explaingit

id-software/doom

Analysis updated 2026-06-21

★ 18,696C++Audience · developerComplexity · 5/5Setup · hard

TLDR

The original 1993 DOOM first-person shooter source code, released publicly by id Software, a historic C codebase for studying early 3D game engine techniques.

Mindmap

mindmap
  root((DOOM source))
    What it is
      1993 game source
      id Software release
      C codebase
    Study topics
      Rendering engine
      Map format WAD
      Game loop design
    Use cases
      Platform ports
      Engine study
      Retro game dev
    Audience
      C developers
      Game developers
      History enthusiasts
Click or tap to explore — scroll the page freely

Code map

Detail Auto

An interactive map of this repo's files and how they connect — its source is parsed live in your browser. Click Visualize to build it.

filefunction / class

What do people build with it?

USE CASE 1

Study how a 1993 game engine renders a 3D-like world without a modern GPU using raycasting techniques.

USE CASE 2

Port the DOOM game to a new platform or embedded device using the original C source as a base.

USE CASE 3

Learn how early game programmers handled collision detection, game loops, and map loading in plain C.

What is it built with?

CC++

How does it compare?

id-software/doomfacebook/yogarizinorg/cutter
Stars18,69618,72818,764
LanguageC++C++C++
Setup difficultyhardhardmoderate
Complexity5/54/53/5
Audiencedeveloperdeveloperdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · hard Time to first run · 1day+

No setup documentation is provided in the repository, requires resolving 1993-era C compatibility issues for modern compilers.

No license information mentioned in the explanation.

In plain English

This is the open-source release of the original DOOM source code, published by id Software. DOOM is the landmark 1993 first-person shooter game. The repository contains the game's C source code as it was released publicly. No further description or setup documentation is provided in the repository itself.

Copy-paste prompts

Prompt 1
I have the original DOOM source code from id Software. Walk me through how the rendering engine draws walls without a modern GPU, explain the core loop in plain English.
Prompt 2
I want to compile the original DOOM source code on a modern Linux machine. What build system changes and header compatibility fixes do I need to make it compile with gcc today?
Prompt 3
Explain how the DOOM WAD file format works: what data is stored, how the engine reads it, and show me a Python script to parse and list the lumps in a WAD file.
Prompt 4
Show me which files and functions in the DOOM source code handle player movement and collision detection, walk me through the relevant C code.

Frequently asked questions

What is doom?

The original 1993 DOOM first-person shooter source code, released publicly by id Software, a historic C codebase for studying early 3D game engine techniques.

What language is doom written in?

Mainly C++. The stack also includes C, C++.

What license does doom use?

No license information mentioned in the explanation.

How hard is doom to set up?

Setup difficulty is rated hard, with roughly 1day+ to a first successful run.

Who is doom for?

Mainly developer.

Open on GitHub → Explain another repo

This repo across BitVibe Labs

Scan in gitsafehub Deploy in gitdeployhub id-software on gitmyhub

Verify against the repo before relying on details.

Alternatives & similar repos