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LuaSystem

System that executes lua scripts, either at a global scale or attached to a GameObject through a LuaComponent.

Members

Constructor

The constructor automatically defines the following functions for lua scripts:

  • getGameObjects(): returns all the GameObjects currently in existence.
  • createEntity(string type, string name)
  • removeEntity(string name)
  • getEntity(string name)
  • hasEntity(string name)
  • getDeltaTime()
  • getFixedDeltaTime()
  • getDeltaFrames()
  • stopRunning()

The GameObject type is also registered.

Scripts attached to GameObjects can use the self global variable to access the GameObject they are attached to.

/!\

Calling createEntity or removeEntity from a script attached to a GameObject will result in the entity being created or remove only at the end of the current frame. This is necessary to avoid memory corruption errors, as the newly created entities could invalidate iterators in the collection of entities being currently iterated on by the LuaSystem.

If a "scripts" directory is found, addScriptDirectory("scripts") is called.

registerType
template<typename T>
void registerType() noexcept;

Registers the Reflectible type T with the underlying lua state.

This allows lua scripts to access any attribute or method in T's Reflectible API.

This also defines the following function for lua scripts:

  • sendT(T packet) (e.g. sendLog(Log packet)): sends packet as a datapacket to all Systems

If T is a Component, the following member functions is added to the GameObject lua type for lua scripts:

  • getT() (e.g. getMetaComponent())
  • hasT() (e.g. hasMetaComponent())
  • attachT() (e.g. attachMetaComponent())
  • detachT() (e.g. detachMetaComponent())

A global getGameObjectsWithT() is also defined, that returns all the GameObjects with a T component.

This allows lua scripts to perform any operation on GameObjects if the necessary types are registered. Client code can either give full access to lua scripts by registering all its types (and therefore having a fully extensible game that can be developed almost entirely in lua), or only register a small set of types and/or members, to restrict what modders can do.

registerTypes
template<typename ...Types>
void registerTypes() noexcept;

For each type in Types, call registerType for it.

addScriptDirectory
void addScriptDirectory(std::string_view dir) noexcept;

Adds dir as one of the directories in which to execute lua scripts. Each frame, all the files in dir will be interpreted as lua scripts and executed.