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Reply 40 of 56, by Calvero

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This is awesome. There are a bunch of games I would like to see get the same treatment. Games that only use 4 colors on the PC, but more colors on other platforms:
Contra,
Crazy Cars,
Karateka,
Mach 3,
Manhattan Dealers,
Montezuma's Revenge,
Soko-Ban
and the Epyx "Games" series

Reply 41 of 56, by VileR

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Jo22 wrote:
The pictures were taken from a cheap LCD monitor, which claims to be multi standard (PAL/NTSC/SECAM). I wished I still had my Co […]
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The pictures were taken from a cheap LCD monitor, which claims to be multi standard (PAL/NTSC/SECAM).
I wished I still had my Commodore 1702 monitor, so I could have provided you with higher quality pictures.
Or any other old school monitor with a comb filter..

My setup:
386DX-40 with turbo brake enabled, caches disabled.
Epson Model Q205A ("CGA" card with mono/colour switch)
Philips 15PF4121

Here's a picture of my CGA wanna-be and a dump from that crystal memory.
I hope they're useful. I've tried to capture the resistors as best as I could.

Heh, not that many 386 systems with CGA cards around.
Interesting setup -- and sort of an interesting card... thanks for that character ROM image. Although looking at these bitmaps, I'm not too sure what to make of it. Any chance that this is just a bad dump? 😉

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Calvero wrote:
This is awesome. There are a bunch of games I would like to see get the same treatment. Games that only use 4 colors on the PC, […]
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This is awesome. There are a bunch of games I would like to see get the same treatment. Games that only use 4 colors on the PC, but more colors on other platforms:
Contra,
Crazy Cars,
Karateka,
Mach 3,
Manhattan Dealers,
Montezuma's Revenge,
Soko-Ban
and the Epyx "Games" series

I recall seeing some information regarding those Epyx games, which indicated that at least some PC versions had composite color support? Can't quite find it now, but it may turn out that such a port does exist...

I've had a slightly different idea myself regarding Montezuma's Revenge. Some of the better versions (C64, Atari, etc.) keep things graphically interesting by varying the color scheme between rooms. This effect can be achieved in the PC version by keeping it at 4 colors, but tweaking the palette mapping (e.g. Alley Cat, Pyramids of Egypt, etc.) - of course, that would require PCjr/Tandy/EGA/VGA.

There's also this old thing which was just my 'practice run' for this type of hack (although technically that offers *more* colors on PC than on its original 8-bit platforms, heh).

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Reply 42 of 56, by Jo22

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VileRancour wrote:
Jo22 wrote:
The pictures were taken from a cheap LCD monitor, which claims to be multi standard (PAL/NTSC/SECAM). I wished I still had my Co […]
Show full quote

The pictures were taken from a cheap LCD monitor, which claims to be multi standard (PAL/NTSC/SECAM).
I wished I still had my Commodore 1702 monitor, so I could have provided you with higher quality pictures.
Or any other old school monitor with a comb filter..

My setup:
386DX-40 with turbo brake enabled, caches disabled.
Epson Model Q205A ("CGA" card with mono/colour switch)
Philips 15PF4121

Here's a picture of my CGA wanna-be and a dump from that crystal memory.
I hope they're useful. I've tried to capture the resistors as best as I could.

Heh, not that many 386 systems with CGA cards around.
Interesting setup -- and sort of an interesting card... thanks for that character ROM image. Although looking at these bitmaps, I'm not too sure what to make of it. Any chance that this is just a bad dump? 😉

Hey, thanks a lot for your interest! And yeah, my setup isn't the usual one (haven't got a XT yet).. 😁

But sorry about that dump.. I double checked and I'm afraid it's okay. 🙁

I've used a dedicated EPROM reader for that purpose,
because I wasn't sure about the font's exact location in memory.

The chip is an old 2764 by the way (ceramic type, non-CMOS, 70s style),
so there might be a compatibility issue with the reader..

