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music.rkt
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music.rkt
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#lang racket
#|
Racket Arcade (r-cade) - a simple game engine
Copyright (c) 2020 by Jeffrey Massung
All rights reserved.
|#
(require racket/match)
(require csfml)
;; ----------------------------------------------------
(require "riff.rkt")
(require "sound.rkt")
(require "voice.rkt")
;; ----------------------------------------------------
(provide (all-defined-out))
;; ----------------------------------------------------
(define note-freqs
(hash "C0" 16.35
"C#0" 17.32
"Db0" 17.32
"D0" 18.35
"D#0" 19.45
"Eb0" 19.45
"E0" 20.60
"F0" 21.83
"F#0" 23.12
"Gb0" 23.12
"G0" 24.50
"G#0" 25.96
"Ab0" 25.96
"A0" 27.50
"A#0" 29.14
"Bb0" 29.14
"B0" 30.87
"C1" 32.70
"C#1" 34.65
"Db1" 34.65
"D1" 36.71
"D#1" 38.89
"Eb1" 38.89
"E1" 41.20
"F1" 43.65
"F#1" 46.25
"Gb1" 46.25
"G1" 49.00
"G#1" 51.91
"Ab1" 51.91
"A1" 55.00
"A#1" 58.27
"Bb1" 58.27
"B1" 61.74
"C2" 65.41
"C#2" 69.30
"Db2" 69.30
"D2" 73.42
"D#2" 77.78
"Eb2" 77.78
"E2" 82.41
"F2" 87.31
"F#2" 92.50
"Gb2" 92.50
"G2" 98.00
"G#2" 103.83
"Ab2" 103.83
"A2" 110.00
"A#2" 116.54
"Bb2" 116.54
"B2" 123.47
"C3" 130.81
"C#3" 138.59
"Db3" 138.59
"D3" 146.83
"D#3" 155.56
"Eb3" 155.56
"E3" 164.81
"F3" 174.61
"F#3" 185.00
"Gb3" 185.00
"G3" 196.00
"G#3" 207.65
"Ab3" 207.65
"A3" 220.00
"A#3" 233.08
"Bb3" 233.08
"B3" 246.94
"C4" 261.63
"C#4" 277.18
"Db4" 277.18
"D4" 293.66
"D#4" 311.13
"Eb4" 311.13
"E4" 329.63
"F4" 349.23
"F#4" 369.99
"Gb4" 369.99
"G4" 392.00
"G#4" 415.30
"Ab4" 415.30
"A4" 440.00
"A#4" 466.16
"Bb4" 466.16
"B4" 493.88
"C5" 523.25
"C#5" 554.37
"Db5" 554.37
"D5" 587.33
"D#5" 622.25
"Eb5" 622.25
"E5" 659.25
"F5" 698.46
"F#5" 739.99
"Gb5" 739.99
"G5" 783.99
"G#5" 830.61
"Ab5" 830.61
"A5" 880.00
"A#5" 932.33
"Bb5" 932.33
"B5" 987.77
"C6" 1046.50
"C#6" 1108.73
"Db6" 1108.73
"D6" 1174.66
"D#6" 1244.51
"Eb6" 1244.51
"E6" 1318.51
"F6" 1396.91
"F#6" 1479.98
"Gb6" 1479.98
"G6" 1567.98
"G#6" 1661.22
"Ab6" 1661.22
"A6" 1760.00
"A#6" 1864.66
"Bb6" 1864.66
"B6" 1975.53
"C7" 2093.00
"C#7" 2217.46
"Db7" 2217.46
"D7" 2349.32
"D#7" 2489.02
"Eb7" 2489.02
"E7" 2637.02
"F7" 2793.83
"F#7" 2959.96
"Gb7" 2959.96
"G7" 3135.96
"G#7" 3322.44
"Ab7" 3322.44
"A7" 3520.00
"A#7" 3729.31
"Bb7" 3729.31
"B7" 3951.07
"C8" 4186.01
"C#8" 4434.92
"Db8" 4434.92
"D8" 4698.63
"D#8" 4978.03
"Eb8" 4978.03
"E8" 5274.04
"F8" 5587.65
"F#8" 5919.91
"Gb8" 5919.91
"G8" 6271.93
"G#8" 6644.88
"Ab8" 6644.88
"A8" 7040.00
"A#8" 7458.62
"Bb8" 7458.62
"B8" 7902.13))
;; ----------------------------------------------------
(define note-regexp #rx"([CDFGA]#|[DEGAB]b|[A-G]|[. ])([0-8])?(-+)?")
;; ----------------------------------------------------
(struct note [key octave length])
;; ----------------------------------------------------
(define (parse-notes bpm tune)
(for/list ([note-string (regexp-match* note-regexp tune)])
(match (regexp-match note-regexp note-string)
[(list _ key octave hold)
; determine the length of time this note should be held for
(let* ([note-length (+ 1 (if hold (string-length hold) 0))]
[duration (/ (* note-length 60.0) bpm)]
[length (inexact->exact (round (* duration sample-rate)))])
(note key octave length))])))
;; ----------------------------------------------------
(define dt-per-sample (/ sample-rate))
;; ----------------------------------------------------
(define basic-note (voice sin adsr-envelope))
;; ----------------------------------------------------
(define (music tune #:tempo [bpm 160] #:voice [voice basic-note])
(let* ([notes (parse-notes bpm tune)]
[num-samples (for/sum ([n notes]) (note-length n))]
[samples (make-vector (* num-samples bytes-per-sample))]
[instrument (voice-instrument voice)]
[envelope (voice-envelope voice)])
(for/fold ([offset 0] [last-octave "4"])
([note notes])
(let* ([key (note-key note)]
[len (note-length note)]
; default to the previous octave if not set for this note
[octave (or (note-octave note) last-octave)]
; lookup the frequency of this note+octave
[freq (hash-ref note-freqs (string-append key octave) 0.0)])
; write all the samples for this note
(for ([n (range len)])
(let* ([t (* (+ offset n) dt-per-sample)]
[u (/ n len)]
; amplitude and volume
[amp (instrument (* t freq pi 2))]
[vol (envelope u)]
; wave sample
[sample (inexact->exact (round (* half-peak vol amp)))]
; bytes of sample
[b0 (bitwise-bit-field sample 0 8)]
[b1 (bitwise-bit-field sample 8 16)])
(vector-set! samples (* (+ offset n) 2) b0)
(vector-set! samples (+ (* (+ offset n) 2) 1) b1)))
; update loop state
(values (+ offset len) octave)))
; compile the riff
(make-riff samples sample-rate channels bytes-per-sample)))
;; ----------------------------------------------------
(define (write-music tune #:tempo bpm #:voice voice)
(let* ([tune (music tune #:tempo bpm #:voice voice)])
(with-output-to-file "test-music.wav"
(λ () (write-bytes tune))
#:exists 'replace)))
(define (test)
(write-music ".--E4-B3C4D-CB3A-AC4E-DCB3-C4D-E-C-A3-A-.D4-FA-GFE-CE-DCB3-BC4D-E-C-A3-A-.E4---C---D---B3---C4---A3---Ab---B-E4---C---D---B3--C4--E-A4--Ab---.E4-B3C4D-CB3A-AC4E-DCB3-C4D-E-C-A3-A-.D4-FA-GFE-CE-DCB3-BC4D-E-C-A3-A-"
#:tempo 280
#:voice (voice triangle-wave adsr-envelope)))