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Daniel Nylander edited this page Aug 14, 2026 · 7 revisions

Mission Flow

Documentation baseline: v1.1.126. Captive's authentic DOSBox-X verification currently stops at the real Mission 0001 FLIGHT PATH SET boundary.

OpenCaptive has two distinct mission structures: Captive's 10-mission dungeon campaign and Liberation's city-based missions.

State Machine

The game progresses through states defined by GameStateMode:

STATE_MENU
STATE_INTRO
STATE_DROID_CONFIG
STATE_GAME
STATE_SHOP
STATE_TERMINAL
STATE_INVENTORY
STATE_PAUSE
STATE_HELP
STATE_HOLAMAP
STATE_CITY_MAP
STATE_GAMEOVER
STATE_VICTORY

Captive State Flow

STATE_MENU --> STATE_INTRO --> STATE_DROID_CONFIG --> STATE_GAME
                                                        |
                                                        v
                                              (destroy generators)
                                                        |
                                                        v
                                                  STATE_HOLAMAP
                                                   (shop access)
                                                        |
                                                        v
                                                  STATE_GAME (next mission)
                                                        |
                                              (mission >= 10?)
                                                        |
                                                        v
                                                  STATE_VICTORY

Liberation State Flow

Liberation uses boolean flags for substates rather than separate GameStateMode values:

  • liberation_intro_active -- decoded CD32 intro frame
  • liberation_mission_menu_active -- AMOS sprite mission menu
  • lib_mission_briefing -- city name, victim, news source
  • lib_in_building -- building interaction (shop, bar, police, etc.)
  • lib_in_combat -- turn-based combat
  • lib_in_dungeon -- reuses Captive dungeon engine inside Liberation buildings
STATE_MENU --> liberation_intro --> liberation_mission_menu --> STATE_GAME (city)
                                                                   |
                                                          (enter building)
                                                                   |
                                                          lib_in_building
                                                                   |
                                                     (special building found)
                                                                   |
                                                          lib_in_dungeon
                                                                   |
                                                     (destroy generators)
                                                                   |
                                                     mission complete

Captive Campaign

Captive is a 10-mission campaign. Each mission follows the same structure:

Mission Generation

The native compatibility implementation must not be presented as proof of a complete original mission. Original media and the original runtime remain the source of truth for planet selection, arrival, orbit, landing coordinates and dungeon entry. Procedural compatibility code is an implementation slice until it is checked against the corresponding disassembly and real data.

  1. Seed calculation: mission_seed = (mission - 1) * 11 + base_id
  2. Dungeon generation: procedural cellular automaton rules generate the dungeon layout.
    • Cell data uses a 5-byte format with ca_segments (5-bit wall segments) and ca_thickness (wall thickness codes: 0x10, 0x18, 0x80, 0xC0).
  3. Generator placement: placed using the disassembled algorithm from address 0x1C3C in the original binary.
  4. Feature placement: doors, puzzles, and traps placed via the pipeline from address 0x33D7.
  5. Level linking: STAIRS_UP connections link levels; an exterior level is prepended as the base.
  6. Party placement: the party starts at the first CELL_FLOOR or CELL_STAIRS_UP cell found.

Mission Objective

Destroy all generators on all levels. The game tracks generators_total and generators_destroyed. When generators_destroyed >= generators_total, the mission is complete.

Between Missions: Holamap

After completing a mission, game_state_complete_mission transitions to STATE_HOLAMAP:

  • Displays the planet name for the next mission.
  • Provides shop access for equipment upgrades.
  • Advancing from Holamap starts the next mission.

Victory

When mission 10 is completed (mission >= 10), the game transitions to STATE_VICTORY.

Dungeon Parameters

  • Map size: 64 x 32 cells per level (MAP_WIDTH x MAP_HEIGHT)
  • Maximum levels per mission: 15 (MAX_LEVELS)
  • Cell types: wall, floor, door, locked door, stairs up/down, shop, teleporter, generator, terminal, elevator, pressure plate, pit

Liberation Campaign

Liberation uses a city-based structure with up to 256 missions.

City Navigation

  • 8 city themes cycling by (mission - 1) % 8: blue, desert, industrial, coastal, twilight, forest, arid, tundra.
  • Day/night cycle: hour = (tick / 60) % 24. Day is 6:00-18:00, sunset 18:00-21:00, night otherwise.
  • Random encounters: triggered when (encounter_roll & 0x1F) == 0 after movement.

Mission Structure

  1. Mission briefing: PlotGen-driven briefing with city name, victim name, and news source.
  2. City exploration: navigate the city, enter buildings.
  3. Special building: investigating the special building triggers a dungeon crawl (reusing the Captive dungeon engine).
  4. Generator destruction: destroying all generators in the dungeon completes the mission.

Taxi System

  • Activated via phone box interaction.
  • Costs 50 gold.
  • Teleports the party directly to the special building (building type 8).

Liberation Victory

Victory is achieved when mission >= 256.

Industrial Hazards

Liberation dungeons apply environmental damage: 5 + mission * 2 per hazard encounter.

Game Over

The game transitions to STATE_GAMEOVER when all 4 droids are destroyed (all have hp <= 0).

Droid Configuration

STATE_DROID_CONFIG is entered before the first mission. It displays all 4 droids with options to:

  • R: rename a droid
  • S: swap weapons

The current native prototype records initial droid stats as HP 100, energy 100, XP 1024, weapon damage 0x050A, all body parts at item ID 1 with condition 255, and starting gold 100. The native name generator is placeholder logic, not original Captive data; it must not be presented as authentic game content or used as a substitute for names loaded from verified original data.

Source Files

  • Main loop and state machine: src/main.c
  • Game state and mission logic: src/engine/engine.c, include/game_state.h

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