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40 Column Text Mode Issues

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Reply 20 of 457, by Qbix

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well It's darker. but you could modify your tv to show it lighter.

I prefer the darker variant so I coded that in as default. a personal touch from me that would be 😀 (changed the darkness a bit to the darker side) I don't have any plans on making that user selectable before you ask it 😀

recompilation is the only way. although it will always be a lot darker then EGA

But yes. CGA 16 is darker. partly by design. partly by me (a tinybit).(
4 % or so)
🙄 🙄

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Reply 23 of 457, by DosFreak

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I think the screen was dark. I remember seeing a friend play KQ1 on his monitor outputted to his TV back in the day. Can't remember what kind of a computer he had but this was back in teh early 90's....it definetly wasn't as bright as was shown.....of course his TV could have had the brightness turned down.

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Reply 24 of 457, by Qbix

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dosfreak: Even darker then then my shots ?
Hmm could be possbile though. got the saturnation still to the max. but I think it's quite enjoyable with these defaults.

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Reply 25 of 457, by DosFreak

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Nah, I was referring to the older screenshots with brighter than the sun brightness. 😉

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Reply 26 of 457, by DosFreak

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Was browsing oldskool http://www.oldskool.org/shrines/pcjr_tandy today and found these:

kq1_1_04.gif
4 Color CGA

kq1_1_16.gif
16 Color

The 4 Color is what I remember seeing back then and why I remeber it being "dark". heh. The green grass looks more like grass instead of Nickelodeon Goo. Weird, look at the banner son the walls and the flags, looks like they are different colors compared to qbix's screenshots from DosBox.

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Reply 28 of 457, by Great Hierophant

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I'm not sure whether that CGA screenshot taken from the Oldskool PC site is shown at the proper intensity. As we all should know, the two main CGA palettes (Red, Green and Brown; Cyan, Magenta and Light Gray) can also be set to display in high intensity (Pink, Light Green and Yellow; Light Cyan, Light Magenta and White) (I don't know about the third, unofficial Cyan, Red and White palette.) I am not sure whether King's Quest, either the PC Booter or the DOS installable, use the intense palette.

Can someone with a real IBM CGA card test the games and tell us whether or no? It does look nicer, I think, with the intense palette.

While we are on the subject, how is the 6845 emulation in CGA mode?

Reply 29 of 457, by NewRisingSun

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Looks like I have to register at every forum to get points across. Anyway:

Comparing the screenshots of NewRisingSun's algorithm to the MobyGames screenshot linked from that thread, it seems he has red artifacts where the MobyGames shot has blue, and vice-versa.

That's not a function of the algorithm, but of the ROM font used --- apparently the person who made the MobyGames shots used a graphics card that shifted the font by one pixel. The "O" character looks different, too. Also, my original algorithm reduced the artifacts to the level they occur on a TV screen, but that would require 16/32 bit rendering, and I'm told DosBox at the moment only supports 8-bit palettized rendering.

The text is readable I would say.

Those screenshots have "flagOptimizeText" disabled; you said you wanted to keep it enabled, only disable "flagFilterChroma" because of DosBox's restrictions.

Is it supposed to be that much darker?

Yes. The brightness is controlled by the lower four bits of port 0x3d9. KQ1 writes 27 to that register, so it's at half the brightness; other games (BC's Quest for Tires, Winnie the Pooh in the Hundred Acre Wood) write 3F to that register, so they're at full brightness.

I prefer the darker variant so I coded that in as default.

You're not supposed to code any value as a "default", but to use whatever the game writes to port 0x3d9.

although it will always be a lot darker then EGA. But yes. CGA 16 is darker. partly by design. partly by me (a tinybit).(4 % or so)

No, only if you implemented the algorithm incorrectly.

I'm not sure whether that CGA screenshot taken from the Oldskool PC site is shown at the proper intensity.

No, it isn't. It's supposed to be at half the intensity in "RGB mode".

Reply 31 of 457, by Great Hierophant

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No, it isn't. It's supposed to be at half the intensity in "RGB mode".

I had been wondering about that for years. If you see yellow instead of brown, your adapter or emulation is not showing the true graphics correctly.

Yes. The brightness is controlled by the lower four bits of port 0x3d9. KQ1 writes 27 to that register, so it's at half the brightness; other games (BC's Quest for Tires, Winnie the Pooh in the Hundred Acre Wood) write 3F to that register, so they're at full brightness.

I wondered why MobyGames' screenshots of the color composite mode didn't always have the same looking colors. TV differences notwithstanding, now I know why.

That's not a function of the algorithm, but of the ROM font used --- apparently the person who made the MobyGames shots used a graphics card that shifted the font by one pixel. The "O" character looks different, too. Also, my original algorithm reduced the artifacts to the level they occur on a TV screen, but that would require 16/32 bit rendering, and I'm told DosBox at the moment only supports 8-bit palettized rendering.

