Open-Ragnarok is mainly a free open-source implementation for reading and writing ragnarok online file types.
It's aimed to be multi-platform, developed in C++ with a Python-ready interface.
It reads all major filetypes (GRF, RSM, RSW, GAT, GNT, ACT, SPR) used by the main ragnarok game.

The full project includes three major libraries:

• ROInt - The Interface that reads and write the formats used by the game
• ROGL -The graphics library to draws the game objects. Currently only OpenGL
• RONet - Responsible in handling incoming packets and generating outgoing packets using the Ragnarok Protocol.

And, on top of those, the Client itself.