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//
// dolmetschctl
//
//
// Copyright (C) 2019 Christian Pointner <equinox@spreadspace.org>
//
// This file is part of dolmetschctl.
//
// dolmetschctl is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// any later version.
//
// dolmetschctl is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
//
package mixer
import (
"errors"
"log"
"strings"
"github.com/scgolang/midi"
)
type Channel uint8
type FaderLevel uint8
type Mixer struct {
DevIn *midi.Device
DevOut *midi.Device
}
// TODO: make this confgurabel
const (
CC_MUTE = byte(0xB1)
CC_FADER = byte(0xB0)
FaderLevelMax = FaderLevel(0x7F)
FaderLevel0db = FaderLevel(0x60)
FaderLevelOff = FaderLevel(0x00)
)
func openDevice(devices []*midi.Device, prefix string) (d *midi.Device, err error) {
for _, device := range devices {
if strings.HasPrefix(device.Name, prefix) {
d = device
}
}
if d == nil {
return nil, errors.New("could not find device with prefix " + prefix)
}
return d, d.Open()
}
func NewMixer(c Config) (*Mixer, error) {
devices, err := midi.Devices()
if err != nil {
return nil, err
}
m := &Mixer{}
if m.DevIn, err = openDevice(devices, c.DevIn); err != nil {
return nil, err
}
if m.DevOut, err = openDevice(devices, c.DevOut); err != nil {
return nil, err
}
m.DevIn.QueueSize = 100
m.DevOut.QueueSize = 100
return m, nil
}
func (m *Mixer) Init() error {
ch, err := m.DevIn.Packets()
if err != nil {
return err
}
go func() {
for {
p := <-ch
log.Printf("mixer: got packet: '%v'", p)
// TODO: send to subscribers
}
}()
return nil
}
func (m *Mixer) Shutdown() error {
if m.DevIn != nil {
m.DevIn.Close()
}
if m.DevOut != nil {
m.DevOut.Close()
}
return nil
}
func (m *Mixer) sendMute(channel byte, value byte) error {
n, err := m.DevOut.Write([]byte{CC_MUTE, channel, value})
if err != nil {
return err
}
if n != 3 {
return errors.New("sending mute command failed.")
}
return nil
}
func (m *Mixer) Mute(ch Channel) error {
return m.sendMute(byte(ch), 0x7F)
}
func (m *Mixer) UnMute(ch Channel) error {
return m.sendMute(byte(ch), 0x00)
}
func (m *Mixer) SetLevel(ch Channel, level FaderLevel) error {
if level > FaderLevelMax {
level = FaderLevelMax
}
n, err := m.DevOut.Write([]byte{CC_FADER, byte(ch), byte(level)})
if err != nil {
return err
}
if n != 3 {
return errors.New("setting fader level failed.")
}
return nil
}
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