In Unreal Engine (UE), an event dispatcher is a mechanism that allows you to send events from one object or component to another. Events are messages that can be sent between objects in your UE scene, and they are used to communicate information about changes that have occurred in the scene.
What is an Event Dispatcher?
An event dispatcher is a special type of class in UE that is responsible for sending events to other objects in the scene. It is typically used by components or objects that need to communicate with other objects in order to update their state.
For example, if you have a character controller component that needs to notify an animation controller component when the character has completed an action, you can use an event dispatcher to send this information.
In UE, events are typically defined as classes that inherit from the UEvent class. This class provides the basic functionality for sending and receiving events. When you create a new event class, you can define any number of properties or methods that will be included in the event message.
These properties and methods are used to pass information about the event to the recipient object.
How does an Event Dispatcher Work?
When you want to send an event from one object or component to another, you can create an instance of the UEventDispatcher class and call its SendEvent() method with an instance of your custom event class as an argument.
The SendEvent() method will then create a new message based on the properties and methods defined in your custom event class, and it will send this message to all objects that have registered to receive events of this type.
To register to receive events, you can use the UClass::GetEvent() method to retrieve a reference to the event class, and then call its AddListener() method with a reference to your own object or component. When an event is sent, all objects that have registered as listeners will receive a message containing the event information.
In addition to sending events directly, you can also use event dispatchers to broadcast events to multiple objects at once. For example, if you have a group of objects that need to be notified when a certain condition is met, you can create an event dispatcher and register all of these objects as listeners.
Then, when the condition is met, you can call the SendEvent() method with an instance of your custom event class, and all registered listeners will receive the message.
Conclusion
In conclusion, an Unreal Engine event dispatcher is a powerful tool that allows you to communicate information between objects in your scene. By using events, you can create complex systems that respond to changes in the world around them. Whether you are building a character controller, an animation system, or something else entirely, events can help you create more dynamic and responsive systems.