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Dr. Jay
Account closed
Registered: Jan 2003
Posts: 32 |
Sprite Woes - help, anyone?
I'm coding a demo that uses bitmaps, sprites, etc.
Here's the stats -
Screen @ $0800 and bitmap @ $2000 so
$28 -> $d018
$3b -> $d011
Now my sprite data is at $1000, so I have my sprite pointers set up like this:
$0bf8 $40
$0bf9 $41
..etc..
Now here's the clencher ... maybe I'm doing something wrong with banking, bits, whatnot, but this is killing me: the stupid @$@#$@# sprites won't show up at $1000! Instead, they've got garbage that looks like a horribly shifted character ROM. I can fill memory with $FF and confirm that $00 -> $7f work fine (I even see my routine at $0500 updating pixels with self-modifying code, etc) and I can point them to the bitmap using $80, $81, etc (works fine) but the $40 offset just gets me garbage. I've even filled $1000 - $1fff with $ff and set $40 and I still get ... goofy character ROM.
Now, either
(1) I'm a stupid idiot and have some banking wrong, but I thought my banks were set since the bitmap and screen are successfully coming from $2000 and $0800 (plus if I stick my sprites on zero page I see my zero page variables updated)
(2) there's some bug in WinVICE, which I'm using to test as I develop
Any comments?
P.S. $01 = $37 |
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Dr. Jay
Account closed
Registered: Jan 2003
Posts: 32 |
DOH. Once again I waste thread space. Here it is from the programmer's reference guide:
When VIC II chip is looking at bank 0 or bank 2, there is a ROM IMAGE of the character set. DOH!
Thanks.
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Warnock
Account closed
Registered: Sep 2007
Posts: 27 |
The address $1000 is usually used for sid files....(i.e.- Voicetracker). I've never seen anyone use this area for anything else. Therefore, addresses $1000 - $1fff are never used when I code my demo pages....or whatever I code. I leave that area structly for music.
Hope this helps,
Warnock/Style |
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A3
Registered: Dec 2005
Posts: 362 |
Good job reviving a 7 year dead thread :P |
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Merman
Registered: Dec 2002
Posts: 140 |
Quote: Good job reviving a 7 year dead thread :P
It's not RESERVED for SID files, but since you can't put graphic data there (because of the character ROM image) that's what most people use it for... |
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enthusi
Registered: May 2004
Posts: 675 |
Same with $9000 in case anyone reads this :) |
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Radiant
Registered: Sep 2004
Posts: 639 |
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Radiant
Registered: Sep 2004
Posts: 639 |
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