Each iterator

Collaboration diagram for Each iterator:

Functions
ecs_iter_t	ecs_each_id (const ecs_world_t *world, ecs_id_t component)
	Iterate all entities with a specified (component ID).
bool	ecs_each_next (ecs_iter_t *it)
	Progress an iterator created with ecs_each_id().
ecs_iter_t	ecs_children (const ecs_world_t *world, ecs_entity_t parent)
	Iterate children of a parent.
ecs_iter_t	ecs_children_w_rel (const ecs_world_t *world, ecs_entity_t relationship, ecs_entity_t parent)
	Same as ecs_children(), but with a custom relationship argument.
bool	ecs_children_next (ecs_iter_t *it)
	Progress an iterator created with ecs_children().

Detailed Description

Find all entities that have a single (component) ID.

Function Documentation

ecs_children()

ecs_iter_t ecs_children	(	const ecs_world_t *	world,
		ecs_entity_t	parent )

Iterate children of a parent.

This operation is usually equivalent to doing:

ecs_iter_t it = ecs_each_id(world, ecs_pair(EcsChildOf, parent));

The only exception is when the parent has the EcsOrderedChildren trait, in which case this operation will return a single result with the ordered child entity IDs.

This operation is equivalent to doing:

ecs_children_w_rel(world, EcsChildOf, parent);

Parameters

world	The world.
parent	The parent.

Returns

An iterator that iterates all children of the parent.

See also

ecs_each_id()

ecs_children_next()

bool ecs_children_next

(

ecs_iter_t *

it

)

Progress an iterator created with ecs_children().

Parameters

it	The iterator.

Returns

True if the iterator has more results, false if not.

ecs_children_w_rel()

ecs_iter_t ecs_children_w_rel	(	const ecs_world_t *	world,
		ecs_entity_t	relationship,
		ecs_entity_t	parent )

Same as ecs_children(), but with a custom relationship argument.

Parameters

world	The world.
relationship	The relationship.
parent	The parent.

Returns

An iterator that iterates all children of the parent.

ecs_each_id()

ecs_iter_t ecs_each_id	(	const ecs_world_t *	world,
		ecs_id_t	component )

Iterate all entities with a specified (component ID).

This returns an iterator that yields all entities with a single specified component. This is a much lighter-weight operation than creating and iterating a query.

Usage:

ecs_iter_t it = ecs_each(world, Player);
while (ecs_each_next(&it)) {
  for (int i = 0; i < it.count; i ++) {
    // Iterate as usual.
  }
}

If the specified ID is a component, it is possible to access the component pointer with ecs_field() just like with regular queries:

ecs_iter_t it = ecs_each(world, Position);
while (ecs_each_next(&it)) {
  Position *p = ecs_field(&it, Position, 0);
  for (int i = 0; i < it.count; i ++) {
    // Iterate as usual.
  }
}

Parameters

world	The world.
component	The component to iterate.

Returns

An iterator that iterates all entities with the (component) ID.

ecs_each_next()

bool ecs_each_next

(

ecs_iter_t *

it

)

Progress an iterator created with ecs_each_id().

Parameters

it	The iterator.

Returns

True if the iterator has more results, false if not.