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Wile Coyote
Registered: Mar 2004
Posts: 642 |
Limitations - Sprites in the Borders
hello,
I was thinking, has anyone drawn up a doc with (pictures :)explaining *all known* possibilities with placing sprites into the border areas of the screen.
I know:
8 sprites can be placed in the upper and lower borders.
7 sprites can be placed in the side borders.
I was thinking, what about the corner borders,is that classed as a sideborder or a top or bottom border (8 sprites).
Another question :) when 7 sprites are placed into the sideborders can the 8th free sprite be placed into the main (center) screen areas or by opening up the side borders, is the option for an 8th sprite not available.
I am asking these questions as i am thinking about designs that use the border areas :)
thanks
/wec
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tlr
Registered: Sep 2003
Posts: 1714 |
From mapping the c64:
Quote:Bit 5: Bit 5 controls the VIC-II chip Reset line. Setting this bit
to 1 will completely stop the video chip from operating. On older
64s, the screen will go black. It should always be set to 0 to insure
normal operation of the chip.
Maybe it's only available on the very old VIC-II's (i.e 5 luma levels).
My original c64 was one of those. (i.e 9,8,7,1,7,8,9 looks like gold!)
It's in the attic right now though.
Roland has one of them...
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
The VIC-II's reset bit is a pretty mysterious thing. I have never encountered in real life, perhaps only the very early NTSC VIC-II's have it. I'm pretty certain that no PAL VIC-II has it, although you can never be sure... |
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tlr
Registered: Sep 2003
Posts: 1714 |
But it is still a read/writeable bit?
Very odd indeed...
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tlr
Registered: Sep 2003
Posts: 1714 |
BTW, while poking around with $d016 I just noticed that the 38 column mode is borked in VICE (WinVICE 1.17 and 1.19 tested).
It covers 7 pixels to the left and 9 pixels to the right instead of 8, 8. :)
POKE53270,0 I reported it to the team just now.
EDIT: Or is it supposed to be this way? CCS64 is the same....
I have forgotten way too much stuff. :P
Note that the PAL C64 DTV covers 8/8... so I guess that one is wrong then?
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Jetboy
Registered: Jul 2006
Posts: 216 |
@_@
Just checked it on a real thing (its good to have real thing at work).
well... on standard c64 its 7-9 too.
so it seems there is no bug.
but all the time up to now i was sure it's 8-8 @_@
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Jetboy
Registered: Jul 2006
Posts: 216 |
Sorry for double posting.
At least now i finaly understand why opening sideborders works.
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Style
Registered: Jun 2004
Posts: 498 |
why was it so hard to understand? :)
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Smasher
Registered: Feb 2003
Posts: 512 |
oh yeah, 10 yrs later necro-posting! :)
so: sideborder sprites at badline, using no fld or similar tricks, no reu (hehe), etc... 4 is still the practical not theoretical max you can get, or? |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
If i understand things correctly, is possible to have 7 sprites (from 0 to 6) using INC $D016 at cycle 10 of the line (because of last 2 Write cycles of INC) to open border:
./victimer -b -s 127
| 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 6 6 6 6 |
0 |1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 |
| |===========01020304050607080910111213141516171819202122232425262728293031323334 353637383940===========| |
--|----------------------------------------------------------------------------- -------------------------------------------------|
| x x x W W W W W w |
| r r r r rcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgcgc g |
ss|3sss4sss5sss6sss7 0sss1sss2sss|
| i i i |
--|----------------------------------------------------------------------------- -------------------------------------------------|
| ^(close sideborder) ^(open sideborder)
| ^---FLI-----------------> ^-----^(double line)
| ^---DMA Delay--------------------------------------------------------------^
badline sprenable=7f
CPU: 3 (+ 5= 8)
VIC: 54 (+ 1=55)
63
x - CPU regular cycles
W - CPU write cycles
w - CPU 3rd write cycle
c - VIC video ram
g - VIC color ram
0..7 - VIC sprite pointer fetches
s - VIC sprite data accesses
i - VIC idle accesses |
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Joe
Registered: Apr 2002
Posts: 224 |
You can do quite a lot with the restrictions. Here are two examples from last year, coded by Firehawk/Hoaxers.
Disconnect, October |
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