From 78fcce82676bc64a7d523e369204bb7f79802357 Mon Sep 17 00:00:00 2001
From: Michiel Roos <michiel@michielroos.com>
Date: Mon, 30 Sep 2024 12:45:28 +0200
Subject: [PATCH 1/2] Update noise.rs

Add brown noise generator
---
 knyst/src/gen/noise.rs | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/knyst/src/gen/noise.rs b/knyst/src/gen/noise.rs
index bacab38..33ca368 100644
--- a/knyst/src/gen/noise.rs
+++ b/knyst/src/gen/noise.rs
@@ -6,7 +6,7 @@ use super::GenState;
 use crate as knyst;
 use crate::Sample;
 
-/// Whate noise (fastrand RNG based on wyrand)
+/// White noise (fastrand RNG based on wyrand)
 pub struct WhiteNoise {
     rng: fastrand::Rng,
 }
@@ -98,3 +98,43 @@ impl PinkNoise {
         GenState::Continue
     }
 }
+
+/// Brown noise (also known as red noise)
+///
+/// Brown noise is generated by integrating white noise.
+/// This implementation uses a simple integration of white noise samples with a small step size,
+/// and clamps the output to prevent it from exceeding the [-1.0, 1.0] range.
+pub struct BrownNoise {
+    rng: fastrand::Rng,
+    last_output: Sample,
+}
+
+#[impl_gen(range = normal)]
+impl BrownNoise {
+    #[allow(missing_docs)]
+    pub fn new() -> Self {
+        let mut rng = fastrand::Rng::new();
+        rng.seed(next_randomness_seed());
+        Self {
+            rng,
+            last_output: 0.0,
+        }
+    }
+
+    #[allow(missing_docs)]
+    pub fn process(&mut self, output: &mut [Sample]) -> GenState {
+        for out in output.iter_mut() {
+            let white = self.rng.f32() as Sample * 2.0 - 1.0;
+            // Adjust the coefficient to control the step size
+            self.last_output += white * 0.1;
+            // Clamp to [-1.0, 1.0] to prevent output from exceeding the range
+            if self.last_output > 1.0 {
+                self.last_output = 1.0;
+            } else if self.last_output < -1.0 {
+                self.last_output = -1.0;
+            }
+            *out = self.last_output;
+        }
+        GenState::Continue
+    }
+}

From 2c51f2664a08c566e4aed544d29b21f0c35b49cd Mon Sep 17 00:00:00 2001
From: Michiel Roos <michiel@michielroos.com>
Date: Mon, 30 Sep 2024 21:53:28 +0200
Subject: [PATCH 2/2] Use more readable clamp code

---
 knyst/src/gen/noise.rs | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/knyst/src/gen/noise.rs b/knyst/src/gen/noise.rs
index 33ca368..2d94fa6 100644
--- a/knyst/src/gen/noise.rs
+++ b/knyst/src/gen/noise.rs
@@ -128,11 +128,7 @@ impl BrownNoise {
             // Adjust the coefficient to control the step size
             self.last_output += white * 0.1;
             // Clamp to [-1.0, 1.0] to prevent output from exceeding the range
-            if self.last_output > 1.0 {
-                self.last_output = 1.0;
-            } else if self.last_output < -1.0 {
-                self.last_output = -1.0;
-            }
+            self.last_output = self.last_output.clamp(-1.0, 1.0);
             *out = self.last_output;
         }
         GenState::Continue