Struct FilteredEntityMut 

pub struct FilteredEntityMut<'w, 's> { /* private fields */ }

Provides mutable access to a single entity and some of its components defined by the contained Access.

To define the access when used as a QueryData, use a QueryBuilder or QueryParamBuilder. The FilteredEntityMut must be the entire QueryData, and not nested inside a tuple with other data.

// This gives the `FilteredEntityMut` access to `&mut A`.
let mut query = QueryBuilder::<FilteredEntityMut>::new(&mut world)
    .data::<&mut A>()
    .build();

let mut filtered_entity: FilteredEntityMut = query.single_mut(&mut world).unwrap();
let component: Mut<A> = filtered_entity.get_mut().unwrap();

Also see UnsafeFilteredEntityMut for a way to bypass borrow-checker restrictions.

Implementations

impl<'w, 's> FilteredEntityMut<'w, 's>

pub fn reborrow(&mut self) -> FilteredEntityMut<'_, 's>

Returns a new instance with a shorter lifetime. This is useful if you have &mut FilteredEntityMut, but you need FilteredEntityMut.

pub fn into_readonly(self) -> FilteredEntityRef<'w, 's>

Consumes self and returns read-only access to all of the entity’s components, with the world 'w lifetime.

pub fn as_readonly(&self) -> FilteredEntityRef<'_, 's>

Gets read-only access to all of the entity’s components.

pub fn try_into_all(self) -> Result<EntityMut<'w>, TryFromFilteredError>

Consumes self and returns mutable access to the entity and all of its components, with the world 'w lifetime. Returns an error if the access does not include read and write access to all components.

Errors

• TryFromFilteredError::MissingReadAllAccess - if the access does not include read access to all components.
• TryFromFilteredError::MissingWriteAllAccess - if the access does not include write access to all components.

pub fn as_unsafe_entity_cell(&mut self) -> UnsafeEntityCell<'_>

Get access to the underlying UnsafeEntityCell.

pub fn id(&self) -> Entity

Returns the ID of the current entity.

Examples found in repository

examples/ecs/dynamic.rs (line 212)

fn main() {
    let mut world = World::new();
    let mut lines = std::io::stdin().lines();
    let mut component_names = HashMap::<String, ComponentId>::new();
    let mut component_info = HashMap::<ComponentId, ComponentInfo>::new();
    let mut event_names = HashMap::<String, EventKey>::new();

    println!("{PROMPT}");
    loop {
        print!("\n> ");
        let _ = std::io::stdout().flush();
        let Some(Ok(line)) = lines.next() else {
            return;
        };

        if line.is_empty() {
            return;
        };

        let Some((first, rest)) = line.trim().split_once(|c: char| c.is_whitespace()) else {
            match &line.chars().next() {
                Some('c') => println!("{COMPONENT_PROMPT}"),
                Some('s') => println!("{ENTITY_PROMPT}"),
                Some('q') => println!("{QUERY_PROMPT}"),
                Some('e') => println!("{EVENT_PROMPT}"),
                Some('t') => println!("{EMIT_PROMPT}"),
                _ => println!("{PROMPT}"),
            }
            continue;
        };

        match &first[0..1] {
            "c" => {
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };
                    let size = match component.next().map(str::parse) {
                        Some(Ok(size)) => size,
                        _ => 0,
                    };
                    // Register our new component to the world with a layout specified by it's size
                    // SAFETY: [u64] is Send + Sync
                    let id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            name.to_string(),
                            StorageType::Table,
                            Layout::array::<u64>(size).unwrap(),
                            None,
                            true,
                            ComponentCloneBehavior::Default,
                            None,
                        )
                    });
                    let Some(info) = world.components().get_info(id) else {
                        return;
                    };
                    component_names.insert(name.to_string(), id);
                    component_info.insert(id, info.clone());
                    println!("Component {} created with id: {}", name, id.index());
                });
            }
            "s" => {
                let mut to_insert_ids = Vec::new();
                let mut to_insert_data = Vec::new();
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };

                    // Get the id for the component with the given name
                    let Some(&id) = component_names.get(name) else {
                        println!("Component {name} does not exist");
                        return;
                    };

                    // Calculate the length for the array based on the layout created for this component id
                    let info = world.components().get_info(id).unwrap();
                    let len = info.layout().size() / size_of::<u64>();
                    let mut values: Vec<u64> = component
                        .take(len)
                        .filter_map(|value| value.parse::<u64>().ok())
                        .collect();
                    values.resize(len, 0);

