EgoComponents and Component Queries

At the start of the game, EgoCS makes sure that every GameObject has an attached EgoComponent.

A GameObject's EgoComponent uses a bitmask to keep track of attached components, and saves you from writing multiple GetComponent<C>() checks. This also makes querying attached Components super fast.

You can query if the GameObject has one or more Components attached using HasComponents<...>(), where the type parameters are Component types:

var egoComponent = gameObject.GetComponent<EgoComponent>();

// One Component
if( egoComponent.HasComponents<Rigidbody>() )
{
    // ...
}

// Multiple Components
if( egoComponent.HasComponents<Rigidbody, BoxCollider, ExampleComponent>() )
{
    // ...
}

When you pass multiple Component types into HasComponents<...>(), it will only return true if all of the specified Component types are attached to the GameObject.

You can check if a GameObject has certain Components and get references to them if it does, all in one shot using TryGetComponents<...>():

var egoComponent = gameObject.GetComponent<EgoComponent>();

Rigidbody rigidbody;
BoxCollider boxCollider;
Example example;

// One Component
if( egoComponent.TryGetComponents( out rigidbody ) )
{
    rigidbody.AddForce( Vector3.up );
}

// Multiple Components
if( egoComponent.TryGetComponents( out rigidbody, out boxCollider, out example ) )
{
    rigidbody.AddForce( Vector3.down );
    
    // ...
}

You don't need to specify the type parameters for TryGetComponents<...>() since the compiler can infer them from the function parameters.

Like with HasComponents<...>(), TryGetComponents<...>() will only return true, and send out Component references if all of the specified Component types are attached to the GameObject.

For now, HasComponents<...>() and TryGetComponents<...>() only support querying up to 5 Component types at once. This limit will be increased soon.

These methods are especially useful for collision detection, as they let you quickly and easily filter out undesired GameObjects:

// Let's say we're making a Breakout clone:
public class BallCollisionSystem : EgoSystem
{
    public override void Start()
    {
        EgoEvents<CollisionEnterEvent>.AddHandler( Handle );
    }

    // Here, we're detecting when the Ball hits a Brick
    void Handle( CollisionEnterEvent e )
    {
        if( e.egoComponent1.HasComponents<Brick>() && e.egoComponent2.HasComponents<Ball>() )
        {
            // The first colliding GameObject is a brick
            DestroyBrick( e.egoComponent1 );
        }
        else if( e.egoComponent1.HasComponents<Ball>() && e.egoComponent2.HasComponents<Brick>() )
        {
            // The second colliding GameObject is a brick
            DestroyBrick( e.egoComponent2 );
        }
    }

    void DestroyBrick( EgoComponent brickEgoComponent )
    {
        // ...
    }
}