What is Entry.SetComponent()?

[setanarut]

There are no examples in the documentation. Can you explain with an example what the usage of Entry.SetComponent() is?

[yohamta]

Hello, it's equivalent to the donburi.Set() method.

donburi/entry.go

Lines 44 to 47 in 680901d

	// Set sets the comopnent of the entry.
	func Set[T any](e *Entry, c component.IComponentType, component *T) {
	e.SetComponent(c, unsafe.Pointer(component))
	}

[setanarut]

What does 'Set' mean and how is it different from adding and removing components? I really don't understand. Example please?

[yohamta]

Here's the example. It doesn't add or remove component, but update the pointer to the data.

// Component is any struct that holds some kind of data.
type PositionData struct {
  X, Y float64
}

// ComponentType represents kind of component which is used to create or query entities.
var Position = donburi.NewComponentType[PositionData]()

// Create an entity by specifying components that the entity will have.
// Component data will be initialized by default value of the struct.
entity = world.Create(Position, Velocity)

// We can use entity (it's a wrapper of int64) to get an Entry object from World
// which allows you to access the components that belong to the entity.
entry := world.Entry(entity)

entry.Set(Position, unsafe.Pointer(&PositionData{
  X: 100, Y: 200,
})

[setanarut]

Looks the same as component.Set(). Am I wrong?

[yohamta]

Your understanding is absolutely right. It's the same as the comopnent.Set().

[setanarut]

Thanks