224 lines
4.9 KiB
Forth
224 lines
4.9 KiB
Forth
module SoundGen
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open System.IO
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let sampleRate = 48000.
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let bpm = 128.
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let beatDuration = 60. / bpm
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let pitchStandard = 440.
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let volume = 0.5
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let attackMs = 100.
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let getHzBySemitones semi =
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pitchStandard * (2. ** (1. / 12.)) ** semi
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let getSemitonesByNote (str:string) =
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let defaultOctave = 4
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let notes = ["A"; "A#"; "B"; "C"; "C#"; "D"; "D#"; "E"; "F"; "F#"; "G"; "G#" ] |> List.toArray
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let octave = str.Substring(str.Length - 1) |> int
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let noteShift = Array.findIndex (fun e -> e = str.Substring(0, str.Length - 1)) notes
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(octave - defaultOctave - 1) * 12 + noteShift
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let toInt16Sample sample = sample |> (*) 32767. |> int16
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let freq hz duration =
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let samples = seq { 0.0..(duration * sampleRate) }
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let attack =
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let samplesToRise = (sampleRate * (0.001 * attackMs));
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let risingDelta = 1. / samplesToRise
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let mutable i = 0.
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seq { while true do
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i <- i + risingDelta
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yield min i 1.
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}
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let output = Seq.map
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(fun x -> x
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|> (*) (2. * System.Math.PI * hz / sampleRate)
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|> sin
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|> (*) volume
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)
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samples
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let adsrLength = Seq.length output
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let attackArray = attack |> Seq.take adsrLength
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let release = Seq.rev attackArray
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Seq.zip3 release attackArray output
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|> Seq.map (fun (x, y, z) -> (x * y * z) |> toInt16Sample)
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let note semitone beats =
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let hz = getHzBySemitones semitone
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freq hz (beats * beatDuration)
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let song =
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[
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//
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.5
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25
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note 0 0.25;
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note 0 0.5;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25
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note 5 0.25;
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note 5 0.5;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25
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note 3 0.25;
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note 3 0.5
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note (-2) 0.5
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//
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//
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.5
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25
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note 0 0.25;
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note 0 0.5;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25
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note 5 0.25;
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note 5 0.5;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25
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note 3 0.25;
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note 3 0.5
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note (-2) 0.5
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//
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//
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.5
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25
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note 0 0.25;
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note 0 0.5;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25
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note 5 0.25;
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note 5 0.5;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25
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note 3 0.25;
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note 3 0.5
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note (-2) 0.5
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//
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//
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.5
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25;
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note 0 0.25
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note 0 0.25;
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note 0 0.5;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25;
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note 5 0.25
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note 5 0.25;
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note 5 0.5;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25;
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note 3 0.25
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note 3 0.25;
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note 3 0.5
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note (-2) 0.5
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//
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] |> Seq.concat
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let pack (d:int16[]) =
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let stream = new MemoryStream();
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let writer = new BinaryWriter(stream, System.Text.Encoding.ASCII);
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let dataLength = Array.length d * 2
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// RIFF
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writer.Write(System.Text.Encoding.ASCII.GetBytes("RIFF"))
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writer.Write(Array.length d)
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writer.Write(System.Text.Encoding.ASCII.GetBytes("WAVE"))
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// fmt
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let sr = sampleRate |> int
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writer.Write(System.Text.Encoding.ASCII.GetBytes("fmt "))
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writer.Write(16)
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writer.Write(1s) // PCM
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writer.Write(1s) // mono
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writer.Write(sr) // sample rate
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writer.Write(sr * 16 / 8) // byte rate
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writer.Write(2s) // bytes per sample
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writer.Write(16s) // bits per sample
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// data
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writer.Write(System.Text.Encoding.ASCII.GetBytes("data"))
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writer.Write(dataLength)
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let data:byte[] = Array.zeroCreate dataLength
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System.Buffer.BlockCopy(d, 0, data, 0, dataLength)
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writer.Write(data)
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stream
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let write (ms:MemoryStream) =
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use fs = new FileStream(Path.Combine(__SOURCE_DIRECTORY__,"test.wav"), FileMode.Create)
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ms.WriteTo(fs)
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song |> Seq.toArray |> pack |> write
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// let drawWave(freq, duration) =
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// Chart.Line(seq { 1. .. (duration * sampleRate) }, sound)
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// |> Chart.saveHtml("chart.html")
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// drawWave(440., 1.)
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