#!/usr/bin/env ruby

def note_on(delay, channel, note, volume)
    # note on
    putc delay * 6
    putc 0x90 + channel
    putc note
    putc volume
end

def note_off(delay, channel, note)
    # note on
    putc delay * 6
    putc 0x80 + channel
    putc note
    putc 0x00
end

def program_change(delay, channel, instrument)
    putc delay * 6
    putc 0xc0 + channel
    putc instrument
end

def end_of_track

    putc 0x00
    putc 0xff
    putc 0x2f
    putc 0x00

end

# Instrument 20 has normal tuning, instrument 21 is -3

program_change(0x1, 1, 20)
program_change(0x1, 2, 21)

# Play through some notes, making the same note on each of the two channels.

for i in 10..64
    note_on(10, 1, i, 100)
    note_on(10, 2, i, 100)
    note_off(10, 1, i)
    note_off(0, 2, i)
end

# end of track

end_of_track