A little help modding Doom for the 32X

[Diogo Ribeiro]

Hi. Lately I've been trying to change some stuff in the 32X version of Doom. A full hack or mod is still a long ways off as I'm still getting reacquainted with Doom and the 32X version, and am still at the planning stages and taking into account the port's limitations. The other day I decided to look into the ROM and see what I could change. I discovered some offsets that handle the Options menu, for instance, and that the HUD and fonts can be edited - through the use of specialized romhacking image editors, which makes the process kind of slow and meticulous, if not outright exasperating as a wrong turn will mess up the palettes.

I know many don't look fondly at the port but still I am looking into ways to make it slightly better. While I am not considering going saxman's route of restoring levels (he already did a fine job there), I have already done the following:

*Fixed the lost Imp behind the level geometry in E1M2 (Level 2);
*Fixed the lost monsters and items in E2M2 (Level 10) by adding a small sector and door into the area, which also had to be textured and walled;
*Fixed a texture misalignment in E2M6 (Level 14), which would not show the end of level switch;
*Fixed the secret part of the level not being shown in E1M9's minimap (Level 17);
*Fixed the missile's forward facing orientation;
*Removed all the multiplayer Things from the maps.

I am also working on very minor tweaks to the HUD in order to make it follow more closely the PC original. Additionaly, I may either include the BFG9000 in some level (possibly the military base, as it is the secret level), or not include it but edit the HUD accordingly, showing weapons from 1 to 6 instead of from 2 to 7. Including it would probably also require I spread ammo along some of the game's levels, though.

However, there are two things I can't seem to get at right now and I was wondering if anyone ever managed to change.

The first is the Doomguy's portrait orientation, which is flipped (a known bug). I can easily edit the portrait itself but at this point I'm not sure if the problem is visual or code related. Also, has anyone ever found out if the item pickup text is actually programmed into the port but is simply forced to not be displayed, or if it's leftover code that isn't used at all? The messages are easy to find in the ROM as well as (what I believe are) the pointers but pretty much any change freezes the game.

[Sik]

I should probably mention that the HUD in the prototypes was much closer to the original, so they probably changed it to make it more readable on composite (in particular the red text becoming pink).

Pretty much all the protos here up to September 14:
https://tcrf.net/Protooom_(32X)

I know there's a hack that imports all the missing levels from the Jaguar version. They mostly work, except one map that crashes by running out of memory (somebody needs to edit it :/). I imagine the BFG is in one of those maps already?

[vexatious]

Don't forget Atari Jaguar and Mars share the same code. Just use variable "MARS" before building to target Mars (32x).

Not sure what your goals are but look into paging for 8bit Nintendo. You'll need paging (sometimes termed mapper) if you want uncut content and/or better quality content since mars is only a 16-bit machine (4 megabytes memory space). 315-5755 Sega i.c. is used (sometimes nicknamed Super Street Fighter 2 mapper) on some catalogs; it's a 6-bit pager with 512kb pages. I think "Ultimate Doom" for MS-Dos necessitates at least 12-16 megabytes (e.g. 128 megabits). Try to use something standard; 74ls612 is a more standard and well documented 8-bit pager with 256kb page size. Try to improve the buffer; heard rumors Mars Doom is choppy because of buffering, not so much the CPUs.

Hate to say it but I know more than I'd like about mars doom.

[Diogo Ribeiro]

@Sik: Thanks for the heads up! I'll look into and study the prototypes, see what I can do with those. Oh, for those Jaguar levels and crash, I believe there's a fix already up on Romhacking.net. And one of those levels does include the BFG, yes, but I'm not looking into bringing those levels back, just fixing the base game and maybe including the BFG in one of the already included levels on the official release.

@vexatious: Ah, I'm sorry. My post was likely poorly worded. I'm not a programmer; I couldn't code "Hello, world" to save my own life. Unfortunately my time is very limited and programming is not something I can devote myself to, at least to acceptable levels. My strenghts reside in graphics editing and translation, but with Doom there is a plethora of tools available to edit the *.wad so I've been looking into making the game better by fixing things (hence the level fixes). Using mappers to improve the game in the manner in which you describe would probably take me 27,3 lifetimes and I've already spent half of one

Going through the game now, my main concern is really fixing errors to provide a final, correct/stable build of the game. With the levels now corrected, I'm really hunting for the item pickup texts. I'd really like to bring those back as I feel those are a significant aspect of Doom's identity. But I've had no luck there yet...

On the other hand, I'm finding the offsets for enemy states and animations which will help me a lot if I decide to go ahead with my full hack/mod (but as I've said, that'll take quite a while).

[Sik]

Well, I assumed you'd want the Jaguar maps back in since those seem to be the real reference and the BFG is already included. It feels like the only reason they were removed is because they went with 3MB instead of 4MB.

You may want to look up Doom RR too which are prototypes post-release, by the way. Sega kept using Doom to test whenever the SH-2 compiler upgraded to look for regressions and such.
https://hiddenpalace.org/Categoryoom_RR_prototypes

[Allard]

I believe there are two hacks that import the missing Jaguar maps (edited for memory) into the 32X version.

