ROOM - Rusty Doom

This is a personal project to rewrite Doom C in Rust. Where possible I try to keep the original Doom behaviour intact, while also making some improvements. I am also trying to document everything as I go along.

I originally started by following along with https://github.com/amroibrahim/DIYDoom

Take a look at how I progressed through

Be warned that because the initial code is transliterated as much as possible from the Doom C except where that causes issues, many things may not be optimal or idiomatic rust. There will be things like dodgy casts, unrequired as casts, unused fields or args, lots of unsafe blocks etc. The main thing I tried to do was bring up the game to a fully playable state fast, and then begin to optimise, refactor, or redesign components - it is much easier to do when you have a working playable state to begin with that can be used for play-testing and such.

The code can dramatically change as I learn new or better ways to do things.

Goals

Not sure. I started this as a personal project to pretty much try and rewrite Doom in Rust only. But, as time went on and I learned more of the engine I saw more areas I could improve, or things that would maybe work well as split-out crates (gameplay for example). I think the final goal boils down to the following points:

• Try to be as close as possible to original Doom source
• But try to improve things where possible while somehow keeping classic behaviour
• Compartmentalise the engine in to crates where possible, such that:
  • Sound is independant
  • Rendering (each renderer/drawer; player view, status, hud etc) and be swapped out
  • Expose the minimal possible API to gameplay crate such that it could be used on its own to drive Doom, with all non-gamplay (read, level loaded and playing) related stuff is delegated out
• Boom improvements compatibility
• Add an example isometric renderer
• Hi-Res mode
• Widescreen modes

And maybe write a book on all I've learned about writing a Doom engine.

Implemented (so far):

• Software rendering
• Menus (not all items complete though)
• HUD + statusbar (improved)
• Intermission and finales.
• Lighting (diminished, animated)
• Movers (environment things, like doors, platforms)
• Thinkers (used for the above + demons)
• Thinker states and changing
• Sprites
• Input
• Cheats (partial for debugging)
• CLI options (use --help)
• Basic surface shaders (ROOM renders to a surface that a shader can manipulate)
• Sound
• Music
• Shooting
• Item pickup and use
• 99% of gameplay (Need to do Doom II boss and pain elemental then it's done)

Some of the improvements I've made (so far):

• BSP used for collisions (Doom used the blockmap)
• BSP used for aiming, shooting, and LoS (Doom used the blockmap)
• Floats instead of fixed-point (this may cause slight behaviour changes)
• Hi-Res mode

TODO:

I keep a list of things to do in TODO. It's worth looking at I guess because it serves sort of as a list of major points of interest, a kinda-sorta changelog, and a snapshot of where the engine state is right now.

Functionality TODO:

• Automap
• Save/load game

Building

I use and develop on Linux exclusively so although I once did a Windows build I don't maintain it.

• Distro SDL2: cargo build

The distro requires SDL2 + SDL2-mixer to be installed along with the related dev packages including alsa-lib-devel and pulseaudio-libs-devel. Music support requires fluidsynth or timidity to be installed along with files in the data/sound/ being installed to ~/.local/share/room4doom/sound/.

User Config

On start a user config file is created at ~/.config/room4doom/user.toml. This can be edited by hand.

Options set via CLI are saved to the user-config file.

Starting room4doom without CLI options after previously setting options then exiting will load those options (as saved to ~/.config/room4doom/user.toml).

Use room4doom --help to see all available CLI options.

Documentation

I've not been as good as I should be at this because I've been on a mad rush to implement as much as I can. Plus the nature of doing large blocks hasn't helped. misc/code-review/ has a semi-broken out series of files where I try to note things of interest, or even write a full code review. Each of these files and additions will be updated and fleshed out over time.

The magnificance of rust/cargo being able to produce a static website full of code documentation means that I try to maintain docs somewhat at https://flukejones.gitlab.io/room4doom/room4doom/index.html. Browsing wad is a good example of what I would like to achieve here.

Screenshots

Comparison:

SI6IL

License change

The original Linux Doom source as licensed under the DSL is being used as an educational resource as stated under clause 2 of the DSL to enable a rewrite of the source under MPL.

Portions of the "Source Code" which is the "Linux Doom Source Code" may appear in the source in this repository but the "Source Code" is not duplicated as a whole. These portions are translated and the end result often bares little resemblance to said portions except where portion is of such generic code flow there is little other way to write it.

Where possible, relevant comments in the "Source Code" are kept as historical artifacts.

DSL for reference

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