Design Pattern for Social Game Mission Mechanics

Question

When we want to design a mission sub-system like in the The Ville or Sims Social, what kind of design pattern / idea would fit the best? There may be relation between missions (first do this then this etc...) or not. What do you think sims social or the ville or any other social games is using for this?

I'm looking for a best-practise method to contruct a mission framework for tha game. How the well-known game firms do this stuff for their large scale social facebook games?

• Giving missions to the players and wait players to complete them. when they finished the missions, providing a method to catch this mission complete events considering large user database by not using server-side not so much to prevent high-traffic / resource consumption.

how should i design the database and server-client communication to achive this design condidering this trade-off.

Answer 1

There is not one silver bullet. You can use an event driven paradigm:

• Whenever something happens in your game that can be relevant for a quest, raise an event.
• Define classes for your quests with event listeners to react to these events.
• Store the currently active quests (and their status and parameters) in a database
• When initializing your game state, also initialize quest objects for each active quest of the player
• Register the quest objects' event listeners at your game state object

For example:

class Character {
    function heal(amount) {
        this->hp += amount;
        event = new HealingEvent(this, amount);
        raise event;
    }
}

class PracticeYourHealingSpellQuest extends Quest (extends ActiveRecordBaseClass) {
    // property healingDone is provided by a database record
    function reactToHealingEvent(event) {
        this->healingDone += amount;
        if(this->healingDone > 1000) {
            this->state = completed;
        }
        this->update();
    }
    function registerAtCharacter(character) {
        character->onHealingEvent = this->reactToHealingEvent
    }
}

class GameController {
    function init() {
        character = DB->findMeACharacter
        quests = DB->findMeActiveQuests(character->id)
        foreach(quests as quest) {
            quest->registerAtCharacter(character);
        }
    }
}

Don't worry about database performance. Your facebook app will never have enough users playing at the same time to make this approach unviable with MySQL. (If it does, you can still use caching techniques, parallel database servers, etc.) The most important thing is to have a quest system that is flexible and that has all the quest-related code where it belongs, namely in quest classes.

Answer 2

Your question is general enough that there's probably no definitive answer to it. I think you could find the answer in the book Game Coding Complete though. It describes a process manager that allows you to chain processes together, so that once you achieve a step in a mission the next one would automatically activate. They discuss how you could even make a C# tool that would let you drag and drop to create mission trees in this manner. Might be the kind of architecture you're looking for.