31 lines
1008 B
Forth
31 lines
1008 B
Forth
module SoundGen.Fx
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type Effect =
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| Saturator
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| Reverb
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type ReverbParam = { Wet: float; Room: float }
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type SaturatorParam = { Gain: float }
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type WaveshaperParam = { Gain: float; Factor: float }
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let saturator (param: SaturatorParam) (x: float) = tanh (param.Gain * x)
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let waveshaper (param: WaveshaperParam) x =
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(x + param.Gain * sin (param.Factor * x)) |> saturator { Gain = 1.0 }
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let reverb (buffer: float seq) =
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let delayMilliseconds = 500. //((1./8.) * beatDuration) // 500 is half a second
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let delaySamples = (delayMilliseconds * 48.0) |> int // assumes 44100 Hz sample rate
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let decay = 0.5
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let mutable newBuffer = Array.ofSeq buffer
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for i in 0 .. Seq.length buffer do
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if Array.length newBuffer > (i + delaySamples) then
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let smpl = newBuffer.[i] * decay
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newBuffer.[i + delaySamples] <- smpl
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//else newBuffer <- Array.append newBuffer (smpl |> Array.singleton)
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Seq.zip buffer newBuffer |> Seq.map (fun (x, y) -> x + y * 0.8)
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