R-Type Protocol Documentation

This document provides a detailed overview of the communication protocol for the R-Type server. It outlines the purpose, payload, and transmission method (TCP/UDP) for each operation code (OpCode). The protocol ensures consistent communication between the server and clients.

Overview

Transport Protocols

  • TCP: Reliable communication for operations requiring acknowledgment (e.g., player creation, hotkey inputs).
  • UDP: Lightweight and fast communication for real-time updates (e.g., player positions, bullets, obstacles).

Message Structure

All messages follow this general structure:

FieldTypeSize (bytes)Description
OpCodeint16_t2Identifies the operation (see below).
PayloadVariesVariableData relevant to the specific operation.

OpCode Definitions

1. DEFAULT

  • Value: 0
  • Description: Used to save the client on the server.
  • Payload: None.
  • Sent To: Server or specific client.
  • Transport: TCP.

2. HOTKEY_PRESSED

  • Value: 1
  • Description: Notifies the server of a key press by a specific player.
  • Payload:
    • playerId (int32_t): The ID of the player who pressed the key.
    • hotkeyCode (int16_t): The code of the pressed key.
  • Sent To: Server.
  • Transport: TCP.

3. CREATE_PLAYER

  • Value: 10
  • Description: Requests the creation of a new player on the server.
  • Payload:
    • playerName (string): The name of the player to create.
  • Sent To: Server.
  • Transport: TCP.

4. CREATE_PLAYER_CALLBACK

  • Value: 11
  • Description: Confirms the creation of a new player to the requesting client.
  • Payload:
    • playerId (int32_t): The ID of the newly created player.
    • width (int16_t): The width of the player’s sprite.
    • height (int16_t): The height of the player’s sprite.
  • Sent To: Specific client (the one who requested the creation).
  • Transport: TCP.

5. CREATE_PLAYER_BROADCAST

  • Value: 12
  • Description: Broadcasts the creation of a new player to all connected clients.
  • Payload:
    • playerId (int32_t): The ID of the new player.
    • playerName (string): The name of the new player.
    • width (int16_t): The width of the player’s sprite.
    • height (int16_t): The height of the player’s sprite.
  • Sent To: All clients.
  • Transport: UDP.

6. UPDATE_PLAYERS

  • Value: 20
  • Description: Updates player positions and states.
  • Payload:
    • playerId (int32_t): The ID of the player.
    • posX (int32_t): The player’s X-coordinate.
    • posY (int32_t): The player’s Y-coordinate.
  • Sent To: All clients.
  • Transport: UDP.

7. UPDATE_VIEWPORT

  • Value: 21
  • Description: Updates the current map viewport.
  • Payload:
    • viewport (double): The viewport’s position.
  • Sent To: All clients.
  • Transport: UDP.

8. UPDATE_OBSTACLES

  • Value: 22
  • Description: Updates obstacle positions or states.
  • Payload:
    • obstacleId (int32_t): The ID of the obstacle.
    • posX (int32_t): The obstacle’s X-coordinate.
    • posY (int32_t): The obstacle’s Y-coordinate.
    • size (int16_t): The size of the obstacle.
    • type (int16_t): The type of the obstacle.
  • Sent To: All clients.
  • Transport: UDP.

9. UPDATE_BULLETS

  • Value: 23
  • Description: Updates bullet positions or states.
  • Payload:
    • bulletId (int32_t): The ID of the bullet.
    • posX (int32_t): The bullet’s X-coordinate.
    • posY (int32_t): The bullet’s Y-coordinate.
    • type (int16_t): The type of the bullet.
  • Sent To: All clients.
  • Transport: UDP.

10. UPDATE_ENEMIES

  • Value: 24
  • Description: Updates enemy positions or states.
  • Payload:
    • enemyId (int32_t): The ID of the enemy.
    • posX (int32_t): The enemy’s X-coordinate.
    • posY (int32_t): The enemy’s Y-coordinate.
    • width (int16_t): The width of the enemy’s sprite.
    • height (int16_t): The height of the enemy’s sprite.
    • type (int16_t): The type of the enemy.
  • Sent To: All clients.
  • Transport: UDP.

11. UPDATE_ENTITY_HEALTH

  • Value: 25
  • Description: Broadcasts changes in the health of an entity (player or enemy).
  • Payload:
    • entityId (int32_t): The ID of the entity.
    • health (int16_t): The current health of the entity.
    • maxHealth (int16_t): The maximum health of the entity.
  • Sent To: All clients.
  • Transport: UDP.

12. UPDATE_PLAYER_INFOS

  • Value: 26
  • Description: Updates player's infos.
  • Payload:
    • playerId (int32_t): The ID of the player.
    • kills (int16_t): The kills amount of the player.
    • score (int32_t): The score of the player.
  • Sent To: Specific client.
  • Transport: UDP.

13. DELETE_ENTITY

  • Value: 30
  • Description: Deletes an entity from the game (e.g., player, enemy, bullet).
  • Payload:
    • entityId (int32_t): The ID of the entity to delete.
  • Sent To: All clients.
  • Transport: UDP.

Notes

  • The server and clients must strictly adhere to the protocol to ensure consistency.
  • Payloads must be interpreted exactly as defined.
  • TCP is used for operations requiring reliable delivery, while UDP is optimized for real-time updates.