67 lines
1.7 KiB
Racket
67 lines
1.7 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{(v-osc rate bufpos freq phase)}
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Variable wavetable oscillator. A wavetable lookup oscillator which
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can be swept smoothly across wavetables. All the wavetables must be
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allocated to the same size. Fractional values of table will
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interpolate between two adjacent tables.
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This oscillator requires a buffer to be filled with a wavetable
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format signal. This preprocesses the Signal into a form which can
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be used efficiently by the oscillator. The buffer size must be a
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power of 2.
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This can be acheived by creating a Buffer object and sending it one
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of the "b_gen" messages ( sine1, sine2, sine3 ) with the wavetable
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flag set to true.
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This can also be acheived by creating a Signal object and sending
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it the 'asWavetable' message, saving it to disk, and having the
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server load it from there.
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Note about wavetables: Vosc requires the b_gen sine1 wavetable flag
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to be ON.
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Allocate and fill tables 0 to 7 [see also Vosc3]
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@racketblock[
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(with-sc3
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(lambda (fd)
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(let* ((square
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(lambda (a) (* a a)))
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(nth
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(lambda (i)
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(async fd (b-alloc i 1024 1))
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(let* ((n (expt (+ i 1) 2))
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(a (map1 (lambda (j) (square (/ (- n j) n)))
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(enum-from-to 0 (- n 1)))))
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(async fd (b-gen1 i "sine1" (cons 7 a)))))))
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(for-each nth (enum-from-to 0 7)))))
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]
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oscillator at buffers 0 through 7.
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@racketblock[
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(let ((b (mouse-x kr 0 7 0 0.1))
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(f (mce2 120 121)))
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(audition (out 0 (mul (v-osc ar b f 0) 0.3))))
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]
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Reallocate buffers while oscillator is running.
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@racketblock[
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(with-sc3
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(lambda (fd)
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(for-each
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(lambda (i)
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(async fd (b-gen1 i "sine1" (cons 7 (replicate-m 16 (random 0 1))))))
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(enum-from-to 0 7))))
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]
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