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DhrBaksteen / ArduinoOPL2

Arduino library for use with the OPL2 board (YM3812) and OPL3Duo (YMF262)
MIT License
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Bug when setting registers for melodic instruments #48

Closed virtuaCode closed 4 years ago

virtuaCode commented 4 years ago

https://github.com/DhrBaksteen/ArduinoOPL2/blob/61e03ff184a575fb7db65fb2ffecdecd9f1b98fe/src/OPL2.cpp#L260-L266

The parameters for the registers C0...C8 are stored in the instrument data at instrument[5]. Since we always do i + 1 when accessing the instrument data, the condition at line 260 have to be i == 4. Also accessing the instrumentBaseRegs array has to be done this way:

reg = instrumentBaseRegs[i == 5 ? 4 : i % 6] + getRegisterOffset(channel, i > 5);

After I fixed this issue I played some notes with the instrument in midi_instrument.h and realized that for every patch the "synthtype" bit is inverted. :open_mouth: Can you confirm this?

DhrBaksteen commented 4 years ago

The library code is correct. The problem is with the export of the new instruments. The OPL2 registers in the instruments are not supposed to be in order, but 0x20, 0x40, 0x60, 0x80, 0xE0, 0xC0, etc. The original instruments.h has this correct, but the midi exports have registers 0xC0 and 0xE0 switched.

DhrBaksteen commented 4 years ago

I'm in doubt whether there is actually anything wrong with the instruments. Trying to swap the two columns results in very broken instruments. My suspicion is that there is additional bits left on the 0xE0 registers that were not filtered out during export. I need to check this with the BNK file where the instruments came from...

Still comments on the instruments files are wrong. Also length of instrumentBaseRegs in opl2.h should be declared as 6.