Class: Badline::VIC::Sprite

Inherits:
Object
  • Object
show all
Defined in:
lib/badline/vic/sprite.rb

Constant Summary collapse

X_OFFSET = 
104
ROWS = 
21

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(index, registers, bank, width) ⇒ Sprite

Returns a new instance of Sprite.



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# File 'lib/badline/vic/sprite.rb', line 11

def initialize(index, registers, bank, width)
  @index = index
  @registers = registers
  @bank = bank
  @width = width
  @bit = 1 << index
  @displaying = false
  @counter = 0
  @bits = nil
  @line_pixels = nil
  @pixel_buffer = Array.new(48)
end

Instance Attribute Details

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/badline/vic/sprite.rb', line 9

def index
  @index
end

#line_pixels ⇒ Object (readonly)

Returns the value of attribute line_pixels.



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# File 'lib/badline/vic/sprite.rb', line 9

def line_pixels
  @line_pixels
end

Instance Method Details

#color ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 38

def color = @registers[0x27 + index] & 0x0f

#displaying? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 24

def displaying? = @displaying

#enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 26

def enabled? = @registers[0x15].anybits?(@bit)

#leftmost ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 40

def leftmost = (x + X_OFFSET) % @width

#multicolor? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 27

def multicolor? = @registers[0x1c].anybits?(@bit)

#pixel(raster_x) ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 62

def pixel(raster_x)
  return nil unless @line_pixels

  dist = raster_x - leftmost
  dist += @width if dist.negative?
  dist < pixel_width ? @line_pixels[dist] : nil
end

#pixel_width ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 41

def pixel_width = x_expanded? ? 48 : 24

#priority? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 30

def priority? = @registers[0x1b].anybits?(@bit)

#start_line(line) ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 43

def start_line(line)
  if !@displaying && enabled? && line == y
    @displaying = true
    @counter = 0
  end

  return @line_pixels = nil unless @displaying

  row = y_expanded? ? @counter / 2 : @counter
  if row >= ROWS
    @displaying = false
    return @line_pixels = nil
  end

  @counter += 1
  fetch(row)
  decode_line
end

#x ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 32

def x
  msb = @registers[0x10].anybits?(@bit) ? 0x100 : 0
  msb | @registers[index * 2]
end

#x_expanded? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 28

def x_expanded? = @registers[0x1d].anybits?(@bit)

#y ⇒ Object 



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# File 'lib/badline/vic/sprite.rb', line 37

def y = @registers[(index * 2) + 1]

#y_expanded? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/badline/vic/sprite.rb', line 29

def y_expanded? = @registers[0x17].anybits?(@bit)