Hi! |
A|A
(n n)
\_/
Manuel Bilderbeek asked:
> (...) I recently found out (...) that sprites in screen 6
> and 7 can only be on even lines! Because the X-coordinate
> is given by a byte...! Isn't this a crazy thought of the
> V9938 designers??? How is this problem solved in games? Or
> aren't there screen 7 games?
>
> Any other suggestions/remarks about this strange phenomenon?
That strange feature of the `sprites' in 512 columns graphic
modes is in the VDP documentation (I thought everyone already
knew it). It was one of the first things I tested when I turned
my first MSX (a Brazilian Expert 1.1) to 2.0 (DDX board).
Why? Because I have already seen "Xak", which I knew uses 512
columns mode. I expected the `sprites' to appear slim, because
of the "tall and thin" appearance of "Xak" characters, but they
didn't. The `sprites' were still a perfect square. "Xak" doesn't
use `sprites', it uses bit-mapped shapes, which are applied
using VDP block transfer operations. The same method is used by
Graph Saurus (Bit2) to draw the cursor (of course, because each
`sprite' pixel has the same size it has in 256 columns modes).
"Why?" Simple: keeping `sprites' unchanged from mode to mode
reduces the amount of circuit elements in the VDP I.C., what
reflects in a reduction of final cost (`sprite' handling
circuits were not cheap at that time to implement). I know, I
know, it was a very nasty solution, but then, it is too late
now to sorrow.
As I explained, the most obvious solution to the `sprite'
problem is to not use them at all, or use them only to render
very fast objects, like shots, or static elements, like score
boards (yes, it is a waste of a very versatile "creature", but
we can't trust something that cannot handle the "odds"...)
... Cyberknight...
<Over>
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