Dissecting Sega Saturn Doom

[Mattfrie1]

I reached out to Jim on Twitter to ask who the other person was in SKY21.CHR

 

 

Ed is thanked in the credits screen that never appears during gameplay for giving tech support assistance.

[ludicrous_peridot]

Wow. The hidden credits are there in the binary strings by the way. Was thinking about adding them to a credits section of the small Saturn-insprired mod for GZDoom I'm toying with. Longer credits would actually mean enough time to listen to the "credits tune" :). One may think that there was a legit way to see the pics and read the text though...

[taufan99]

20 minutes ago, ludicrous_peridot said:

Wow. The hidden credits are there in the binary strings by the way. Was thinking about adding them to a credits section of the small Saturn-insprired mod for GZDoom I'm toying with. Longer credits would actually mean enough time to listen to the "credits tune" :). One may think that there was a legit way to see the pics and read the text though...

Ooh, can't wait to play/test that mod soon.

[ludicrous_peridot]

Thanks, @InDOOMnesia. I'm highly unproductive lately and but have intention to share something sooner or later.

[Mattfrie1]

15 hours ago, ludicrous_peridot said:

Wow. The hidden credits are there in the binary strings by the way. Was thinking about adding them to a credits section of the small Saturn-insprired mod for GZDoom I'm toying with. Longer credits would actually mean enough time to listen to the "credits tune" :). One may think that there was a legit way to see the pics and read the text though...

 

Jim added that those pictures were only meant to be Easter eggs when I asked in a follow up tweet, although those credits definitely should have been seen in-game I think.  I did some more detective work and both Ed Hollingshead and Tamar Tashin were a part of the Sega European Tech Support team according to this document.

 

https://antime.kapsi.fi/sega/files/DTS-0197.pdf

[Mattfrie1]

I've been reading a lot of old game magazines on the Internet Archive lately, and I came across this interesting preview of Saturn Doom from the October 1996 issue of GamePro.

 

 

Note the slightly different HUD and Doom II sky at E1M1 in the screenshots. Also interesting how the magazine pegged the release date for October 1996 when it really wasn't released until March 1997. Here's a link to the magazine for anyone interested as well.

[A Nobody]

On 3/13/2016 at 12:24 PM, VGA said:

I think they overestimated the Saturn. They should have based their work on the Jaguar port.

Hah! No.

 

See the thing is, Rage planned to use a hardware renderer for the game, but Carmack told them to switch, which resulted in the bad port we got. The Saturn could have definitely handled Doom very well. Would have been one of the best ports if Carmack let Rage do their thing. Just look at Exhumed on the Saturn.

[Mattfrie1]

The SlaveDriver engine games from Lobotomy often get mentioned when talking about Saturn Doom, but I think that many people also tend to overlook several "Doom-clone" type titles ported to the Saturn which handled a lot better as well. Of course Hexen on the Saturn is the first that comes to mind, but other rather forgotten titles like Defcon 5 and Space Hulk: Vengeance of the Blood Angels were ported from their PSX versions and ran fine on the Saturn. I even found that Defcon 5 uses a similar column based renderer for it's walls across both ports and still manages to run at a respectable framerate on Saturn, although being a corridor FPS like Wolfenstein 3-D probably helped matters.

[A Nobody]

30 minutes ago, Mattfrie1 said:

The SlaveDriver engine games from Lobotomy often get mentioned when talking about Saturn Doom, but I think that many people also tend to overlook several "Doom-clone" type titles ported to the Saturn which handled a lot better as well. Of course Hexen on the Saturn is the first that comes to mind, but other rather forgotten titles like Defcon 5 and Space Hulk: Vengeance of the Blood Angels were ported from their PSX versions and ran fine on the Saturn. I even found that Defcon 5 uses a similar column based renderer for it's walls across both ports and still manages to run at a respectable framerate on Saturn, although being a corridor FPS like Wolfenstein 3-D probably helped matters.

Apparently one guy brought Defcon 5 over to the Saturn.

[knight0fdragon]

On 4/15/2020 at 12:02 PM, Mattfrie1 said:

It appears that the link-up modes are still potentially compatible in the North American version of the game. I've managed to locate the area in system memory that handles main menu choices, and by setting one single value to either 0001 or 0002 will set the game into link mode with the on screen message about attempting to connect. As I've mentioned previously in this thread, most of the elements about the multiplayer link modes are still mentioned in memory (Intermission screen text, number of frags, etc.) so there is a good chance that the link cable is still fully functional but just simply had the option to select it removed from the main menu. Unfortunately Saturn emulation currently doesn't emulate the link cable and I don't own one to test this out on actual hardware, but if anyone reading this happens to have the capability to test this out please let us know. The Action Replay code to enter is as follows:

 

1604A2B0 0001 
OR 
1604A2B0 0002

 

These codes may be off.

