DRMG - Doom Random Monster Generator

DRMG generates randomized DECORATE monster variants for UZDoom, packaged as PK3 files. Each variant gets randomized stats (health, speed, pain chance), attack parameters, visual effects (translations, render styles, blood color), behavioral properties, and optional flags — creating unique encounters every time you play.

Features

• 18 supported monsters covering all enemies from Ultimate Doom and Doom 2
• Faithful attack types for every monster — hitscan bursts, projectile volleys, melee combos, charge attacks, homing tracers, archvile fire, pain elemental spawning, and more
• Multi-prong projectile spreads — monsters with projectile attacks have a chance to fire 3-way or 5-way volleys
• Seeded RNG for fully reproducible output
• Spawner actors (--replaces) that drop into any map and randomly select a variant at load time
• Doom version filtering — generate for Ultimate Doom or Doom 2 monster sets
• Health economy balancing — tougher variants automatically drop health pickups to compensate
• Randomized visuals — color translations, render styles (translucent, fuzzy, stencil), scaled sizes, and blood colors
• Optional flags — AMBUSH, QUICKTORETALIATE, MISSILEMORE, speed modifiers, and per-monster extras rolled independently

Supported Monsters

Installation

Pre-built binary

Download drmg.exe from the Releases page.

Build from source

Requires Crystal 1.19+.

shards install
shards build --release

The binary will be at bin/drmg.

Usage

drmg [options]

Options

Examples

# Generate 1 variant of every Doom 2 monster
drmg

# 5 variants per monster with a fixed seed
drmg --variants 5 --seed 42

# Only Imps and Demons, custom counts
drmg --monsters imp:3,demon:2

# Ultimate Doom monsters with spawner replacements
drmg --replaces --doom 1

# Full generation for a mod
drmg --monsters all --variants 10 --replaces --output mymod.pk3

Loading in UZDoom

uzdoom -file drmg_output.pk3

Or drag and drop the PK3 onto uzdoom.exe.

When using --replaces, the spawner actors automatically replace the original monsters in any map. Without --replaces, the generated actors can be placed manually in a map editor (e.g., Ultimate Doom Builder).

How It Works

1. Templates define each monster's base stats, valid ranges, attack type, drop tables, sprites, sounds, and flags
2. Generator rolls randomized values within those ranges using seeded RNG, including stats, attacks, visuals, and behavioral properties
3. DecorateWriter renders valid UZDoom DECORATE lump text for each variant, plus any custom projectile/tracer actors they need
4. Pk3Writer packages the DECORATE lump into a PK3 (ZIP) file ready for UZDoom

Development

# Run tests
crystal spec

# Build debug
shards build

# Build release
shards build --release

License

MIT

Author

Mark Ridlen