antigravity one shot

src/music/Tunings.ts

@@ -0,0 +1,64 @@
+
+
+export interface Tuning {
+    name: string;
+    strings: number[]; // MIDI numbers for strings, usually low to high (6th to 1st)
+}
+
+// Low E2 (40), A2 (45), D3 (50), G3 (55), B3 (59), E4 (64)
+export const STANDARD_TUNING: Tuning = {
+    name: "Standard",
+    strings: [40, 45, 50, 55, 59, 64]
+};
+
+// Low D2 (38), A2 (45), D3 (50), G3 (55), B3 (59), E4 (64)
+export const DROP_D_TUNING: Tuning = {
+    name: "Drop D",
+    strings: [38, 45, 50, 55, 59, 64]
+};
+
+export const TUNINGS: Record<string, Tuning> = {
+    "standard": STANDARD_TUNING,
+    "drop_d": DROP_D_TUNING,
+};
+
+export interface FretPosition {
+    stringIndex: number; // 0-based index of the string in the strings array (0 = lowest string)
+    fret: number;
+}
+
+/**
+ * Finds all places on the fretboard where a specific note can be played.
+ * Assumes 20 frets by default.
+ */
+export function getFretboardPositions(midiNote: number, tuning: Tuning = STANDARD_TUNING, maxFrets: number = 20): FretPosition[] {
+    const positions: FretPosition[] = [];
+
+    tuning.strings.forEach((openNote, stringIndex) => {
+        const fret = midiNote - openNote;
+        if (fret >= 0 && fret <= maxFrets) {
+            positions.push({ stringIndex, fret });
+        }
+    });
+
+    return positions;
+}
+
+
+/**
+ * Helpers to get useful ranges for beginners
+ */
+export function getOpenStringNotes(tuning: Tuning = STANDARD_TUNING): number[] {
+    return tuning.strings;
+}
+
+export function getFirstPositionNotes(tuning: Tuning = STANDARD_TUNING): number[] {
+    const notes = new Set<number>();
+    tuning.strings.forEach(openNote => {
+        // First position usually means frets 0-4
+        for (let i = 0; i <= 4; i++) {
+            notes.add(openNote + i);
+        }
+    });
+    return Array.from(notes).sort((a, b) => a - b);
+}