C++ reflection

Hush Engine contains a C++ reflection system that allows you to introspect and manipulate C++ (and scripting) objects at runtime. This is mostly useful for the editor. We encourage you to not rely on this system in your game code.

Introduction

Hush Engine’s reflection system is built around two main components: the runtime reflection system and the tooling to generate the reflection data. The runtime reflection system consists of a set of classes that allow you to introspect and manipulate C++ objects at runtime. The tooling is made up with Libtooling and annotations that allow you to generate the reflection data at compile time.

The reflection system only exposes the public members of a class, annotated member functions, and free functions. This means that you cannot use the reflection system to introspect non explicitly annotated members of a class.

The tooling also provides a serialization system that allows you to serialize and deserialize C++ objects to and from JSON. The serialization system is built around the rapidjson library.

Annotations

Annotations are used to mark classes, member functions, and free functions that should be included in the reflection system. Annotations use standard C++ attributes syntax to mark the members.

The following annotations are available: - [[hush::property]]: Marks a member function as a property. It also receives the following optional arguments:

• setter: The name of the setter function. If not provided and the member is public, a custom setter is generated.

• getter: The name of the getter function. If not provided and the member is public, a custom getter is generated.

• description: A description of the property. This is used for documentation purposes.

• [[hush::function]]: Marks a member function as a function. It also receives the following optional arguments:

  • description: A description of the function. This is used for documentation purposes.

  • command: If it is a free function that receives the editor as argument, this will be exposed as an editor command (docs TODO).

• [[hush::reflect]]: Marks a class as reflectable. It also receives the following optional arguments:

  • description: A description of the class. This is used for documentation purposes.