Increase tick rate for waveform visualizers from 20 to 30 FPS

Waveform modes (wave, scope, heartbeat) skip FFT entirely, so they can
tick faster without meaningful CPU cost. Adds TickWave (32ms) alongside
TickFast (50ms) and reuses the y-position buffer across frames to reduce
GC pressure.

Author: bjarneo

ui/tick.go

@@ -4,6 +4,7 @@ import "time"
 
 // Tick intervals: fast for visualizer animation, slow for time/seek display.
 const (
-	TickFast = 50 * time.Millisecond  // 20 FPS — visualizer active
+	TickWave = 32 * time.Millisecond  // ~30 FPS — waveform modes (no FFT)
+	TickFast = 50 * time.Millisecond  // 20 FPS — spectrum modes (FFT)
 	TickSlow = 200 * time.Millisecond // 5 FPS — visualizer off or overlay
 )

ui/vis_wave.go

@@ -14,7 +14,12 @@ func (v *Visualizer) renderWave() string {
 	n := len(samples)
 
 	// Downsample audio to one y-position per horizontal dot column.
-	ypos := make([]int, dotCols)
+	if cap(v.waveYBuf) >= dotCols {
+		v.waveYBuf = v.waveYBuf[:dotCols]
+	} else {
+		v.waveYBuf = make([]int, dotCols)
+	}
+	ypos := v.waveYBuf
 	for x := range dotCols {
 		var sample float64
 		if n > 0 {

ui/visualizer.go

@@ -231,8 +231,9 @@ type visEntry struct {
 }
 
 type renderOnlyDriver struct {
-	spec   VisAnalysisSpec
-	render func(*Visualizer, []float64) string
+	spec         VisAnalysisSpec
+	render       func(*Visualizer, []float64) string
+	tickDuration time.Duration // 0 = use defaultDriverTickInterval
 }
 
 func (d *renderOnlyDriver) AnalysisSpec(*Visualizer) VisAnalysisSpec {
@@ -247,7 +248,10 @@ func (d *renderOnlyDriver) Tick(v *Visualizer, ctx VisTickContext) {
 	defaultDriverTick(v, ctx, d.spec)
 }
 
-func (*renderOnlyDriver) TickInterval(_ *Visualizer, ctx VisTickContext) time.Duration {
+func (d *renderOnlyDriver) TickInterval(_ *Visualizer, ctx VisTickContext) time.Duration {
+	if d.tickDuration > 0 && ctx.Playing && !ctx.OverlayActive {
+		return d.tickDuration
+	}
 	return defaultDriverTickInterval(ctx)
 }
 
@@ -275,6 +279,12 @@ func newRenderOnlyDriver(spec VisAnalysisSpec, render func(*Visualizer, []float6
 	}
 }
 
+func newFastRenderOnlyDriver(spec VisAnalysisSpec, tick time.Duration, render func(*Visualizer, []float64) string) func() visModeDriver {
+	return func() visModeDriver {
+		return &renderOnlyDriver{spec: NormalizeAnalysisSpec(spec), render: render, tickDuration: tick}
+	}
+}
+
 func newNoOpDriver() visModeDriver {
 	return &noOpDriver{}
 }
@@ -315,6 +325,7 @@ type Visualizer struct {
 	Mode           VisMode
 	Rows           int       // display height in terminal rows (default 5)
 	waveBuf        []float64 // raw samples for wave mode
+	waveYBuf       []int     // reusable y-position buffer for wave rendering
 	frame          uint64    // tick-driven animation clock
 	sampleBuf      []float64 // reusable buffer for reading audio tap samples
 	drivers        [VisCount]visModeDriver
@@ -362,7 +373,7 @@ var visModes = [VisCount]visEntry{
 	VisBricks:      {"Bricks", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderBricks)},
 	VisColumns:     {"Columns", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderColumns)},
 	VisClassicPeak: {"ClassicPeak", newClassicPeakDriver},
-	VisWave:        {"Wave", newRenderOnlyDriver(spectrumAnalysisSpec(0), func(v *Visualizer, _ []float64) string { return v.renderWave() })},
+	VisWave:        {"Wave", newFastRenderOnlyDriver(spectrumAnalysisSpec(0), TickWave, func(v *Visualizer, _ []float64) string { return v.renderWave() })},
 	VisScatter:     {"Scatter", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderScatter)},
 	VisFlame:       {"Flame", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderFlame)},
 	VisRetro:       {"Retro", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderRetro)},
@@ -373,8 +384,8 @@ var visModes = [VisCount]visEntry{
 	VisFirework:    {"Firework", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderFirework)},
 	VisLogo:        {"Logo", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderLogo)},
 	VisTerrain:     {"Terrain", newTerrainDriver},
-	VisScope:       {"Scope", newRenderOnlyDriver(spectrumAnalysisSpec(0), func(v *Visualizer, _ []float64) string { return v.renderScope() })},
-	VisHeartbeat:   {"Heartbeat", newRenderOnlyDriver(spectrumAnalysisSpec(0), func(v *Visualizer, _ []float64) string { return v.renderHeartbeat() })},
+	VisScope:       {"Scope", newFastRenderOnlyDriver(spectrumAnalysisSpec(0), TickWave, func(v *Visualizer, _ []float64) string { return v.renderScope() })},
+	VisHeartbeat:   {"Heartbeat", newFastRenderOnlyDriver(spectrumAnalysisSpec(0), TickWave, func(v *Visualizer, _ []float64) string { return v.renderHeartbeat() })},
 	VisButterfly:   {"Butterfly", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderButterfly)},
 	VisAscii:       {"Ascii", newRenderOnlyDriver(spectrumAnalysisSpec(DefaultSpectrumBands), (*Visualizer).renderAscii)},
 	VisNone:        {"None", newNoOpDriver},