VOGONS


First post, by Diduz

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Hi, guys!
I'm really impressed by the quality Dosbox has achieved.
Kudos to the team. 😀

Here's my..."problem" (more like a "wish").
I dig the idea of emulating the CGA NTSC Composite Mode, but I'd like an option to turn the emulation off. 😳
Why?
I know it sounds silly, but back in the day I used to run Manhunter and other AGI Sierra Games on an old CGA machine.
The CGA pc was connected to monitor (not a tv set), so when I activated the "RGB Toggle" from the menu all I got was the 640x200 b&w mode with all the micro vertical lines.
Well, I liked it a lot, I liked that better than the plain CGA 4-color mode! 😁

I hope no one will get offended by this request, because the multicolor CGA composite mode emulation was a great effort, but I'd really like to experience that b&w environment again (which is totally different from the Hercules mode, btw).

I thought F11 could do the trick, but when I press the key nothing happens.

Thanks anyway,
Dom

Reply 1 of 18, by IIGS_User

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Diduz wrote:

I hope no one will get offended by this reques

Nice idea, but someone with the programming experience needs to provide a patch for it.

P.S.:
What about ScummVM to play AGI games?
I know ScummVM displays color only (even on old Mac game versions, which originally are b/w games)...

Klimawandel.

Reply 2 of 18, by Diduz

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IIGS_User wrote:
Diduz wrote:

I hope no one will get offended by this reques

Nice idea, but someone with the programming experience needs to provide a patch for it.

I know, I would do that myself but unfortunately I am not a programmer... 😊

Reply 3 of 18, by ripsaw8080

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Well, you could run the games with machine=svga_s3 and force them into CGA mode with a command line switch, because the color burst processing only works with machine=cga. Normally you run them with SIERRA.COM, so use a command of "sierra -c" to force CGA mode. Or, if you've decrypted the AGI module into AGI.EXE, use "agi -c". However, I don't know if you'll get mode 6 (640x200 mono) like you're expecting; some AGI games use mode 4 (320x200 4-color).

Reply 4 of 18, by Diduz

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ripsaw8080 wrote:

Well, you could run the games with machine=svga_s3 and force them into CGA mode with a command line switch, because the color burst processing only works with machine=cga. Normally you run them with SIERRA.COM, so use a command of "sierra -c" to force CGA mode. Or, if you've decrypted the AGI module into AGI.EXE, use "agi -c". However, I don't know if you'll get mode 6 (640x200 mono) like you're expecting; some AGI games use mode 4 (320x200 4-color).

Oh, I didn't know the Sierra games featured command line options (I used the command line a lot with Lucasfilm Games stuff).
I'll give it a try and let you know about that.
Thank you very much! 😀

Reply 6 of 18, by ripsaw8080

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I don't think timing will be a problem; but 640x200 mono is wanted for "nostalgia" reasons, and the games I tried set mode 4 and change to B&W with CGA hardware registers, which won't work in other machine types.

I think the desired effect can only be achieved by changing the DOSBox source (see attached screenshot); but in this case the price of nostalgia might be eye strain. 😉

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Reply 7 of 18, by Diduz

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Diduz wrote:
Oh, I didn't know the Sierra games featured command line options (I used the command line a lot with Lucasfilm Games stuff). I'l […]
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ripsaw8080 wrote:

Well, you could run the games with machine=svga_s3 and force them into CGA mode with a command line switch, because the color burst processing only works with machine=cga. Normally you run them with SIERRA.COM, so use a command of "sierra -c" to force CGA mode. Or, if you've decrypted the AGI module into AGI.EXE, use "agi -c". However, I don't know if you'll get mode 6 (640x200 mono) like you're expecting; some AGI games use mode 4 (320x200 4-color).

Oh, I didn't know the Sierra games featured command line options (I used the command line a lot with Lucasfilm Games stuff).
I'll give it a try and let you know about that.
Thank you very much! 😀

I've tried that, but unfortunately Manhunter switches from CGA green-brownish-red to magenta-cyan-black and viceversa. What the-? Isn't the "RGB toggle" supposed to activate the CGA Composite mode?
I'm lost, but I swear I saw Manhunter running in the way Space Quest runs in the screenshot ripsaw posted.
@ripsaw: How did you achieve that display?
No programmer here. 😜

Reply 9 of 18, by ripsaw8080

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You get 4-color mode with VGA machine types because the games use CGA hardware registers to switch from 320x200x4 to 640x200x2. I achieved the effect by changing the DOSBox source. Change VGA_SetMode(M_CGA16); to VGA_SetMode(M_TANDY2); in vga_other.cpp; and you'll have exactly what you're looking for (deactivated color burst mode) with machine=cga.

Reply 10 of 18, by Diduz

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ripsaw8080 wrote:

You get 4-color mode with VGA machine types because the games use CGA hardware registers to switch from 320x200x4 to 640x200x2. I achieved the effect by changing the DOSBox source. Change VGA_SetMode(M_CGA16); to VGA_SetMode(M_TANDY2); in vga_other.cpp; and you'll have exactly what you're looking for (deactivated color burst mode) with machine=cga.

Okay, I'll try that and let you know. Thanks for your help!
P.S.: I know, it's ugly, but you know... nostalgia makes the gamer a dull boy... 😳 😁

Reply 11 of 18, by Servo

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As a workaround you can set machine type=tandy (or pcjr probably) and then use the command line switch to force CGA mode. The register tweaks Sierra uses should work fine with tandy (unlike VGA) and DOSBox doesn't emulate a composite monitor in Tandy mode.

Reply 13 of 18, by ripsaw8080

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@Servo: I had tried that, but at least the few original AGI interpreters I tried would not respect the CGA override switch when a Tandy machine is detected, and always used mode 9 16-color graphics. And DOSBox stopped responding (hung) when I tried to run the AGI games with machine=pcjr.

@eL_PuSHeR: The AGI games support hercules graphics that looks nicer, IMO. After all the vertical lines with CGA are intended to produce artifact colors... but I guess it's subjective.

Reply 14 of 18, by eL_PuSHeR

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I know that. Hercules had got WAY BETTER resolution than CGA. 720x348 or something like that.

I remember to have tried LSL1 using Hercules and text was nice and crisp.

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Reply 16 of 18, by ripsaw8080

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After a little experimenting I found the AGI games work OK with machine=pcjr if you run loadfix with the standard 64kB allocation. However, as with the tandy machine type, they ignore the CGA mode command line switch.

It is not the game code that is hanging without loadfix; DOSBox enters an infinite loop in its internal DOS function for resizing a memory block, so it seems like there's some bug there.

Reply 17 of 18, by leileilol

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eL_PuSHeR wrote:

It doesn't look that bad to me. It reminds me of Hercules. 😎

When you consider the monochrome-only "portable" systems of the era this tends to glow green with very blurry bright phosphors that ghost badly at a refresh rate of 43hz (iirc)

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