API Reference Instrument functions

createInstrument

Instrument OPL2::createInstrument();

Create a new blank instrument structure.

Returns

Instrument A new blank Instrument structure with all parameters reset

loadInstrument

Instrument OPL2::loadInstrument(const unsigned char *instrument, bool fromProgmem = INSTRUMENT_DATA_PROGMEM);
Instrument OPL2::loadInstrument(const unsigned char *instrument);    // Raspberry Pi only!

Create an Instrument structure from an array of 12-bytes of instrument data either in PROGMEM or SRAM. On Raspberry Pi instrument data con only be loaded from SRAM.

An instrument data array has the following structure:

Index	Data
0	Rhythm mode drum channel. Drum channels are predefined by the YM3812 and cannot be redefined. Regular instruments have their channel set to `0x00` and can be assigned to any channel by the setInstrument function. Rhythm mode instruments can only be used when rhythm mode is active (see OPL2.setPercussion).
1	Operator 1, register 0x20
2	Operator 1, register 0x40
3	Operator 1, register 0x60
4	Operator 1, register 0x80
5	Operator 1, register 0xE0
6	Register 0xC0
7	Operator 2, register 0x20
8	Operator 2, register 0x40
9	Operator 2, register 0x60
10	Operator 2, register 0x80
11	Operator 2, register 0xE0

If the loaded instrument has its instrument.type to 0 or INSTRUMENT_TYPE_MELODIC then it can be assigned to any channel using the setInstrument(). If this value is non-zero then is should be set using setDruminstrument() and it will assigned to the appropriate percussion channel.

Drum	Instrument type definition	Channel
Melodic	INSTRUMENT_TYPE_MELODIC	any
Bass	INSTRUMENT_TYPE_BASS	6
Snare	INSTRUMENT_TYPE_SNARE	7
Tom tom	INSTRUMENT_TYPE_TOM	8
Cymbal	INSTRUMENT_TYPE_CYMBAL	9
Hi-hat	INSTRUMENT_TYPE_HI_HAT	10

Arguments

• const unsigned char *instrument - Pointer to the start of the instrument data array
• bool fromProgmem - When set to true (default) the data of the instrument is located in PROGMEM

Returns

Instrument New Instrument structure created from the 12-byte data structure

setInstrument

void OPL2::setInstrument(byte channel, Instrument instrument, float volume = 1.0);

Set the given instrument to a certain channel. This will load all the operators of the channel with the instrument data.

Arguments

• byte channel - Index of the channel [0, MAX_CHANNEL]
• Instrument instrument - The instrument structure
• float volume - Optional volume for the instrument [0.0, 1.0] where 0.0 is silence and 1.0 is full volume. By default volume will be 1.0.

setDrumInstrument

void OPL2::setDrumInstrument(Instrument instrument, float volume = 1.0);

Set the given drum instrument to the drum channel that is defined in the Instrument structure.

Arguments

• Instrument instrument - The instrument structure
• float volume - Optional volume to apply to the drum channel. Defaults to full volume

getInstrument

Instrument OPL2::getInstrument(byte channel);

Convert the given channel into an instrument structure.

Arguments

• byte channel - Index of the channel [0, MAX_CHANNEL]

Returns

Instrument New Instrument structure converted from the given channel

getDrumInstrument

Instrument OPL2::getDrumInstrument(byte drumType);

Convert the channel parameters of the given drum type into an instrument structure.

Arguments

• byte drumType - Type of drum from which to create the instrument [6, 10]

Drum	Instrument type definition	Value
Bass	INSTRUMENT_TYPE_BASS	6
Snare	INSTRUMENT_TYPE_SNARE	7
Tom tom	INSTRUMENT_TYPE_TOM	8
Cymbal	INSTRUMENT_TYPE_CYMBAL	9
Hi-hat	INSTRUMENT_TYPE_HI_HAT	10

Returns

Instrument New Instrument structure converted from the the channel used for the given drum type