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IDProjectCategoryView StatusLast Update
0001469OpenMPTPlayback Compatibilitypublic2021-06-04 19:13
ReporterLachesis Assigned ToSaga Musix  
Status resolvedResolutionfixed 
Platformx64OSWindowsOS Version10
Product VersionOpenMPT / libopenmpt 0.5.9 (upgrade first) 
Target VersionOpenMPT / libopenmpt 0.5.10 (upgrade first)Fixed in VersionOpenMPT / libopenmpt 0.5.10 (upgrade first) 
Summary0001469: GDM extra fine portamento effects are not correctly converted.

The following effects are not correctly converted by the GDM loader:

  • E8x — Extra fine portamento up. This is left as the mod effect E8x (pan position).
  • E9x — Extra fine portamento down. This is converted to Q0x (multi-retrigger).

These might seem unusual, but this really is how 2GDM maps these effects. See the MenTaLguY document for reference (a format doc that is actually correct, for a change... it probably helps that BWSB was GPL by that point).

OpenMPT converts the entire Exx block as if they're standard MOD effects. Following this further confirms that E8x is left as-is and E9x is converted to CMD_RETRIG, which lines up with what I see when I load a test module.

Steps To Reproduce

Do any of the following:

  • Load the attached modules gdm_fx.s3m and GDM_FX.GDM into OpenMPT and compare the effects. (In this case, the E8x is converted to a volume channel effect.)
  • Convert gdm_fx.s3m with 2GDM and compare.
  • Load the attached module LB2_7.GDM in OpenMPT and look at patterns 17-22, channels 4 and 5. (In this case, E8x is left as-is.)
Additional Information

libxmp and MikMod convert these correctly but probably not in any releases (yet), as both had much worse handling of the fine effects before I patched them. An interesting note, even though these should be converted to Exx and Fxx, I found that BWSB doesn't actually implement continue variants of any of the fine portamento effects (unlike fine volume slide, which shares memory with regular volume slide). 2GDM evaluates E00/F00 for these at conversion time for some reason.

TagsNo tags attached.
Has the bug occurred in previous versions?Yes (1.29.5 tested).
Tested code revision (in case you know it)




2021-06-04 12:37

reporter   ~0004785

Wish it had told me I couldn't upload GDMs before I submitted... � (403 bytes) (354 bytes) (119,817 bytes)
Saga Musix

Saga Musix

2021-06-04 19:13

administrator   ~0004787

Good find - I probably didn't read gdm.txt carefully enough when I wrote the GDM loader back then. Fixed in r15282.

Issue History

Date Modified Username Field Change
2021-06-04 12:31 Lachesis New Issue
2021-06-04 12:37 Lachesis Note Added: 0004785
2021-06-04 12:37 Lachesis File Added:
2021-06-04 12:37 Lachesis File Added:
2021-06-04 12:37 Lachesis File Added:
2021-06-04 12:40 Saga Musix Assigned To => Saga Musix
2021-06-04 12:40 Saga Musix Status new => assigned
2021-06-04 19:13 Saga Musix Status assigned => resolved
2021-06-04 19:13 Saga Musix Resolution open => fixed
2021-06-04 19:13 Saga Musix Fixed in Version => OpenMPT / libopenmpt 0.5.10 (upgrade first)
2021-06-04 19:13 Saga Musix Target Version => OpenMPT / libopenmpt 0.5.10 (upgrade first)
2021-06-04 19:13 Saga Musix Note Added: 0004787