Doom in 8-Bit?

[Fellowzdoomer]

Well, I was thinking of holding this back, but alas, my conscience wouldn't let me.

This has been bugging me for a full week. I was thinking of a TC that changed Doom to be 8-Bit NES style. (Music, sprites, etc. I don't mean MM8BDM). I'm wondering. Is there such a TC? Homebrewn NES rom? Or is this a mere figment of my imagination?

[MFG38]

Far as I recall, there was some sort of 8-bit Doom TC, at least at some point. It didn't change the music, though, so a separate WAD containing the 8-bit soundtrack had to be downloaded.

[Doominator2]

EDIT: Sorry the video would not work properly just look at 40oz post.

[Fellowzdoomer]

Not what I'm looking for...

[Maes]

[40oz]

If you're looking for something like this, you could run the EGA Doom Pallete WAD on a port that supports PC Speaker Emulation. If you don't play with a port that supports PC Speaker Emulation, you could try playing with this PC Speaker Emulation WAD (not quite as authentic)

[Fellowzdoomer]

What was in my mind was the Doom for NES video that Maes posted up.

[Blastfrog]

I suppose this thread gives me an excuse to post this stupid concept piece again:



It's not entirely accurate to what an NES can do (can only assign one of 4 palettes to every 8x8 tile) but is a demonstration of the kind of art and rendering resolution/size. The idea would be to add a Z80 co-processor to do the heavy lifting. The engine would likely need to be rewritten from scratch ala SNES Doom, but it could more closely follow the way Doom actually plays (at least using the Jaguar version mechanics as a reference).

I wonder if using a Marathon-like polygon portal engine would make things run any faster without resorting to taking up space in memory with a BSP tree, or doing the processing required to figure out what's visible via that tree.

At the very least, levels should be broken into smaller pieces to fit into memory, and they can be dynamically streamed from there. Probably have a "save state" of sorts for all actors in each "zone", saving it when the zone is left and loading it back up when the zone is re-entered. It'd be like Strife if you could run 2 maps at once, with the map you're closest to entering being the other one in memory (there'd have to be manually placed map load triggers, like if you're near the Sanctuary load MAP01 in the cache, if near the Front base load MAP03, etc.).

[Fellowzdoomer]

I guess my curiosity for doom 8 bit is all because I'm trying to put some 8 bit sprites in a project on my free time. It doesn't work well. It appears as though it works well with that ega palette... but not doom palette.

[TheEndOfUs]

Sodaholic said:

I suppose this thread gives me an excuse to post this stupid concept piece again:

Sexy

[Jaxxoon R]

40oz said:

Video

I'd like to say I'd rather listen to 32X Doom but...

[Doomkid]

I know this isn't exactly what you're asking for, but I just wanted to follow up on Maes' post and say that a Wolf3D-like game running on a real NES would definitely have been possible:

For like 10 years now I've entertained the thought of remaking all the Doom graphics in 8-bit form, but after many attempts it's just a very difficult task, and the result never looked as smooth as what Sodaholic posted.

There's a mod out there that changes all the guns to 8 bit, but I can't recall it's name at the moment, it would have been quite a few years since I last saw it.

@40oz, that video brings back memories of not being able to set up the SFX in Doom no matter how hard I tried (I woulda been like 5 or 6 and all the different options for a Sound Blaster alone seemed very daunting) but managing to get the music working, but having to settle for PC speaker sounds!

[Jeremy]

I always hoped someone would do this. That concept piece is actually pretty cool looking. Also, the music from the GBA version of Doom sounds pretty chippy, although 8-bit versions of the Doom music can be found all over Youtube.

[Fellowzdoomer]

I've been thinking.

NES Doom would have only 4 directional sprites for enemies (Same sprite as xxxxX2X8, ex. POSSA2A8 same as POSSA1) No flats detailed, low animation. Chip tune music. Levels would be chopped due to memory.

[Doomkid]

Fellowzdoomer said:

I've been thinking.

NES Doom would have only 4 directional sprites for enemies (Same sprite as xxxxX2X8, ex. POSSA2A8 same as POSSA1) No flats detailed, low animation. Chip tune music. Levels would be chopped due to memory.