 

 

1604A2B2 0001 is Coop

1604A2B2 0002 is Deathmatch



1604A2AE 00## is for Level

 

The reason it is not B0 is because the data is an int, so it takes 4 bytes.  If you set it to B0, you will tell the game the value you are looking for is 0x00010000, which will pass the simple single player test of "if zero then single player," but may fail afterwards when it is unable to determine the game mode. If you set B2, then your value will be 0x00000001,  making it the value for coop.

 

[out_of_service]

The back of the Sega Saturn box showcases levels from Final Doom. The Sega Saturn version of Doom only features levels from Doom and Doom II right?

 

[Mattfrie1]

14 hours ago, knight0fdragon said:

The reason it is not B0 is because the data is an int, so it takes 4 bytes.  If you set it to B0, you will tell the game the value you are looking for is 0x00010000, which will pass the simple single player test of "if zero then single player," but may fail afterwards when it is unable to determine the game mode. If you set B2, then your value will be 0x00000001,  making it the value for coop.

Thanks for the info, by any chance would you happen to have a link cable setup to test this out on real hardware? I've been meaning to get one but haven't gotten around to it due to the cost of the link cable.

 

@PSXDoomer Saturn Doom contains the same level set as PSX Doom, so no Final Doom levels here. That error also exists on the US version's packaging as well, they simply took stock shots from the PC Final Doom box and called it a day. The manual also includes screenshots from the PC version of Doom II as well, meaning that no actual Sega Saturn screenshots exist anywhere on the product.

[knight0fdragon]

17 minutes ago, Mattfrie1 said:

Thanks for the info, by any chance would you happen to have a link cable setup to test this out on real hardware? I've been meaning to get one but haven't gotten around to it due to the cost of the link cable.

 

@PSXDoomer Saturn Doom contains the same level set as PSX Doom, so no Final Doom levels here. That error also exists on the US version's packaging as well, they simply took stock shots from the PC Final Doom box and called it a day. The manual also includes screenshots from the PC version of Doom II as well, meaning that no actual Sega Saturn screenshots exist anywhere on the product.

somebody with a link cable has brought this to my attention, so we should be able to test this sometime soon.  They do not have an action replay, so I have been writing a patch to the binary for them.  (Definitely weird how all of the text for the various options are in the game, but the actual choice is removed.  There is a lot of similarities to the UK build)

[Mattfrie1]

5 minutes ago, knight0fdragon said:

somebody with a link cable has brought this to my attention, so we should be able to test this sometime soon.  They do not have an action replay, so I have been writing a patch to the binary for them.  (Definitely weird how all of the text for the various options are in the game, but the actual choice is removed.  There is a lot of similarities to the UK build)

Very cool, I believe the link modes should work. The back of the boxart for the US version mentions the 2-player link mode in error, but I personally believe it was removed from the US version since the link cable was never officially released here.

 

On another random note, I found by going through the Saturn Software Development Standards manual from Sega of America several interesting requirements that Sega had on developers in order to get their games published on the system. Most notably, page 13 of the manual (17 in the PDF) mentions that all games on the Saturn which have a Stereo sound mode must have a Mono sound mode as well to get final approval. I guess Sega was looking out for those with older TVs back then, but it shatters the myth that the mono sound mode of Saturn Doom was included because the stereo sound is broken. I should also point out that the sound in Revolution X (which shares the same sound driver as I mentioned on the last page) is in mono, so chances are that the driver wasn't able to be completely updated to support stereo in time for Doom's release. I feel like I've mentioned this fact somewhere else before, but I didn't see it in this thread so I figured I'd add it here just in case.

[A Nobody]

We need a true Saturn port of Classic Doom.

[Dexiaz]

I'd like to play Saturn port with PSX maps. Just without lagging. But with fast weapons. It makes a kinda unique feel. I know, the fast weapons were made due to low FPS, but still.

[viti95]

5 hours ago, The Strife Commando said:

We need a true Saturn port of Classic Doom.

 

True, I think is doable, as the Saturn has the 4MB extended RAM cartridge and that's the bare minimum amount of RAM to execute Vanilla Doom. Also the Saturn is more than powerful enough to run Vanilla Doom in full detail. I've started learning how to use libYaul, maybe in the future I'll create one port (based on my experience with FastDoom, but I promise nothing as I've got very limited time to develop and creating a whole new port for a console is a really big task)

[Kroc]

4 hours ago, viti95 said:

Also the Saturn is more than powerful enough to run Vanilla Doom in full detail.

Yes, but also no. The Saturn has two 20MHz processors, a decent SPU and a bunch of 2D features that are almost entirely useless to Doom. The sky could be done by the background hardware, but one has to understand that outside of backgrounds the Saturn's 2D quads/sprites are really, really slow. The PSX might not have backgrounds in hardware, but its fill rate is several times that of the Saturn. Multi-threading does not help Doom much; the 33 MHz PSX CPU is still better than 2x20MHz unless someone can pull off some god-level programming.

