Observers

Functions for working with events and observers. More...

Collaboration diagram for Observers:

Classes
struct	ecs_observer_desc_t
	Used with ecs_observer_init(). More...
struct	ecs_event_desc_t
	Used with ecs_emit(). More...

Typedefs
typedef struct ecs_observer_desc_t	ecs_observer_desc_t
	Used with ecs_observer_init().
typedef struct ecs_event_desc_t	ecs_event_desc_t
	Used with ecs_emit().

Functions
void	ecs_emit (ecs_world_t *world, ecs_event_desc_t *desc)
	Send an event.
void	ecs_enqueue (ecs_world_t *world, ecs_event_desc_t *desc)
	Enqueue an event.
ecs_entity_t	ecs_observer_init (ecs_world_t *world, const ecs_observer_desc_t *desc)
	Create an observer.
const ecs_observer_t *	ecs_observer_get (const ecs_world_t *world, ecs_entity_t observer)
	Get the observer object.

Detailed Description

Functions for working with events and observers.

Function Documentation

ecs_emit()

void ecs_emit	(	ecs_world_t *	world,
		ecs_event_desc_t *	desc )

Send an event.

This sends an event to matching observers and is the mechanism used by Flecs itself to send OnAdd, OnRemove, etc. events.

Applications can use this function to send custom events, where a custom event can be any regular entity.

Applications should not send built-in Flecs events, as this may violate assumptions the code makes about the conditions under which those events are sent.

Observers are invoked synchronously. It is therefore safe to use stack-based data as event context, which can be set in the "param" member.

Parameters

world	The world.
desc	The event parameters.

See also

ecs_enqueue()

ecs_enqueue()

void ecs_enqueue	(	ecs_world_t *	world,
		ecs_event_desc_t *	desc )

Enqueue an event.

Same as ecs_emit(), but enqueues an event in the command queue instead. The event will be emitted when ecs_defer_end() is called.

If this operation is called when the provided world is not in deferred mode, it behaves just like ecs_emit().

Parameters

world	The world.
desc	The event parameters.

ecs_observer_get()

const ecs_observer_t * ecs_observer_get	(	const ecs_world_t *	world,
		ecs_entity_t	observer )

Get the observer object.

Return the observer object. Can be used to access various information about the observer, like the query and context.

Parameters

world	The world.
observer	The observer.

Returns

The observer object.

ecs_observer_init()

ecs_entity_t ecs_observer_init	(	ecs_world_t *	world,
		const ecs_observer_desc_t *	desc )

Create an observer.

Observers can subscribe for one or more terms. An observer only triggers when the source of the event meets all terms.

See the documentation for ecs_observer_desc_t for more details.

Parameters

world	The world.
desc	The observer creation parameters.

Returns

The observer, or 0 if the operation failed.