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Load_HGR() better HGR mode based on "Le Chat Mauve" real display

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Thomas Bernard 2018-12-04 21:49:13 +01:00 committed by Adrien Destugues
parent 92d8a600e9
commit 99224fd6d0
1 changed files with 27 additions and 10 deletions
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37
src/miscfileformats.c
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@ -6784,18 +6784,35 @@ void Load_HGR(T_IO_Context * context)
}
else
{
if (x & 1)
/// HGR emulation following the behaviour of a "Le Chat Mauve"
/// RVB adapter for the Apple //c.
/// Within the bit stream, the color of the middle pixel is :<br>
/// <tt>
/// 111 \ <br>
/// 110 }- white <br>
/// 011 / <br>
/// 010 \ _ color <br>
/// 101 / <br>
/// 000 \ <br>
/// 001 }- black <br>
/// 100 / <br>
/// </tt>
/// Color depends on the selected palette for the current byte
/// and the position of the pixel (odd or even).
if ((color & 3) == 3) // 11 => white
{
if ((color & 6) == 6) // 2 bits to 1 => force White
{
Set_pixel(context, x - 2, y, 3 + previous_palette);
Set_pixel(context, x - 1, y, 3 + palette);
}
else
Set_pixel(context, x - 1, y, (color & 3) + palette);
Set_pixel(context, x, y, (color & 3) + palette);
previous_palette = palette;
Set_pixel(context, x - 1, y, 3 + previous_palette);
Set_pixel(context, x, y, 3 + palette);
}
else if ((color & 1) == 0) // 0 => black
Set_pixel(context, x, y, palette);
else // 01 => color
{
if ((color & 7) == 5) // 101
Set_pixel(context, x - 1, y, 2 - (x & 1) + previous_palette);
Set_pixel(context, x, y, 2 - (x & 1) + palette);
}
previous_palette = palette;
}
b >>= 1;
x++;