design.md

Design

The gamestate is handled completly by the server. The gamestate consists of an array of players which consist of a ID and an array of units.

The clients send commands to the server and receive the current gamestate.

Network protocol

State machine

This is the state machine on the Server:

┏━━━━━━━┓   ┏━━━━━━━━━━━┓   ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃*start*┠──►┃ClientHello┠──►┃ServerHello(ClientId, World)┠─╮
┗━━━━━━━┛   ┗━━━━━━━━━━━┛   ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛ │
                                                           │
            ┏━━━━━━━━━━━┓                                  │
            ┃*connected*┃◄─────────────────────────────────┴──┬─╮
            ┗┯┯━━━━━━━━━┛                                     │ │
             ││                                               │ │
             ││  ┏━━━━━━━━━━━━━━━━┓   ┏━━━━━━━━━━━━━━━━━━━━━┓ │ │
             │╰─►┃Command(Command)┠──►┃UpdateGamestate(Game)┠─╯ │
             │   ┗━━━━━━━━━━━━━━━━┛   ┗━━━━━━━━━━━━━━━━━━━━━┛   │
             │                                                  │
             │   ┏━━━━━━━━━━━━━━━━━━━━━━━━━┓                    │
             ╰──►┃ClientReconnect(ClientId)┠────────────────────╯
                 ┗━━━━━━━━━━━━━━━━━━━━━━━━━┛

• Initially, the server waits for a ClientHello message.
• It responds with a ServerHello message that contains the client ID that can be used by the client for reconnecting with a ClientReconnect message when the connection was lost.
• Then the server enters a loop and waits for a Command from the client. When such a command results in a world change, the world is sent back to the client as an UpdateGamestate message.

Connect

Hello from client! Server responds with an ID that was assigned to the client.

After that only Update Gamestate commands follow.

Update Gamestate

The server sends the current gamestate to the client.

Command

Client sends a move command to the server.

References

Here are some interesting links about networking in games:

• http://gafferongames.com/networking-for-game-programmers/what-every-programmer-needs-to-know-about-game-networking/

Notes

Server

• Lobby
  • Players are allowd to connect
  • Settings may be changed
• Running
  • Players are only allowed to reconnect

Settings

• World shape, size
• Unit size, speed, HP