Class: SynthBlocks::Mod::AdsrOld

Inherits:
Object
  • Object
show all
Defined in:
lib/synth_blocks/mod/adsr_old.rb

Overview

Implementation of a linear ADSR envelope generator with a tracking value so that envelope restarts don’t click

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attack, decay, sustain, release) ⇒ AdsrOld

Creates new ADSR envelope

attack, decay and release are times in seconds (as float)

sustain should be between 0 and 1



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 28

def initialize(attack, decay, sustain, release)
  @value = 0
  @start_value = 0
  @attack = attack
  @decay = decay
  @sustain = sustain
  @release = release
end

Instance Attribute Details

#attack ⇒ Object

attack time in seconds



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 9

def attack
  @attack
end

#decay ⇒ Object

decay time in seconds



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 13

def decay
  @decay
end

#release ⇒ Object

release time in seconds



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 20

def release
  @release
end

#sustain ⇒ Object

sustain level (0.0-1.0)



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 16

def sustain
  @sustain
end

Instance Method Details

#run(t, released) ⇒ Object

run the envelope.

if released is given (should be <= t), the envelope will enter the release stage returns the current value between 0 and 1



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# File 'lib/synth_blocks/mod/adsr_old.rb', line 42

def run(t, released)
  attack_decay = attack + decay
  if !released
    if t < 0.0001 # initialize start value (slightly hacky, but works)
      @start_value = @value
      return @start_value
    end
    if t <= attack # attack
      return @value = linear(@start_value, 1, attack, t)
    end
    if t > attack && t < attack_decay # decay
      return @value = linear(1.0, sustain, decay, t - attack)
    end
    if t >= attack + decay # sustain
      return @value = sustain
    end
  else # release
    if released <= attack # when released in attack phase
      attack_level = linear(@start_value, 1, attack, released)
      return [linear(attack_level, 0, release, t - released), 0].max
    end
    if released > attack && released <= attack_decay # when released in decay phase
      decay_level = linear(1.0, sustain, decay, released - attack)
      return @value = [linear(decay_level, 0, release, t - released), 0].max
    end
    if released > attack_decay  # normal release
      return @value = [linear(sustain, 0, release, t - released), 0].max
    end
  end
  0.0
end