From 4edafbe664d4c2418f07c1e59216f6e78abead03 Mon Sep 17 00:00:00 2001
From: HiveBeats <38073817+HiveBeats@users.noreply.github.com>
Date: Tue, 1 Nov 2022 11:19:46 +0400
Subject: [PATCH] feat: private functions && fix reverb

---
 SoundGen/Fx.fs         | 27 ++++++++++++++-------------
 SoundGen/Oscillator.fs |  2 +-
 SoundGen/PCMWave.fs    |  4 ++--
 SoundGen/Program.fs    |  2 +-
 SoundGen/Synth.fs      | 14 +++++++-------
 5 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/SoundGen/Fx.fs b/SoundGen/Fx.fs
index 5727e1c..99f4853 100644
--- a/SoundGen/Fx.fs
+++ b/SoundGen/Fx.fs
@@ -1,5 +1,5 @@
 module SoundGen.Fx
-
+open Settings
 type Effect =
     | Saturator
     | Reverb
@@ -9,21 +9,22 @@ type Saturator = { Gain: float }
 
 let saturate (param: Saturator, x: float) = tanh (param.Gain * x)
 
-let sineWaveShape gain factor x  =
-    x + gain * sin (factor * x)
+let sineWaveShape gain factor x = x + gain * sin (factor * x)
+
+let reverb (buffer: float seq) =
+    let delayMilliseconds = 500.//((1./8.) * beatDuration) // 500 is half a second
+
+    let delaySamples =
+        (delayMilliseconds * 48.0) |> int // assumes 44100 Hz sample rate
 
-let reverb (buffer:float seq) =
-    let delayMilliseconds = 50.; // 500 is half a second
-    let delaySamples = (delayMilliseconds * 48.0) |> int; // assumes 44100 Hz sample rate
     let decay = 0.5
     let mutable newBuffer = Array.ofSeq buffer
-    
-    for i in 0..Seq.length buffer do
-        let smpl = newBuffer.[i] * decay
+
+    for i in 0 .. Seq.length buffer do
         if Array.length newBuffer > (i + delaySamples) then
+            let smpl = newBuffer.[i] * decay
             newBuffer.[i + delaySamples] <- smpl
-        else newBuffer <- Array.append newBuffer (smpl |> Array.singleton)
-            
-    newBuffer
-
+    //else newBuffer <- Array.append newBuffer (smpl |> Array.singleton)
 
+    Seq.zip buffer newBuffer
+    |> Seq.map (fun (x, y) -> x + y * 0.8)
diff --git a/SoundGen/Oscillator.fs b/SoundGen/Oscillator.fs
index e53ad61..fcd7ca9 100644
--- a/SoundGen/Oscillator.fs
+++ b/SoundGen/Oscillator.fs
@@ -18,7 +18,7 @@ type GenerationParameter =
 
 
 
-let pos hz x = (hz * x / sampleRate) % 1.
+let private pos hz x = (hz * x / sampleRate) % 1.
 
 let sineosc hz x =
     x |> (*) (2. * Math.PI * hz / sampleRate) |> sin
diff --git a/SoundGen/PCMWave.fs b/SoundGen/PCMWave.fs
index a16639c..80975f2 100644
--- a/SoundGen/PCMWave.fs
+++ b/SoundGen/PCMWave.fs
@@ -2,10 +2,10 @@ module SoundGen.PCMWave
 open Settings
 open System.IO
 
-let toInt16Sample sample = sample |> (*) 32767. |> int16
+let private toInt16Sample sample = sample |> (*) 32767. |> int16
 
 
-let pack (d: int16 []) =
+let private pack (d: int16 []) =
     let stream = new MemoryStream()
 
     let writer =
diff --git a/SoundGen/Program.fs b/SoundGen/Program.fs
index d6b847e..af1ab46 100644
--- a/SoundGen/Program.fs
+++ b/SoundGen/Program.fs
@@ -55,9 +55,9 @@ let writeToFile (ms: MemoryStream) =
     ms.WriteTo(fs)
 
 song
+//|> reverb
 |> Seq.map (fun x ->
     let x1 = sineWaveShape 1.5 2.5 x
     saturate ({ Gain = 1.0 }, x1))
-//|> reverb
 |> createWAV
 |> writeToFile
diff --git a/SoundGen/Synth.fs b/SoundGen/Synth.fs
index 2190b3d..f8283ff 100644
--- a/SoundGen/Synth.fs
+++ b/SoundGen/Synth.fs
@@ -4,10 +4,10 @@ open Settings
 open Oscillator
 open SoundGen.Oscillator
 
-let getHzBySemitones semi =
+let private getHzBySemitones semi =
     pitchStandard * (2. ** (1. / 12.)) ** semi
 
-let getSemitonesByNote (str: string) =
+let private getSemitonesByNote (str: string) =
     let defaultOctave = 4
 
     let notes =
@@ -34,7 +34,7 @@ let getSemitonesByNote (str: string) =
     (octave - defaultOctave - 1) * 12 + noteShift
 
 
-let freq hz duration (osc: OscillatorParameter list) =
+let private freq hz duration (osc: OscillatorParameter list) =
     let samples =
         seq { 0.0 .. (duration * sampleRate) }
 
@@ -70,11 +70,11 @@ let freq hz duration (osc: OscillatorParameter list) =
 
 
 let note semitone beats =
-    let hz = getHzBySemitones (semitone - 12.)
+    let hz = getHzBySemitones (semitone)
 
     freq
         hz
         (beats * beatDuration)
-        [ { Osc = Sine; Freq = hz / 4. }
-          { Osc = Saw; Freq = (hz + 1.) }
-          { Osc = Saw; Freq = (hz - 1.3) } ]
+        [ { Osc = Sine; Freq = hz / 4. };
+           { Osc = Saw; Freq = (hz + 1.) };
+           { Osc = Saw; Freq = (hz - 1.3) } ]