Or maybe that code is intended as some kind of control program for the card itself ?
Would be be interesting to find out! In any case, there was no other graphics card installed.
I wonder where that font came from.. The system BIOS maybe ? Nah, it's just an ordinary AMI BIOS (or not ?).

Maybe that piece of code is also accessible from DOS (debug, nssi) ?
If you provide me with some instructions, I would be happy to dump the chip once more. ^^

În the mean time, I'll keep looking for more information about this card.

So far, I've found a few more photos regarding this card :
http://www.recycledgoods.com/epson-q205a-8-bi … rome-w-rca.html
http://www.ebay.it/itm/231934847764

That eBay auction includes links to additional photos :
http://s26.postimg.org/esywto49l/00_2668.jpg
http://s26.postimg.org/zedolkluh/00_3586.jpg
http://s26.postimg.org/luwufv7vd/01_3589.jpg
http://s26.postimg.org/jcb5f6m55/02_2674.jpg
(I mention these links here in case the auction is no longer listed.)

Edit: I think I can make out some characters! I've highlighted to what I think are numbers and letters.
But it's hard to see, so maybe there's some corruption going on. Maybe another dump will clarify the matter.

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In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 43 of 56, by Scali

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Jo22 wrote:

I wonder where that font came from.. The system BIOS maybe ? Nah, it's just an ordinary AMI BIOS (or not ?).

Although there is a font in the system BIOS, it is only meant for graphics modes.
In pure text modes, the font always comes from a ROM on the card itself (or some kind of RAM on newer cards, where you can upload/modify the font yourself).
In theory you could design some card that has a ROM which copies the font from system BIOS to its onboard font RAM at bootup, so it won't have 'carry' any font data itself. But I don't think anyone ever went that route 😀

It's funny by the way that different system BIOS can have different fonts. Eg I have a PC with Phoenix BIOS, and in 40-column graphics mode, I get very different characters compared to a real IBM (which you can see eg in the 8088 MPH intro screen).

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 44 of 56, by VileR

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@Jo22:
I've split off the font discussion to this thread, if you don't mind- it's probably more on-topic over there...

Scali wrote:

In theory you could design some card that has a ROM which copies the font from system BIOS to its onboard font RAM at bootup, so it won't have 'carry' any font data itself. But I don't think anyone ever went that route 😀

One likely reason is that the system BIOS only contains the lowest 128 characters, and CGA/MDA text modes need the rest to be hardcoded, as it were.

Anyway, I'm half-seriously considering doing Keen 5 and 6 now, as well (astute observers will have noticed that I did convert those "preview" shots in the Order Info help screen). 😁 Won't be as interesting/instructive as working on 4 was, but it somehow feels 'incomplete' without them...

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Reply 46 of 56, by keropi

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VileRancour wrote:

[...]

Anyway, I'm half-seriously considering doing Keen 5 and 6 now, as well (astute observers will have noticed that I did convert those "preview" shots in the Order Info help screen). 😁 Won't be as interesting/instructive as working on 4 was, but it somehow feels 'incomplete' without them...

YES. Do it. It's almost self-compulsory 🤣

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Reply 47 of 56, by Jo22

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@VileRancour
Thanks, that's a good idea. I was already afraid of spamming this nice thread. 😀
Was also the reason I crambed as much information required in only a few posts..

@Scali
Thank you for this explanation. I always wondered about how CGA works.
Had my first experience with CGA in GWBasic back in the last century.
I think my PC also had a Phoenix variant. The first time I've seen Composite CGA
was when I read a review about "Ultima II:The Revenge of the Enchantress" in an old magazine.
That title screen with the dragon looked so awesome to me. Couldn't believe it was actually CGA..
The second game was Starquake, which used normal CGA but also the alternate palette.

