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feat: envelopexp ported to go synth

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This commit is contained in:
qm210
2024-10-22 01:04:39 +02:00
parent cf05e68471
commit 9678108fd1
2 changed files with 15 additions and 8 deletions
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19
vm/go_synth.go
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@ -330,25 +330,27 @@ func (s *GoSynth) Render(buffer sointu.AudioBuffer, maxtime int) (samples int, t
stack = append(stack, output)
}
case opEnvelopexp:
// TODO @qm210 - for now, this just clones the envelope so everything is wired up, but IT IS NOT IMPLEMENTED YET
// is ignoring for now
// - params[1] - attack shape parameter (center value should mean "linear")
// - params[3] - decay shape parameter (center value should mean "linear")
if !voices[0].sustain {
unit.state[0] = envStateRelease // set state to release
}
state := unit.state[0]
level := unit.state[1]
exponent := float64(1)
baseline := float32(0)
switch state {
case envStateAttack:
exponent = scaledEnvelopExponent(params[1])
level += nonLinearMap(params[0])
if level >= 1 {
level = 1
state = envStateDecay
}
case envStateDecay:
exponent = scaledEnvelopExponent(params[3])
sustain := params[4]
baseline = sustain
level -= nonLinearMap(params[2])
if sustain := params[4]; level <= sustain {
if level <= sustain {
level = sustain
}
case envStateRelease:
@ -359,7 +361,8 @@ func (s *GoSynth) Render(buffer sointu.AudioBuffer, maxtime int) (samples int, t
}
unit.state[0] = state
unit.state[1] = level
output := level * params[6]
expLevel := float32(math.Pow(float64(level), exponent))
output := (baseline + (1-baseline)*expLevel) * params[6]
stack = append(stack, output)
if stereo {
stack = append(stack, output)
@ -646,6 +649,10 @@ func nonLinearMap(value float32) float32 {
return float32(math.Exp2(float64(-24 * value)))
}
func scaledEnvelopExponent(value float32) float64 {
return math.Pow(2, 6*(0.5-float64(value)))
}
func clip(value float32) float32 {
if value < -1 {
return -1