Re: A86: Question on tile maps
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Re: A86: Question on tile maps
Hmm, that might work. You'd have to drop the lower 3 bits of the X coord.
On that line, I wonder if it would be much faster to draw sprites if they
were pre-shifted, then all drawn as 16 bit sprites. You could do it when
the program starts and store them on ram page 1 or something, so they
wouldn't take up extra room in the program.
Yeah, you're right. It's not about tilemaps =)
----- Original Message -----
From: Jimmy Mårdell <yarin@acc.umu.se>
To: <assembly-86@lists.ticalc.org>
Sent: Thursday, January 28, 1999 2:28 PM
Subject: Re: A86: Question on tile maps
At 23:44 1999-01-27 -0600, you wrote:
>>Also, the sprite routine doesn't get that much slower...
>
>Gosh, I hate to disagree with Jimmy Mardell, but I do. For a masked sprite
>routine, there just aren't enough registers to shift both mask bytes, both
>sprite bytes and both background bytes in one loop. To shift the
background
>bytes back into a single sprite would require adding a second re-shift loop
>to the routine. It would also require another pointer like IY, though that
>wouldn't be that big of a deal.
Hehe... you don't necessarily have to shift back the bits; you could read
16 bits in each row and then just put those out again (using a special,
16-bit aligned sprite routine).
This discussion is running out of topic so I propose EOD.
//Jimmy Mårdell
E-mail: yarin@acc.umu.se
Homepage: http://www.acc.umu.se/~yarin/
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