Re: A83: map

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Re: A83: map


Yes, but you'll have to write new sprite routines yourself. The map would take
up 3-4k in memory if you store it in normal bitmap mode (about 16k in lo-res
chunky, so don't use that...). When displaying a "window" of the map, you must
split up the x coordinate into byte-offset and bit-offset (divide by 8, the
remainder is the bit-offset). Then you make f.ex. hl point to the first byte
to copy, fetch the byte that it's pointing to, shift it left [bitoffset]
times, store it in some other register. Then fetch the byte at (hl+1), shift
it right [8-bitoffset] times, then or it together with the byte you just
saved. Write this byte to the lcd. Then do this 12 times to go through the
whole row. I think you can figure it out.
Pasting imagery onto the map would be done in somewhat the same way, shifting
n bits and so on. Probably wouldn't be too hard. And as always, to save speed
you can 8-pixels-align alot of stuff to make it easy to just "or in".

Linus

On 12-Jul-98, Chris Hiszpanski wrote:

>I am no sure if I am in the right spot to add a message to the ASM Digest,
>but here I go anyway. I have a few questions. Can I make a smooth scrolling
>map 5 times larger thatn the LCD on the TI-83 and how much memory would it
>take up. If so, where can I find some routines to learn from or could
>anyone show me in a message? And last how can I alter the map by pasting a
>sprite anywhere on the map and permanently keep it there as long as the
>program is running. Thanks.

>From: Chris
>mecad@scv.net
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