General Midi Constants

package cas.cs4tb3.mellowd.midi;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

This class will house various MIDI constants for reference throughout the compiler. The MIDI protocol has many constants that are standard despite seeming out of place and so it is important for the meaning behind the various numbers to be explicitly stated.

public class GeneralMidiConstants {

In GM1 standard there are 16 MIDI channels. Channel 10 (index 9) is the channel set aside for percussion and will sound different than the regular channels in that notes played on the drum channels are sound mappings for percussion noises and not pitches.

    public static final Set<Integer> REGULAR_CHANNELS;
    public static final Set<Integer> DRUM_CHANNELS;

    static {

Firstly build the regular channel set

        Set<Integer> regChannels = new HashSet<>();
        for (int i = 0; i < 10; i++)
            regChannels.add(i);
        for (int i = 11; i < 16; i++)
            regChannels.add(i);

Then wrap channel 9 in a set because in other standards the drum channels span multiple channels and so the compiler is setup to take more than one.

        Set<Integer> drumChannels = new HashSet<>();
        drumChannels.add(9);

Lastly wrap the exposed fields in unmodifiable sets and assign them to their respective fields.

        REGULAR_CHANNELS = Collections.unmodifiableSet(regChannels);
        DRUM_CHANNELS = Collections.unmodifiableSet(drumChannels);
    }

The pitch bend controller value that resets the pitch bend. This value sets the bend to no bend.

    public static final int NO_PITCH_BEND = 8192;

In GM2 a standard controller message was assigned for switching the sound bank to support more instruments. The first message is a controller change with controller BANK_SELECT_CC_1 and value BANK_SELECT_CC_1_VAL. This is followed by a controller change for controller BANK_SELECT_CC_2 with a value specifying the bank number.

Following the bank switch a regular instrument change message will select an instrument from that bank.

    public static final int BANK_SELECT_CC_1 = 0;
    public static final int BANK_SELECT_CC_1_VAL = 121;
    public static final int BANK_SELECT_CC_2 = 32;
}