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rogerdv

Unity RPG item/spell/combat system

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rogerdv    418

Im working in the implementation of the combat system for my RPG (made with Unity3d and c#), which depends on the item system, skill system, etc. The idea is to have real time pausable combat, so my initial idea was to have a queue of actions. An action can be a weapon attack or an spell, and can be created by the AI or the player input during combat. But when started to work on the actual implementaiton I thought that perhaps my system was too complex.

Described in pseudocode, it something like this:

 

On the Update() of each entity (including player)

if queue is not empty

 get the first action if cooldown timer expired and it is loopable, else, remove and get next

 is it an item action?

    if the item is a weapon then get the item dmg properties, the target protect properties and decide if it is a succesful attack, dmg, etc

    if the item is something else, decide what to do

 is it a spell cast?

     then do the spell stuff, etc

 set the cooldown timer

 

The advantage I see: the item class is generic and can contain any item, because it just hold properties, doesnt knows how to actually use the item.

The disadvantage: the same. Also, the gameplay code becomes complex (you have to compare all the item damage types against all the target protection types). The action class is a mess: it must contain all possible combinations of actions: item on actor (like a sword attack), spell on actor, and any other I can figure out later.

Is there any other more optimal solution to this?

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gdunbar    2198

I'm the author of a real-time pausable RPG. To answer your basic question, "Do I have to do all that stuff?" Yes, you do. In fact, I think you simplified; for an attack, my code runs three timers. One for a character preparing to attack, but not yet attacking, who should display a fighting animation. Second, when the character actually is attacking, to display the attacking animation. And third, when the character is recovering from his attack, displaying a recover animation (i.e. moving his sword back from the extended position to the ready position). Real-time is complicated!

 

Now, how to handle it in code? For your action class, I have a similar set of classes. However, I subclass depending on the particular action. So "attack with a weapon" in one subclass, "cast a spell" is another, etc. Is something like that possible in your architecture? If so, you should be able to avoid having one mega-action class. I actually have one giant class that handles running all the actions through a switch statement. I'm not proud of this architecture, but there are not that many types of actions, so I live with it, and it works fine. You can probably do better than that, though, if you are writing code from scratch, by moving some or all of the action-running code into the sub-classes.

 

Hope that helps a little,

Geoff

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Brain    18906

Well, you say you have a base class, for example "Attack" and that spells, sword swipes etc Derive from it?

 

The details of how to use the item should be handled by the derived class. The caller should not be concerned with this and should just call some "activate()" or "use()" method.

 

You could also have a factory system, whereby the sword generates attack derived objects and the spellbook (or whatever is source of your magic) does the same. These can be created dynamically based on the attack type. 

 

If you can't make it work like that currently and the caller directly reads properties from the class and internally performs the action this is what is causing the confusion, refactor it to black box the use/cooldown code.

 

Hope this helps!

Edited by braindigitalis

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rogerdv    418

Well, you say you have a base class, for example "Attack" and that spells, sword swipes etc Derive from it?

 

The details of how to use the item should be handled by the derived class. The caller should not be concerned with this and should just call some "activate()" or "use()" method.

 

You could also have a factory system, whereby the sword generates attack derived objects and the spellbook (or whatever is source of your magic) does the same. These can be created dynamically based on the attack type. 

 

If you can't make it work like that currently and the caller directly reads properties from the class and internally performs the action this is what is causing the confusion, refactor it to black box the use/cooldown code.

 

Hope this helps!

 

Nope, I dont have a class Attack. What I do plan to have (not yet) are classess for abilities you can apply on targets. I will follow your advice and derive specialized item classes, that will help to clear my game logic code.

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lede    591

You might look into creating an interface for your attack items and implement this in your derived classes.  This would then allow separation of the data structures and game logic of how they work but still allow you to store them in a simple data structure.

 

For example if we have an interface defined like:

interface iAttackable
{
    void Attack();
}

Then we could define a sword and spell class like this:

public class Sword : iAttackable
{
    public void Attack()
    {
        //...Do some logic in the attack
    }
}

public class Spell : iAttackable
{
    public void Attack()
    {
        //...Do some logic in the attack
    }
}

This way now you don't have to do a check on an object to see how to perform a specific attack.  Abstracting it this way now allows for different logic to be handled by the unique class.  You may need to add parameters to the interface in order to share objects between class but this information would be something you will need to figure out in your design.  Now then back to the interface and now that we have defined the usage in two classes we could write code like:

//....Update method definition skipped
iAttackable attackItem = new Sword(); // Or this could very well be "new Spell();"
attackItem.Attack();

Because the attackItem is a generic interface class we can store either the Spell class or the Sword class in this variable.  With this you can now even stack different kind of attacks so if a player wanted to use a sword and a spell they could without bloating your code just create a data structure to manage it.  Having a generic enough way to access different types of classes can be beneficial in a complex system.  One class can also implement multiple interfaces which then can allow you to blend different features generically into one class.  For example you may need to do something special on the spell being cast during the update process.  You can use type casting to these specific interfaces and then test if the cast worked before your proceed.

 

This is just one different approach that could help solve your design problem.  Try a couple of different ideas and see how it works best for your design.

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