Creating custom items

See Items for a detailed description about item instances and item definitions.

Item Registry

The ItemRegistry is responsible for keeping track of all item instances. Keep in mind that if you're going to create a new item instance you'll have to register it with the item registry. Note that using ItemFactory will automatically register new item instances for you.

// Registering an item in the registry.
ItemRegistry.Register(itemGuid, item);

// Un-Registering an item from the registry.
ItemRegistry.UnRegister(itemGuid);

// Getting an item from the registry
var item = ItemRegistry.Get(itemGuid);

Item Instance

using Devdog.General2;
using Devdog.Rucksack;
using Devdog.Rucksack.Items;
using System;

using UnityEngine;

[System.Serializable]
public class MyItemInstance : UnityItemInstance, IEquatable<MyItemInstance>
{
    public float strengthMultiplier = 1.0f;
    public float healthMultiplier = 1.0f;

    // For (de)serialization...
    protected MyItemInstance()
    { }

    public MyItemInstance(Guid ID, IUnityItemDefinition itemDefinition)
        : base(ID, itemDefinition)
    { }

    public override Result<bool> CanUse(Character character, ItemContext useContext)
    {
        var canUse = base.CanUse(character, useContext);
        if (canUse.result == false)
        {
            return canUse;
        }

        // Fetch a custom component from your player object and check its level.
        var myComponent = character.GetComponent<MyComponent>();
        if (myComponent.playerLevel < ((MyItemDefinition)itemDefinition).level)
        {
            return new Result<bool>(false, new Error(123, "Player level is too low"));
        }

        return true;
    }

    public override Result<ItemUsedResult> DoUse(Character character, ItemContext useContext)
    {
        // Do something fancy here...
        var myComponent = character.GetComponent<MyComponent>();
        myComponent.strengthMultiplier *= strengthMultiplier;
        myComponent.healthMultiplier *= strengthMultiplier;

        return new Result<ItemUsedResult>(new ItemUsedResult(useContext.useAmount, false, 0f));
    }

    public bool Equals(MyItemInstance other)
    {
        return base.Equals(other);
    }
}

Item Definition

using Devdog.Rucksack.Items;
using UnityEngine;

public class MyItemDefinition : UnityItemDefinition
{
    [SerializeField]
    private int _level;
    public int level
    {
        get { return this.GetValue(t => t._level); }
    }
}

Custom character component

This is just a simple example of a component that can be attached to your character that an item can interact with.

public class MyComponent : MonoBehaviour
{
    public float strengthMultiplier = 1.0f;
    public float healthMultiplier = 1.0f;

    public int playerLevel = 4;
}

Item Factory binding

The ItemFactory is a simple static class that is used to create new item instances of item definition types.

// Create a binding between the UnityItemDefinition and the UnityItemInstance.
// When you're trying to create a new instance of UnityItemDefinition this will ensure a new instance of UnityItemInstance will be returned.
ItemFactory.Bind<UnityItemDefinition, UnityItemInstance>();

// Creates a new instance for the given itemDefinition. Based on the itemDefinition type and the set bindings a new instance will be returned.
var inst = ItemFactory.CreateInstance(itemDefinition, System.Guid.NewGuid()) as MyItemInstance;
inst.healthMultiplier = 1.1f;

Keep in mind that if you're going to create a item instance this item will be to registered in item registry. If you don't need this instance anymore unregister this instance.

ItemRegistry.UnRegister(itemGuid);