                    // Collect the id and array to be inserted onto our entity
                    to_insert_ids.push(id);
                    to_insert_data.push(values);
                });

                let mut entity = world.spawn_empty();

                // Construct an `OwningPtr` for each component in `to_insert_data`
                let to_insert_ptr = to_owning_ptrs(&mut to_insert_data);

                // SAFETY:
                // - Component ids have been taken from the same world
                // - Each array is created to the layout specified in the world
                unsafe {
                    entity.insert_by_ids(&to_insert_ids, to_insert_ptr.into_iter());
                }

                println!("Entity spawned with id: {}", entity.id());
            }
            "q" => {
                let mut builder = QueryBuilder::<FilteredEntityMut>::new(&mut world);
                parse_query(rest, &mut builder, &component_names);
                let mut query = builder.build();
                query.iter_mut(&mut world).for_each(|filtered_entity| {
                    let terms = filtered_entity
                        .access()
                        .try_iter_access()
                        .unwrap()
                        .map(|component_access| {
                            let id = *component_access.index();
                            let ptr = filtered_entity.get_by_id(id).unwrap();
                            let info = component_info.get(&id).unwrap();
                            let len = info.layout().size() / size_of::<u64>();

                            // SAFETY:
                            // - All components are created with layout [u64]
                            // - len is calculated from the component descriptor
                            let data = unsafe {
                                std::slice::from_raw_parts_mut(
                                    ptr.assert_unique().as_ptr().cast::<u64>(),
                                    len,
                                )
                            };

                            // If we have write access, increment each value once
                            if matches!(component_access, ComponentAccessKind::Exclusive(_)) {
                                data.iter_mut().for_each(|data| {
                                    *data += 1;
                                });
                            }

                            format!("{}: {:?}", info.name(), data[0..len].to_vec())
                        })
                        .collect::<Vec<_>>()
                        .join(", ");

                    println!("{}: {}", filtered_entity.id(), terms);
                });
            }
            "e" => {
                rest.split(',').for_each(|event| {
                    let name = event.trim();
                    if name.is_empty() {
                        return;
                    }

                    // Register a ComponentId for this event, no Rust type needed.
                    // SAFETY: ZST with no drop
                    let event_component_id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            format!("event:{name}"),
                            StorageType::Table,
                            Layout::new::<()>(),
                            None,
                            false,
                            ComponentCloneBehavior::Ignore,
                            None,
                        )
                    });
                    // SAFETY: event_component_id was just registered for this event
                    let event_key = unsafe { EventKey::new(event_component_id) };
                    event_names.insert(name.to_string(), event_key);

                    // Build a dynamic observer that prints when the event fires.
                    let runner: ObserverRunner = |mut world, _observer, ctx, _event, _trigger| {
                        println!("  Observer fired!");
                        if let Some(mut counts) = world.get_resource_mut::<EventFireCount>() {
                            *counts.0.entry(ctx.event_key).or_insert(0) += 1;
                        }
                    };

                    // SAFETY: event_key was just registered, runner ignores pointers
                    let observer =
                        unsafe { Observer::with_dynamic_runner(runner).with_event_key(event_key) };
                    world.spawn(observer);

                    println!(
                        "Event '{name}' registered (key: {}) with a dynamic observer",
                        event_component_id.index()
                    );
                });

                // Ensure the counter resource exists.
                world.init_resource::<EventFireCount>();
            }
            "t" => {
                let name = rest.trim();
                let Some(&event_key) = event_names.get(name) else {
                    println!(
                        "Event '{name}' does not exist. Register it first with 'event {name}'"
                    );
                    continue;
                };

                let mut event_data = ();
                let mut trigger_data = ();
                // SAFETY: event_key was registered in this world, both pointers are valid ZSTs
                unsafe {
                    world.trigger_dynamic(
                        event_key,
                        PtrMut::from(&mut event_data),
                        PtrMut::from(&mut trigger_data),
                    );
                }

                let count = world
                    .get_resource::<EventFireCount>()
                    .map_or(0, |c| c.0.get(&event_key).copied().unwrap_or(0));
                println!("Event '{name}' triggered ({count} fires)");
            }
            _ => continue,
        }
    }
}

pub fn location(&self) -> EntityLocation

Gets metadata indicating the location where the current entity is stored.

pub fn archetype(&self) -> &Archetype

Returns the archetype that the current entity belongs to.

pub fn access(&self) -> &Access

Returns a reference to the underlying Access.

