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packages.dart/deprecated/flutter_midi/macos/Classes/AudioUnitMIDISynth.swift
2026-01-15 14:38:46 -08:00

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Swift
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//
// AudioUnitMIDISynth.swift
// MIDISynth
//
// Created by Gene De Lisa on 2/6/16.
// Copyright © 2016 Gene De Lisa. All rights reserved.
//
import Foundation
import AudioToolbox
import CoreAudio
// swiftlint:disable function_body_length
// swiftlint:disable type_body_length
// swiftlint:disable file_length
// swiftlint:disable line_length
/// # A Core Audio MIDISynth `AudioUnit` example.
/// This will add a polyphonic `kAudioUnitSubType_MIDISynth` audio unit to the `AUGraph`.
///
/// - author: Gene De Lisa
/// - copyright: 2016 Gene De Lisa
/// - date: February 2016
class AudioUnitMIDISynth: NSObject {
var processingGraph: AUGraph?
var midisynthNode = AUNode()
var ioNode = AUNode()
var midisynthUnit: AudioUnit?
var ioUnit: AudioUnit?
var musicSequence: MusicSequence!
var musicPlayer: MusicPlayer!
let patch1 = UInt32(46)
let patch2 = UInt32(0)
var pitch = UInt32(60)
var bankUrl: URL!
init(soundfont: URL) {
super.init()
prepare(soundfont:soundfont)
}
func prepare(soundfont: URL) {
bankUrl = soundfont;
augraphSetup()
loadMIDISynthSoundFont()
initializeGraph()
self.musicSequence = createMusicSequence()
musicPlayer = createPlayer(musicSequence)
loadPatches()
startGraph()
}
/// Create the `AUGraph`, the nodes and units, then wire them together.
func augraphSetup() {
var status = OSStatus(noErr)
status = NewAUGraph(&processingGraph)
// // AudioUtils.CheckError(status)
createIONode()
createSynthNode()
// now do the wiring. The graph needs to be open before you call AUGraphNodeInfo
status = AUGraphOpen(self.processingGraph!)
// // AudioUtils.CheckError(status)
status = AUGraphNodeInfo(self.processingGraph!, self.midisynthNode, nil, &midisynthUnit)
// AudioUtils.CheckError(status)
status = AUGraphNodeInfo(self.processingGraph!, self.ioNode, nil, &ioUnit)
// AudioUtils.CheckError(status)
let synthOutputElement: AudioUnitElement = 0
let ioUnitInputElement: AudioUnitElement = 0
status = AUGraphConnectNodeInput(self.processingGraph!,
self.midisynthNode, synthOutputElement, // srcnode, SourceOutputNumber
self.ioNode, ioUnitInputElement) // destnode, DestInputNumber
// AudioUtils.CheckError(status)
}
/// Create the Output Node and add it to the `AUGraph`.
func createIONode() {
var cd = AudioComponentDescription(
componentType: OSType(kAudioUnitType_Output),
componentSubType: OSType(kAudioUnitSubType_MIDISynth),
componentManufacturer: OSType(kAudioUnitManufacturer_Apple),
componentFlags: 0, componentFlagsMask: 0)
let status = AUGraphAddNode(self.processingGraph!, &cd, &ioNode)
// AudioUtils.CheckError(status)
}
/// Create the Synth Node and add it to the `AUGraph`.
func createSynthNode() {
var cd = AudioComponentDescription(
componentType: OSType(kAudioUnitType_MusicDevice),
componentSubType: OSType(kAudioUnitSubType_MIDISynth),
componentManufacturer: OSType(kAudioUnitManufacturer_Apple),
componentFlags: 0, componentFlagsMask: 0)
// let status = AUGraphAddNode(self.processingGraph!, &cd, &midisynthNode)
// AudioUtils.CheckError(status)
}
/// This will load the default sound font and set the synth unit's property.
/// - postcondition: `self.midisynthUnit` will have it's sound font url set.
func loadMIDISynthSoundFont() {
if var bankURL = bankUrl {
let status = AudioUnitSetProperty(
self.midisynthUnit!,
AudioUnitPropertyID(kMusicDeviceProperty_SoundBankURL),
AudioUnitScope(kAudioUnitScope_Global),
0,
&bankURL,
UInt32(MemoryLayout<URL>.size))
// AudioUtils.CheckError(status)
print("loaded sound font")
} else {
print("Could not load sound font")
}
}
/// Pre-load the patches you will use.
///
/// Turn on `kAUMIDISynthProperty_EnablePreload` so the midisynth will load the patch data from the file into memory.
/// You load the patches first before playing a sequence or sending messages.
/// Then you turn `kAUMIDISynthProperty_EnablePreload` off. It is now in a state where it will respond to MIDI program
/// change messages and switch to the already cached instrument data.
