Adjust wave forms to Pico-8

Wave forms in Pi are slightly different from Pico-8.

Author: elgopher

audio/internal/oscillator.go

@@ -18,13 +18,11 @@ func (o *Oscillator) NextSample() (v float64) {
 	return
 }
 
-const volume = 0.7
-
 func Triangle(pos float64) float64 {
 	phase := math.Mod(pos, 1)
 	value := math.Abs(phase*2-1)*2 - 1
 
-	return value * volume
+	return value * 0.45
 }
 
 func TiltedSaw(pos float64) float64 {
@@ -35,12 +33,12 @@ func TiltedSaw(pos float64) float64 {
 	} else {
 		v = (1 - phase) * 16
 	}
-	return (v - 1) * volume
+	return (v - 1) * 0.45
 }
 
 func Saw(pos float64) float64 {
 	phase := math.Mod(pos, 1)
-	return (phase - 0.5) * 0.9
+	return (phase - 0.5) * 0.65
 }
 
 func Square(pos float64) float64 {
@@ -49,7 +47,7 @@ func Square(pos float64) float64 {
 	if phase < 0.5 {
 		v = 1.0
 	}
-	return v / 3.0
+	return v / 4.0
 }
 
 func Pulse(pos float64) float64 {
@@ -58,13 +56,15 @@ func Pulse(pos float64) float64 {
 	if phase < 0.3125 {
 		v = 1.0
 	}
-	return v / 3.0
+	return v / 4.0
 }
 
 // Organ is triangle / 2
 func Organ(pos float64) float64 {
 	pos = pos * 4
 
-	return (math.Abs(math.Mod(pos, 2)-1) - 0.5 +
-		(math.Abs((math.Mod(pos*0.5, 2))-1)-0.5)/2 - 0.1) * volume
+	v := math.Abs(math.Mod(pos, 2)-1) - 0.5 +
+		(math.Abs((math.Mod(pos*0.5, 2))-1)-0.5)/2 - 0.1
+
+	return v * 0.55
 }

examples/audio/audio.go

@@ -10,9 +10,9 @@ func main() {
 	sfx := audio.SoundEffect{
 		Notes: [32]audio.Note{
 			{
-				Pitch:      audio.PitchC2,
-				Instrument: audio.InstrumentTriangle,
-				Volume:     4,
+				Pitch:      audio.PitchG3,
+				Instrument: audio.InstrumentOrgan,
+				Volume:     7,
 			},
 		},
 		Speed: 255,