Quest System in Sword Art Online

Like many RPG games, Sword Art Online features a comprehensive quest system where guild members can post quests and adventurers can complete them for rewards. Kayaba's implementation follows specific rules to ensure fairness and efficiency.

Core Mechanics

The quest system allows players to both create and undertake quests, fostering a player-driven economy and community engagement.

Quest Rules

1. Posting Limitation

• Each player may only have one active quest posted at any time

2. Participation Restriction

• Quest creators cannot participate in their own quests

3. Completion Status

• Each quest can only be completed once
• Only one player can accept a quest at a time

4. Reward System

• Successful completion grants the specified rewards to the completing player
• The quest creator must verify completion before rewards are distributed

Quest Flow

1. Player posts a quest with defined rewards
2. Another player accepts the quest
3. Player completes the required tasks
4. Quest creator verifies completion
5. System distributes rewards to the completing player

Events

In order to facilitate the quest system, the game uses a series of events to manage quest creation, acceptance, and completion.

event QuestCreated(uint256 id, address indexed creator, Quest quest);

• Emitted when a player creates a new quest

event QuestTaken(uint256 id, address indexed taker, Quest quest);

• Emitted when a player accepts a quest

event QuestCompleted(uint256 id, address indexed completer, Quest quest);

• Emitted when a player completes a quest

event QuestVerified( uint256 id, address indexed verifier, address indexed completer, Quest quest );

• Emitted when a quest creator verifies completion

Data Structures

Quests are represented using the following struct:

 struct Quest {
      // Quest description
      string description;
      // Quest reward in wei
      uint reward;
      // Quest completion status
      bool completed;
      // Quest verification status
      bool verified;
      // Who take and will complete the quest
      address completer;
  }

Functions

1. function createQuest(Quest memory quest) public payable

• Allows a player to create a new quest with the specified reward

2. function takeQuest(uint questId) public

• Allows a player to accept a quest

3. function completeQuest() public

• Allows a player to complete a quest

4. function verifyComplete() public

• Allows a quest creator to verify quest completion. Since each player can only have one active quest, the system can easily determine the quest to verify.

Code