Yeah, Doom on NES wouldn't really be practical - It hardly ran on the SNES, after all. Wolf3D would be the more practical choice, or at the very most a "Doom clone" that played like Wolf3D.

[Maes]

Throw in 8 more bits, some more mbits, and you get this:

I'd say a 16-bit machine (at least one at the 68000 level) is really the bare minimum where you can run a 3D game, be it with polygons or a raycaster/Wolf3D-like engine, in real time and with a semblance of being something more than a slideshow.

With 8 bits, you just simply run out of available computrons too quickly, as other things like memory size, bandwidth etc. scale down too. Maybe with a co-processor to at least lift the heavily taxing rendering from the main system...but I doubt a single Z80 would cut it: it would be just like having two main CPUs, in a NES-class machine.

The ZX Spectrum port used an interesting method for its "textures" and sprites: rather than scaling them up to blocky pixels, they were simply fixed resolution patterns that "filled" walls and looked the same regardless of scale (I think they did have 2 or 3 variants for near, mid and far distances though).

[Face23785]

I don't know why I even enter threads like this, much less keep reading them. I don't know the second thing about computers, so all of this is just jibberish to me. Boredom will make you do stupid things.

[Blastfrog]

Maes said:

I'd say a 16-bit machine (at least one at the 68000 level) is really the bare minimum where you can run a 3D game, be it with polygons or a raycaster/Wolf3D-like engine, in real time and with a semblance of being something more than a slideshow.

With 8 bits, you just simply run out of available computrons too quickly, as other things like memory size, bandwidth etc. scale down too. Maybe with a co-processor to at least lift the heavily taxing rendering from the main system...but I doubt a single Z80 would cut it: it would be just like having two main CPUs, in a NES-class machine.

Yes, a Z80 would be fairly limiting, but I bet it could be done if one really squeezed it in there. I'm trying to find a demo for the TI-83 I've seen that is wireframe and sector based with non-orthogonal walls and height differences, but I haven't had much luck in locating it so far.

Consider this:

56x80 view-port, 4x2 scale pixels (thus occupying a 224x160 area)
10hz target speed (6 refreshes NTSC, 5 refreshes PAL)
Low vertical FOV to reduce visible planes and lower/upper sidedefs, as well as correct aspect ratio
Low accuracy pre-calculated table for scaling columns (ala PC Wolf 3D)
Half resolution graphic assets (ala SNES Wolf 3D)
3-bpp monochrome assets plus color overlay metadata. Similar to the ZX Spectrum, except with 7 shades (4 with 3 dithered inbetweens) instead of 2. One color would be used for transparency.
No plane textures (ala SNES Doom)
No per-sector lighting (ala GBA Doom)
Universal and fixed fog with a 2048 max view distance
Said fog merely being subtractive or otherwise table based
Low resolution map geometry (every 8 PC units is 1 NES unit)
Maps become hubs, sections of levels become maps, hub is cleared upon next level (E1M1 could be a 3 map hub or something)
One angle monsters, 360 degree view, always deaf (ala SNES, except that they respond to being shot)
Reduced level count (Jag set as basis, remove anything not found in SNES). Would be 17 level total, very close to 32X's 16 level.


The hardware would be an overclocked Z80 (10-15Mhz?) and extra, shared RAM (32-64kb?).

Face23785 said:

I don't know why I even enter threads like this, much less keep reading them.

Then why did you bother to post in it? I mean no offense, but I fail to see what use it is to walk into a conversation and say "Hi, guys, I have no idea why I'm here!".

[Maes]

Sodaholic said:

Yes, a Z80 would be fairly limiting, but I bet it could be done if one really squeezed it in there.

A second 6502 would be far more helfpul, the Z80 was a much more conservative and rigid architecture, not really ideal when you are thinking of using it as a GPU, doing a lot of pixel-based ops.

Sodaholic said:

3-bpp monochrome assets plus color overlay metadata. Similar to the ZX Spectrum, except with 7 shades (4 with 3 dithered inbetweens) instead of 2.

Using non-8bpp (or less than a word-width) assets is a bitch, if you are trying to use the display in a "chunky" mode and you need to be able to write a pixel exactly where you want it to. Almost all such modes are bit-planar, and only tile-based rendering or color-filling modes are reasonably fast to implement.

