From a78f43d5a79e0bbe0d41d60b3527da3cfec7f117 Mon Sep 17 00:00:00 2001
From: Jacob Lee <jacob@unabridgedsoftware.com>
Date: Thu, 11 Nov 2021 13:05:20 -0500
Subject: Implement White/Brown noise. Refactor needed

---
 klangfarbrs/src/lib.rs | 23 ++++++++++++++++++++---
 klangfarbrs/src/osc.rs | 14 ++++++++++++--
 2 files changed, 32 insertions(+), 5 deletions(-)

(limited to 'klangfarbrs/src')

diff --git a/klangfarbrs/src/lib.rs b/klangfarbrs/src/lib.rs
index ef9417c..1fdc0fb 100644
--- a/klangfarbrs/src/lib.rs
+++ b/klangfarbrs/src/lib.rs
@@ -11,6 +11,8 @@
 
 use gdnative::prelude::*;
 use gdnative::core_types::TypedArray;
+use rand::Rng;
+use std::f32::consts::TAU;
 
 mod osc;
 use osc::Osc;
@@ -32,7 +34,8 @@ pub enum Waveform {
     Square,
     Triangle,
     Sawtooth,
-    // Noise,
+    WhiteNoise,
+    BrownNoise,
 }
 
 #[derive(NativeClass)]
@@ -116,6 +119,7 @@ impl MonoSynth {
             frequency_modulation: false,
             fm_frequency: 10.0,
             fm_depth: 0.1,
+    // Noise,
             fm_phasor: Phasor { phase: 0.0 },
             current_envelope_position: 0,
         }
@@ -146,6 +150,16 @@ impl MonoSynth {
         self.waveform = Waveform::Sawtooth
     }
 
+    #[export]
+    fn white_noise(&mut self, _owner: &Node) {
+        self.waveform = Waveform::WhiteNoise
+    }
+
+    #[export]
+    fn brown_noise(&mut self, _owner: &Node) {
+        self.waveform = Waveform::BrownNoise
+    }
+
     #[export]
     fn frequency(&mut self, _owner: &Node, frequency: Hz) {
         self.frequency = frequency
@@ -197,13 +211,16 @@ impl MonoSynth {
     #[export]
     pub fn frames(&mut self, _owner: &Node, samples: i32) -> TypedArray<Vector2> {
         let mut frames = TypedArray::new();
+        let mut rng = rand::thread_rng();
+        let mut last_value = (rng.gen::<f32>() * TAU).sin();
 
         for _i in 0..samples {
-            let mut sample = Osc::generate_sample(&self.waveform, self.phasor.phase);
+            let mut sample = Osc::generate_sample(&self.waveform, self.phasor.phase, last_value);
+            last_value = sample;
             let next_phase : f32;
 
             if self.frequency_modulation {
-                let modulation_value = Osc::generate_sample(&Waveform::Sine, self.fm_phasor.phase) * self.fm_depth;
+                let modulation_value = Osc::generate_sample(&Waveform::Sine, self.fm_phasor.phase, last_value) * self.fm_depth;
                 self.fm_phasor.phase = self.fm_phasor.next_phase(self.fm_frequency, self.sample_rate);
                 next_phase = self.phasor.next_phase(self.frequency + modulation_value, self.sample_rate);
             } else {
diff --git a/klangfarbrs/src/osc.rs b/klangfarbrs/src/osc.rs
index 9e3b147..fd78de1 100644
--- a/klangfarbrs/src/osc.rs
+++ b/klangfarbrs/src/osc.rs
@@ -1,11 +1,13 @@
 use std::f32::consts::TAU;
+use rand::Rng;
 use crate::{Waveform, Phase, Sample};
 
 pub struct Osc {}
 
 impl Osc {
-    pub fn generate_sample(waveform: &Waveform, phase: Phase) -> Sample {
+    pub fn generate_sample(waveform: &Waveform, phase: Phase, last_value: Sample) -> Sample {
         let phase = phase;
+        let mut rng = rand::thread_rng();
 
         match waveform {
             Waveform::Sine => {
@@ -30,7 +32,15 @@ impl Osc {
 
             Waveform::Sawtooth => {
                 2.0 * phase - 1.0
-            }
+            },
+
+            Waveform::WhiteNoise => {
+                (rng.gen::<f32>()).sin()
+            },
+
+            Waveform::BrownNoise => {
+                (last_value + (rng.gen::<f32>()) * 0.2 - 0.1).clamp(-1.0, 1.0)
+            },
         }
     }
 }
-- 
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