Class: PicoTune::WaveSample

Inherits:
Object
  • Object
show all
Defined in:
lib/picotune.rb

Instance Method Summary collapse

Constructor Details

#initialize(tone, samples_per_wave) ⇒ WaveSample 



79
80
81
82
 
# File 'lib/picotune.rb', line 79

def initialize tone, samples_per_wave
  @tone = tone
  @samples_per_wave = samples_per_wave
end

Instance Method Details

#noise(index) ⇒ Object 



118
119
120
121
122
 
# File 'lib/picotune.rb', line 118

def noise index
  value = sine index
  rand = Random.rand - 0.5
  value * rand
end

#sample(index) ⇒ Object 



84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
 
# File 'lib/picotune.rb', line 84

def sample index
  value = case @tone
    when 'square'
      square index
    when 'sine'
      sine index
    when 'triangle'
      triangle index
    when 'noise'
      noise index
    when 'saw'
      saw index
    else
      sine index
    end

  PicoTune::Sample.new value, value
end

#saw(index) ⇒ Object 



107
108
109
110
111
112
 
# File 'lib/picotune.rb', line 107

def saw index
  interval = @samples_per_wave / 2
  half_interval = interval / 2
  percent = ((index + half_interval) % interval) / interval.to_f
  ((0.6 * percent) - 0.3)
end

#sine(index) ⇒ Object 



103
104
105
 
# File 'lib/picotune.rb', line 103

def sine index
  Math.sin(index / (@samples_per_wave / (Math::PI * 2)))
end

#square(index) ⇒ Object 



114
115
116
 
# File 'lib/picotune.rb', line 114

def square index
  (index <= @samples_per_wave / 2 ? 1.0 : -1.0)
end

#triangle(index) ⇒ Object 



124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
 
# File 'lib/picotune.rb', line 124

def triangle index
  half = @samples_per_wave / 2
  quarter = @samples_per_wave / 4
  ramp = 1.0 / quarter

  if index <= half
    if index <= quarter
      index * ramp
    else
      (half - index) * ramp
    end
  else
    if index <= half + quarter
      -((index - half) * ramp)
    else
      -((@samples_per_wave - index) * ramp)
    end
  end
end