This document discusses various tips and tricks for hacking Unity through serialization, assets, runtime, and reflection. It provides code examples and demos for serializing polymorphic types by creating custom ScriptableObjects, creating default inspectors for any object type, reusing importer settings across assets, accessing private editor APIs at runtime, and more advanced techniques for optimizing games developed in Unity.

1. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Ryan Hipple
Senior Engineer
Schell Games
@roboryantron

2. The World of Lexica
● Transformational game
● Tablets in the classroom
● More than 50 people
● 2 ½ years

3. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Serialization
Assets
Runtime
Reflection

4. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Serialization
Assets
Runtime
Reflection

5. Serialization
Polymorphic Serialization
● Polymorphism is awesome
● Unity does not serialize it well (fields or arrays)
Name
Name Name Name
Intelligence Ferocity Deliciousness

6. Serialization
Polymorphic Serialization
● ScriptableObject instead of [Serializable]
● One problem : lots of files

7. Serialization
Polymorphic Serialization
● Want to make it one file...
● AssetDatabase.AddObjectToAsset

8. Serialization
Polymorphic Serialization
● Want to make it seem like a normal file?
● hideFlags = HideFlags.HideInHierarchy

10. Serialization
Polymorphic Serialization
● Streamline with custom inspectors
● CreateInstance on Add
● Destroy on Remove
● Dropdown with available types

11. Serialization
Polymorphic Serialization
Demo

12. Serialization
Serializable Long
● 64 bit integer
● Great for IDs
● Used by other software
● Unity does not serialize the type ‘long’

13. Serialization
Serializable Long
● Break into two ints for serialization
● Custom Inspector
● Implicit casting

14. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Serialization
Assets
Runtime
Reflection

15. Assets
Auto Scriptable Objects
● Not like assigning MonoBehaviours
● Can only create ScriptableObjects from code

16. Assets
Auto Scriptable Objects
● Custom editor for MonoScript (inspector)
● Check for ScriptableObject inheritance
● Button to CreateInstance

17. Assets
Auto Scriptable Objects
Demo

18. Assets
Default Object Inspector
● No inspectors for directories
● No inspectors for scenes
● No inspectors for unknown extensions
● No inspectors for asset roots

19. Assets
Default Object Inspector
● Create Custom Editor for “Object”
● Draw differently for each type
○ If statements?
● Better Option - Copy Unity’s Inspector
pattern

20. Assets
Default Object Inspector
● Custom Editor for Object
● OnEnable, finds all “ObjectInspector” types
○ Assembly.GetTypes
● Any ObjectInspector where “IsValid” returns
true is added to a list
● Draw Valid Inspectors in OnInspectorGUI

21. Assets
Default Object Inspector
● Simple to Create
● Extend ObjectInspector
● Override IsValid
○ example: return extension == (".unity");
● Override OnInspectorGUI

22. Assets
Default Object Inspector
Demo scene folder and file encoding

23. Assets
Reusing Importer Settings
● Often want same importer settings
● Per project
● Per directory
● Should be automatic

24. Assets
Reusing Importer Settings
● Two-Part Solution
○ AssetPostprocessor script
○ Postprocessor settings scriptable objects
● Each directory has a settings object
● Override options for each importer option
● Applies to new assets automatically

25. Assets
Reusing Importer Settings
Demo

26. Assets
Custom Metadata
● Data about a file - not in the file
● Loading full file takes long
● New objects can get deleted, renamed
● Unity stores in meta file
● You can too!

27. Assets
Custom Metadata
● AssetImporter.userData - string
● Save key value pairs or json
● Use AssetModificationProcessor to update
● Display in inspector

28. Assets
Custom Metadata
Demo

29. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Serialization
Assets
Runtime
Reflection

30. Runtime
References, Resources, and Memory
● Useful to load a list of other assets
● Object references in prefabs or SOs?
○ Loads all assets at once
● Paths for Resources.Load?
○ Loads only when needed
○ Typo prone

31. Runtime
References, Resources, and Memory
● Asset Path Attribute for string fields
● Property Drawer for the attribute
○ Draw as an object field
○ Save path to string

32. Runtime
Runtime Level Listing
● At runtime, don’t know what scenes exist
● EditorBuildSettings has a list
● Lets steal it

33. Runtime
Runtime Level Listing
● AssetModificationProcessor for
EditorBuildSettings.asset
● Copy EditorBuildSettings.scenes to a
ScriptableObject in Resources
● Add any custom data in the list

34. Runtime
Runtime Level Listing
Demo

35. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Serialization
Assets
Runtime
Reflection

36. Reflection
Reflection Primer
● Information about all Assemblies and Types
● Get a list of all types
● List all functions in a type - Public or Private!
● Call functions, set fields

37. Reflection
Developer Debug Options
● API Design - If it is public, they will call it
● Attach to your API with reflection
● Debugging
● Testing

38. Reflection
Call Editor Code from Game
● If building DLLs, can’t use UnityEditor in
game code
● SelectGameObjectInHierarchy
● Call your own editor code
● EDITOR ONLY!

39. Reflection
Call Editor Code from Game

40. Reflection
Call Editor Code from Game
Demo calling editor code from runtime

41. Reflection
Use Private APIs
● Unity exposes a lot out of the box
● Much more to explore
● Browse with ILSpy or Reflector

42. Reflection
Use Private APIs
● Open any editor window; issue commands
● Take control of the window layout
● “Borrow” editor assets
● Tons of private calls waiting to be explored

43. Reflection
Use Private APIs

44. Reflection
Use Private APIs

45. Reflection
Use Private APIs

46. Reflection
Use Private APIs
Demo window layout

48. The Hack Spectrum:
Tips, Tricks, and Hacks for Unity
Ryan Hipple
Senior Engineer
Schell Games
@roboryantron