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gurixandClaude Opus 4.6 6b2db48339 feat(synth): add LFO modulation, ADSR envelopes, pentatonic tuning, and soft limiter
Replace static EMA-smoothed drones with an evolving ambient soundscape:
- ADSR envelope system with sustained (2s attack, 4s release) and bursty
  (30ms attack, no sustain) modes per protocol group
- LFO pitch wobble and amplitude tremolo with incommensurable rates per
  group (Eno technique) so modulation patterns never repeat
- C major pentatonic frequency tuning (just intonation) — any combination
  of active protocols sounds consonant
- tanh soft limiter on master output prevents clipping
- Sync all documentation: README, PROJECT.md, ARCHITECTURE.md, v1.2
  requirements traceability

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-27 19:38:58 +01:00

124 lines
3.2 KiB
Go

package synth_test
import (
"testing"
"github.com/netsynth/netsynth/synth"
)
func TestEnvelopeAttackRise(t *testing.T) {
// Sustained protocol (Bursty=false): slow 2s attack
cfg := synth.FreqConfig{
BaseHz: 440.0,
Harmonics: []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}},
Pan: 0.0,
Group: "Web",
}
layer := synth.NewLayer(cfg, synth.SampleRate, 1.0)
// Trigger envelope by sending traffic
layer.UpdateTarget(100, 100)
// After 2 seconds (full attack), envelope level should be significant
for i := 0; i < synth.SampleRate*2; i++ {
layer.AdvanceSample()
}
if layer.CurrentAmp() <= 0.5 {
t.Errorf("expected envelope level > 0.5 after 2 second attack, got %.4f", layer.CurrentAmp())
}
}
func TestBurstyEnvelopeFastAttack(t *testing.T) {
// Bursty protocol: fast 30ms attack
cfg := synth.FreqConfig{
BaseHz: 440.0,
Harmonics: []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}},
Pan: 0.0,
Group: "Infrastructure",
Bursty: true,
}
layer := synth.NewLayer(cfg, synth.SampleRate, 1.0)
layer.UpdateTarget(100, 100)
// After 100ms, bursty envelope should have peaked and be decaying
for i := 0; i < synth.SampleRate/10; i++ {
layer.AdvanceSample()
}
// Bursty: sustain=0, so it should already be fading
// But it should have been triggered (not zero at peak)
if !layer.Seen() {
t.Error("expected layer.Seen() to be true after receiving traffic")
}
}
func TestEnvelopeRelease(t *testing.T) {
cfg := synth.FreqConfig{
BaseHz: 440.0,
Harmonics: []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}},
Pan: 0.0,
Group: "Web",
}
layer := synth.NewLayer(cfg, synth.SampleRate, 1.0)
// Build up
layer.UpdateTarget(100, 100)
for i := 0; i < synth.SampleRate*3; i++ {
layer.AdvanceSample()
}
peakAmp := layer.CurrentAmp()
// Release: set count to 0
layer.UpdateTarget(0, 100)
for i := 0; i < synth.SampleRate*5; i++ {
layer.AdvanceSample()
}
// After 5 seconds of release (release time is 4s), should be much lower
if layer.CurrentAmp() >= peakAmp*0.5 {
t.Errorf("expected envelope to decay significantly, peak=%.4f, current=%.4f", peakAmp, layer.CurrentAmp())
}
}
func TestLayerNotSeenIssilent(t *testing.T) {
cfg := synth.FreqConfig{
BaseHz: 440.0,
Harmonics: []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}},
Pan: 0.0,
Group: "Web",
}
layer := synth.NewLayer(cfg, synth.SampleRate, 1.0)
// Never seen — UpdateTarget with zero count
layer.UpdateTarget(0, 100)
if layer.Seen() {
t.Error("expected Seen()=false for layer that never had traffic")
}
// Advance some samples — output should be zero
for i := 0; i < 100; i++ {
sample := layer.AdvanceSample()
if sample != 0 {
t.Errorf("expected zero output for unseen layer, got %v at sample %d", sample, i)
break
}
}
}
func TestLayerSeenFlag(t *testing.T) {
cfg := synth.FreqConfig{
BaseHz: 440.0,
Harmonics: []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}},
Pan: 0.0,
Group: "Web",
}
layer := synth.NewLayer(cfg, synth.SampleRate, 1.0)
if layer.Seen() {
t.Error("expected Seen()=false initially")
}
layer.UpdateTarget(1, 100)
if !layer.Seen() {
t.Error("expected Seen()=true after receiving traffic")
}
}