fix: correct GP5 bass clef detection (#2531)

Author: Danielku15

packages/alphatab/src/importer/Gp3To5Importer.ts

@@ -435,9 +435,9 @@ export class Gp3To5Importer extends ScoreImporter {
     }
 
     /**
-     * Guitar Pro 3-6 changes to a bass clef if any string tuning is below B2;
+     * Guitar Pro 3-6 changes to a bass clef if any string tuning is below B1
      */
-    private static readonly _bassClefTuningThreshold = ModelUtils.parseTuning('B2')!.realValue;
+    private static readonly _bassClefTuningThreshold = ModelUtils.parseTuning('B1')!.realValue;
 
     public readTrack(): void {
         const newTrack: Track = new Track();

packages/alphatab/test-data/visual-tests/music-notation/clefs-gp5.png

@@ -548,7 +548,7 @@ describe('Gp5ImporterTest', () => {
 
     it('tuning-bass-clef', async () => {
         const score = (await GpImporterTestHelper.prepareImporterWithFile('guitarpro5/bass-tuning.gp5')).readScore();
-        expect(score.tracks[0].staves[0].bars[0].clef).to.equal(Clef.F4);
+        expect(score.tracks[0].staves[0].bars[0].clef).to.equal(Clef.G2);
         expect(score.tracks[1].staves[0].bars[0].clef).to.equal(Clef.F4);
         expect(score.tracks[2].staves[0].bars[0].clef).to.equal(Clef.F4);
         expect(score.tracks[3].staves[0].bars[0].clef).to.equal(Clef.F4);

packages/alphatab/test/importer/Gp5Importer.test.ts

@@ -3,6 +3,7 @@ import { NotationElement } from '@coderline/alphatab/NotationSettings';
 import { Settings } from '@coderline/alphatab/Settings';
 import { StaveProfile } from '@coderline/alphatab/StaveProfile';
 import { ScoreLoader } from '@coderline/alphatab/importer/ScoreLoader';
+import { TestPlatform } from 'test/TestPlatform';
 import { VisualTestHelper, VisualTestOptions, VisualTestRun } from 'test/visualTests/VisualTestHelper';
 
 describe('MusicNotationTests', () => {
@@ -21,6 +22,21 @@ describe('MusicNotationTests', () => {
         await VisualTestHelper.runVisualTest('music-notation/clefs.gp', settings);
     });
 
+    it('clefs-gp5', async () => {
+        const score = ScoreLoader.loadScoreFromBytes(
+            await TestPlatform.loadFile('test-data/guitarpro5/bass-tuning.gp5')
+        );
+        const settings: Settings = new Settings();
+        settings.display.layoutMode = LayoutMode.Page;
+
+        const referenceFileName = 'test-data/visual-tests/music-notation/clefs-gp5.png';
+
+        const o = new VisualTestOptions(score, [new VisualTestRun(-1, referenceFileName)], settings);
+        o.tracks = score.tracks.map(t => t.index);
+
+        await VisualTestHelper.runVisualTestFull(o);
+    });
+
     it('key-signatures-mixed', async () => {
         const settings: Settings = new Settings();
         settings.display.staveProfile = StaveProfile.Score;