Flecs v3.2
A fast entity component system (ECS) for C & C++
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Getting & Setting

Functions for getting/setting components. More...

Collaboration diagram for Getting & Setting:

Functions

const void * ecs_get_id (const ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Get an immutable pointer to a component.
 
ecs_ref_t ecs_ref_init_id (const ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Create a component ref.
 
void * ecs_ref_get_id (const ecs_world_t *world, ecs_ref_t *ref, ecs_id_t id)
 Get component from ref.
 
void ecs_ref_update (const ecs_world_t *world, ecs_ref_t *ref)
 Update ref.
 
void * ecs_get_mut_id (ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Get a mutable pointer to a component.
 
void * ecs_get_mut_modified_id (ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Combines get_mut + modified in single operation.
 
ecs_record_tecs_write_begin (ecs_world_t *world, ecs_entity_t entity)
 Begin exclusive write access to entity.
 
void ecs_write_end (ecs_record_t *record)
 End exclusive write access to entity.
 
const ecs_record_tecs_read_begin (ecs_world_t *world, ecs_entity_t entity)
 Begin read access to entity.
 
void ecs_read_end (const ecs_record_t *record)
 End read access to entity.
 
ecs_entity_t ecs_record_get_entity (const ecs_record_t *record)
 Get entity corresponding with record.
 
const void * ecs_record_get_id (const ecs_world_t *world, const ecs_record_t *record, ecs_id_t id)
 Get component from entity record.
 
void * ecs_record_get_mut_id (ecs_world_t *world, ecs_record_t *record, ecs_id_t id)
 Same as ecs_record_get_id(), but returns a mutable pointer.
 
bool ecs_record_has_id (ecs_world_t *world, const ecs_record_t *record, ecs_id_t id)
 Test if entity for record has component.
 
void * ecs_emplace_id (ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Emplace a component.
 
void ecs_modified_id (ecs_world_t *world, ecs_entity_t entity, ecs_id_t id)
 Signal that a component has been modified.
 
ecs_entity_t ecs_set_id (ecs_world_t *world, ecs_entity_t entity, ecs_id_t id, size_t size, const void *ptr)
 Set the value of a component.
 

Detailed Description

Functions for getting/setting components.

Function Documentation

◆ ecs_emplace_id()

void * ecs_emplace_id ( ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Emplace a component.

Emplace is similar to ecs_get_mut_id() except that the component constructor is not invoked for the returned pointer, allowing the component to be "constructed" directly in the storage.

Emplace can only be used if the entity does not yet have the component. If the entity has the component, the operation will fail.

Parameters
worldThe world.
entityThe entity.
idThe component to obtain.
Returns
The (uninitialized) component pointer.

◆ ecs_get_id()

const void * ecs_get_id ( const ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Get an immutable pointer to a component.

This operation obtains a const pointer to the requested component. The operation accepts the component entity id.

Parameters
worldThe world.
entityThe entity.
idThe id of the component to get.
Returns
The component pointer, NULL if the entity does not have the component.

◆ ecs_get_mut_id()

void * ecs_get_mut_id ( ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Get a mutable pointer to a component.

This operation returns a mutable pointer to a component. If the component did not yet exist, it will be added.

If get_mut is called when the world is in deferred/readonly mode, the function will:

  • return a pointer to a temp storage if the component does not yet exist, or
  • return a pointer to the existing component if it exists
Parameters
worldThe world.
entityThe entity.
idThe entity id of the component to obtain.
Returns
The component pointer.

◆ ecs_get_mut_modified_id()

void * ecs_get_mut_modified_id ( ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Combines get_mut + modified in single operation.

This operation is a more efficient alternative to calling ecs_get_mut_id() and ecs_modified_id() separately. This operation is only valid when the world is in deferred mode, which ensures that the Modified event is not emitted before the modification takes place.

Parameters
worldThe world.
entityThe entity.
idThe id of the component to obtain.
Returns
The component pointer.

◆ ecs_modified_id()

void ecs_modified_id ( ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Signal that a component has been modified.

This operation is usually used after modifying a component value obtained by ecs_get_mut_id(). The operation will mark the component as dirty, and invoke OnSet observers and hooks.

Parameters
worldThe world.
entityThe entity.
idThe id of the component that was modified.

◆ ecs_read_begin()

const ecs_record_t * ecs_read_begin ( ecs_world_t * world,
ecs_entity_t entity )

Begin read access to entity.

This operation provides safe read access to the components of an entity. Multiple simultaneous reads are allowed per entity.

This operation ensures that code attempting to mutate the entity's table will throw an assert. Note that for this to happen, asserts must be enabled. It is up to the application to ensure that this does not happen, for example by using a read-write mutex.

