Amulets & Armor

Amulets & Armor is a 1997 first person role playing game released as open source. The codebase is written primarily in C and builds for both DOS and Windows.

Repository layout

• Artwork/ – icons and related artwork
• Build/ – build scripts for DOS (MAKEFILE) and Windows (Visual Studio projects)
• Exe/ – packaged binaries, game data and forms
• Include/ – header files for all modules
• Lib/ – third-party libraries such as SDL and debug helpers
• Source/ – main game source code
• Utils/ – small helper tools

Build system

The DOS version uses the legacy Watcom makefile found under Build/DOS. Windows builds are set up with Visual Studio projects in Build/Windows/VC2010 and VC2013. SDL provides input, video and networking for the Windows port.

Code structure

The entry point for the game is Source/TESTME.C. It initializes configuration, sets up subsystems, then runs the main loop. The source directory is divided into many modules such as graphics, input, networking and UI. Each .c file begins with a short header describing its purpose, and has a matching header in Include/.

Networking

Networking originally supported modem, serial and IPX connections through a layer called "Direct Talk" (DITALK.C). Later a synchronization layer (CSYNCPCK.C) was added so all clients advance in lock step. Random numbers come from a shared table to keep simulations deterministic.

During a synchronization round the client waits until it has received a sync packet from every active player. Once all packets are present, ClientSyncUpdateReceived() processes them and advances the synchronized time.

Synchronized time

SYNCTIME.C maintains a global synchronized clock. Other modules read it when scheduling events, and networking code advances it after each synchronization round.

Modules

A large number of modules make up the game. Examples include 3D rendering (3D_VIEW.C), creature logic (CRELOGIC.C), object movement (OBJMOVE.C), the packet queue (CMDQUEUE.C) and the server/client code (SERVER.C, CLIENT.C). The Doxygen configuration in the repository can generate full documentation listing every module.

• 3D_COLLI.C - 3D collision routines
• 3D_IO.C - 3D map loading/unloading
• 3D_TRIG.C - 3D math utilities
• 3D_VIEW.C - 3D rendering system
• ACTIVITY.C - Processing of map script activities
• AREASND.C - Area-based sound effects
• BANKUI.C - Bank user interface
• BANNER.C - Bottom banner UI
• BUTTON.C - Generic UI button component
• CLIENT.C - Player actions and top-level control
• CLI_RECV.C - Client side packet reception
• CLI_SEND.C - Client side packet sending
• CMDQUEUE.C - Networking command/packet queue
• COLOR.C - Palette color control
• COLORIZE.C - Palette colorization helpers
• COMWIN.C - Communications window UI
• CONFIG.C - CONFIG.INI handling
• CONTROL.C - Mouse input in game
• CRELOGIC.C - Creature logic/AI routines
• CSYNCPCK.C - Synchronized packet handling
• DBLLINK.C - Double linked list utilities
• DEBUG.C - Debug call stack system
• DEBUGBOR.C - Borland C debug utilities
• DITALK.C - Direct Talk system
• DOOR.C - Door control code
• EFFECT.C - Item and spell effects
• EFX.C - Special effects in 3D world
• FILE.C - File I/O helpers
• FORM.C - Generic form UI component
• GRAPHIC.C - Graphic UI component helpers
• GRAPHICS.C - Low level drawing system
• GUILDUI.C - Guild user interface
• HARDFORM.C - Hard form UI game system
• HOUSEUI.C - Housing user interface
• INIFILE.C - INI file parser
• INNUI.C - Inn user interface
• INVENTOR.C - Inventory user interface
• KEYBOARD.C - Keyboard controls
• KEYMAP.C - Key remapping system
• LIGHT.C - Map lighting tables
• LOOK.C - "Look" user interface
• MAINUI.C - Character creation main UI
• MAP.C - Map interface
• MAPANIM.C - Map animation configuration
• MEMORY.C - Memory allocation/freeing
• MESSAGE.C - Message rendering
• MOUSEMOD.C - OS-level mouse interface
• NOTES.C - Notes banner window
• OBJECT.C - Objects in the world
• OBJGEN.C - Object generator
• OBJMOVE.C - Object movement subsystem
• OBJTYPE.C - Object type definitions
• OVERHEAD.C - Overhead map view
• OVERLAY.C - Overlay animations
• PACKETDT.C - Packet communications
• PEOPHERE.C - "People here" window
• PICS.C - Picture resource loader
• PLAYER.C - Player object
• PROMPT.C - Prompt status bar UI
• RANDOM.C - Random number generator
• RESOURCE.C - Resource file system
• SCHEDULE.C - Event scheduler
• SCRFORM.C - Script-based forms
• SCRIPT.C - Script system
• SERVER.C - Server/world code
• SERVERSH.C - Code shared with servers
• SLIDER.C - Sliding wall/door system
• SLIDR.C - UI scroll bar component
• SMACHINE.C - Generic state machine system
• SMCCHOOS.C - Character selection state machine
• SMCPLAY.C - In-game state machine
• SMMAIN.C - State machine top level
• SOUND.C - Sound system
• SPELLS.C - Spell logic
• STATS.C - Player statistics
• STORE.C - Store user interface
• SYNCMEM.C - Synchronization memory utilities
• SYNCTIME.C - Synchronized time module
• TESTME.C - Main entry point and loop
• TEXT.C - Text UI component
• TICKER.C - Timer/ticker system
• TOWNUI.C - Town user interface
• TXTBOX.C - UI text box component
• TXTFLD.C - UI text field component
• UI.C - UI top-level control
• UIBUTTON.C - UI button implementation
• UITEXT.C - UI text helpers
• UPDATE.C - Miscellaneous updates
• VIEW.C - Map view drawing
• VM.C - Virtual memory helpers
• DOS/DOSDTALK.C - DOS implementation of Direct Talk
• Win32/WINDTALK.C - Windows implementation of Direct Talk
• Win32/ipx_client.* - IPX networking over UDP (Windows)

Learning more

1. Run Doxygen using Doxyfile to browse module documentation.
2. Examine Build/ to see how the DOS and Windows versions are compiled.
3. Start with TESTME.C and follow calls into the various subsystems to understand game flow.
4. Explore the assets under Exe/ to learn how content is organized.