Game Boy Advance Dev: Link Cable Networking
5 hours ago
- #Embedded Programming
- #Link Cable Multiplayer
- #Game Boy Advance
- The afska/gba-link-connection C++ library is essential for Game Boy Advance link cable multiplayer, supporting various connection types like standard multiplayer, e-Reader, and GameCube.
- To use the library in a C project, copy the necessary files (like C_LinkCable.cpp, LinkCable.hpp) and adjust includes; mixing C and C++ files is possible with devkitpro/tonc.
- Use libugba's interrupt system instead of libtonc's to avoid packet loss in serial and timer interrupts, as libtonc has a bug that causes issues.
- Set up interrupts for vblank, serial, and timer by initializing them with ugba wrapper functions, enabling/disabling based on multiplayer mode activation.
- Define the C_LinkCableHandle (cLinkCable) in your game, initialize it with parameters like baud rate, and activate the connection for use.
- Send data via C_LinkCable_send using 16-bit values (avoid 0 and 0xffff), and receive by syncing with C_LinkCable_sync, then reading all packets in a loop.
- Test multiplayer in mGBA by opening a new multiplayer window; note that the new window is player 1 and the original is player 2, which may affect connection roles.
- Design a robust networking protocol, such as using top bits for message types and lower bits for payloads, and implement a handshake process to ensure both sides are ready.
- Synchronize gameplay start times by having players exchange sync messages, with player 2 waiting an extra frame to align precisely.
- Adjust the link cable interval (e.g., multiply by 3) to reduce CPU load if audio (like music) causes lockups, especially in slower-paced games.
- Be aware of multiboot mode for single-cartridge multiplayer, which is supported by the library but more complex than standard link cable play.