Doom

[escarlata]

Hi guys! I'm new to this forum, and there's been sometime that I'm wondering... having Doom for many 68k platforms, like Amiga and Mac. Do you think it could be possible to port it to X68000? Could it achieve a decent 15/20 fps with a X68030@25?

[kamiboy]

Games like doom are framebuffer games designed for the way that early 90's PC hardware worked.

The X68000 and indeed any other sprite based hardware is designed to perform well in a very different scenario.

There are graphic modes that allow you to put random pixels in a framebuffer on the X68000, that is how all those 3D games for it work, but rendering your game that way is often very slow.

I've never tried my hand at using the X68000 that way though, so I can only guess. I believe it is technically possible to run a game like DOOM on the X68000 but whether it can be made to run at a decent framerate at full screen with sound and music is anyone's guess.

My guess would be prolly no, unless you are a coding wizard.

[Neshek]

I remember some Doom engine port on amiga 68030 back from the days. Can't remember frequency, and memory specs of the machine. I don't know if chunky to planar conversion killed the machine or don't remember if general midi music worked. Software midi play.. erm.. CPU cycle killer i guess... But well... Didn't perform great at all.. Less than 10fps for sure.
On the other hand, Gloom, which was a clone (a good one) and not a port ran much better and could be considered kind of playable on stock A1200... It flew on 030 if remembering correctly.

Could it be done? Probably. Optimizing like crazy for what result? Who would play Doom clone or Doom-like game in 2014? What made some sense so many years ago is pointless now, i'd rather have a fun "Japanized" Wolfenstein running on stock x68000 than 1fps Doom port or clone on a 030 nobody owns.

Better, new 2d games with the stock x68000 in mind.
I'm sure it would be fun for everyone, gamers, developers, especially for coders who aren't up for some pointless challenges.

Having a new 2d game out this year for x68000, that can be an interesting challenge

[papa_november]

If the Amiga can do it, the X68000 can do it, but it'll still be a huge undertaking to port it. The X68000's video hardware is versatile enough to handle framebuffer 3D graphics decently, there's no chunky-to-planar BS like the Amiga has. Hell, some of the system's 2D games run in a pseudo-framebuffer mode (complete with software sprites) for no good reason.

The main chokepoint is the processor. You'll need an 030 for anything resembling a game, full stop. (You might not need an 030 to get Wolfenstein 3D going though.)

I'm actually a bit suprised nobody's done it already. The X68000 is one of the few systems left in existence without a port of Doom.

[neko68k]

Don't think I haven't thought about it a few times...

[H68k]

One of the things, you have to take in to account is... when Doom was ported to the Mac, Most 68k based Mac's that were still on the ruling majority. Had the luxury of higher clocked 030 and 040 68k CPUs... giving them some considerable extra headroom to play with, over a stock X68030.

I'd say it isn't impossible to port Doom and get it running on a '030 model... but you'd probably end up with a version of Doom that plays in a small square of a picture, has no music and maybe a few to no sound effects whatsoever...

Now if your one of them lucky few... with a Jupiter-X 040 or 060Turbo(I... SIR... think your a jammy bastard! if you do...) processor expansion boards.. you could most likely have a version of Doom that would run very smoothly, in full screen at the maximum resolution the X68k's Video Controller chip set could output.
and maybe with software sound mixing. allowing you to play many digital sound effects at once. (given the limitations of the ADPCM chip... it would still only be in mono... not that would bother be much though) and perhaps, using the YM2151 for rather cheesy FM synthesis renditions of the Doom music.

On another thought though... if those coding aces, ID contracted to port Doom to Atari's Jaguar... managed to get a half decent port running (rather playably)
on a stock 13Mhz low cost edition 68k... it might be a bit more possible than i first thought... on an X68030.

[papa_november]

It's all a matter of optimization. There's newer, better-optimized ports of Doom on Amiga that can run acceptably on an 030-50. (I don't know if it's possible to get the X68030 going at 50 MHz - it's either impossible or a simple matter of changing the oscillator and CPU.)

Conversely, the NeXT version of Doom runs like dogshit even on an 040 because it was an internal id proof-of-concept.

[H68k]

From what I've read, trying to overclock a X68030 is a similar deal to overclocking any other X68k model, one crystal drives the CPU and the chips of the IO chipset's clocks, each X68k model could... in theory.. could be overclocked to the maximum the CPU will allow... but at the end of the day.. the threshold is set by the IO chipset? in which they can only be clocked so high, before instability sets in?

I don't know if the 030 in the X'030 model will be able to be clocked that high, as it's a plastic QFP low cost edition.. maybe if it had a heat sinc glued on? if it was a ceramic and metal shim'd one, with a heat sinc... you could in theory... over clock it's nutsack off.


I also read somewhere, that both the majority of Doom and Quakes development was on NeXT hardware and NeXTSTEP.. The final months of development being spent on porting them over to DOS and Win9x?

They say John Carmack was apparently reluctant to drop NeXTSTEP as a development platform, but he had to 'bite the bullet' and go down the path of the Win32 API and Microsoft's integrated development environments...