VOGONS


VIDEO - Experimental VGA patch (vgaonly commited)

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First post, by h-a-l-9000

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It emulates the video drawing as well as the palette and a few other things scanline by scanline. This is mostly needed by demo software but also by a few games. Some parts of it are hackish but the new output looks nice. The internal screenshot / video functions cannot capture it properly.

Build: http://home.arcor.de/h-a-l-9000/test/dosbox_demovga.zip

To enable, set machine=demovga in dosbox.conf.
It also adds the parameter ibmtiming under [dosbox] which might fix horizontal scrolling problems for certain games/demos (true/false).

Reply 1 of 90, by Kippesoep

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Very nice. Might be useful with CGA too (background colour, in particular). That would help tremendously with Frogger (which changes background colour to blue for the water part at the top of the screen).

My site: Ramblings on mostly tech stuff.

Reply 2 of 90, by wd

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Yep fine thing (though it looks a bit slow 😀 did you measure the impact)
and nice screenshots!
Kellogs comes to my mind, uses pel mask changing to draw some part
of the screen blue (water level).

Reply 3 of 90, by IIGS_User

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Yeah, I see. In previous versions of DOSBox, the sky always was dark blue. Now, in 0.70, ithe sky flickers between dark blue and blue.

Klimawandel.

Reply 4 of 90, by h-a-l-9000

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> Kellogs comes to my mind, uses pel mask changing to draw some part
> of the screen blue (water level).

That's why I brought it up recently 😉 can't get it to run.
Runtime error 002 at 0004:2C46.

The impact is not as much as I thought it would be. I can still play Terminal Velocity at ~27fps at fullscreen (normally ~30fps).

Frogger... I'll have a look if I find it.

I can add more screenshots if you like 😀

Reply 5 of 90, by wd

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Maybe make some videos 😀

Got to see about kellogs...

Reply 6 of 90, by h-a-l-9000

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> Maybe make some videos Happy

Can't capture the palettes 🙁

1+1=10

Reply 7 of 90, by wd

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Kellogs works in rc2 but not in rc3 btw.

Reply 8 of 90, by h-a-l-9000

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0.65 rc2 ?

1+1=10

Reply 9 of 90, by wd

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0.66rc2

Reply 10 of 90, by h-a-l-9000

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hmm no it doesn't? Any special settings?

1+1=10

Reply 11 of 90, by wd

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Damdam...
joysticktype=none

Reply 12 of 90, by h-a-l-9000

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It doesn't even bother about timed=true/false...

Reply 13 of 90, by h-a-l-9000

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WOOT they use port 0x61 to have some control on system timer 2.
I knew such a game exists 😉

1+1=10

Reply 14 of 90, by wd

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Kellogs is a masterpiece of funky programming, wonder that it displays
anything at all in dosbox...

Reply 15 of 90, by h-a-l-9000

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Frogger gets its timing wrong...

Reply 16 of 90, by augnober

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Nice work. I was thinking about this earlier (a little over a year ago, I guess) when I was making a patch to synchronize (/substitute) the internal emulation vertical refresh with the host display's vertical refresh (to remove shear, get smooth scrolling, etc. in certain apps). It would be interesting to try and get both of those changes to work together -- could lead to the feeling of a very real machine.

My patch didn't work out so well in the end. It worked great in Windows, but I wasn't able to find a reliable way to detect the retrace status in Linux.. and so I ended up dropping it after the workarounds for this got too complicated.

Reply 18 of 90, by augnober

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DosFreak:
I think it belongs in the patches section. I'd been wondering about that (I'd like to see this get adopted by some builds, or perhaps make it into cvs).

Reply 19 of 90, by h-a-l-9000

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Should this be in the DosBox patches section?

As you like.

or perhaps make it into cvs).

too hackish at some places