Examples found in repository

examples/ecs/dynamic.rs (line 181)

fn main() {
    let mut world = World::new();
    let mut lines = std::io::stdin().lines();
    let mut component_names = HashMap::<String, ComponentId>::new();
    let mut component_info = HashMap::<ComponentId, ComponentInfo>::new();
    let mut event_names = HashMap::<String, EventKey>::new();

    println!("{PROMPT}");
    loop {
        print!("\n> ");
        let _ = std::io::stdout().flush();
        let Some(Ok(line)) = lines.next() else {
            return;
        };

        if line.is_empty() {
            return;
        };

        let Some((first, rest)) = line.trim().split_once(|c: char| c.is_whitespace()) else {
            match &line.chars().next() {
                Some('c') => println!("{COMPONENT_PROMPT}"),
                Some('s') => println!("{ENTITY_PROMPT}"),
                Some('q') => println!("{QUERY_PROMPT}"),
                Some('e') => println!("{EVENT_PROMPT}"),
                Some('t') => println!("{EMIT_PROMPT}"),
                _ => println!("{PROMPT}"),
            }
            continue;
        };

        match &first[0..1] {
            "c" => {
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };
                    let size = match component.next().map(str::parse) {
                        Some(Ok(size)) => size,
                        _ => 0,
                    };
                    // Register our new component to the world with a layout specified by it's size
                    // SAFETY: [u64] is Send + Sync
                    let id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            name.to_string(),
                            StorageType::Table,
                            Layout::array::<u64>(size).unwrap(),
                            None,
                            true,
                            ComponentCloneBehavior::Default,
                            None,
                        )
                    });
                    let Some(info) = world.components().get_info(id) else {
                        return;
                    };
                    component_names.insert(name.to_string(), id);
                    component_info.insert(id, info.clone());
                    println!("Component {} created with id: {}", name, id.index());
                });
            }
            "s" => {
                let mut to_insert_ids = Vec::new();
                let mut to_insert_data = Vec::new();
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };

                    // Get the id for the component with the given name
                    let Some(&id) = component_names.get(name) else {
                        println!("Component {name} does not exist");
                        return;
                    };

                    // Calculate the length for the array based on the layout created for this component id
                    let info = world.components().get_info(id).unwrap();
                    let len = info.layout().size() / size_of::<u64>();
                    let mut values: Vec<u64> = component
                        .take(len)
                        .filter_map(|value| value.parse::<u64>().ok())
                        .collect();
                    values.resize(len, 0);

                    // Collect the id and array to be inserted onto our entity
                    to_insert_ids.push(id);
                    to_insert_data.push(values);
                });

                let mut entity = world.spawn_empty();

                // Construct an `OwningPtr` for each component in `to_insert_data`
                let to_insert_ptr = to_owning_ptrs(&mut to_insert_data);

                // SAFETY:
                // - Component ids have been taken from the same world
                // - Each array is created to the layout specified in the world
                unsafe {
                    entity.insert_by_ids(&to_insert_ids, to_insert_ptr.into_iter());
                }

                println!("Entity spawned with id: {}", entity.id());
            }
            "q" => {
                let mut builder = QueryBuilder::<FilteredEntityMut>::new(&mut world);
                parse_query(rest, &mut builder, &component_names);
                let mut query = builder.build();
                query.iter_mut(&mut world).for_each(|filtered_entity| {
                    let terms = filtered_entity
                        .access()
                        .try_iter_access()
                        .unwrap()
                        .map(|component_access| {
                            let id = *component_access.index();
                            let ptr = filtered_entity.get_by_id(id).unwrap();
                            let info = component_info.get(&id).unwrap();
                            let len = info.layout().size() / size_of::<u64>();

                            // SAFETY:
                            // - All components are created with layout [u64]
                            // - len is calculated from the component descriptor
                            let data = unsafe {
                                std::slice::from_raw_parts_mut(
                                    ptr.assert_unique().as_ptr().cast::<u64>(),
                                    len,
                                )
                            };

                            // If we have write access, increment each value once
                            if matches!(component_access, ComponentAccessKind::Exclusive(_)) {
                                data.iter_mut().for_each(|data| {
                                    *data += 1;
                                });
                            }

                            format!("{}: {:?}", info.name(), data[0..len].to_vec())
                        })
                        .collect::<Vec<_>>()
                        .join(", ");

                    println!("{}: {}", filtered_entity.id(), terms);
                });
            }
            "e" => {
                rest.split(',').for_each(|event| {
                    let name = event.trim();
                    if name.is_empty() {
                        return;
                    }