The Spectrum version essentially uses tiles/UDGs (the Spectrum's "sprites"), which get written a block at a time to the screen, while the C64 version basically uses a very low resolution and performs solid color fills of each big pixel block. So even with a co-processor, you would still have quite coarse-looking rendering. Even if sprites could be "hi-res", any geometrical 3D asset would have to be rendered in a very low-res, blocky mode, dictated by the smallest size of display tile that the hardware could manage (that's 8x8 on the speccy).

The only way to get a significantly better rendering, would be to have a dedicated coprocessor which could do direct chunky rendering in 4-bit or 3-bit mode, and only then converting the resulting bitmap to fit the machine's display limits. This method is time-consuming, as seen in some ZX spectrum demos, which feature apparently "impossible" static images with no color clash (actually, it's very cleverly hidden).

In that respect, the Amstrad CPC or C64, which have a true 4-bit 160x200 mode without color clash, would be much better candidates than the speccy or the NES, IMO. The Amstrad even featured tweak modes which could go up to 27 (out of 32) colors on screen, so think of the interesting visuals this could produce ;-)

I'd just map Doom's 256 color to the available 16 or 27, use an efficient and "renderer-friendly" chunky 8-bit format, and then just lose the top 4 bits or something, while feeding display data to the computer in block. Ofc, with any external co-processor module, there'd be significant memory bandwidth issues involved.

[Face23785]

Sodaholic said:

Then why did you bother to post in it? I mean no offense, but I fail to see what use it is to walk into a conversation and say "Hi, guys, I have no idea why I'm here!".

As you can guess, I don't have a great answer to that question. I haunt the forums in the middle of the night at work when it's dead and I have nothing better to do. I was thinking it, had nothing better to do, so I wrote it. Sorry to interrupt ya'lls discussion. So this post isn't a total loss, I'll add:

Fuck it, if you (rhetorical you, not you specifically) think it can be done, why not? Doom can be played on just about everything else. I'm disappointed the LCD panel on my air conditioner doesn't have a stripped down version of Doom in the menu somewhere.

[Fellowzdoomer]

I'm disappointed that my microwave can't run doom. It can run on calculators, flip phones, even on a ballpoint pen, but not an alarm clock or microwave?!

*insert witty "time to kill" pun here*

[Maes]

Fellowzdoomer said:

I'm disappointed that my microwave can't run doom. It can run on calculators, flip phones, even on a ballpoint pen, but not an alarm clock or microwave?!

Then you must upgrade your microwave, as it's obviously obsolete and unable to cope with the increased demands of the New Technologies in the Modern Era.

[William Blazkowicz]

If DooM was on the NES would probably just be one of those early 80s 90-egree-first person maze things. Like Bomberman 3D or 3D Monster Maze, sumthing like that

[wildweasel]

William Blazkowicz said:

If DooM was on the NES would probably just be one of those early 80s 90-egree-first person maze things. Like Bomberman 3D or 3D Monster Maze, sumthing like that

That might not be too bad. I can think of one game that has already done this sort of thing; a Turbografx 16/PC Engine title called Silent Debuggers. 90-degree mazes in an action setting, free-floating crosshair, very high on suspense due to limited vision range.

[Jaxxoon R]

I fucking love the TurboGrafX. It's got the charm of the NES with the power to present SNES/MD-quality titles.

[Waffenak]

I want to see nes style doom cover art and a real box

[Avoozl]

Virtual Boy Doom would be quite an eyesore because of all the obvious red.

[William Blazkowicz]

Avoozl said:

Virtual Boy Doom would be quite an eyesore because of all the obvious red.

Huh, I could imagine. "Is that some gibs or part of the wall? Oh wait, I-I think it may be a-yep, that is indeed the main menu."

[LockeRequiem]

You should try playing doom music in Mega Man 2 or Mega Man 3 soundfont. Boom, 8-Bits of pure beauty (heh).

Or, listen to E1M8 with the Final Fantasy 6 Soundfont.

[Jaxxoon R]

Where may one find these magic soundfonts you speak of?