Vibrato (4xy) and vibrato+volslide (6xy): should not have been implemented with IT vibrato. I assigned GDM vibrato a UNI effect opcode and for now it maps to PT vibrato with the tick 0 bug disabled (same as S3M/XM). Specific characteristics of GDM vibrato: no tick 0 update, sine is positive, ramp down actually ramps up (didn't bother supporting—seems like a BWSB bug), all waveforms continue to a new note rather than restarting (didn't bother supporting—seems like a BWSB bug), ramp "down" has a bizarre stair-step nature I didn't bother reproducing (EDIT: this only happens with the SB drivers, not with GUS, so likely a bug/limitation), random waveform is a repeat of square (didn't bother supporting).
Tremolo (7xy): should not have been implemented with S3M tremolo. I assigned GDM tremolo a UNI effect opcode and for now it maps to PT tremolo with the tick 0 bug disabled. Characteristics: same as vibrato. (EDIT: doesn't work with GUS for some reason, tested with SB16 instead)
Fine vibrato (14xy): should not have been implemented with IT fine vibrato. I assigned GDM fine vibrato a UNI effect opcode and for now it maps to S3M fine vibrato. Characteristics: same as vibrato.
Glissando control (E3x), vibrato waveform (E4x), set finetune (E5x), loop (E6x), and tremolo waveform (E7x) should all map directly to their Protracker equivalents (S00 is not supported by BWSB so there's no reason to use the S3M/IT equivalents). Prior to this most of these were being mapped to S3M/IT Sxy sub-effect codes(!) which never worked and makes me question how well this loader was originally tested. Loop was the only one of these that worked correctly.
Set global volume (13xx) was doubling the parameter value for no good reason.
Other changes:
Because GDM vibrato/tremolo are more copypaste of the PT versions with different flags and S3M/XM vibrato already do exactly what GDM vibrato needed to do, I combined these into a single function (one for vibrato and one for tremolo). I think it's still a good thing to have opcodes assigned for these since it allows them to be tweaked independently later if needed.
Protracker tremolo should have the tick 0 bug (just like vibrato). This flag is implemented now but isn't actually used yet because, like vibrato, there are numerous other formats using PT tremolo directly that could be effected.
I missed this in the big vibrato PR, but S3M fine vibrato was implemented incorrectly and exhibited the PT tick 0 bug when it never should have. It was also halving the depth when it should not have. Tested with Scream Tracker 3.
GLISS.GDM.zip: glissando control (E3x). Note that glissando control is not implemented yet in MikMod and both glissando sequences will sound identical, but previously these were getting mapped to opcode 1 and would audibly glitch.
GVOLUME.GDM.zip: set global volume (13xx). Should gradually decrease from 100% to 0% and back. Prior, this would cap at 100% for too long at the start and end due to a doubled parameter.
sezero
commented
3 years ago
Fixes the following GDM effects:
4xy) and vibrato+volslide (6xy): should not have been implemented with IT vibrato. I assigned GDM vibrato a UNI effect opcode and for now it maps to PT vibrato with the tick 0 bug disabled (same as S3M/XM). Specific characteristics of GDM vibrato: no tick 0 update, sine is positive, ramp down actually ramps up (didn't bother supporting—seems like a BWSB bug), all waveforms continue to a new note rather than restarting (didn't bother supporting—seems like a BWSB bug), ramp "down" has a bizarre stair-step nature I didn't bother reproducing (EDIT: this only happens with the SB drivers, not with GUS, so likely a bug/limitation), random waveform is a repeat of square (didn't bother supporting).7xy): should not have been implemented with S3M tremolo. I assigned GDM tremolo a UNI effect opcode and for now it maps to PT tremolo with the tick 0 bug disabled. Characteristics: same as vibrato. (EDIT: doesn't work with GUS for some reason, tested with SB16 instead)14xy): should not have been implemented with IT fine vibrato. I assigned GDM fine vibrato a UNI effect opcode and for now it maps to S3M fine vibrato. Characteristics: same as vibrato.E3x), vibrato waveform (E4x), set finetune (E5x), loop (E6x), and tremolo waveform (E7x) should all map directly to their Protracker equivalents (S00is not supported by BWSB so there's no reason to use the S3M/IT equivalents). Prior to this most of these were being mapped to S3M/ITSxysub-effect codes(!) which never worked and makes me question how well this loader was originally tested. Loop was the only one of these that worked correctly.13xx) was doubling the parameter value for no good reason.Other changes:
Test modules:
4xy), fine vibrato (14xy), tremolo (7xy), vibrato waveform (E4x), tremolo waveform(E7x).E3x). Note that glissando control is not implemented yet in MikMod and both glissando sequences will sound identical, but previously these were getting mapped to opcode 1 and would audibly glitch.E5x).13xx). Should gradually decrease from 100% to 0% and back. Prior, this would cap at 100% for too long at the start and end due to a doubled parameter.