/
tracker.go
242 lines (215 loc) · 5.01 KB
/
tracker.go
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package tracker
import (
"audio"
"bytes"
"encoding/gob"
"fmt"
"io"
"io/ioutil"
"time"
)
// A mockGenerator is only intended for testing or debugging.
type MockGenerator struct{}
func (m MockGenerator) Play(e Event) {}
func (m MockGenerator) String() string { return "Mock generator." }
func (e Event) String() string {
return fmt.Sprintf("%v %v", e.NoteNum, e.Velocity)
}
type AudioGenerator struct {
Sampler *audio.Sampler
}
func NewAudioGenerator(filepath string) (*AudioGenerator, error) {
a := AudioGenerator{}
if s, err := audio.NewLoadedSampler(filepath); err != nil {
return &AudioGenerator{}, err
} else {
a.Sampler = s
}
return &a, nil
}
func (a AudioGenerator) Play(e Event) {
go a.Sampler.Play(e.NoteNum, float32(e.Velocity)/127.0)
}
func (a AudioGenerator) String() string {
return "Audio generator." // TODO(aoeu): Return something useful.
}
func NewTrack(g Generator, velocity int, notes ...int) *Track {
t := make(Track, len(notes))
for i := 0; i < len(t); i++ {
t[i] = &Event{Generator: g, NoteNum: notes[i], Velocity: velocity}
}
return &t
}
func NewPattern(filePath string) (*Pattern, error) {
b, err := ioutil.ReadFile(filePath)
if err != nil {
return &Pattern{}, err
}
// TODO(aoeu): Is there a programmatic way of registering the types?
gob.Register(Pattern{})
gob.Register(MockGenerator{})
dec := gob.NewDecoder(bytes.NewReader(b))
pat := Pattern{}
err = dec.Decode(&pat)
if err != nil && err != io.EOF {
return &Pattern{}, err
}
return &pat, nil
}
func (p Pattern) maxTrackLen() int {
maxLen := 0
for _, track := range p {
if len(track) > maxLen {
maxLen = len(track)
}
}
return maxLen
}
func (p Pattern) minTrackLen() int {
// TODO(aoeu): Is this actually needed?
minLen := int(^uint(0) >> 1)
for _, track := range p {
if len(track) < minLen {
minLen = len(track)
}
}
return minLen
}
// GetLine returns a Line containing the Events
// associated with all of the Tracks at a given
// offest in a Pattern.
//
// If a Pattern is thought of as a "table", and
// Tracks are thought of as "columns", GetLine
// returns "row" of the table.
func (p Pattern) GetLine(offset int) Line {
l := make(Line, len(p))
for i, track := range p {
switch {
case len(track) > offset:
l[i] = track[offset]
default:
l[i] = &Event{}
}
}
return l
}
// GetLines returns a series of Line types
// containing the Events associated with all of
// the Tracks in a Pattern.
//
// Any Track that is shorter in length than others
// in the pattern is still still represented in a
// respective Line with empty Event values (as padding).
func (p Pattern) GetLines() []Line {
maxTrackLen := p.maxTrackLen()
l := make([]Line, maxTrackLen)
for i := range l {
l[i] = p.GetLine(i)
}
return l
}
func NewPlayer(filepath string) (*Player, error) {
p := Player{}
p.PatternTable = make(PatternTable, 1)
if pattern, err := NewPattern(filepath); err != nil {
return &Player{}, err
} else {
p.PatternTable[0] = pattern
}
p.BPM = 120 // TODO(aoeu): Don't hardcode the BPM.
return &p, nil
}
func (t *Tracker) TogglePlayback() {
if t.isPlaying {
t.Stop()
} else {
go t.Play()
}
}
func (t *Tracker) Stop() {
t.stop <- true
}
func (t *Tracker) Play() {
t.isPlaying = true
defer func() {
t.isPlaying = false
t.screen.lineOffset = -1
t.screen.redraw <- true
}()
// TODO(aoeu): Can pieces of this be decoupled from Tracker?
nsPerBeat := 60000000000 / t.Player.BPM
for _, pattern := range t.Player.PatternTable {
for _, line := range pattern.GetLines() {
t.screen.lineOffset += 1
t.screen.redraw <- true
for _, e := range line {
if e.Generator != nil {
// TODO(aoeu): Reconsider ownership of Events and Generators.
go e.Generator.Play(*e)
}
}
select {
case <-time.After(time.Duration(nsPerBeat) * time.Nanosecond):
case <-t.stop:
return
}
}
}
}
func (t *Tracker) ApplySampler(samplerConfig string) error {
g, err := NewAudioGenerator(samplerConfig)
if err != nil {
return err
}
if err := g.Sampler.Run(); err != nil {
return err
}
for _, pattern := range t.Player.PatternTable {
pattern.ApplyGenerator(g)
}
return nil
}
func (p *Pattern) ApplyGenerator(g Generator) {
for _, track := range *p {
track.ApplyGenerator(g)
}
}
func (t *Track) ApplyGenerator(g Generator) {
for _, e := range *t {
e.Generator = g
}
}
func NewTracker(trkrFilepath string) (*Tracker, error) {
t := Tracker{}
if p, err := NewPlayer(trkrFilepath); err != nil {
return &Tracker{}, err
} else {
t.Player = p
}
t.screen = NewScreen()
t.screen.currentPattern = t.Player.PatternTable[0]
t.stop = make(chan bool)
return &t, nil
}
func (p *Pattern) InsertAt(x, y int, e *Event) {
if len(*p) < x {
return //TODO - Return error ???????
}
t := (*p)[x]
l := len((*p)[x])
switch {
case l > y:
t[y].NoteNum, t[y].Velocity = e.NoteNum, e.Velocity
case l == y:
(*p)[x] = append(t, e)
fmt.Println("yea")
default:
k := make([]*Event, y-l)
for i := range k {
k[i] = &Event{}
}
(*p)[x] = append((*p)[x], k...)
(*p)[x] = append((*p)[x], e)
}
}