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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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Oswald
Registered: Apr 2002
Posts: 5017 |
I'll better shut up and release something. I hope hollowman will be happy with my new plasma. cheers.
ps: Zeus, what problem does amiga have ? have u heard of overscan ?
Hcl, "Well, that's very much what c64-effect coding is all about, finding out a way to do something that noone has done before" couldnt agree more, finally not that "I dont care how easy it was to code until It looks nice" attitude
hollowman, ahh.. forget it...
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Something which none has done before CAN still be easy to code :) |
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Zeus
Registered: Jun 2005
Posts: 16 |
Quoting Oswald
ps: Zeus, what problem does amiga have ? have u heard of overscan ?
Well I got my Amiga in 1987 and was coding in assembler (SEKA was so damn sexy! ;)). Usually the copper was used for doing the infamous raster bars and the plasma effects. As far as I remember 2 registers were used: $dff180 (screen color reg) and the screen address to sync with which was depending on the screen resolution. Folks that had unusual monitor settings put the rasters wrong. Same goes for (bitmap) scrolling. Since scrollers on Amiga were done by using the Blitter and a pixel exact range, the scroll area depended on the monitor settings. |
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Krill
Registered: Apr 2002
Posts: 2839 |
Yes, me wants optional bigger vice borders (although it would reveal i coded +h2k with a tv instead of a monitor, heh).
And well, i also grew tired of sideborders done just for the sake of it.
If it supports transitions and the "no limits" feeling, great, if it's just a supercommon effect expanded in x to contract it in y, no thanks.
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WVL
Registered: Mar 2002
Posts: 886 |
OK, I find (according to one of my parts where i really checked things out) that the first visible rasterline in the whole vice/ccs64/real thing combo is $d012 = $0b. The last visible rasterline is $12c...
that gives $12c-$b+1 = 290 visible rasterlines :)... you can see this is more than VICE is showing... |
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HCL
Registered: Feb 2003
Posts: 716 |
Hmm, what do you mean by "vice/ccs64/real thing combo"!? My aim was to not care for any emulators here, but *only* the real thing of course. Does your numbers change then? |
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WVL
Registered: Mar 2002
Posts: 886 |
Quote: Hmm, what do you mean by "vice/ccs64/real thing combo"!? My aim was to not care for any emulators here, but *only* the real thing of course. Does your numbers change then?
Unfortunately i didnt write it down for each system separately.. But the numbers i put worked for me on all systems, so no lines missing in vice, no lines missing in ccs AND no lines missing on the real thing (i think it was either a 1084s or 1901 monitor)..
ofcourse, it can still depend on your monitor, i presume :-(, well, you have to draw the line (get it) somewhere ;)
I just also checked HOXS64 emulator, and also in that one there are no missing lines.
hmmm.. so HCL seems to have 3 more lines visible at the top, and I've got one more visible at the bottom. |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Someone with a test picture generator here? Use it on a 1084, adjust the 1084 so that only the rectangle is visible which should be visible and after that check what x/y positions now are visible when you connect a C64. |
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Ninja
Registered: Jan 2002
Posts: 404 |
WVL: Are you really sure that $12C is inclusive? I assume that the VIC requests a vertical retrace at that line, and it wouldn't make sense to me, if a CRT would delay this for another rasterline.
Side note: It seems that I can see 37 pixels in the right border, can anyone confirm this? |
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WVL
Registered: Mar 2002
Posts: 886 |
Quote: WVL: Are you really sure that $12C is inclusive? I assume that the VIC requests a vertical retrace at that line, and it wouldn't make sense to me, if a CRT would delay this for another rasterline.
Side note: It seems that I can see 37 pixels in the right border, can anyone confirm this?
well, i'm getting the $12c from the code i wrote for that. But I can't be 100% sure... it _might_ be $12b also :).. for sakes I'll just use $12c to be safe. |
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