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Area 5150 for IBM PC 4.77MHz

carlos12

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And, as has driven into the ground, it would be really pointless to incorporate as an alternate code path into a demo that's specifically supposed to demo the fixed configuration of a 4.77mhz 5150 or exact compatible with CGA. Maybe if someone wants to write *THE* killer demo for IBM PS/2s it'd be a trick that'd come in handy.
Well, I wasn't thinking on this demo specifically, I also understand that it's intended for a very specific system+characteristics.

I've being rather thinking on the multiple possibilities that these techniques open. For example, and arcade machine port could be programmed, and it could have multiple colors at med resolution, and it could work on every color card (namely CGA,EGA,MCGA,VGA and compatibles) with a better definition than former multicolor attempts, like the undocumented how-to (but weirdly mentioned in documentation... LOL) 160x100x16 colors.

BTW, the Keen intro is one of the most hilarious things I've seen in a long time :biggrin:. Kudos for the great technical achievement but also for your great sense of humor. Could be done another Commander Keen 4/5 port for CGA 16 colors, but for CRT instead of composite?
 

VERAULT

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Id like to see a 5150 hercules and/or IBM monochrome video adapter demo... If there are such things point me to them please.
 

VileR

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BTW, the Keen intro is one of the most hilarious things I've seen in a long time :biggrin:. Kudos for the great technical achievement but also for your great sense of humor. Could be done another Commander Keen 4/5 port for CGA 16 colors, but for CRT instead of composite?

Thanks ;)
I assume you meant RGBI rather than CRT. Unfortunately CGA doesn't have enough VRAM for a full-screen Keen port at the same level of detail as the intro... perhaps something could be done using "ANSI-from-hell" at 80x100 characters (2 scanlines per row), although the attribute clash won't be pretty. And even if you go with Prohibition-style hardware scrolling, the snow-avoidance will slow it down - it already barely crawls at 4,77Mhz....
 

JohnElliott

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At some point I'd like to see what these talented folks can do with the 3270PC display subsystem. But that's much rarer and less-well-documented hardware.
 

VileR

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At some point I'd like to see what these talented folks can do with the 3270PC display subsystem. But that's much rarer and less-well-documented hardware.
Tell me about it - there's no easily accessible info about it other than on your site. It's a very interesting video setup... but even if we were to source one and learn the ropes, there's barely a handful of people on the planet who'd be able to enjoy the results. ;)
Gotta wonder if that video signal can be used with a decent multisync monitor (although those funny custom colors won't be available, I suppose).

Id like to see a 5150 hercules and/or IBM monochrome video adapter demo... If there are such things point me to them please.
There's 3 Shades of Gray (the "mirrors" link has some working downloads) but the .nfo says "8MHz or faster 8086 PC"... closest thing I know of.

IIRC, Hercules/MDA make it even more difficult to "race the beam" on slow systems, since the H/V blanking periods are ridiculously short. Horizontal blanking is barely even there - blink (poll in a loop?) and you'll miss it.
 

kdr

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IIRC, Hercules/MDA make it even more difficult to "race the beam" on slow systems, since the H/V blanking periods are ridiculously short. Horizontal blanking is barely even there - blink (poll in a loop?) and you'll miss it.
Not to mention that the MDA dot clock runs off a separate crystal so you can't do cycle-counting either.... so your code would have to spend quite a bit of time polling the status bits to try and keep in sync with the beam....
 

VileR

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Not to mention that the MDA dot clock runs off a separate crystal so you can't do cycle-counting either.... so your code would have to spend quite a bit of time polling the status bits to try and keep in sync with the beam....
True, that's what I meant with my "poll in a loop" reference ;)
The French game Hexsider is the only one I've ever seen doing hardware scrolling on Hercules. Luckily that doesn't require all that much precision beyond polling for vertical sync (which happens just after the last scanline displayed, as there's no overscan, unlike CGA).
 

resman

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My CGA to HDMI video adapter chain finally came in. I was able to hook up to my Compaq Portable to an LCD screen and view Area 5150 in stunning color! Recorded on an iPhone that struggled to get the correct white balance and glare from the lights above (sorry, I'm no videographer). The video signal converter chain also introduced some screen tearing artifacts, no doubt due to the conversion to a 1024x768 digital signal. Still looks amazing in person, though:

 

VileR

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Quién es esa niña?
Ella es mi mujercita. She too finds it very important that this demo be viewed at 4:3 aspect ratio - anything wider will elicit some strong words when that screen comes up. 😅

My CGA to HDMI video adapter chain finally came in. I was able to hook up to my Compaq Portable to an LCD screen and view Area 5150 in stunning color! Recorded on an iPhone that struggled to get the correct white balance and glare from the lights above (sorry, I'm no videographer). The video signal converter chain also introduced some screen tearing artifacts, no doubt due to the conversion to a 1024x768 digital signal. Still looks amazing in person, though:
Awesome! Is that RGB2HDMI?

If there's are any tearing, it's not visible in the video. But yeah, scaling that resolution up to 1024x768 will probably introduce some artifacting due to non-integer scale factors.

To maintain CGA's pixel aspect ratio at integer factors, you'd have to scale up by 5x12, which isn't practical; ginormous target resolution, and most converters are probably going to drop frames like they're hot. 2x5 is close enough (4% difference), but you'd still need a monitor with a vertical resolution of x1200. Gotta love current display technologies with their physically fixed pixel grids... three cheers for progress! ;)
 

resman

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Ella es mi mujercita. She too finds it very important that this demo be viewed at 4:3 aspect ratio - anything wider will elicit some strong words when that screen comes up. 😅


Awesome! Is that RGB2HDMI?

If there's are any tearing, it's not visible in the video. But yeah, scaling that resolution up to 1024x768 will probably introduce some artifacting due to non-integer scale factors.

To maintain CGA's pixel aspect ratio at integer factors, you'd have to scale up by 5x12, which isn't practical; ginormous target resolution, and most converters are probably going to drop frames like they're hot. 2x5 is close enough (4% difference), but you'd still need a monitor with a vertical resolution of x1200. Gotta love current display technologies with their physically fixed pixel grids... three cheers for progress! ;)
It's a chain of GGLABS CGA2RGB adapter plugged into a RGB to HDMI Arcade Game Video Converter Output Board. It looks better than I expected, but I think the HDMI output is a little harsh. I'm getting the RGB to VGA Converter Board and connect it to a good old analog VGA monitor.
 

fs5500

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I think Area 5150 is a great demo program that proves that it is absolutely impossible for an emulator to implement 100% exactly like the real one.
 

VileR

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Some CRT footage off the IBM 5153. Tried to get a decent video that's both 60fps and (mostly) free of flickering/banding artifacts:


Captures are cleaner, but on a CRT you do get that nice effect when there's graphics in the overscan area right up to the bezel...
 

kdr

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Some CRT footage off the IBM 5153. Tried to get a decent video that's both 60fps and (mostly) free of flickering/banding artifacts:

Captures are cleaner, but on a CRT you do get that nice effect when there's graphics in the overscan area right up to the bezel...
That's a very good video, and it's focused well enough to see some scanlines, which I think really contributes to the 'feels' of this amazing demo!

Graphics (and the transitions!) extending into the overscan area is one of the major accomplishments of Area 5150 because, just like most of the other tricks in the demo, there's simply not enough VRAM available on the CGA for this to work.... :D
 

SomeGuy

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Finally got a minute to try it on my Columbia Data Products 1600. It looks nice up until the end, I guess when it does the water effects, and the video goes totally out of sync.

Yea, still seeing what I can get away with on a cheap dirty rip-off clone. :)

Very impressive for plain RGB.
 

VileR

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Finally got a minute to try it on my Columbia Data Products 1600. It looks nice up until the end, I guess when it does the water effects, and the video goes totally out of sync.

Yea, still seeing what I can get away with on a cheap dirty rip-off clone. :)
Thanks for checking - that's a bit surprising because the CDP 1600 was touted as 100% compatible, with explicit comparisons to the Compaqs... wouldn't have thought to put it in the "cheap dirty ripoff" category! Gotta wonder whether it's the motherboard design or the CGA clone they bundled with it.
 

1ST1

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Today, anyhow, I tryed on M24. It really does not look like expected. But it shows that the M24 can do things never seen before. Someone should try to make something nice out of this...
 
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