Yup, here they are
http://www.romhacking.net/hacks/618/
http://www.romhacking.net/hacks/619/

[Wesker]

The bad thing about the restored Jaguar levels hack is that the game still behaves like only having the default 32X levels if you play it from the beginning, so level 15 still jumps ahead to level 23 (or ends the game prematurely in map 15 with the "DOS prompt" bad ending if you start from another level from 2 up to 15) instead of bridging level 15 to level 16 like it should do according to the Jaguar version. If you start in level 16 with the hacked level select, then you follow a new continuity of levels up to level 23, but the game still ends with the "DOS prompt" bad ending instead of showing the good one, which is not possible to achieve with the restored Jaguar levels.

I suppose the game logic of the 32X version would need to be modified in order to solve this issue and have a full game finishable from the very beginning like the Jaguar version.

[Allard]

Well, I guess a hack that fixes that and makes them follow up from the previous levels naturally would be a good imporvement.

[Diogo Ribeiro]

Hi. Well, finding the routine for the erroneous sprite flipping is proving too much for me (though I'm pretty sure it's the Genesis doing the sprite work on the HUD) but in the process I've been fixing several other things in the game. I'm not restoring levels, as I've already said but several things were poorly handled during the level conversion made by American McGee, who was also responsible for converting the levels to the Jaguar.

So far, the fixes include:

Fixes (General):

• Removed all multiplayer and deatmach Things (entities) left in the game to alleviate map memory. Some were not even labelled as multiplayer or deatmatch, so some maps had to be combed over.
• Fixed the forward facing rocket sprite issue.

Fixes (Levels):

• Level 2 (E1M2): When the level was converted, an Imp was left behind level geometry in the exit area meaning it was impossible to achive 100% kills in higher difficulties.
• Level 4 (E1M4): Two shotgun shells were never given any skill flags, so they never spawned.
• Level 5 (E1M5): There is a pentagram on the level that should act as a teleporter but didn't work. Turns out the teleport function was coded and there was even a destination point, but the destination sector did not have the corresponding tag that linked both teleporter and destination.
• Level 7 (E1M7): Several barrels were not assigned a skill flag and never spawned in the level.
• Level 10 (E2M2): A barrel was lacking a skill flag, so it never appeared.
• Level 10: The alcove in the room with the blue armor had a "BROWN96" texture reference for its door, but that texture does not exist in the game so it reverted to the default, rocky ASH01 texture, at odds with the remaining texures in the level.
• Level 10: On conversion, a secret area with a Chainsaw and some enemies was left behind but got cut off from the rest of the map, which made it impossible to achieve 100% kills and 100% items. The area itself was also untextured and the sector had to be closed to avoid rendering issues. Nothing a door and interior decoration couldn't handle.
• Level 11 (E2M3): The southwestern area with lava, which connects to a staircase leading to the room with the Plasma Gun, had its geometry simplified but the secret tag was removed from the sector making it impossible to get 100% secrets.
• Level 12 (E2M4): The minimap did not show the secret platforms near the exit after they had been activated.
• Level 13 (E2M5): A room not far from the starting area had two adjacent linedefs facing opposite directions between the door and the wall, making them invisible.
• Level 13: There were linedefs which did not produce the doomguy's "ungh" sound when trying to interact with non-interactive things. Turns out they were lacking an impassable definition. This might be a leftover from the original version, as in one case one of these could be passed through to reach a secret later removed from the 32X version.
• Level 14 (E2M6): During conversion, a tunnel was cut off from the game but a box of shells was left floating in the void where the tunnel used to be.
• Level 14: A trap room referenced a non-existing texture, defaulting back to ASH01, which clashed with the metallic look of the level.
• Level 14: A trap room was meant to activate near the exit once the player obtained the yellow skull key in the original. When the map was simplified the skull key (now a yellow card key since skull keys aren't used) was moved but the triggers for the trap were simply deleted and not recreated. This prevented 100% kills and 100% items on some difficulties.
• Level 14: The exit column's texture was terribly offset, meaning that while the linedef was fully functional you'd never see the switch to exit the level.
• Level 15 (E2M7): Considerably reworked in comparison to the original version, it now uses a lot of stone texturing. Perhaps because of this, several walls were left untextured leading the game to apply the default ASH01. As a matter of tidying things up, I've applied that one directly and aligned the textures where there were none.
• Level 15: Two hanging leg decorations had no flags for skill setting, so they were never spawned.
• Secret Level (E1M9): The back of the room after the pentagram where a slew of enemies ambushes you, where a Berserk pack resides, was not showing at all on the minimap.