                    // Register a ComponentId for this event, no Rust type needed.
                    // SAFETY: ZST with no drop
                    let event_component_id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            format!("event:{name}"),
                            StorageType::Table,
                            Layout::new::<()>(),
                            None,
                            false,
                            ComponentCloneBehavior::Ignore,
                            None,
                        )
                    });
                    // SAFETY: event_component_id was just registered for this event
                    let event_key = unsafe { EventKey::new(event_component_id) };
                    event_names.insert(name.to_string(), event_key);

                    // Build a dynamic observer that prints when the event fires.
                    let runner: ObserverRunner = |mut world, _observer, ctx, _event, _trigger| {
                        println!("  Observer fired!");
                        if let Some(mut counts) = world.get_resource_mut::<EventFireCount>() {
                            *counts.0.entry(ctx.event_key).or_insert(0) += 1;
                        }
                    };

                    // SAFETY: event_key was just registered, runner ignores pointers
                    let observer =
                        unsafe { Observer::with_dynamic_runner(runner).with_event_key(event_key) };
                    world.spawn(observer);

                    println!(
                        "Event '{name}' registered (key: {}) with a dynamic observer",
                        event_component_id.index()
                    );
                });

                // Ensure the counter resource exists.
                world.init_resource::<EventFireCount>();
            }
            "t" => {
                let name = rest.trim();
                let Some(&event_key) = event_names.get(name) else {
                    println!(
                        "Event '{name}' does not exist. Register it first with 'event {name}'"
                    );
                    continue;
                };

                let mut event_data = ();
                let mut trigger_data = ();
                // SAFETY: event_key was registered in this world, both pointers are valid ZSTs
                unsafe {
                    world.trigger_dynamic(
                        event_key,
                        PtrMut::from(&mut event_data),
                        PtrMut::from(&mut trigger_data),
                    );
                }

                let count = world
                    .get_resource::<EventFireCount>()
                    .map_or(0, |c| c.0.get(&event_key).copied().unwrap_or(0));
                println!("Event '{name}' triggered ({count} fires)");
            }
            _ => continue,
        }
    }
}

pub fn contains<T>(&self) -> bool

where T: Component,

Returns true if the current entity has a component of type T. Otherwise, this returns false.

Notes

If you do not know the concrete type of a component, consider using Self::contains_id or Self::contains_type_id.

pub fn contains_id(&self, component_id: ComponentId) -> bool

Returns true if the current entity has a component identified by component_id. Otherwise, this returns false.

Notes

• If you know the concrete type of the component, you should prefer Self::contains.
• If you know the component’s TypeId but not its ComponentId, consider using Self::contains_type_id.

pub fn contains_type_id(&self, type_id: TypeId) -> bool

Returns true if the current entity has a component with the type identified by type_id. Otherwise, this returns false.

Notes

• If you know the concrete type of the component, you should prefer Self::contains.
• If you have a ComponentId instead of a TypeId, consider using Self::contains_id.

pub fn get<T>(&self) -> Option<&T>

where T: Component,

Gets access to the component of type T for the current entity. Returns None if the entity does not have a component of type T.

pub fn get_ref<T>(&self) -> Option<Ref<'_, T>>

where T: Component,

Gets access to the component of type T for the current entity, including change detection information as a Ref.

Returns None if the entity does not have a component of type T.

pub fn get_mut<T>(&mut self) -> Option<Mut<'_, T>>

where T: Component<Mutability = Mutable>,

Gets mutable access to the component of type T for the current entity. Returns None if the entity does not have a component of type T or if the access does not include write access to T.

pub unsafe fn get_mut_unchecked<T>(&self) -> Option<Mut<'_, T>>

where T: Component<Mutability = Mutable>,

Gets mutable access to the component of type T for the current entity. Returns None if the entity does not have a component of type T or if the access does not include write access to T.

This only requires &self, and so may be used to get mutable access to multiple components.

Example

#[derive(Component)]
struct X(usize);
#[derive(Component)]
struct Y(usize);

let mut entity = world.spawn((X(0), Y(0))).into_mutable();

// This gives the `FilteredEntityMut` access to `&mut X` and `&mut Y`.
let mut query = QueryBuilder::<FilteredEntityMut>::new(&mut world)
    .data::<(&mut X, &mut Y)>()
    .build();

let mut filtered_entity: FilteredEntityMut = query.single_mut(&mut world).unwrap();

// Get mutable access to two components at once
// SAFETY: We don't take any other references to `X` from this entity
let mut x = unsafe { filtered_entity.get_mut_unchecked::<X>() }.unwrap();
// SAFETY: We don't take any other references to `Y` from this entity
let mut y = unsafe { filtered_entity.get_mut_unchecked::<Y>() }.unwrap();
*x = X(1);
*y = Y(1);

Safety

No other references to the same component may exist at the same time as the returned reference.

