Mission Flow

Mission Flow

Documentation baseline: v1.1.99.

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

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

Initial droid stats: HP 100, energy 100, XP 1024, weapon_damage 0x050A, all body parts at item ID 1 with condition 255, starting gold 100. Names are generated procedurally via captive_generate_name with seed 42.

Source Files

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