From 2a9b6ef0be04b5b5cacc47922e19c05d190d6ade Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@spork.org>
Date: Sat, 26 Jul 2025 14:55:53 -0400
Subject: first stab at fretboard player.

need to handle actual chord positions so everything isn't in 4, but
otherwise works?
---
 scale.mjs | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

(limited to 'scale.mjs')

diff --git a/scale.mjs b/scale.mjs
index 5b04831..fbd3617 100644
--- a/scale.mjs
+++ b/scale.mjs
@@ -8,12 +8,22 @@ function notesBetween(a, b) {
     }
 }
 
+export function toCents([aNote, aChord], [bNote, bChord]) {
+    console.debug('- a', [aNote, aChord]);
+    console.debug('- b', [bNote, bChord]);
+    const offset = (aNote.distanceTo(bNote)) * 100;
+    console.debug('- offset', offset);
+    const scale = (bChord - aChord) * 1200;
+    console.debug('- scale', scale);
+    return scale + offset;
+}
+
 export class Note {
     static natural = '♮';
     static sharp = '♯';
     static flat = '♭';
 
-    static range = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];
+    static range = ['C', 'D', 'E', 'F', 'G', 'A', 'B'];
     static get first() {
         return this.range.at(0);
     }
@@ -26,6 +36,16 @@ export class Note {
         return this.noSharps.map(n => String.fromCharCode(n.charCodeAt()+1))
     }
 
+    static get noteRange() {
+        return this.range.flatMap(n => {
+            if (this.noSharps.includes(n)) {
+                return new Note(n);
+            } else {
+                return [new Note(n, false), new Note(n, true)];
+            }
+        })
+    }
+
     static fromString(string) {
         const [root, accidental] = [string[0], string[1]];
         switch (accidental) {
@@ -62,6 +82,14 @@ export class Note {
         this.isSharp = isSharp;
     }
 
+    distanceTo(dest) {
+        const srcFromC = Note.noteRange.findIndex(t =>
+            t.toString() === this.toString());
+        const destFromC = Note.noteRange.findIndex(t =>
+            t.toString() === dest.toString());
+        return destFromC - srcFromC;
+    }
+
     toString() {
         return this.root + (this.isSharp ? Note.sharp : '');
     }
-- 
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