Changes (Aesthetic):

• Level 1 (E1M1) and Level 2 (E1M2): Added the missing corpses at the start of the levels. The standard dead player sprite of the original version does not seem to exist at all in the 32x version, so for the player corpse I've used a former human corpse (the standard enemy). These were included for the sake of the minute yet striking visual narrative both levels established in the game. I might look around the game for an unused sprite and remake the dead marine's sprite just to make it closer.
• Level 2: Centered the player's starting position (it was offset a bit to the right in the 32X in comparison to the original).
• Level 10: Added the BFG 9000, as per the Jaguar level.

[LinkueiBR]

Finally someone interesting to improve Doom 32x!

About the music: I made a quick hack to make the Music instruments a little better than the released version, but unfortunatelly, the OST lack totally percussion.
The music need to be completely remade and using 32x sound capabilities.

[Raijin Z]

It would be nice if it could be made to use the mouse in addition to a 6 button controller, using ABC and Y as WASD, and maybe X and Z to change weapons. Of course, that would be a mess to hack in, and it makes me think that the game would be better off being remade from the ground up, but also, who would expend so much effort on a 32X game?

[Diogo Ribeiro]

Finally someone interesting to improve Doom 32x!

Thank you! It's nice seeing your work appreciated

About the music: I made a quick hack to make the Music instruments a little better than the released version, but unfortunatelly, the OST lack totally percussion.
The music need to be completely remade and using 32x sound capabilities.

Wait, you did that? That sounds pretty good :O Did you use GEMS?

Speaking of sounds I've spent the last week cataloguing the sound locations. The game uses 50 sounds (54 if you count the ones from the options menu), and amazingly has:

*1 sound for punching (which is either unused or is drowned out by remaining sounds in combat, since I've never heard it)
*2 variations of the weapon pickup sound (most people online refer to this as the shotgun reload sound, and the two versions are virtually identical with the exception of volume. It's also the sound you hear when crossing teleporters)
*3 variations of the "ungh" sound (the one the Doomguy makes when falling down and/or trying to use something that cannot be used such as a wall or a door requiring a keycard).

If you or anyone can look into the game's sound format I'm leaving an example file here, extracted from the ROM. It's the rocket/barrel explosion sound, roughly half the size of its PC equivalent but I don't understand the format. They all seem to have a header and the last 3 bytes might just be padding. [EDIT] If the original Doom sound .lmp format is anything to go by, bytes 3 and 4 are the Hz and bytes 6 and 7 are the samples.[/EDIT]

Also, just for fun for now:

[LinkueiBR]

Thank you! It's nice seeing your work appreciated



Wait, you did that? That sounds pretty good :O Did you use GEMS?

Speaking of sounds I've spent the last week cataloguing the sound locations. The game uses 50 sounds (54 if you count the ones from the options menu), and amazingly has:

*1 sound for punching (which is either unused or is drowned out by remaining sounds in combat, since I've never heard it)
*2 variations of the weapon pickup sound (most people online refer to this as the shotgun reload sound, and the two versions are virtually identical with the exception of volume. It's also the sound you hear when crossing teleporters)
*3 variations of the "ungh" sound (the one the Doomguy makes when falling down and/or trying to use something that cannot be used such as a wall or a door requiring a keycard).

If you or anyone can look into the game's sound format I'm leaving an example file here, extracted from the ROM. It's the rocket/barrel explosion sound, roughly half the size of its PC equivalent but I don't understand the format. They all seem to have a header and the last 3 bytes might just be padding. [EDIT] If the original Doom sound .lmp format is anything to go by, bytes 3 and 4 are the Hz and bytes 6 and 7 are the samples.[/EDIT]

Also, just for fun for now:

Hey
I just hacked the Music Instruments values to sound less crap LOL. I just did the first stage, but the soundtrack lacks percussion. The music need to be reinserted (i dont know how)!
If you need any help in the sound departmend, i can help you.

[Diogo Ribeiro]

Hey
I just hacked the Music Instruments values to sound less crap LOL. I just did the first stage, but the soundtrack lacks percussion. The music need to be reinserted (i dont know how)!
If you need any help in the sound departmend, i can help you.

Hey there

For now, my primary concern with the sound is figuring out to include the teleport sound in the game. I have to find the teleporter's sound pointer, then carefully rearrange the other repeated/unused sounds and pointers and make the best of the space available.

We can also look into the music and see how it can be placed in the game.

Sent you a PM, hope you don't mind

[vexatious]

I built and partially tested some build tools on a Windows RT 8.1 local host. Not sure how many Windows RT ARM users exist but, the suite of tools should be enough to build "Doom" for 32x from the Atari Jaguar upload with Windows RT 8.1. You'd still need other tools to concatenate the program and a WAD into a usable ROM (cartridge or CD + buffer). There might be enough msdos tools to use with dosbox on RT 8.1 to do this but not sure.

https://www.sega-16.com/forum/showth...Windows-RT-8-1

edit 10-20-20:
Included code with SubQmod's smac and sln. This builds with llvm-mingw and it's getting very hard to find. Included a BAT windows script for llvm-mingw users; if building 8086 just press key to continue without signing the programs. See here https://www.sega-16.com/forum/showth...408#post868408