///
/// - precondition: the graph must be initialized
///
/// [Doug's post](http://prod.lists.apple.com/archives/coreaudio-api/2016/Jan/msg00018.html)
func loadPatches() {
if !isGraphInitialized() {
fatalError("initialize graph first")
}
let channel = UInt32(0)
var enabled = UInt32(1)
var status = AudioUnitSetProperty(
self.midisynthUnit!,
AudioUnitPropertyID(kAUMIDISynthProperty_EnablePreload),
AudioUnitScope(kAudioUnitScope_Global),
0,
&enabled,
UInt32(MemoryLayout<UInt32>.size))
// AudioUtils.CheckError(status)
// let bankSelectCommand = UInt32(0xB0 | 0)
// status = MusicDeviceMIDIEvent(self.midisynthUnit, bankSelectCommand, 0, 0, 0)
let pcCommand = UInt32(0xC0 | channel)
status = MusicDeviceMIDIEvent(self.midisynthUnit!, pcCommand, patch1, 0, 0)
// AudioUtils.CheckError(status)
status = MusicDeviceMIDIEvent(self.midisynthUnit!, pcCommand, patch2, 0, 0)
// AudioUtils.CheckError(status)
enabled = UInt32(0)
status = AudioUnitSetProperty(
self.midisynthUnit!,
AudioUnitPropertyID(kAUMIDISynthProperty_EnablePreload),
AudioUnitScope(kAudioUnitScope_Global),
0,
&enabled,
UInt32(MemoryLayout<UInt32>.size))
// AudioUtils.CheckError(status)
// at this point the patches are loaded. You still have to send a program change at "play time" for the synth
// to switch to that patch
}
/// Check to see if the `AUGraph` is Initialized.
///
/// - returns: `true` if it's running, `false` if not
/// - seealso: [AUGraphIsInitialized](/https://developer.apple.com/library/prerelease/ios/documentation/AudioToolbox/Reference/AUGraphServicesReference/index.html#//apple_ref/c/func/AUGraphIsInitialized)
func isGraphInitialized() -> Bool {
var outIsInitialized = DarwinBoolean(false)
let status = AUGraphIsInitialized(self.processingGraph!, &outIsInitialized)
// AudioUtils.CheckError(status)
return outIsInitialized.boolValue
}
/// Initializes the `AUGraph.
func initializeGraph() {
let status = AUGraphInitialize(self.processingGraph!)
// AudioUtils.CheckError(status)
}
/// Starts the `AUGraph`
func startGraph() {
let status = AUGraphStart(self.processingGraph!)
// AudioUtils.CheckError(status)
}
/// Check to see if the `AUGraph` is running.
///
/// - returns: `true` if it's running, `false` if not
func isGraphRunning() -> Bool {
var isRunning = DarwinBoolean(false)
let status = AUGraphIsRunning(self.processingGraph!, &isRunning)
// AudioUtils.CheckError(status)
return isRunning.boolValue
}
/// Generate a random pitch between 36 (C below middle C) and 100.
///
/// - postcondition: self.pitch is modified
func generateRandomPitch() {
pitch = arc4random_uniform(64) + 36 // 36 - 100
}
// /// Send a note on message using patch1 on channel 0
// func playPatch1On() {
//
// let channel = UInt32(0)
// let noteCommand = UInt32(0x90 | channel)
// let pcCommand = UInt32(0xC0 | channel)
// var status = OSStatus(noErr)
//
// generateRandomPitch()
// print(pitch)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, pcCommand, patch1, 0, 0)
// // AudioUtils.CheckError(status)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, pitch, 64, 0)
// // AudioUtils.CheckError(status)
// }
//
// /// Send a note off message using patch1 on channel 0
// func playPatch1Off() {
// let channel = UInt32(0)
// let noteCommand = UInt32(0x80 | channel)
// var status = OSStatus(noErr)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, pitch, 0, 0)
// // AudioUtils.CheckError(status)
// }
//
// /// Send a note on message using patch2 on channel 0
// func playPatch2On(midi: Int) {
//
// let channel = UInt32(0)
// let noteCommand = UInt32(0x90 | channel)
// let pcCommand = UInt32(0xC0 | channel)
// var status = OSStatus(noErr)
// pitch = UInt32(midi)
// //generateRandomPitch()
// print(pitch)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, pcCommand, patch2, 0, 0)
// // AudioUtils.CheckError(status)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, pitch, 64, 0)
// // AudioUtils.CheckError(status)
// }
//
// /// Send a note off message using patch2 on channel 0
// func playPatch2Off() {
// let channel = UInt32(0)
// let noteCommand = UInt32(0x80 | channel)
// var status = OSStatus(noErr)
// status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, pitch, 0, 0)
// // AudioUtils.CheckError(status)
// }
//
/// Send a note on message using patch2 on channel 0
func playPitch(midi: Int, velocity: Int) {
let channel = UInt32(0)
let noteCommand = UInt32(0x90 | channel)
let pcCommand = UInt32(0xC0 | channel)
var status = OSStatus(noErr)
status = MusicDeviceMIDIEvent(self.midisynthUnit!, pcCommand, patch2, 0, 0)
// AudioUtils.CheckError(status)
status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, UInt32(midi), UInt32(velocity), 0)
// AudioUtils.CheckError(status)
}
/// Send a note off message using patch2 on channel 0
func stopPitch(midi: Int, velocity: Int) {
let channel = UInt32(0)
let noteCommand = UInt32(0x80 | channel)
var status = OSStatus(noErr)
status = MusicDeviceMIDIEvent(self.midisynthUnit!, noteCommand, UInt32(midi), UInt32(velocity), 0)
// AudioUtils.CheckError(status)
}
/// Create a test `MusicSequence`.
