feat(tracker, gioui): add visual indicators to show which instruments are playing

Closes #44

tracker/gioui/instruments.go

@@ -3,6 +3,8 @@ package gioui
 import (
 	"fmt"
 	"image"
+	"image/color"
+	"math"
 	"strconv"
 	"time"
 
@@ -129,6 +131,21 @@ func (t *Tracker) layoutInstrumentNames(gtx C) D {
 			grabhandle.Text = ":::"
 		}
 		label := func(gtx C) D {
+			c := 0.0
+			voice := t.Song().Patch.FirstVoiceForInstrument(i)
+			for j := 0; j < t.Song().Patch[i].NumVoices; j++ {
+				released, event := t.player.VoiceState(voice)
+				vc := math.Exp(-float64(event)/15000) * .5
+				if !released {
+					vc += .5
+				}
+				if c < vc {
+					c = vc
+				}
+				voice++
+			}
+			k := byte(255 - c*127)
+			color := color.NRGBA{R: 255, G: k, B: 255, A: 255}
 			if i == t.InstrIndex() {
 				for _, ev := range t.InstrumentNameEditor.Events() {
 					_, ok := ev.(widget.SubmitEvent)
@@ -141,7 +158,7 @@ func (t *Tracker) layoutInstrumentNames(gtx C) D {
 					t.InstrumentNameEditor.SetText(n)
 				}
 				editor := material.Editor(t.Theme, t.InstrumentNameEditor, "Instr")
-				editor.Color = instrumentNameColor
+				editor.Color = color
 				editor.HintColor = instrumentNameHintColor
 				editor.TextSize = unit.Dp(12)
 				dims := layout.Center.Layout(gtx, editor.Layout)
@@ -152,7 +169,7 @@ func (t *Tracker) layoutInstrumentNames(gtx C) D {
 			if text == "" {
 				text = "Instr"
 			}
-			labelStyle := LabelStyle{Text: text, ShadeColor: black, Color: white, FontSize: unit.Sp(12)}
+			labelStyle := LabelStyle{Text: text, ShadeColor: black, Color: color, FontSize: unit.Sp(12)}
 			return layout.Center.Layout(gtx, labelStyle.Layout)
 		}
 		return layout.Inset{Left: unit.Dp(6), Right: unit.Dp(6)}.Layout(gtx, func(gtx C) D {

tracker/player.go

@@ -13,12 +13,13 @@ type Player struct {
 
 	playCmds chan uint64
 
-	mutex         sync.Mutex
-	runningID     uint32
-	voiceNoteID   []uint32
-	voiceReleased []bool
-	synth         sointu.Synth
-	patch         sointu.Patch
+	mutex             sync.Mutex
+	runningID         uint32
+	voiceNoteID       []uint32
+	voiceReleased     []int32
+	synth             sointu.Synth
+	patch             sointu.Patch
+	samplesSinceEvent []int32
 
 	synthNotNil int32
 }
@@ -66,6 +67,13 @@ func (p *Player) Enabled() bool {
 	return atomic.LoadInt32(&p.synthNotNil) == 1
 }
 
+func (p *Player) VoiceState(voice int) (bool, int) {
+	if voice >= len(p.samplesSinceEvent) || voice >= len(p.voiceReleased) {
+		return true, math.MaxInt32
+	}
+	return atomic.LoadInt32(&p.voiceReleased[voice]) == 1, int(atomic.LoadInt32(&p.samplesSinceEvent[voice]))
+}
+
 func NewPlayer(service sointu.SynthService, closer <-chan struct{}, patchs <-chan sointu.Patch, scores <-chan sointu.Score, samplesPerRows <-chan int, posChanged chan<- struct{}, syncOutput chan<- []float32, outputs ...chan<- []float32) *Player {
 	p := &Player{playCmds: make(chan uint64, 16)}
 	go func() {
@@ -189,6 +197,9 @@ func NewPlayer(service sointu.SynthService, closer <-chan struct{}, patchs <-cha
 						default:
 						}
 					}
+					for i := range p.samplesSinceEvent {
+						atomic.AddInt32(&p.samplesSinceEvent[i], int32(timeAdvanced))
+					}
 					for _, o := range outputs {
 						o <- buffer[:rendered*2]
 					}
@@ -243,7 +254,10 @@ func (p *Player) trigger(voiceStart, voiceEnd int, note byte) uint32 {
 	oldestVoice := 0
 	for i := voiceStart; i < voiceEnd; i++ {
 		for len(p.voiceReleased) <= i {
-			p.voiceReleased = append(p.voiceReleased, true)
+			p.voiceReleased = append(p.voiceReleased, 1)
+		}
+		for len(p.samplesSinceEvent) <= i {
+			p.samplesSinceEvent = append(p.samplesSinceEvent, 0)
 		}
 		for len(p.voiceNoteID) <= i {
 			p.voiceNoteID = append(p.voiceNoteID, 0)
@@ -253,7 +267,7 @@ func (p *Player) trigger(voiceStart, voiceEnd int, note byte) uint32 {
 		// case two voices are both playing or or both are released, we prefer
 		// the older one
 		id := p.voiceNoteID[i]
-		isReleased := p.voiceReleased[i]
+		isReleased := atomic.LoadInt32(&p.voiceReleased[i]) == 1
 		if id < oldestID && (oldestReleased == isReleased) || (!oldestReleased && isReleased) {
 			oldestVoice = i
 			oldestID = id
@@ -261,7 +275,8 @@ func (p *Player) trigger(voiceStart, voiceEnd int, note byte) uint32 {
 		}
 	}
 	p.voiceNoteID[oldestVoice] = newID
-	p.voiceReleased[oldestVoice] = false
+	atomic.StoreInt32(&p.voiceReleased[oldestVoice], 0)
+	atomic.StoreInt32(&p.samplesSinceEvent[oldestVoice], 0)
 	if p.synth != nil {
 		p.synth.Trigger(oldestVoice, note)
 	}
@@ -273,8 +288,9 @@ func (p *Player) release(ID uint32) {
 		return
 	}
 	for i := 0; i < len(p.voiceNoteID); i++ {
-		if p.voiceNoteID[i] == ID && !p.voiceReleased[i] {
-			p.voiceReleased[i] = true
+		if p.voiceNoteID[i] == ID && atomic.LoadInt32(&p.voiceReleased[i]) != 1 {
+			atomic.StoreInt32(&p.voiceReleased[i], 1)
+			atomic.StoreInt32(&p.samplesSinceEvent[i], 0)
 			p.synth.Release(i)
 			return
 		}