From a88545b6afc9084f3a1c5f17491c160ac26809b9 Mon Sep 17 00:00:00 2001
From: Felix Roos <flix91@gmail.com>
Date: Fri, 28 Jun 2024 09:02:40 +0200
Subject: [PATCH] add slew limiter

---
 packages/core/src/audiograph.js | 21 +++++++++++++++++++++
 packages/core/src/graph.js      |  8 ++++++++
 2 files changed, 29 insertions(+)

diff --git a/packages/core/src/audiograph.js b/packages/core/src/audiograph.js
index f79e692..6a3c507 100644
--- a/packages/core/src/audiograph.js
+++ b/packages/core/src/audiograph.js
@@ -584,6 +584,26 @@ class Lag {
   }
 }
 
+class Slew {
+  constructor() {
+    this.last = 0;
+  }
+
+  update(input, up, dn) {
+    const upStep = up * ISR;
+    const downStep = dn * ISR;
+
+    let delta = input - this.last;
+    if (delta > upStep) {
+      delta = upStep;
+    } else if (delta < -downStep) {
+      delta = -downStep;
+    }
+    this.last += delta;
+    return this.last;
+  }
+}
+
 /**
  * Slide/portamento node
  */
@@ -838,6 +858,7 @@ export let NODE_CLASSES = {
   Tri: TriOsc,
   // Scope: Scope,
   Slide: Slide,
+  Slew: Slew,
   Lag: Lag,
   Filter: Filter,
   Fold: Fold,
diff --git a/packages/core/src/graph.js b/packages/core/src/graph.js
index ad92159..95dd1c1 100644
--- a/packages/core/src/graph.js
+++ b/packages/core/src/graph.js
@@ -292,6 +292,7 @@ export let saw = makeNode("Saw");
 export let sine = makeNode("Sine");
 export let tri = makeNode("Tri");
 export let slide = makeNode("Slide");
+export let slew = makeNode("Slew");
 export let lag = makeNode("Lag");
 export let filter = makeNode("Filter");
 export let fold = makeNode("Fold");
@@ -523,6 +524,13 @@ export const NODE_SCHEMA = {
       { name: "rate", default: 1 },
     ],
   },
+  Slew: {
+    ins: [
+      { name: "in", default: 0 },
+      { name: "up", default: 1 },
+      { name: "dn", default: 1 },
+    ],
+  },
   Tri: {
     ins: [{ name: "freq", default: 0 }],
   },