 

Yes, the Saturn could run Doom but it'd take a _lot_ more effort, to run well, than a straight port might imply but I would love to see it.

[Shadow Hog]

I know one of the VDPs excelled at doing Mode 7-style infinite planes. If that were something you could alter to change at certain columns/scanlines, maybe you could accelerate the flat drawing using that, since that's pretty much visplanes in a nutshell. Wouldn't particularly help with wall-drawing, though!

[Mattfrie1]

20 hours ago, Shadow Hog said:

I know one of the VDPs excelled at doing Mode 7-style infinite planes.

 

I believe that this might be how the renderer in Saturn Hexen handles drawing flats, since VDP2 handles drawing the level to the screen. I've been messing around with corrupting Saturn Hexen through emulation lately and it is very easy to screw up how the ground scrolls in relation to the player's viewpoint as well as seeing the flat extend out to the horizon if walls aren't drawn properly. I'm admittedly no expert in this but it definitely looks like it from what I've seen in several other Saturn ports (Independence Day, MechWarrior 2).

[A Nobody]

10 minutes ago, Mattfrie1 said:

 

I believe that this might be how the renderer in Saturn Hexen handles drawing flats, since VDP2 handles drawing the level to the screen. I've been messing around with corrupting Saturn Hexen through emulation lately and it is very easy to screw up how the ground scrolls in relation to the player's viewpoint as well as seeing the flat extend out to the horizon if walls aren't drawn properly. I'm admittedly no expert in this but it definitely looks like it from what I've seen in several other Saturn ports (Independence Day, MechWarrior 2).

Wasn't Saturn Hexen a rushed port? Either that, the PS1 version, or both used the beta version of Hexen.

[Mattfrie1]

I did a rundown on the Hexen console ports a couple of years ago, and both PSX and Saturn versions appear to be based off of the beta version. However Probe, who handled the PSX port, outsourced the Saturn port to a Swedish game company called Atod who at least wrote a new renderer to take advantage of the Saturn's dual VDP setup. It also strongly looks like they wrote a new game engine as well, the main program file on the disc has tons of uncompiled assembly code when viewed in a hex editor which seems to point to this fact.

[Erick194]

Hello, as far as I have seen in reverse engineering Hexen PSX uses the same rendering routines of Psx Doom, practically the same, the only thing that differs is in the rendering of the walls which draws the pictures to the size of the texture and puts it one on top of the other to avoid the infamous stretch of textures that PsxDoom suffered, another interesting fact is that the native PSYQ function "Drawprim" is a little slower than the "Drawprim" that Williams developed in PsxDoom causing it to drop a little frame rate in Hexen Psx.

[Dimon12321]

On 7/12/2021 at 10:24 AM, Dexiaz said:

I'd like to play Saturn port with PSX maps. Just without lagging. But with fast weapons. It makes a kinda unique feel. I know, the fast weapons were made due to low FPS, but still.

Well, it's not as complicated as it might be. Erick194 made a successful reverse engineering for PSX Final Doom.
I'm not good at reading Doom architecture and how weapon speeds are originally composed (kinda like, pre-Dehacked times), but I think it's possible to change some numbers in the code (maybe somewhere in the table of states), compile it and get a working .iso ROM.
An imaginary Saturn port would have better performance, but existing PSX Doom is not that laggy.

[Dexiaz]

1 hour ago, Dimon12321 said:

Well, it's not as complicated as it might be. Erick194 made a successful reverse engineering for PSX Final Doom.

 

Well, thanks, but I was already knew about it. This is what I was hinting for GEC.

[Dimon12321]

6 minutes ago, Dexiaz said:

 

Well, thanks, but I was already knew about it. This is what I was hinting for GEC.

Oh, that sounds great! An option in settings to toggle weapons' speed would be a great improvement for Master Edition.

[Devalaous]

I'd be happy enough just to play a modification of the PSX TC with all the Saturn 'features', ie the lighting disabled, the fire sky repalced with the intended E3 sky (not the glitched city sky), the lesser music and the status bar, and any other things that the Saturn does, just without the actual hardware flaws.

[Dexiaz]

Just now, Devalaous said:

I'd be happy enough just to play a modification of the PSX TC with all the Saturn 'features', ie the lighting disabled, the fire sky repalced with the intended E3 sky (not the glitched city sky), the lesser music and the status bar, and any other things that the Saturn does, just without the actual hardware flaws.

 

That sounds the most interesting, because it will keep the Saturn's "atmosphere". I think that's also a point to keep such "features"

[ludicrous_peridot]

How about the dotted teleport / specter sprites? A cornerstone of Saturn atmosphere if you ask me ;)

 

A year ago I was actually trying to put together something close to what @Devalaous described, but intention was to run with GZDoom on PC and Android. Alas, while the beta I have shared was playable it quicky became obsolete with GZDoom 4.5 release. I have also shared the modifies PSX TC maps to play with the mod.

 

You can see those here here.  

[ludicrous_peridot]

How does this look?

 

Spoiler