User Guide

User Guide

Updated for v1.1.79. The launcher caches unchanged data-scan results and asks which verified version to launch when several versions are present.

System requirements

• OS: Linux (x86_64), macOS 14+ (Apple Silicon), Windows 10+, Android 8+, iOS 15+
• Dependencies: SDL3, zlib (bundled in release builds)
• Game data: original Captive and/or Liberation media files (not included)

Installation

From release packages

Download from GitHub Releases:

Platform	Package
Linux (Debian/Ubuntu)	opencaptive_X.Y.Z_amd64.deb
Linux (Fedora/RHEL)	opencaptive-X.Y.Z.x86_64.rpm
Linux (universal)	opencaptive-x86_64.AppImage
macOS (Apple Silicon)	OpenCaptive-macos-arm64.dmg
Windows	OpenCaptive-X.Y.Z-setup-x64.exe
Android	opencaptive-arm64.apk
iOS	opencaptive-arm64.ipa

Building from source

Requires CMake 3.20+, a C17 compiler (clang or MSVC), SDL3, zlib and Ninja.

cmake -S . -B build -DCMAKE_C_COMPILER=cc -G Ninja
ninja -C build

Release build:

cmake -S . -B build -DCMAKE_C_COMPILER=cc -G Ninja -DCMAKE_BUILD_TYPE=Release
ninja -C build

Run tests:

ctest --test-dir build -j4 --output-on-failure

Running

Basic usage

opencaptive --data /path/to/your/media
opencaptive --data /path/to/your/media --game captive
opencaptive --data /path/to/your/media --game liberation
opencaptive --data /path/to/your/media --lang sv

Default data paths

• Linux / macOS: ~/.opencaptive
• Windows: installdir\data (relative to the installation directory)
• Android: /sdcard/OpenCaptive
• iOS: Documents/OpenCaptive

Command-line flags

Game selection

Flag	Description
--data <path>	Path to game data directory
--game <name>	Select game: captive or liberation
--lang <code>	Language code (see Internationalization below)
--verify-data <scope>	Verify data integrity: captive, liberation, or all

Display settings

Flag	Description
--fullscreen	Start in fullscreen mode
--scale <N>	Window scale factor (1-8, default: 3)
--scanlines	Enable scanline effect
--crt	Enable CRT curvature effect
--bilinear	Enable bilinear texture filtering
--integer-scaling	Force integer scaling (default: on)
--no-integer-scaling	Allow non-integer scaling
--vsync	Enable vertical sync (default: on)
--no-vsync	Disable vertical sync
--fps <N>	FPS limit: 0 (unlimited), 30, 60, 120 (default: 60)
--brightness <N>	Brightness level 0-100 (default: 50)
--contrast <N>	Contrast level 0-100 (default: 50)
--renderer <mode>	Render mode: original or enhanced
--platform <name>	Platform variant: dos, amiga, or atarist

Information

Flag	Description
--help, -h	Show all available options
--version, -v	Show version and author

Start Menu

The start menu uses an 8-item card layout:

Top row: game cards

• Captive card — click or press Enter to start a new Captive game
• Liberation card — click or press Enter to start a new Liberation game
• Each card displays a checkmark (green) if game data passes SHA-256 verification, or a cross (red) if data is missing or fails verification

Continue row

Appears only when save files exist (opencaptive.sav or liberation.sav). Resumes from the most recent save.

Lower rows

• Settings — opens the 24-item settings panel
• About — version, credits, and license information
• Controls — input reference
• Quit — exit the application

Keyboard shortcuts in the start menu

• D — opens the Data Scanner (scans the data path, reports ZIP count, per-game SHA-256 verification status)
• F1 — opens the Controls reference overlay

Settings

The settings panel contains 24 configurable items with vertical scrolling:

Setting	Values
Renderer	Auto / GPU / Software
Window Size	Preset dimensions
Scale	1x through 5x
Fullscreen	On / Off
Integer Scale	On / Off
VSync	On / Off
FPS Limit	Unlimited / 30 / 60 / 120
Filtering	Nearest / Bilinear
Scanlines	On / Off
CRT Curve	On / Off
Brightness	0-100%
Contrast	0-100%
Gamma	0-100%
Volume	0-100%
Music	On / Off
SFX	On / Off
Reverb	On / Off
Sample Rate	22050 / 44100 / 48000
Game Speed	50-200%
Mouse Sensitivity	1-10
Data Path	Editable text field
Language	19 languages (see below)
Enhanced	On / Off
Back	Return to start menu

Controls

Movement

Key	Action
W / Up	Move forward
S / Down	Move backward
A / Left	Turn left
D / Right	Turn right

Combat

Key	Action
Space	Fire weapon
Enter	Use item / interact

User interface

Key	Action
Tab	Cycle droids
I	Inventory
M	Minimap
Shift+M	City map (Liberation only)

System

Key	Action
F5	Save game
F9	Load game
F6	Cycle save slots
F7	Debug HUD
F8	Minimap toggle

Menu and help

Key	Action
H	Help screen
ESC	Pause menu
F1	Controls reference

Speed

Key	Action
Numpad +	Increase game speed (if enabled)
Numpad -	Decrease game speed (if enabled)

Internationalization

OpenCaptive supports 19 languages, selectable via --lang <code> or in the Settings menu:

Code	Language
en	English
sv	Swedish
cs	Czech
da	Danish
de	German
es	Spanish
fi	Finnish
fr	French
hu	Hungarian
it	Italian
ja	Japanese
ko	Korean
nl	Dutch
no	Norwegian
pl	Polish
pt	Portuguese
ro	Romanian
ru	Russian
zh	Chinese

Game Data

Content identity

OpenCaptive identifies all game files by SHA-256 content hash, never by filename. This means files can have any name and be placed in any directory structure.

Supplying data

Place ZIP archives containing your original game media in the data directory. OpenCaptive transparently scans:

• ZIP archives (including nested ZIPs)
• ADF disk images
• ISO tracks (BIN/CUE)

Verification requirements

Game	Verified files needed
Captive	12
Liberation	7

Data Scanner

Press D in the start menu to open the Data Scanner. It scans the configured data path and reports:

• Number of ZIP archives found
• Per-game SHA-256 verification status for each required file

CLI verification

opencaptive --data /path/to/media --verify-data all
opencaptive --data /path/to/media --verify-data captive
opencaptive --data /path/to/media --verify-data liberation

Diagnostics

Headless smoke test (Unix):

SDL_VIDEODRIVER=dummy SDL_AUDIODRIVER=dummy \
  timeout 5 ./build/opencaptive --data /path/to/media --game captive

The expected result is a timeout exit after the game loop starts, with log lines for texture loading and verified startup.