Class: GBTiles::GBT::Export::ASM::Channel

Inherits:
Object
  • Object
show all
Includes:
Effects
Defined in:
lib/gbtiles/gbt/export/asm/channel.rb

Constant Summary collapse

NOTES = 
[
  1712,1616,1524,1440,1356,1280,1208,1140,1076,1016, 960, 907,
   856, 808, 762, 720, 678, 640, 604, 570, 538, 508, 480, 453,
   428, 404, 381, 360, 339, 320, 302, 285, 269, 254, 240, 226,
   214, 202, 190, 180, 170, 160, 151, 143, 135, 127, 120, 113,
   107, 101,  95,  90,  85,  80,  75,  71,  67,  63,  60,  56,
    53,  50,  47,  45,  42,  40,  37,  35,  33,  31,  30,  28
]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Effects

#effect_arpeggio, #effect_break_and_set_step, #effect_cut_note, #effect_jump, #effect_pan, #effect_speed, #effect_volume

Constructor Details

#initialize(channel_number) ⇒ Channel

Returns a new instance of Channel.



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 41

def initialize channel_number
  @channel_number = channel_number
end

Instance Attribute Details

#channel_number ⇒ Object

Returns the value of attribute channel_number.



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 25

def channel_number
  @channel_number
end

Instance Method Details

#convert_effect ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 102

def convert_effect
  if effect_number == 0x0 then
    return effect_arpeggio
  end

  if effect_number == 0xB then
    return effect_jump
  end

  if effect_number == 0xC then
    return effect_volume
  end

  if effect_number == 0xD then
    return effect_break_and_set_step
  end

  if effect_number == 0xE && effect_param_1 == 0x8 then
    return effect_pan
  end

  if effect_number == 0xE && effect_param_1 == 0xC then
    return effect_cut_note
  end

  if effect_number == 0xF then
    return effect_speed
  end

  throw "Unsupported effect"
end

#convert_speed(speed) ⇒ Object

Amiga’s 50 Hz to GB’s 60 Hz



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 98

def convert_speed speed
  speed * 60 / 50
end

#convert_volume ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 93

def convert_volume
  (effect_param == 64) ? 0xF : (effect_param >> 2);
end

#data ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 29

def data
  @data
end

#data=(value) ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 33

def data=(value)
  if value.kind_of?(Array) then
    @data = value
  else
    @data = value.unpack('CCCC')
  end
end

#effect_number ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 73

def effect_number
  @data[2] & 0xF
end

#effect_param ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 77

def effect_param
  @data[3]
end

#effect_param_1 ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 81

def effect_param_1
  (@data[3] & 0xF0) >> 4
end

#effect_param_2 ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 85

def effect_param_2
  @data[3] & 0x0F
end

#effect_param_as_bcd ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 89

def effect_param_as_bcd
  (((effect_param & 0xF0) >> 4) * 10) + (effect_param & 0xF)
end

#is_empty_effect? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 69

def is_empty_effect?
  effect_number == 0 && effect_param == 0
end

#is_noise? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 55

def is_noise?
  false
end

#is_pulse? ⇒ Boolean

Channel information

Returns:

  • (Boolean) 


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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 47

def is_pulse?
  false
end

#is_wav? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 51

def is_wav?
  false
end

#note_index ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 134

def note_index
  period = sample_period

  if period <= 0 then
    return -1
  end

  if !is_noise? then
    if !period.between?(NOTES.last, NOTES.first) then
      throw "Note `#{period}` out of bounds"
    end
  end

  NOTES.index(
    NOTES.min_by { |x| (period - x).abs }
  )
end

#sample_number ⇒ Object

Data



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 61

def sample_number
  (@data[0] & 0xF0) | ((@data[2] & 0xF0) >> 4)
end

#sample_period ⇒ Object 



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# File 'lib/gbtiles/gbt/export/asm/channel.rb', line 65

def sample_period
  @data[1] | ((@data[0] & 0xF) << 8)
end