I've been playing around with this, but I can't find anything in Adventure in Serenia that would support composite mode. I hacked the executable to force composite mode, but this doesn't look anything like the screenshots on MobyGames, for instance. For example, on the "snake" screen, the MG screenshot has green cacti and a distinctly different colour for the snake and the large rock. When forcing composite mode, the cacti are grey (so no amount of adjusting the hue will change that) and the snake and the rock are pretty much the same colour.

Also is there no code that sets the graphics mode to monochrome mode 6, which when followed by disabling bit 2 in the mode control register is the proper way to enable composite colour mode afaik.

Note: several version can be found on the internet, one of them has both (yes, there are only 2 😀 ) writes to the mode control register nop-ed out. In the original it is used only to disable screen display for a while (by clearing, then setting bit 3: enable video output).

Unless there's other versions still or the code is simply obscure beyond my ability to interpret it, I am tempted to call shenanigans on the composite CGA screenshots of this game.

Kippesoep wrote:

Unless there's other versions still or the code is simply obscure beyond my ability to interpret it, I am tempted to call shenanigans on the composite CGA screenshots of this game.

I checked the MobyGames page, and I got a deja-vu when seeing the 'main street' composite mode screen shot. A bit of searching (well, I had a good idea where to look, so it wasn't that hard) found me what is probably the longest thread ever here, and especially this page. Seems like it is quite authentic, dispite your reservations Chickensoup! (Would've been a hell of a job forging those images anyway :)). See also Great Hierophant's remark in this thread on composite colours: not always (also mentioned in that other thread, try reading all 22 pages :)) the colour burst is set for composite output.

JAL

Isn't it the case that DOSBox supports only the "Mode 6"-based composite (monochrome on RGB monitor) mode but not the "Mode 4"-based composite (4-color on RGB monitor) mode?

Yeah, TeaRex, that is the case. It does indeed set mode 4. I forced it into composite mode 4, but it still looks off, as described in my previous post -- that could be the result of not having direct support for it, though. I never had a CGA so it's not something I ever dealt with on real hardware 😀

Kippesoep wrote:

I never had a CGA so it's not something I ever dealt with on real hardware 😀

I did have a CGA, but the main problem would be that a) most CGAs didn't have a TV-out to begin with, and b) composite mode only works for NTSC monitors, not for PAL (so Europeans couldn't benefit, especially in those days most PAL TVs couldn't do NTSC.

JAL

You guys may not have realized, but all Mode 4 CGA games, which must encompass 95% of all CGA-compatible games, support composite color output. The real CGA card had a composite color output, and many CGA-only derivatives did as well.

The color bit in Mode 4 is always set, and if you turn it off, then you have Mode 5 and a different palette. Mode 5 does not support color composite output, only monochrome. Mode 6 does not by default, but the bit can be set without changing any other attributes.

The question is not whether a CGA game supported composite color graphics, but how well they were supported.

Hmmm... wasn't the Question whether DOSBox supported composite color mode for those games?

Some Mode 4 games seem to be "made for composite" so to speak, they look weird/wrong on a RGB monitor, since they employ "artifact color" (color caused by strategically placed vertical stripes, has no coloring effect in RGB) in combination with the standard documented CGA coloring method.

And it is this mode that, as I understand, DOSBox does not yet support.

TeaRex wrote:

Hmmm... wasn't the Question whether DOSBox supported composite color mode for those games?

Some Mode 4 games seem to be "made for composite" so to speak, they look weird/wrong on a RGB monitor, since they employ "artifact color" (color caused by strategically placed vertical stripes, has no coloring effect in RGB) in combination with the standard documented CGA coloring method.

And it is this mode that, as I understand, DOSBox does not yet support.

It does not as far as I know.

There are excellent illustrations of how some games were meant for composite color. However, as not everybody had composite color monitors available, the artists still had to make sure the game was playable for everyone with RGB monitors.

EGA and VGA games that support CGA by means of an algorithm will not look very good on a composite color monitor, but will not show random patterns or something similar.

DOSBox cannot make calls as to which game should support composite color and which should not, and the only way to properly support such a mode is by designating a new machine type.

Interesting Web Page from MESS project on CGA composite stuff (scroll down a bit):

http://www.reenigne.org/crtc.html