38 lines
2.2 KiB
Markdown
38 lines
2.2 KiB
Markdown
# The Realm Online: Engine & Protocol Documentation
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## 1. Game Engine: Sierra Creative Interpreter (SCI) 2.1
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The Realm Online was developed using a heavily modified version of the **SCI 2.1** engine.
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### Key Modifications:
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- **Networking Stack**: Unlike standard single-player SCI games (e.g., King's Quest), Realm includes a proprietary networking layer for real-time multiplayer interactions.
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- **Resource Management**: Uses `.res` and `.pqc` (Packaged Quest Content) files for storing tiles, sprites, and sounds.
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- **Client Logic**: Much of the client logic is written in SCI script (a Smalltalk-like language), but the core engine handles the rendering and networking primitives.
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### Tools for Asset Extraction:
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- **SCI Companion**: A modern tool for editing and viewing SCI resources.
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- **QuickBMS**: Can be used with custom scripts to extract files from `.pqc` archives.
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- **SCI Resource Viewer**: Useful for browsing sprites and tiles.
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## 2. Network Protocol
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The game uses a client-server architecture with multiple dedicated TCP ports for different services.
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### Port Mapping:
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- **6002 (Realm Server)**: Main game world communication.
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- **6003 (Auth Server)**: Login and authentication.
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- **6005 (Patch Server)**: Version checking and file updates.
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- **7002 (Route Server)**: Redirects clients to specific game instances/realms.
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- **8001 (Game Server)**: Individual game instance handling.
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### Handshake & Packet Structure:
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Based on community reverse-engineering (e.g., the `server_poc.py` script):
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- **Framework**: Many modern emulators use the **Twisted** framework (Python) to handle the asynchronous networking required.
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- **Packet Headers**: Packets typically have a size header followed by the payload.
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- **Authentication**: Involves a multi-step handshake where the client identifies itself, sends credentials, and receives a session token or redirection to a game server.
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## 3. Database Schema
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The community-maintained database (TRO-DB) provides schemas for the following:
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- **Mobs/NPCs**: Statistics, drops, and spawn logic.
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- **Items**: Equipment stats, consumable effects, and shop prices.
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- **Spells**: Damage formulas, mana costs, and requirements.
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- **Maps**: Area definitions, warp points, and shop inventory mappings.
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