Difference between revisions of "Fix graphics format"

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The [[fix layer]] uses 8x8 pixels tiles. They're coded in a 4 bits per pixel, linear format with oddly mixed columns. Pixels are coded by pairs as bytes, in columns from top to bottom.
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Note that the pixel positions are swapped in each byte (the left pixel goes in bits 0~3, the right pixel goes in bits 4~7), and that the first stored column is column A.
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[[File:fixgfx.png|center]]
 
[[File:fixgfx.png|center]]
  
Left and right nibbles might be swapped !
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=Size=
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One tile is 8 * 8 pixels * 4 bits per pixel = 256 bits = '''32 bytes'''.
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=ROM addressing=
  
Column order: 4,5,6,7,0,1,2,3
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<pre>
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Bit # ...543210
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      ...nHCLLL
  
The [[fix layer]] uses 8x8 pixels tiles, coded in a 4BPP linear format with mixed columns. The cart and CD systems use the same format.
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n: Tile number (multiple bits)
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H: Half, 0 = right, 1 = left
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C: Column in half, 0 = left, 1 = right
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L: Line number (0~7)
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</pre>
  
One tile is 32 bytes.
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{{Sig|2H1|2H1}} is "C".
  
 
[[Category:Video system]]
 
[[Category:Video system]]

Latest revision as of 09:51, 26 June 2017

The fix layer uses 8x8 pixels tiles. They're coded in a 4 bits per pixel, linear format with oddly mixed columns. Pixels are coded by pairs as bytes, in columns from top to bottom.

Note that the pixel positions are swapped in each byte (the left pixel goes in bits 0~3, the right pixel goes in bits 4~7), and that the first stored column is column A.

Fixgfx.png

Size

One tile is 8 * 8 pixels * 4 bits per pixel = 256 bits = 32 bytes.

ROM addressing

Bit # ...543210
      ...nHCLLL

n: Tile number (multiple bits)
H: Half, 0 = right, 1 = left
C: Column in half, 0 = left, 1 = right
L: Line number (0~7)

2H1 is "C".