VOGONS


40 Column Text Mode Issues

Topic actions

  • This topic is locked. You cannot reply or edit posts.

First post, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

DOSBox and games that use the 40-column CGA text mode don't mix at all, for whatever reason. Cases in point:

Microsoft Adventure: First two columns of text do not appear.
King's Quest (IBM PC or Tandy Booter): Inventory and King Edward's Speech do not appear, and in the Tandy mode some title screen text is improperly "interlaced" whn it should be solid (not connected.)
Icon: Quest for the Ring and The Seven Spirits of RA (Icon Demo): Main screens do not display correctly.

Reply 4 of 457, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

The game will work just fine, until you press TAB to bring up the inventory screen or talk to King Edward. Also, I forgot to mention but the title screen does not seem to display correctly in the Tandy mode (using the Tandy KQ1 disk image.) All the text seems to only display every other pixel column when it should be solid. The titles are barely legible and the names use two colors rather than one. Compare the title screen to the Tandy 1000 MESS driver and you will see the difference. I also note, however, that there are noticeable differences (n, t, b, d) in MESS's font compared to the true IBM 8x8 text font.

While I'm on the subject of font differences, the MESS option that allows you to use the thin, single dot 8x8 font stored on the CGA card differs considerably from the true IBM font. Someone should tell the MESS designers. I wish we could have an option for it in DOSBox though.

Reply 9 of 457, by Qbix

User metadata
Rank DOSBox Author
Rank
DOSBox Author

well I've been looking into the font thing myself fot the KQ1 booter in composite cga mode.
It gets some weird artifacts on the screen with text (red spots) I figured this is caused by our smooth fonts. So either I need to code a filter or add a different font for cga mode. Not sure yet which one to use.

Water flows down the stream
How to ask questions the smart way!

Reply 11 of 457, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

I strongly advise using the font on the following page, which describes IBM's Color Graphics Adapter in more detail than just about anyone would want to know:
http://www.seasip.info/VintagePC/cga.html

The page implies that the font is from a dump of the CGA's character ROM and looks like it (using thin and thick font styles.) Also, please look at:
http://www.seasip.info/VintagePC/mda.html

which has info and the font from IBM's Monochrome and Printer Adapter, which font was probably used on the Hercules Graphics cards.

If the user is selecting the CGA, Tandy or Hercules modes, user selectable fonts have little value as these adapters could not support them (for the most part.)

Reply 12 of 457, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

Also, as far as color composite mode goes, take a look at the results of the algorithm mentioned on this page:

http://www.queststudios.com/forum/viewtopic.p … t=1448&start=25

Comparison to MobyGames screenshots show something quite close to true the color composite mode.

Reply 14 of 457, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

I used no scaler. However, the Tandy font does seem to be different from the CGA's font, but I doubt that to be the cause. The algorithim is probably based on the sort used for the double high resolution color mode on Apple II emulators, the which is the closest analogous method to the CGA. I will ask the guy on the Quest Studios forum for more information because his algorithim seems particularly true.

Reply 15 of 457, by HunterZ

User metadata
Rank l33t++
Rank
l33t++

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.

Still, that's pretty need. I don't think I've never seen CGA on an actual composite monitor before.

Reply 16 of 457, by Qbix

User metadata
Rank DOSBox Author
Rank
DOSBox Author

I've been in contact with the author.
I've implemented a similar algorithm although less advanged, because of restrictions in dosbox

This is a screenshot of the titlescreen. (cga composite mode)
The text is readable I would say.

This isn't in the cvs yet

Attachments

  • burg.png
    Filename
    burg.png
    File size
    43.38 KiB
    Views
    11427 views
    File comment
    burgertime new code
    File license
    Fair use/fair dealing exception
  • burgoud.png
    Filename
    burgoud.png
    File size
    43.67 KiB
    Views
    11427 views
    File comment
    burgertime old code
    File license
    Fair use/fair dealing exception
  • kq1old.png
    Filename
    kq1old.png
    File size
    9.55 KiB
    Views
    11450 views
    File comment
    0.63 code
    File license
    Fair use/fair dealing exception
  • kq1.png
    Filename
    kq1.png
    File size
    12.57 KiB
    Views
    11456 views
    File comment
    kq1 (rescaled) new code (not yet in cvs)
    File license
    Fair use/fair dealing exception

Water flows down the stream
How to ask questions the smart way!

Reply 18 of 457, by Qbix

User metadata
Rank DOSBox Author
Rank
DOSBox Author

well it's not just text artifacts.
it's just anything that blends. We just interpreted the mode wrong

Must have been weird to code for it though.

Some more screenies

Attachments

  • kq1gamenew.png
    Filename
    kq1gamenew.png
    File size
    60.72 KiB
    Views
    11415 views
    File comment
    in game new code
    File license
    Fair use/fair dealing exception
  • kq1gameold.png
    Filename
    kq1gameold.png
    File size
    66.71 KiB
    Views
    11415 views
    File comment
    current 0.63 code
    File license
    Fair use/fair dealing exception

Water flows down the stream
How to ask questions the smart way!