On Wednesday 01 January 2003 20:14, Patriek Lesparre wrote:
> >i have a question. Will the GBA display controler display the change
> >of HOFS of a background layer while he is already in HWRITE? For
> >example, the first 40 y values of a certain scanline will be displayed
> >with a HOFS value of 0, the next 200 y with a value of 1? Or is it not
> >possible to change the scanline while he is in HWRITE? I have tryed it
> >on VisualBoyAdvance, but it doesn't work. So there is possible that
> >the emulator does not work correctly, my code is wrong or that the
> >display controler don't display such a change.
>
> I haven't tested it, but I would assume it's possible. The emulator is
> probably using a line-based renderer instead of a (slow) pixel-based one,
> so you won't be able to see the effect.

i wouldnt bet on that... imagine how the display controller works and how much
memory (ie registers) access it had to do if every register-change would have
an immediate effect on per-pixel basis. this might work for some "simple"
things, like colors (good old "rastersplits" :)) but for more complicated
stuff, like displaying actual character data (which x-offset belongs to),
registers are probably fetched once per scanline, or atleast not per-pixel,
but per character-cell.

however, the babble is void :=P someone gotta clear this up with testcode eh?
:) (if it _would_ work, changing y-offset within a scanline might give
interisting results aswell hehe)

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