@keenmaster486 @keropi
Yay, I fully agree! 😁

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 48 of 56, by Scali

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Jo22 wrote:
@Scali Thank you for this explanation. I always wondered about how CGA works. Had my first experience with CGA in GWBasic back i […]
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@Scali
Thank you for this explanation. I always wondered about how CGA works.
Had my first experience with CGA in GWBasic back in the last century.
I think my PC also had a Phoenix variant. The first time I've seen Composite CGA
was when I read a review about "Ultima II:The Revenge of the Enchantress" in an old magazine.
That title screen with the dragon looked so awesome to me. Couldn't believe it was actually CGA..
The second game was Starquake, which used normal CGA but also the alternate palette.

I'd like to add that the font is the only ROM on a CGA/MDA card. And this ROM can only be accessed by the card itself, not by the CPU.
The 'firmware' for CGA/MDA is included in the standard PC BIOS, just as the font used in graphics mode.
So on CGA/MDA the whole int 10h API is in the PC BIOS, not on the card (CGA and MDA were the standard display adapters for PC, so part of the platform).

EGA and later have their own BIOS extension onboard, and they will hook into int 10h to add support for extra video modes and such.
Pre-EGA third-party solutions such as Hercules and Plantronics didn't use this method yet. So while they have extra features and video modes, there is no support for them through int 10h. You have to bang the hardware directly to use them.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 49 of 56, by Calvero

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VileRancour wrote:

Anyway, I'm half-seriously considering doing Keen 5 and 6 now, as well (astute observers will have noticed that I did convert those "preview" shots in the Order Info help screen). 😁 Won't be as interesting/instructive as working on 4 was, but it somehow feels 'incomplete' without them...

There's also Keen Dreams CGA 😉

Reply 50 of 56, by VileR

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Calvero wrote:

There's also Keen Dreams CGA 😉

Yeah, but I never liked that one, so I have little motivation to touch it. 😉

Anyway, here's that writeup I promised, for interested parties. A big wall of tl;dr, to be sure, but you can always just enjoy the pretty colors of the syntax-highlighted assembly (gotta love the fact that there's an online tool to do it):

http://8088mph.blogspot.com/2016/05/dopefish- … der-keen-4.html

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Reply 51 of 56, by Scali

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Some more captures, both from my Commodore PC10-III (8088 at 9.54 MHz).
First the onboard Paradise PVC4:
https://youtu.be/-eRvF0aSYlc

And then using my ATi Small Wonder:
https://youtu.be/eRVwYCq8X5w

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Reply 52 of 56, by VileR

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Hah, nice ones. Definitely playable at this speed, too - I guess most turbo XT boards would be at least 'close enough', then.
The Paradise is kinda-sorta in the ballpark, although it's obviously off -- the Small Wonder turns everything into a shroom trip, especially the tropical background @4:04 or so. 🤣 If you pause both videos on the same image and flip between the tabs, you can even see the tiny horizontal shift between them... which may be related to the different hues, if it's just the pixel- or color clocks that are different in phase (everything else being equal).

If any of these clone cards was a multiple of 90 degrees off, you could theoretically force the correct colors by rotating the pixel patterns left or right as needed...

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Reply 53 of 56, by Scali

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The weird thing about the ATi Small Wonder is that its phase is only off in mode 6. If I play the unpatched version of Keen, I get the correct cyan/magenta colours and artifacts pretty much equal to a real IBM CGA.
Likewise, colours in 40-column textmode are fine.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 54 of 56, by VileR

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Didn't really think I'd stop at 4, did you? 😉 Here's a composite CGA edit for Keen 5:

- Download (patch only; you need the original KEEN5 CGA v1.4, Apogee release).
- Youtube (DOSBox footage)

As before, it'll work on the same hardware as the Episode 4 mod, but for DOSBox here's my Windows SVN build which includes the improved composite & PC speaker patches.

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Reworking the graphics for this was interesting, since the visual style is quite different to that of Keen 4 despite many elements being the same. Code-wise, the only really 'new' functionality for Keen 5 is the palette animation for the game over screen; the EGA version messes with the galaxy colors before the particle explosion (which, BTW, is a slideshow on a real XT!), but the vanilla CGA version settles for a boring static image, so I had to roll my own routine here.

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