automated snapshot

signals.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"math"
+)
+
+type Signal interface {
+	Eval(t float64) float64
+}
+
+type Const struct{ V float64 }
+func (s Const) Eval(t float64) float64 { return s.V }
+
+type Sine struct {
+	Amp, Freq, Phase, Bias float64
+}
+func (s Sine) Eval(t float64) float64 {
+	return s.Bias + s.Amp*math.Sin(2*math.Pi*s.Freq*t+s.Phase)
+}
+
+type Saw struct {
+	Min, Max, Period float64
+}
+func (s Saw) Eval(t float64) float64 {
+	u := math.Mod(t, s.Period) / s.Period // 0..1
+	return s.Min + (s.Max-s.Min)*u
+}
+