Files
yoloyolo/synth/bank.go
T
gurix 23dcfdba1d feat(02-02): OscillatorBank multi-layer rendering from WindowSnapshot
- NewBank creates 11 layers from ClassFreqConfigs, one per TrafficClass
- RenderWindow transforms WindowSnapshot into SamplesPerWindow stereo frames
- GainPerLayer (1/11) applied per layer guarantees no clipping with all layers at max
- PanGains applied per layer for constant-power stereo positioning
- EMA amplitude smoothing provides temporal convergence across windows
- 7 bank tests: layer count, output length, silence, non-zero, no-clip, stereo pan, EMA convergence
2026-03-26 12:03:06 +01:00

59 lines
1.8 KiB
Go

package synth
import "github.com/netsynth/netsynth/classify"
// OscillatorBank holds 11 synthesis layers, one per TrafficClass.
// It consumes WindowSnapshot data and renders stereo PCM frames.
type OscillatorBank struct {
layers map[classify.TrafficClass]*Layer
tau float64
}
// NewBank creates an OscillatorBank with one Layer per TrafficClass.
// tau is the EMA time constant in seconds (use 1.0 for D-07's "1-2 second" feel).
func NewBank(tau float64) *OscillatorBank {
b := &OscillatorBank{
layers: make(map[classify.TrafficClass]*Layer, NumLayers),
tau: tau,
}
for _, class := range classify.AllClasses() {
cfg := ClassFreqConfigs[class]
b.layers[class] = NewLayer(cfg, SampleRate, tau)
}
return b
}
// RenderWindow updates amplitude targets from snap, then renders SamplesPerWindow
// stereo frames. Each frame is [2]float64{left, right} with values in [-1, 1].
// Per D-10: each layer gets GainPerLayer (1/11) so 11 max-amplitude layers sum to 1.0 (no clipping).
func (b *OscillatorBank) RenderWindow(snap classify.WindowSnapshot) [][2]float64 {
// Find max count for normalization
var maxCount int64
for _, count := range snap.Counts {
if count > maxCount {
maxCount = count
}
}
// Update target amplitudes for all layers
for _, class := range classify.AllClasses() {
count := snap.Counts[class]
b.layers[class].UpdateTarget(count, maxCount)
}
// Render frames
frames := make([][2]float64, SamplesPerWindow)
for i := range frames {
var sumL, sumR float64
for _, class := range classify.AllClasses() {
layer := b.layers[class]
sample := layer.AdvanceSample()
gainL, gainR := PanGains(layer.Config.Pan)
sumL += sample * GainPerLayer * gainL
sumR += sample * GainPerLayer * gainR
}
frames[i] = [2]float64{sumL, sumR}
}
return frames
}