melrōse musical expression player

package midi import ( "fmt" "github.com/emicklei/melrose/core" "github.com/emicklei/melrose/midi/transport" "github.com/emicklei/melrose/notify" ) // https://www.midi.org/specifications-old/item/table-1-summary-of-midi-message const ( noteOn int64 = 0x90 // 10010000 , 144 noteOff int64 = 0x80 // 10000000 , 128 controlChange int64 = 0xB0 // 10110000 , 176 noteAllOff int64 = 0x78 // 01111000 , 120 (not 123 because sustain) sustainPedal int64 = 0x40 anyChannel int = -1 ) type Message struct { audioDevices core.AudioDevice status int deviceID core.HasValue channel core.HasValue data1 core.HasValue data2 core.HasValue } func NewMessage(audioDevices core.AudioDevice, id core.HasValue, status int, channel, data1, data2 core.HasValue) Message { return Message{audioDevices: audioDevices, deviceID: id, status: status, channel: channel, data1: data1, data2: data2} } // S has the side effect that the MIDI message is send using the device of the context func (m Message) S() core.Sequence { // post creation checks deviceID := core.Int(m.deviceID) channel := core.Int(m.channel) data1 := core.Int(m.data1) data2 := core.Int(m.data2) if notify.IsDebug() { notify.Debugf("midi.message: device=%d, status=%d channel=%v data1=%v data2=%v", deviceID, m.status, channel, data1, data2) } devices := m.audioDevices.(*DeviceRegistry) out, err := devices.Output(deviceID) if err != nil { notify.Console.Errorf("failed to send MIDI message(device=%d,status=%d,channel=%v,data1=%v,data2=%v) error:%v", deviceID, m.status, m.channel, m.data1, m.data2, err) return core.EmptySequence } if err := sendRaw(m.status, channel, data1, data2, out.stream); err != nil { notify.Console.Errorf("failed to send MIDI message(device=%d,status=%d,channel=%v,data1=%v,data2=%v) error:%v", deviceID, m.status, m.channel, m.data1, m.data2, err) } return core.EmptySequence } func (m Message) Storex() string { return fmt.Sprintf("midi_send(%v,%d,%v,%v,%v)", core.Storex(m.deviceID), m.status, core.Storex(m.channel), core.Storex(m.data1), core.Storex(m.data2)) } // Evaluate implements core.Evaluatable // perform the message send func (m Message) Evaluate(ctx core.Context) error { m.S() return nil } // if channel < then do not include that information func sendRaw(status, channel, data1, data2 int, out transport.MIDIOut) error { if channel < 1 { return out.WriteShort(int64(status), int64(data1), int64(data2)) } if channel > 16 { return fmt.Errorf("invalid MIDI channel:%d", channel) } return out.WriteShort(int64(status|(channel-1)), int64(data1), int64(data2)) }