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EntityControl Creation

EntityControl is a components in the game that defines what an Entity is and what it can do. It can be considered the building blocks of the game as it represents anything that is created and behaves at runtime.

CreateNewEntity

While there are multiple ways to create an entity, all of them ends up at the same method:

public static EntityControl CreateNewEntity(string name)

The name here has 2 purposes:

  • It will be the name of the root GameObject of the entity which can be useful for debugging purposes
  • It can contain some special strings called modifiers that changes how the entity behaves.

This method will create an object structure that is shared across every entities. While an entity can modify this structure later on, all of them starts the same way by default:

  • The root GameObject is created with its name being the name parameter and an EntityControl component is added to it
  • The transform of the root object is cached into the transform field
  • Another GameObject is created and childed to the root one called Rotater. This won't be assigned to anything until the entity's Start runs on the next frame where it is assigned to the rotater field.
  • Another GameObject is created and childed to the Rotater one called Sprite with a SpriteRender component. It is assigned to the sprite field and its transform into the spritetransform field.
  • Another GameObject is created and childed to the root one called "MoveRotater". It is assigned to the moverotater field.
  • A CapsuleCollider is added to the root object with radius 0.5, height of 2.0, center at (0.0. 1.0, 0.0) and assigned to the ccol field.
  • The layer of the entity is set to 10 which is the Entity layer.

This essentially gives us the following structure:

-> root (named after the name parameter, on the Entity layer)
    -> Rotater
        -> Sprite (has a SpriteRender)
    -> MoveRotater

And the following fields:

  • transform: the root's transform
  • rotater (on Start): the Rotater
  • sprite: the Sprite
  • spritetransform: the Sprite's transform
  • moverotater: the MoveRotater
  • ccol: the CapsuleCollider of the root

However, this is only the most primitive way to create an entity. There are 2 overloads of this method that accepts different parameters, but one is a helper to the other whose signature is the following:

public static EntityControl CreateNewEntity(string name, int anim_id, Vector3 position, EntityControl follow)

The name ends up doing the exact same thing than the primitive version as this method is a wrapper around it. What changes is the ability to specify an AnimID, a position and a follower:

  • anim_id: This is the AnimID of the entity and it is set to the animid field.
  • position: This sets the starting position of the entity's root transform.
  • follow: This parameter is optional because there is an overload that doesn't have it and it sends null to this method. If it is present, a follower is setup on the entity.

The follower is initialized like this when applicable:

  • The game tries to find the last entity of the follow chain. This is done by checking the entity's following field to go up the chain until it is null.
  • The entity found is set to the following field of the entity being created which puts it at the end of the chain.
  • The followeroffset field is set to the position (starting at 1) of the entity in the follow chain multiplied by 0.1.
  • The layer of the entity is overridden to 9 which the Follower layer
  • The tag of the entity is set to PFollower

OnEnable

The creation process doesn't stop there because EntityControl defines an OnEnable which is run immediately on creation OR whenever it gets enabled. This will do 2 things:

  • Do a SetAnim call with empty args and force to true which will force the animation to start on "Idle" as it's the default value of animstate.
  • If the emoticon object exists, it will be set to -1 (None) and its cooldown to 0 frames. Since an entity cannot have one on creation, this only applies when it gets enabled with one present later.

Map entities preset

On top of this, there is a system the game has that allows to define each entities's starting parameters for a map along with an NPCControl stored in npcdata. This data comes from the map entity data and is done by MapControl's CreateEntities which happens on its Start.