Class: Badline::VIC::Sequencer

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

Overview

VIC-II Sequencer

Turns fetched graphics data into output pixels.

Constant Summary collapse

DISPLAY_X_BOUNDS = 
[
  [135, 438].freeze,
  [128, 447].freeze
].freeze
GFX_X_START =

The graphics window always spans the full 40 columns, ignoring CSEL.


      
        
GFX_X_END =
          
        

        
DISPLAY_X_BOUNDS[1][1] + 1

      
        
WINDOW_COMPARES =
          

  

    
left compare, right compare




for the border flip-flop per CSEL state.





  





  



        

        
[
  [DISPLAY_X_BOUNDS[0][0], DISPLAY_X_BOUNDS[0][1] + 1].freeze,
  [GFX_X_START, GFX_X_END].freeze
].freeze

      
        
BORDER_Y_BOUNDS =
          
        

        
[
  [55, 247].freeze,
  [51, 251].freeze
].freeze

      
        
BORDER_FULL =
          

  

    

Border coverage per 8-pixel group, tracked so apply_border can skip window groups and bulk-fill full border groups.



  





  



        

        
0

      
        
BORDER_NONE =
          
        

        
1

      
        
BORDER_MIXED =
          
        

        
2

      
        
NULL_MODE =
          
        

        
GraphicsMode::Null.new

      
        
MODES =
          
        

        
[
  GraphicsMode::Text.new,                   # 000 standard text
  GraphicsMode::MulticolorText.new,         # 001 multicolour text
  GraphicsMode::Bitmap.new,                 # 010 standard bitmap
  GraphicsMode::MulticolorBitmap.new,       # 011 multicolour bitmap
  GraphicsMode::ExtendedBackgroundText.new, # 100 ECM text
  NULL_MODE,                                # 101 invalid
  NULL_MODE,                                # 110 invalid
  NULL_MODE                                 # 111 invalid
].freeze

      
    

  




  
Instance Attribute Summary collapse

  




  
    

      Instance Method Summary
      collapse
    


    
  



  
Constructor Details

  
    

  

  
    #initialize(width, registers, bank)  ⇒ Sequencer 
  

  

  


  

    

Returns a new instance of Sequencer.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 54

def initialize(width, registers, bank)
  @width = width
  @registers = registers
  @bank = bank
  @colors = Array.new(width, 0)
  @fg = Array.new(width, false)
  @border = Array.new(width, true)
  @border_groups = Array.new(width / 8, BORDER_FULL)
  @cur_colors = Array.new(8, 0)
  @cur_fg = GraphicsMode::NO_FG
  @prev_colors = Array.new(8, 0)
  @prev_fg = GraphicsMode::NO_FG
  @vertical_border = true
  @main_border = true
  new_line(0)
end

    		
  





  



  

    
Instance Attribute Details

    
      
      
      

  

  
    #bank  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute bank.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def bank
  @bank
end

    		
  





    
      
      
      

  

  
    #border  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute border.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def border
  @border
end

    		
  





    
      
      
      

  

  
    #colors  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute colors.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def colors
  @colors
end

    		
  





    
      
      
      

  

  
    #cur_colors  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute cur_colors.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def cur_colors
  @cur_colors
end

    		
  





    
      
      
      

  

  
    #cur_fg  ⇒ Object 
  

  

  


  

    

The fg masks are shared frozen patterns assigned by reference, never mutated in place.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 52

def cur_fg
  @cur_fg
end

    		
  





    
      
      
      

  

  
    #fg  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute fg.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def fg
  @fg
end

    		
  





    
      
      
      

  

  
    #registers  ⇒ Object  (readonly)
  

  

  


  

    

Returns the value of attribute registers.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 49

def registers
  @registers
end

    		
  





    
  



  

    
Instance Method Details


    
      

  

  
    #apply_border  ⇒ Object 
  

  

  


  

    

Repaint the border over the composited line, hiding the sprites.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 83

def apply_border
  color = @registers.border
  group = 0
  while group < @border_groups.length
    case @border_groups[group]
    when BORDER_FULL then @colors.fill(color, group * 8, 8)
    when BORDER_MIXED then paint_mixed_border(color, group * 8)
    end
    group += 1
  end
end

    		
  





    
      

  

  
    #emit(screencode, color, col, cell, row)  ⇒ Object 
  

  

  


  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 95

def emit(screencode, color, col, cell, row)
  MODES[@registers.mode].decode(screencode, color, cell, row, self)
  output(col)
  roll
end

    		
  





    
      

  

  
    #emit_idle(col)  ⇒ Object 
  

  

  


  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 101

def emit_idle(col)
  @cur_colors.fill(@registers.background)
  @cur_fg = GraphicsMode::NO_FG
  output(col)
  roll
end

    		
  





    
      

  

  
    #new_line(line)  ⇒ Object 
  

  

  


  

    

Reset the line buffers at the start of a rasterline and re-evaluate the vertical border flip-flop.



  





  



  

    
      


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# File 'lib/badline/vic/sequencer.rb', line 73

def new_line(line)
  update_vertical_border(line)
  @colors.fill(@registers.border)
  @fg.fill(false)
  @border_groups.fill(BORDER_FULL)
  @prev_colors.fill(@registers.background)
  @prev_fg = GraphicsMode::NO_FG
end