Fixing ScriptableObject Data Loss in Unity's Play Mode

Описание: Discover how to resolve issues with Unity's `ScriptableObject` data not saving when entering play mode, and learn effective methods to maintain your sprite references.
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This video is based on the question https://stackoverflow.com/q/72418762/ asked by the user 'Jacob' ( https://stackoverflow.com/u/17653621/ ) and on the answer https://stackoverflow.com/a/72419132/ provided by the user 'Lieke' ( https://stackoverflow.com/u/19200554/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Solve Your ScriptableObject Data Loss Issue in Unity

One common challenge developers face when working with Unity's ScriptableObject is the issue of data loss when entering play mode. Specifically, for those who create and manage sprites, it can be frustrating to see fields reset to empty for no apparent reason. Recently, I was tackling this very problem, and I'm excited to share my findings on how to fix it effectively.

Understanding the Issue

The core of the problem revolves around the way Unity serializes sprite data in ScriptableObjects. When you generate sprites during runtime, they exist only in memory. Once you enter play mode, Unity resets this memory and loses any sprites that weren't explicitly saved as assets. In short, if your sprites aren’t saved to the project, Unity will not retain them between play sessions.

Identifying the Symptoms

Before diving into the solution, let’s clarify some symptoms that indicate you might be facing this issue:

Empty Fields: Your sprites array is empty when you return to edit mode after play mode.

Missing References: Error messages may state that references are missing, leading to null references in your code.

No Asset Storage: Sprites created in memory during play mode do not persist after exiting play mode.

The Root Cause Explained

When sprites get generated and stored in a ScriptableObject, they're treated as references tied to the memory. Here’s how the asset file may look if everything is set up correctly:

[[See Video to Reveal this Text or Code Snippet]]

But if you save the sprites incorrectly, they won't have associated IDs, causing memory references to fail, as shown below:

[[See Video to Reveal this Text or Code Snippet]]

The Solution: Persisting Your Sprites

To ensure that your sprites remain intact even after exiting play mode, you need to save them as assets within your project. Here's how to achieve this effectively:

Step-by-Step Guide to Persist Sprites

Update Your MakeSprites Method: Modify your sprite creation code to include asset database functions that save your sprites.

Here’s a code snippet to illustrate the modification:

[[See Video to Reveal this Text or Code Snippet]]

Check Asset Management: Implement asset management to ensure old sprite assets don’t clutter your project. This may involve deleting or updating existing sprites.

Test the Solution: After implementing the changes, run your game. You should see your sprite references retained when entering and exiting play mode.

Conclusion

By saving your sprites as assets within Unity’s project structure, you create a reliable method for maintaining references that won't reset in play mode. Whether you're a beginner or a seasoned developer, proper asset management enhances your workflow and prevents frustrating data loss.

Keep experimenting with your ScriptableObjects and remember, it's all about how you store and manage your data. Happy developing!