul e (sin-osc ar 440 0)))))

;; The break-point assistant makes a static envelope from a
;; co-ordinate list.  There is a duration and amplitude scalar.
(let* ((d (env-coord (list (cons 0 0)
                           (cons 0.75 1)
                           (cons 1 0))
                     1 1 (replicate 3 "linear")))
       (e (env-gen kr 1 0.1 0 1 remove-synth d)))
  (audition (out 0 (mul e (sin-osc ar 440 0)))))

;; Trapezoidal
(let* ((d (env-trapezoid 0 0.25 2 0.1))
       (e (env-gen kr 1 0.1 0 1 remove-synth d)))
  (audition (out 0 (mul e (sin-osc ar 440 0)))))

;; 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
(env-trapezoid 0 0.25 2 0.1)