redguard-preservation

Preserving The Elder Scrolls Adventures: Redguard (1998) — reverse-engineered file format specifications, engine documentation, and a Rust CLI for parsing and converting game assets.

📖 Full documentation — file format specifications, engine internals, INI references, and more — is published at https://michidk.github.io/redguard-preservation/. This README is the CLI / library / FFI quick reference.

Conversion Matrix

Input Type	Input Extension(s)	Output File(s)
Model	.3d, .3dc	.glb
ROB archive	.rob	.glb
RGM scene	.rgm	directory: .glb + scene/actors/navigation .json + per-actor .soup/.json scripts
WLD world	.wld	.glb + actor metadata .json (scene mode), or map .png set
Font	.fnt	bitmap .png + BMFont .fnt + glyph metadata .json, or .ttf
Visibility octree	.pvo	.json
Palette	.col	swatch .png + palette metadata .json
Sound effects bank	.sfx	extracted .wav files + index.json metadata (directory output)
Dialogue audio	.rtx	extracted .wav files + index.json metadata (directory output)
Texture bank	TEXBSI.###	animated .gif + static .png files + index.json (directory output)
GXA bitmap archive	.gxa	animated .gif + index.json (directory output)
Cheat states	.cht	.json

The scan command recursively detects known Redguard files in a directory tree.

Convert Subcommands

Each format has its own subcommand with scoped flags. convert <FILE> auto-detects the format and uses defaults.

Subcommand	Input	Output	Format-specific flags
convert texbsi	TEXBSI.###	.gif / .png	--format gif|png|frames, --palette, --compress-textures
convert gxa	.gxa	.gif / .png	--format gif|png, --compress-textures
convert fnt	.fnt	.png + .fnt + .json, or .ttf	--format bitmap|ttf, --compress-textures
convert col	.col	.png + .json	--format png|json (default: both), --compress-textures
convert wld	.wld	.glb + .json, or map .png set	--assets, --palette, --terrain-only, --terrain-textures, --compress-textures
convert model	.3d, .3dc, .rob	.glb	--assets, --palette, --compress-textures
convert rgm	.rgm	output directory	--assets, --palette, --compress-textures
convert rtx	.rtx	.wav + index.json	--resolve-names
convert sfx	.sfx	.wav + index.json	(none)
convert cht	.cht	.json	(none)
convert pvo	.pvo	.json	(none)

¹ Exported TTF fonts are bitmap-traced vector outlines without hinting. They can be installed on Windows, used in game engines (Unity, Godot, etc.), and previewed at fontdrop.info.

Documentation

The full documentation is published at https://michidk.github.io/redguard-preservation/ (rendered with mdBook). The Markdown sources live under docs/ and are organised into three sections:

• File Formats (source) — binary format specifications for models, textures, audio, maps, palettes, and other game assets
• Engine Details (source) — reverse-engineered engine internals: cheat system, item attachment, SOUP scripting, sky renderer, water waves
• Configuration (source) — text-based INI files shipped with the game (surface types, combat, keys, etc.)

Repository Layout

• src/ - Rust source
• src/import/ - format importers/parsers
• src/gltf/ - GLTF/GLB conversion (builder, primitives, terrain, texture cache)
• src/ffi/ - C-compatible FFI layer for native plugin use (Unity, etc.)
• src/cli/ - CLI command handlers (cli/convert/ for per-format converters)
• src/error.rs - shared error types
• docs/ - format specifications and engine notes
• tests/ - integration tests

Quick Start

Requirements:

• Rust stable toolchain
• Cargo

Build:

cargo build

Show CLI help:

rgpre --help

CLI Commands

• read (r) — parse an input file and print decoded structure
• convert (c) — export supported inputs to output formats
  • convert <FILE> — auto-detect format, use defaults
  • convert <FORMAT> <FILE> — format-specific subcommand with scoped flags
• scan (s) — recursively scan a directory for known Redguard files

Asset Directories

Redguard shipped with two parallel sets of 3D assets for different renderers:

Directory	Renderer	Model versions	Palette files	Included in GOG
3dart/	Software	v2.6, v2.7	art_pal.col only	Original CD only
fxart/	Glide (3dfx)	v4.0, v5.0	27 .COL palettes (per-scene)	✓

Both directories are supported. The fxart/ Glide assets are recommended — they are included in the GOG release and use the newer model format. Each scene uses its own palette (e.g. ISLAND.COL for the overworld, NECRO.COL for the Necropolis). Pass the matching palette via --palette — without it, 3D exports will have no textures.

Usage Examples

Auto-detect format (uses defaults):

rgpre convert 3dart/LHBM4.3DC -o output/LHBM4.glb
rgpre convert fxart/TEXBSI.302 -o output/TEXBSI_302/

Convert model with palette and asset root:

rgpre convert model fxart/BELLTOWR.ROB --palette fxart/ISLAND.COL --assets . -o output/BELLTOWR.glb

Convert RGM scene with palette and asset root:

rgpre convert rgm maps/BELLTOWR.RGM --palette fxart/ISLAND.COL --assets . -o output/BELLTOWR_scene.glb

Convert WLD world to GLB terrain + companion RGM placement:

rgpre convert wld maps/ISLAND.WLD --palette fxart/ISLAND.COL --assets . -o output/ISLAND_world.glb

Convert WLD terrain only:

rgpre convert wld maps/ISLAND.WLD --palette fxart/ISLAND.COL --assets . --terrain-only -o output/ISLAND_terrain.glb

Convert TEXBSI texture bank with palette:

rgpre convert texbsi fxart/TEXBSI.302 --palette fxart/ISLAND.COL -o output/TEXBSI_302/

Export all animation frames as separate PNGs:

rgpre convert texbsi fxart/TEXBSI.302 --palette fxart/ISLAND.COL --format frames -o output/TEXBSI_302/

Convert font to TrueType:

rgpre convert fnt input/FONT01.FNT --format ttf -o output/FONT01.ttf

Export COL palette as JSON only:

rgpre convert col fxart/ISLAND.COL --format json -o output/ISLAND.json

Extract RTX dialogue with resolved filenames:

rgpre convert rtx input/DIALOG.RTX --resolve-names -o output/dialog/

Scan a directory:

rgpre scan 3dart

Native Plugin (FFI)

The library builds as a C-compatible shared library (cdylib) alongside the CLI binary. This lets game engines like Unity load it as a native plugin and call the conversion functions directly at runtime.

See src/ffi/README.md for the full API reference — architecture, C struct definitions, function signatures, memory management, and error handling.