Scriptable Object Variant for Unity (Scriptable Object Data Overrider)

Description

Adds a field to any scriptable object tagged with the [SOVariant] attribute that lets you select an original SO (parent) and override selected fields in the child object.

When changing values in the original, values are automagically propagated to the children.

Usage

Add the tag [SOVariant] before the class header of any ScriptableObject class you want to be overridable, i.e. to be able to create a variant of.

Example:

using Giezi.Tools;

[SOVariant]
[CreateAssetMenu(fileName = "TestScriptable", menuName = "Create new TestScriptable")]
public class TestScriptable : ScriptableObject
{
    [SerializeField] private float myFloat = 3L;
    [SerializeField] private GameObject myGameObject;
    [SerializeField] private int myInt;
    [SerializeField] private TestScriptable myTestScriptable;
}

Create Scriptable Object Variant from context menu

In Unity, you can right click any scriptable object tagged SOVariant to create a variant of this object (Create > Create SO Variant). The new object will have the selected object as parent.

Advanced usage in Editor Script

A helper script has been implemented (SOVariantHelper.cs) which allows you to changed parents, override states and values from within other editor scripts.

Set a new parent:

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
ScriptableObject parent = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/parent.asset");
        
SOVariantHelper<ScriptableObject>.SetParent(target, parent);

Set a field overridable:

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
        
SOVariantHelper<ScriptableObject>.ChangeFieldOverrideState(target, "MyFloat", true);

Set a new value of a field (automatically propagates to children):

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
        
SOVariantHelper<ScriptableObject>.ChangeFieldValue(target, "MyFloat", 45f);

Set a filed to be overridden and set new value (automatically propagates to children):

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
        
SOVariantHelper<ScriptableObject>.SetFieldOverrideAndSetValue(target, "MyFloat", 45f);

Set a parent and set new overridden value (automatically propagates to children):

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
ScriptableObject parent = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/parent.asset");
    
SOVariantHelper<ScriptableObject>.SetParentOverrideValue(target, parent, "MyFloat", 45f);

Set a parent and set new overridden values (automatically propagates to children):

ScriptableObject target = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/child.asset");
ScriptableObject parent = AssetDatabase.LoadAssetAtPath<ScriptableObject>("Assets/Tests/parent.asset");
    
SOVariantHelper<ScriptableObject>.SetParentOverrideValues(target, parent, new Dictionary<string, object>(){{"MyFloat", 45f},{"MyInt", 12}});

Implementation

The visual interface is implemented in Odin's OdinPropertyProcessor. The data with the parent and the overriden fields is kept serialized inside the asset's metadata, set in unity with AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(targetObject)).userData.

Installation

Requires Odin to be installed before adding the package

Using Unity's package manager

Add the line

"ch.giezi.tools.scriptableobjectvariant": "https://github.com/GieziJo/ScriptableObjectVariant.git#master"

to the file Packages/manifest.json under dependencies, or in the Package Manager add the link https://github.com/GieziJo/ScriptableObjectVariant.git#master under + -> "Add package from git URL....

Using OpenUPM

The package is available on OpenUPM. OpenUPM packages can be installed in different ways:

via OpenUPM CLI: openupm add ch.giezi.tools.scriptableobjectvariant
by downloading the .unitypackage and adding it to your project with Assets > Import Package > Custom Package....

the package will be added as a scoped registry, which you can inspect under Project Settings > Package Manager > OpenUPM.

Alternative

Download and copy all files inside your project.

Known issues and tweaks to be made

List of known issues

Efficiency

The attribute [SOVariant] only acts as tagger, which is then looked for in SOVariantAttributeProcessor:OdinPropertyProcessor -> ProcessMemberProperties, where the first line reads:

if(!Property.Attributes.Select(attribute => attribute.GetType()).Contains(typeof(SOVariantAttribute)))
    return;

The problem with this is that SOVariantAttributeProcessor is thus set to be called for every ScriptableObject:

public class SOVariantAttributeProcessor<T> : OdinPropertyProcessor<T> where T : ScriptableObject

There is probably a way to directly call SOVariantAttributeProcessor from the attribute, but I haven't found how.

Selecting the parent object

The selected parent should be of the exact same class as the overriden item (otherwise fields might be missing) and should not be the child itself. This check is currently done when setting the parent as:

if (parent.GetType() != target.GetType())
{
   Debug.Log("Only equal types can be selected as parent");
   return;
}

if (AssetDatabase.GetAssetPath(parent) == AssetDatabase.GetAssetPath(target))
{
   Debug.Log("You can't select the same object as parent");
   return;
}

It would be alot better to directly filter the possible candidates when selecting in the object, but adding the AssetSelector attribute with a filter, or building a custom ValueDropdown both did not work, not sure why.

GieziJo / ScriptableObjectVariant