There are alot of wrong fonts about these days, it seems. IBM's font characters start at the first pixel column. The font in the MobyGames screenshot seems to start the character in the second column. Additionally, the "A" in Sierra is very different from the true "A". I'm surprised that the scrrenshot taker had a non-IBM CGA card that had the ability to reproduce color composite mode. I also have serious doubts about the font used in the 16 color screenshot above and also in the Tandy screenshot I took earlier. [/code]

Reply 32 of 457, by HunterZ

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NewRisingSun wrote:

Looks like I have to register at every forum to get points across.

Yeah, it's annoying. But this is a cool place. Welcome!

Comparing the screenshots of NewRisingSun's algorithm to the MobyGames screenshot linked from that thread, it seems he has red artifacts where the MobyGames shot has blue, and vice-versa.

That's not a function of the algorithm, but of the ROM font used --- apparently the person who made the MobyGames shots used a graphics card that shifted the font by one pixel. The "O" character looks different, too. Also, my original algorithm reduced the artifacts to the level they occur on a TV screen, but that would require 16/32 bit rendering, and I'm told DosBox at the moment only supports 8-bit palettized rendering. (emphasis added -HunterZ)

Can one of the DOSBox devs or hackers confirm this? I thought DOSBox only renders in 16- or 32-bit and prefers the latter.

Reply 33 of 457, by Kippesoep

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HunterZ wrote:

Can one of the DOSBox devs or hackers confirm this? I thought DOSBox only renders in 16- or 32-bit and prefers the latter.

DOSBox renders internally at 32bit. It prefers 16bit for output, simply because of the reduced memory bandwidth.

NewRisingSun is probably confused by DOSBox supporting only 8bit modes in the emulated machine (at least, in the official branch).

Reply 34 of 457, by Qbix

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no dosbox internally runs on 8 bit. (explaination)
the best way to implement this videomode is to use the vga pallet which is 8 bit. (which refers to 18 bit internal pallette). Harekiet and I had lengthy discussions about it and this is the proper way(as far as we are concerned). (using the internal VGA pallette).

You are right about the fact that I didn't implement the optimize textflag you added.
Most importantly because I didn't try yet. And as it's not that obvious as I had seperate it into pallette and colours.

I just posted these screens to show how it looks at the moment. (It's not even commited yet. First wanted some responses) As the quality of the mode keeps amazing me.

Futher I found at least one game that didn't use a white font. (bruce lee). (more a red font. or maybe it would be white with the optimizeText flag. Still have to memorydump that one)

I didn't code a default in it. I only set the hue and saturnation to values I liked instead of making them selectable. That's what I meant with default.

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Reply 35 of 457, by Kippesoep

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Qbix wrote:

no dosbox internally runs on 8 bit.

I'm sure you know much more about this than I do, but it does seem to pass 32bit to SDL in most cases, at least with most scalers and with any output mode other than surface. Otherwise the things such as blending (in the overscan border patch, for instance) wouldn't work, would they?

BTW, does this mean the overscan border patch doesn't work when using the surface output mode with a scaler that doesn't have NEED_RGB in its flags?

Maybe we just mean different things with "rendering internally". I understood it to be the format which ends up as the final form that is given to SDL. Before that, everything is in 8bit, yes.

Reply 36 of 457, by NewRisingSun

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the best way to implement this videomode is to use the vga pallet which is 8 bit.

Do what you think is best, but keep in mind that composite modes are based on the NTSC color model, which doesn't know "palettes" or "bits", but is purely analog.

I only set the hue and saturnation to values I liked instead of making them selectable.

Ok, I hope those values you liked are "1.0" for saturation and "0.0" for hue, because everything else is wrong. 😀

Further I found at least one game that didn't use a white font. (bruce lee)

Bruce Lee doesn't use composite mode, as far as I can tell. or is there a secret way to make it so?

Last edited by NewRisingSun on 2005-10-08, 14:43. Edited 1 time in total.

Reply 37 of 457, by Qbix

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bruce lee:
Uhm abandonia has a version which asks which output to use.
option A is composite CGA (maybe dosbox machine should be set to cga)

The black cauldron or so (sierra game downloadable from creator page allowe..) uses black text on white. (title bar is white, text is black)

I will restore the hue to 0 ( I set it to 3.0).

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Reply 39 of 457, by NewRisingSun

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Indeed. My version of the game didn't have that monitor selection, but the abandonia one did. Odd. Anyway, here's screenshot with my original algorithm (optimizeText off). Bruce Lee's "red" text is actually gray.
As to your question, optimizeText optimizes text that is black on white and white on black, but no grays. The chroma filter keeps them readable though.

The sky looks a bit greenish though. I wonder if I should add some white-angle color demodulation (sometimes called "one-button color" or "red boost") as found on most consumer TV sets.

Last edited by NewRisingSun on 2005-10-08, 14:49. Edited 2 times in total.