This operation does not provide the same guarantees as a read-write mutex, as it is possible to call ecs_read_begin() after calling ecs_write_begin(). It is up to application has to ensure that this does not happen.

This operation must be followed up with ecs_read_end().

Parameters
worldThe world.
entityThe entity.
Returns
A record to the entity.

◆ ecs_read_end()

void ecs_read_end ( const ecs_record_t * record)

End read access to entity.

This operation ends read access, and must be called after ecs_read_begin().

Parameters
recordRecord to the entity.

◆ ecs_record_get_entity()

ecs_entity_t ecs_record_get_entity ( const ecs_record_t * record)

Get entity corresponding with record.

This operation only works for entities that are not empty.

Parameters
recordThe record for which to obtain the entity id.

◆ ecs_record_get_id()

const void * ecs_record_get_id ( const ecs_world_t * world,
const ecs_record_t * record,
ecs_id_t id )

Get component from entity record.

This operation returns a pointer to a component for the entity associated with the provided record. For safe access to the component, obtain the record with ecs_read_begin() or ecs_write_begin().

Obtaining a component from a record is faster than obtaining it from the entity handle, as it reduces the number of lookups required.

Parameters
worldThe world.
recordRecord to the entity.
idThe (component) id.
Returns
Pointer to component, or NULL if entity does not have the component.

◆ ecs_record_get_mut_id()

void * ecs_record_get_mut_id ( ecs_world_t * world,
ecs_record_t * record,
ecs_id_t id )

Same as ecs_record_get_id(), but returns a mutable pointer.

For safe access to the component, obtain the record with ecs_write_begin().

Parameters
worldThe world.
recordRecord to the entity.
idThe (component) id.
Returns
Pointer to component, or NULL if entity does not have the component.

◆ ecs_record_has_id()

bool ecs_record_has_id ( ecs_world_t * world,
const ecs_record_t * record,
ecs_id_t id )

Test if entity for record has component.

Parameters
worldThe world.
recordRecord to the entity.
idThe (component) id.

◆ ecs_ref_get_id()

void * ecs_ref_get_id ( const ecs_world_t * world,
ecs_ref_t * ref,
ecs_id_t id )

Get component from ref.

Get component pointer from ref. The ref must be created with ecs_ref_init().

Parameters
worldThe world.
refThe ref.
idThe component id.
Returns
The component pointer, NULL if the entity does not have the component.

◆ ecs_ref_init_id()

ecs_ref_t ecs_ref_init_id ( const ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id )

Create a component ref.

A ref is a handle to an entity + component which caches a small amount of data to reduce overhead of repeatedly accessing the component. Use ecs_ref_get() to get the component data.

Parameters
worldThe world.
entityThe entity.
idThe id of the component.
Returns
The reference.

◆ ecs_ref_update()

void ecs_ref_update ( const ecs_world_t * world,
ecs_ref_t * ref )

Update ref.

Ensures contents of ref are up to date. Same as ecs_ref_get_id(), but does not return pointer to component id.

Parameters
worldThe world.
refThe ref.

◆ ecs_set_id()

ecs_entity_t ecs_set_id ( ecs_world_t * world,
ecs_entity_t entity,
ecs_id_t id,
size_t size,
const void * ptr )

Set the value of a component.

This operation allows an application to set the value of a component. The operation is equivalent to calling ecs_get_mut_id() followed by ecs_modified_id(). The operation will not modify the value of the passed in component. If the component has a copy hook registered, it will be used to copy in the component.

If the provided entity is 0, a new entity will be created.

Parameters
worldThe world.
entityThe entity.
idThe id of the component to set.
sizeThe size of the pointed-to value.
ptrThe pointer to the value.
Returns
The entity. A new entity if no entity was provided.

◆ ecs_write_begin()

ecs_record_t * ecs_write_begin ( ecs_world_t * world,
ecs_entity_t entity )

Begin exclusive write access to entity.

This operation provides safe exclusive access to the components of an entity without the overhead of deferring operations.

When this operation is called simultaneously for the same entity more than once it will throw an assert. Note that for this to happen, asserts must be enabled. It is up to the application to ensure that access is exclusive, for example by using a read-write mutex.

Exclusive access is enforced at the table level, so only one entity can be exclusively accessed per table. The exclusive access check is thread safe.

This operation must be followed up with ecs_write_end().

Parameters
worldThe world.
entityThe entity.
Returns
A record to the entity.

◆ ecs_write_end()

void ecs_write_end ( ecs_record_t * record)

End exclusive write access to entity.

This operation ends exclusive access, and must be called after ecs_write_begin().

Parameters
recordRecord to the entity.