122 lines
3.7 KiB
Fennel
122 lines
3.7 KiB
Fennel
(local pxl8 (require :pxl8))
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(var time 0)
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(var step 0)
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(var ctx nil)
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(var melody-params nil)
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(var harmony-params nil)
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(var bass-params nil)
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(var playing false)
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(local bpm 95)
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(local beat (/ 60 bpm))
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(local sixteenth (/ beat 4))
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(local eighth (/ beat 2))
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(local quarter beat)
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(local whole (* 4 beat))
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(local melody [[69 eighth] [0 sixteenth] [72 sixteenth]
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[76 eighth] [74 eighth]
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[72 eighth] [69 eighth]
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[67 eighth] [69 eighth]
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[69 eighth] [0 sixteenth] [72 sixteenth]
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[76 eighth] [79 eighth]
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[77 eighth] [76 eighth]
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[74 quarter]
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[74 eighth] [0 sixteenth] [76 sixteenth]
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[77 eighth] [74 eighth]
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[72 eighth] [69 eighth]
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[67 eighth] [69 eighth]
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[72 eighth] [0 sixteenth] [74 sixteenth]
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[76 eighth] [72 eighth]
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[69 eighth] [67 eighth]
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[69 quarter]])
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(local harmony [[57 whole] ; A3
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[60 whole] ; C4
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[62 whole] ; D4
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[57 whole]]) ; A3
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(local bass [[45 eighth] [45 eighth] [57 eighth] [45 eighth]
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[45 eighth] [57 eighth] [45 eighth] [57 eighth]
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[48 eighth] [48 eighth] [60 eighth] [48 eighth]
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[48 eighth] [60 eighth] [48 eighth] [60 eighth]
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[50 eighth] [50 eighth] [62 eighth] [50 eighth]
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[50 eighth] [62 eighth] [50 eighth] [62 eighth]
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[45 eighth] [45 eighth] [57 eighth] [45 eighth]
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[45 eighth] [57 eighth] [52 eighth] [45 eighth]])
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(local step-duration sixteenth)
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(fn init []
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(set ctx (pxl8.sfx_context_create))
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(pxl8.sfx_mixer_attach ctx)
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(set melody-params (pxl8.sfx_voice_params
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{:waveform pxl8.SFX_WAVE_TRIANGLE
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:attack 0.02 :decay 0.15 :sustain 0.5 :release 0.15
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:filter_type pxl8.SFX_FILTER_LOWPASS
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:filter_cutoff 4000 :filter_resonance 0.0
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:fx_send 0.0}))
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(set harmony-params (pxl8.sfx_voice_params
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{:waveform pxl8.SFX_WAVE_TRIANGLE
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:attack 0.05 :decay 0.2 :sustain 0.3 :release 0.2
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:filter_type pxl8.SFX_FILTER_LOWPASS
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:filter_cutoff 2500 :filter_resonance 0.0
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:fx_send 0.0}))
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(set bass-params (pxl8.sfx_voice_params
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{:waveform pxl8.SFX_WAVE_TRIANGLE
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:attack 0.015 :decay 0.1 :sustain 0.7 :release 0.1
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:filter_type pxl8.SFX_FILTER_LOWPASS
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:filter_cutoff 1200 :filter_resonance 0.0
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:fx_send 0.0})))
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(fn start []
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(set playing true)
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(set time 0)
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(set step 0))
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(fn stop []
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(set playing false)
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(pxl8.sfx_stop_all ctx))
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(fn update [dt]
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(when playing
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(set time (+ time dt))
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(when (>= time step-duration)
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(set time (- time step-duration))
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(local melody-idx (+ 1 (% step (length melody))))
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(local melody-entry (. melody melody-idx))
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(local melody-note (. melody-entry 1))
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(local melody-dur (. melody-entry 2))
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(when (> melody-note 0)
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(pxl8.sfx_play_note ctx melody-note melody-params 0.45 melody-dur))
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(local bar (math.floor (/ step 32)))
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(local harmony-idx (+ 1 (% bar (length harmony))))
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(local harmony-entry (. harmony harmony-idx))
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(local harmony-note (. harmony-entry 1))
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(when (= (% step 32) 0)
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(pxl8.sfx_play_note ctx harmony-note harmony-params 0.25 whole))
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(local bass-step (math.floor (/ step 2)))
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(local bass-idx (+ 1 (% bass-step (length bass))))
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(local bass-entry (. bass bass-idx))
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(local bass-note (. bass-entry 1))
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(local bass-dur (. bass-entry 2))
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(when (= (% step 2) 0)
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(pxl8.sfx_play_note ctx bass-note bass-params 0.55 bass-dur))
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(set step (+ step 1)))))
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{:init init
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:start start
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:stop stop
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:update update
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:is-playing (fn [] playing)}
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