Code archives/Miscellaneous/Component-Object Entity System

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Component-Object Entity System by Nilium
(Posted 21 years ago)
If you can't figure out what this does after looking it over, chances are you probably don't need it. In general, this is a concept that has been proven to be very powerful in the past.

Edit: Crap, wrong extension. That thing should really be changeable through the edit thing. 
Strict


Private

Const COM_UNKNOWN% = -1
Global maxCName%=0


Public

Function RegisterComponentName%( name% )
    name = Abs(name)+1
    If name > maxCName Then maxCName = name
    Return name
End Function

Type IComponent
    Field _disposed% = 0
    Field _link:TLink
    Field _name% = COM_UNKNOWN
    
    Method Update( go:IGameObject ) Abstract
    
    Method Dispose( )
        Assert _disposed=0, "Component is already disposed"
        _disposed = 1
        _name = COM_UNKNOWN
    End Method
End Type

Type IGameObject
    Field _components:IComponent[]
    
    Method New( )
        _components = New IComponent[maxCName]
    End Method
    
    'private - check components array length (and expand if neccessary -- it can only ever expand unless you modify it manually)
    Method CheckCLength( )
        If _components.Length <> maxCName Then..
            _components = _components[..maxCName]
    End Method
    
    Method GetComponent:IComponent( name% )
        If name = COM_UNKNOWN Then Return Null
        If name > _components.Length-1 Then Return Null ' It's obviously not going to have it then
        Return _components[name]
    End Method
    
    ' Components have to be added in the correct order, DO NOT FORGET THIS
    Method AddComponent( c:IComponent )
        If c._name = COM_UNKNOWN Or c._link Then Return ' We don't want to add a used or disposed/unknown component
        If GetComponent( c._name ) Then Return ' And we don't want two of the same component
        CheckCLength( )
        _components[c._name] = c
    End Method
    
    Method RemoveComponent( name% )
        If name = COM_UNKNOWN Then Return
        Local c:IComponent = GetComponent( name )
        If c Then c.Dispose( )
    End Method
    
    Method Update( )
        For Local i:Int = 0 To _components.Length-1
            If _components[i] Then _components[i].Update( Self )
        Next
    End Method
End Type