///
/// - throws: Nothing, but it should
/// - todo: create an `ErrorType` ennum
/// - returns: a `MusicSequence`
func createMusicSequence() -> MusicSequence {
var musicSequence: MusicSequence?
var status = NewMusicSequence(&musicSequence)
if status != noErr {
print("\(#line) bad status \(status) creating sequence")
}
// add a track
var track: MusicTrack?
status = MusicSequenceNewTrack(musicSequence!, &track)
if status != noErr {
print("error creating track \(status)")
}
var channel = UInt8(0)
// bank select msb
var chanmess = MIDIChannelMessage(status: 0xB0 | channel, data1: 0, data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating bank select event \(status)")
}
// bank select lsb
chanmess = MIDIChannelMessage(status: 0xB0 | channel, data1: 32, data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating bank select event \(status)")
}
// program change. first data byte is the patch, the second data byte is unused for program change messages.
chanmess = MIDIChannelMessage(status: 0xC0 | channel, data1: UInt8(patch1), data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating program change event \(status)")
}
// now make some notes and put them on the track
var beat = MusicTimeStamp(0.0)
for i: UInt8 in 60...72 {
var mess = MIDINoteMessage(channel: channel,
note: i,
velocity: 64,
releaseVelocity: 0,
duration: 1.0 )
status = MusicTrackNewMIDINoteEvent(track!, beat, &mess)
if status != noErr {
print("creating new midi note event \(status)")
}
beat += 1
}
// another track
channel = UInt8(1)
track = nil
status = MusicSequenceNewTrack(musicSequence!, &track)
if status != noErr {
print("error creating track \(status)")
}
chanmess = MIDIChannelMessage(status: 0xB0 | channel, data1: 0, data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating bank select msb event \(status)")
}
chanmess = MIDIChannelMessage(status: 0xB0 | channel, data1: 32, data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating bank select lsb event \(status)")
}
chanmess = MIDIChannelMessage(status: 0xC0 | channel, data1: UInt8(patch2), data2: 0, reserved: 0)
status = MusicTrackNewMIDIChannelEvent(track!, 0, &chanmess)
if status != noErr {
print("creating program change event \(status)")
}
beat = MusicTimeStamp(3.0)
for i: UInt8 in 60...72 {
var mess = MIDINoteMessage(channel: channel,
note: i,
velocity: 36,
releaseVelocity: 0,
duration: 1.0 )
status = MusicTrackNewMIDINoteEvent(track!, beat, &mess)
if status != OSStatus(noErr) {
print("creating new midi note event \(status)")
}
beat += 1
}
// associate the AUGraph with the sequence.
status = MusicSequenceSetAUGraph(musicSequence!, self.processingGraph)
// Let's see it
CAShow(UnsafeMutablePointer<MusicSequence>(musicSequence!))
return musicSequence!
}
/// Create a `MusicPlayer` with the specified sequence.
///
/// - parameters:
/// - musicSequence: a valid `MusicSequence` instance
/// - throws: Nothing, but it should
/// - todo: create an `ErrorType` ennum
/// - returns: a `MusicPlayer`
func createPlayer(_ musicSequence: MusicSequence) -> MusicPlayer {
var musicPlayer: MusicPlayer?
var status = NewMusicPlayer(&musicPlayer)
if status != OSStatus(noErr) {
print("bad status \(status) creating player")
// AudioUtils.CheckError(status)
}
status = MusicPlayerSetSequence(musicPlayer!, musicSequence)
if status != OSStatus(noErr) {
print("setting sequence \(status)")
// AudioUtils.CheckError(status)
}
status = MusicPlayerPreroll(musicPlayer!)
if status != OSStatus(noErr) {
print("prerolling player \(status)")
// AudioUtils.CheckError(status)
}
return musicPlayer!
}
/// Make the `MusicPlayer` play its sequence
/// - throws: Nothing, but it should
/// - todo: create an `ErrorType` ennum
func musicPlayerPlay() {
var status = noErr
var playing: DarwinBoolean = false
status = MusicPlayerIsPlaying(musicPlayer, &playing)
if playing != false {
status = MusicPlayerStop(musicPlayer)
if status != noErr {
print("Error stopping \(status)")
// AudioUtils.CheckError(status)
return
}
}
status = MusicPlayerSetTime(musicPlayer, 0)
if status != noErr {
print("setting time \(status)")
// AudioUtils.CheckError(status)
return
}
status = MusicPlayerStart(musicPlayer)
if status != noErr {
print("Error starting \(status)")
// AudioUtils.CheckError(status)
return
}
}
}