Harmonics not parsed correctly

[sandrojologua]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

On some Guitar Pro files (I guess only on .gp format) harmonics does not get correctly parsed. But If I re-export that exact file with Guitar Pro, like change something, save it and parse it again with alphaTab, it works.

Expected Behavior

I expect harmonics to be parsed correctly every time, not just sometimes.

Steps To Reproduce

I have attached the tab file where the problem happens, check the 4-th track. (I could not leave only one track because then it gets fixed, because I will have to re-export).

tab.gp.zip

Link to jsFiddle, CodePen, Project

No response

Version and Environment

This happens everywhere, even on alphatab.net.

Platform

Node.js

Anything else?

No response

[louislam]

For reference, a similar issue had been reported on my repo too.
louislam/its-mytabs#25 (comment)

The tab was exported from Songsterr. After re-saved in Guitar Pro, it got fixed.

[Danielku15]

Root cause is here:

alphaTab/packages/alphatab/src/importer/GpifParser.ts

Lines 2396 to 2417 in 220858a

	switch (htype.innerText) {
	case 'NoHarmonic':
	note.harmonicType = HarmonicType.None;
	break;
	case 'Natural':
	note.harmonicType = HarmonicType.Natural;
	break;
	case 'Artificial':
	note.harmonicType = HarmonicType.Artificial;
	break;
	case 'Pinch':
	note.harmonicType = HarmonicType.Pinch;
	break;
	case 'Tap':
	note.harmonicType = HarmonicType.Tap;
	break;
	case 'Semi':
	note.harmonicType = HarmonicType.Semi;
	break;
	case 'Feedback':
	note.harmonicType = HarmonicType.Feedback;
	break;

These files use lowercase values for HarmonicType but we expect the GP casing.

<Property name="Harmonic">
          <Enable/>
        </Property>
        <Property name="HarmonicType">
          <HType>natural</HType>
        </Property>
        <Property name="HarmonicFret">
          <HFret>7.000000</HFret>
        </Property>

Testing with GP 8.1.4 on Windows the casing is as alphaTab expects it.

@louislam Thanks for the hint with Songsterr. I'm not sure how they modify/export GP files. If they still store the old original GP data and re-export the file with patched modifications this could explain the inconsistency.

Nevertheless should be easy to fix this case in alphaTab by making the mentiones switch case insensitive using lowercase values.