Log inRegister an accountBrowse CSDbHelp & documentationFacts & StatisticsThe forumsAvailable RSS-feeds on CSDbSupport CSDb Commodore 64 Scene Database
You are not logged in - nap
CSDb User Forums


Forums > C64 Coding > FUUUCK ghostbyte in Hires
2009-05-06 11:16
enthusi

Registered: May 2004
Posts: 675
FUUUCK ghostbyte in Hires

god damn. In HiRes-Bitmap-Mode (NOT ECM) the ghostbyte aint at bank+$3fff.
God knows where it is...
Just posting this so someone else gets less insane about fixing it...
enthusi
2009-05-06 11:56
JackAsser

Registered: Jun 2002
Posts: 1989
It's not a ghost byte. I'm quite sure it'll show the $3fff pattern if you read it using a sprite and collision detection. However in hires bitmap mode the $d021 color is never used, but instead the screen colors are used for bg and fg color and the color data is hardwired to 0 in that area, hence black foreground with black background.

To verify it, try place a sprite under the gfx in the border and u'll see the $3fff pattern.
2009-05-06 12:10
enthusi

Registered: May 2004
Posts: 675
Wicked. Will do.
2009-05-06 12:39
MagerValp

Registered: Dec 2001
Posts: 1056
And of course the workaround is to switch back to character mode on line 251. Easy enough to do, as you still need to twiddle d011 when opening the border - the only annoyance is that you need an IRQ at the top of the screen as well to re-enable bitmap mode.

PITA, isn't it?
2009-05-06 12:45
enthusi

Registered: May 2004
Posts: 675
@Mager: yeah, that"s what I do now and at least no extra CPU time since d011 is handled anyway. Yet, I MIGHT need a stable raster now where none was needed before. Anyway, the pain was to NOT find this error of mine very quick.
Its the upper VIC Bank too. So lots fiddling with IRQ in Zeropage to circumvent this bug...
@Jackasser, yeah, I see now...interessting even.
2009-05-06 14:33
Graham
Account closed

Registered: Dec 2002
Posts: 990
AFAIK you get the last displayed background color (the color in the bottom right corner) instead of $D021. Same is true for ECM mode.
2009-05-06 17:56
enthusi

Registered: May 2004
Posts: 675
no, this really seems to be d021.
RefreshSubscribe to this thread:

You need to be logged in to post in the forum.

Search the forum:
Search   for   in  
All times are CET.
Search CSDb
Advanced
Users Online
CA$H/TRiAD
Jetboy/Elysium
Xiny6581/Dees Produc..
TheRyk/MYD!
Clayboy
bOOZElEE
Airwolf/F4CG
Knut Clausen/SHAPE/F..
Fulgore/Excess
Guests online: 154
Top Demos
1 Next Level  (9.8)
2 Mojo  (9.7)
3 Coma Light 13  (9.7)
4 Edge of Disgrace  (9.6)
5 Comaland 100%  (9.6)
6 No Bounds  (9.6)
7 Uncensored  (9.6)
8 Wonderland XIV  (9.6)
9 Memento Mori  (9.6)
10 Bromance  (9.5)
Top onefile Demos
1 It's More Fun to Com..  (9.7)
2 Party Elk 2  (9.7)
3 Cubic Dream  (9.6)
4 Copper Booze  (9.5)
5 TRSAC, Gabber & Pebe..  (9.5)
6 Rainbow Connection  (9.5)
7 Wafer Demo  (9.5)
8 Dawnfall V1.1  (9.5)
9 Quadrants  (9.5)
10 Daah, Those Acid Pil..  (9.5)
Top Groups
1 Nostalgia  (9.3)
2 Oxyron  (9.3)
3 Booze Design  (9.3)
4 Censor Design  (9.3)
5 Crest  (9.3)
Top Graphicians
1 Sulevi  (10)
2 Mirage  (9.8)
3 Lobo  (9.7)
4 Mikael  (9.7)
5 Archmage  (9.7)

Home - Disclaimer
Copyright © No Name 2001-2024
Page generated in: 0.052 sec.