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HCL
Registered: Feb 2003
Posts: 716 |
Screen limits
Once when i got myself a C= monitor, I made some tests to see what the actual limits were. Keeping in mind all the bugs i left in Royal Arte, after this i would never have to leave any visual bugs because of not seing them.
But now in EMU-age, the same horrible bugs appear again in many demos. Vice only shows 272 x 384 pixels, and people appearantly start to think that's the way to go. And it suxx big time!
So when i found my old screen tests yesterday, i thought maybe i should put this up here. I also had some info about sprite-limits in the borders. Let's get started.
Screen limits
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Vertically:
First visible line: 8 (d012 = 8)
Last visible line: 12b (d012 = 2b)
That makes 292 visible lines totally.
Transfered to sprite positions we get..
spt-pos 12a: one line visible in lower border.
spt-pos 12b: one line visible in upper border.
Horizontally:
Left border: 48 visible pixels (6 chars).
Right border: 36 visible pixels (4.5 chars).
That makes 404 pixels, right.
Sprite bugs in left border:
All sprites invisible at positions 1f8-1ff.
spt7 invisible at pos <= 1ce.
spt8 invisivle at pos <= 1ee.
Sprite bugs in right border:
spt1 stretch bug at pos >= 14b.
spt2 stretch bug at pos >= 15b.
Bug above first line at pos => 163: spt 3,4,5.
Bug on last line at pos => 164: spt 3,4,5.
Ok. I think that's all. Does anyone have other specs? Please don't post if you have a lowsy TV-set, they always sukk. Did i get those sprite-bugs correctly? Sounds totally wierd :). And finally: DON'T RELEASE before you checked your demo against this spec >:E. |
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trident
Registered: May 2002
Posts: 75 |
Quote: @Trident: Technically that's also a "recreation" of the border. The border unit is inactive, i.e. open. Using presumably the same trick a Krill mentioned. This also works in ECM-mode btw.
Oh, no! There is a magic poke in the code somewhere! Haven't you read the scrolltext? |
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TDJ
Registered: Dec 2001
Posts: 1879 |
Quote: Oh, no! There is a magic poke in the code somewhere! Haven't you read the scrolltext?
Careful, or you may accidentely use the famous poke that burns your c64 from the inside out! |
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Zyron
Registered: Jan 2002
Posts: 2381 |
I once poked myself into TDJ's kitchen, now that was real scary! |
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trident
Registered: May 2002
Posts: 75 |
Quote: Careful, or you may accidentely use the famous poke that burns your c64 from the inside out!
Yeah that's a dangerous one! ;-) |
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Hein
Registered: Apr 2004
Posts: 933 |
Quote: @Krill: Why didn't I think of that, grrr. I know how, but never when, that's what differs the good from the bad coders. =D Anyway, too late for than now. The transition is done.
I accidently ran into this.. looked pretty, but had no use for it.. possibly some day.
I'm glad Im still at the starting point of coding, I'm pleased with every pixel I manage to move, without rolling my eyes.. |
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TDJ
Registered: Dec 2001
Posts: 1879 |
Quote: I once poked myself into TDJ's kitchen, now that was real scary!
So many bad memories .. |
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MRT
Account closed
Registered: Sep 2005
Posts: 149 |
Quote: If you open the sideborders in hires bitmap mode, they have the colour of the cells's background colours in column 39. This might enable you to save sprites.
This seems to be only true when working in multi-color mode... but what about hires mode? anyone? Krill?
edit:
from: http://noname.c64.org/csdb/forums/?roomid=11&topicid=20121&show..
Quoting Monte CarlosOn the borders you'll always see only black, when in hires bitmap mode. This doesnt depend on which other d011 bits are set. So it doesnt depend on having an illegal or not an illegal mode.
d021 is not read out anymore.
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Krill
Registered: Apr 2002
Posts: 2850 |
MRT: I don't quite get your question. Are you mixing up something? |
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MRT
Account closed
Registered: Sep 2005
Posts: 149 |
Yup.. :)
I was opening up the upper/lower borders in hires mode, but the column (or last char, etc.) trick didn't work there.
edit:
And it did work when I put the image in multicolor bitmap mode. Hence my mixup... :)
At least not on itself... I found out that I had to clear the last byte of the charsetbank! Even though I was using hires bitmap.
And I cleared the last byte of the VIC bank ofcourse...
The combination of those three seem to work and the lack of one of those seem to mask the background color...
But I don't understand it realy. I just filled up the vic bank with values to see what changed. Then later on I pinpointed the actual value that masked the borders. After changing that to $00 it works just fine... :-S
Oh for the record... I've tested this only on Vice and CCS.
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Monte Carlos
Registered: Jun 2004
Posts: 351 |
When i wrote this, i referred to upper/lower border, if i remember correctly.
In standart hires mode used without any tricks, $d021 register
is not of any use.
i think, it was due to some coding for "trip 2 nepa(l)" i wanted to show a hires picture with a background other than black. i wanted to open the upper/lower border too, for some reason. i set d021 to the background color of the hires picture and thoght, that it will be displayed on the upper/lower borders, too.
this guess was wrong, so i had to switch to multicolor mode in line 247 or so to display the borders in the correct color an switch back to hires mode in line 50.
this was not due to $ff in $xfff.
with the sideborders its kinda different, because as was told the color of zero pixels of the rightmost char is expanded into the sideborder.
anyway d021 doesnt play a role here, too.
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