See also

• get_mut for the safe version.

pub fn into_mut<T>(self) -> Option<Mut<'w, T>>

where T: Component<Mutability = Mutable>,

Consumes self and gets mutable access to the component of type T with the world 'w lifetime for the current entity. Returns None if the entity does not have a component of type T.

pub unsafe fn into_mut_assume_mutable<T>(self) -> Option<Mut<'w, T>>

where T: Component,

Consumes self and gets mutable access to the component of type T with the world 'w lifetime for the current entity. Returns None if the entity does not have a component of type T.

Safety

• T must be a mutable component

pub fn get_change_ticks<T>(&self) -> Option<ComponentTicks>

where T: Component,

Retrieves the change ticks for the given component. This can be useful for implementing change detection in custom runtimes.

pub fn get_change_ticks_by_id( &self, component_id: ComponentId, ) -> Option<ComponentTicks>

Retrieves the change ticks for the given ComponentId. This can be useful for implementing change detection in custom runtimes.

You should prefer to use the typed API Self::get_change_ticks where possible and only use this in cases where the actual component types are not known at compile time.

pub fn get_by_id(&self, component_id: ComponentId) -> Option<Ptr<'_>>

Gets the component of the given ComponentId from the entity.

You should prefer to use the typed API Self::get where possible and only use this in cases where the actual component types are not known at compile time.

Unlike FilteredEntityMut::get, this returns a raw pointer to the component, which is only valid while the FilteredEntityMut is alive.

Examples found in repository

examples/stress_tests/many_components.rs (line 50)

fn base_system(access_components: In<Vec<ComponentId>>, mut query: Query<FilteredEntityMut>) {
    #[cfg(feature = "trace")]
    let _span = tracing::info_span!("base_system", components = ?access_components.0, count = query.iter().len()).entered();

    for mut filtered_entity in &mut query {
        // We calculate Faulhaber's formula mod 256 with n = value and p = exponent.
        // See https://en.wikipedia.org/wiki/Faulhaber%27s_formula
        // The time is takes to compute this depends on the number of entities and the values in
        // each entity. This is to ensure that each system takes a different amount of time.
        let mut total: Wrapping<u8> = Wrapping(0);
        for (exponent, component_id) in (1_u32..).zip(access_components.0.iter()) {
            // find the value of the component
            let ptr = filtered_entity.get_by_id(*component_id).unwrap();

            // SAFETY: All components have a u8 layout
            let value: u8 = unsafe { *ptr.deref::<u8>() };

            for i in 0..=value {
                let mut product = Wrapping(1);
                for _ in 1..=exponent {
                    product *= Wrapping(i);
                }
                total += product;
            }
        }

        // we assign this value to all the components we can write to
        for component_id in &access_components.0 {
            if let Some(ptr) = filtered_entity.get_mut_by_id(*component_id) {
                // SAFETY: All components have a u8 layout
                unsafe {
                    let mut value = ptr.with_type::<u8>();
                    *value = total.0;
                }
            }
        }
    }
}

examples/ecs/dynamic.rs (line 186)

fn main() {
    let mut world = World::new();
    let mut lines = std::io::stdin().lines();
    let mut component_names = HashMap::<String, ComponentId>::new();
    let mut component_info = HashMap::<ComponentId, ComponentInfo>::new();
    let mut event_names = HashMap::<String, EventKey>::new();

    println!("{PROMPT}");
    loop {
        print!("\n> ");
        let _ = std::io::stdout().flush();
        let Some(Ok(line)) = lines.next() else {
            return;
        };

        if line.is_empty() {
            return;
        };

        let Some((first, rest)) = line.trim().split_once(|c: char| c.is_whitespace()) else {
            match &line.chars().next() {
                Some('c') => println!("{COMPONENT_PROMPT}"),
                Some('s') => println!("{ENTITY_PROMPT}"),
                Some('q') => println!("{QUERY_PROMPT}"),
                Some('e') => println!("{EVENT_PROMPT}"),
                Some('t') => println!("{EMIT_PROMPT}"),
                _ => println!("{PROMPT}"),
            }
            continue;
        };

        match &first[0..1] {
            "c" => {
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };
                    let size = match component.next().map(str::parse) {
                        Some(Ok(size)) => size,
                        _ => 0,
                    };
                    // Register our new component to the world with a layout specified by it's size
                    // SAFETY: [u64] is Send + Sync
                    let id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            name.to_string(),
                            StorageType::Table,
                            Layout::array::<u64>(size).unwrap(),
                            None,
                            true,
                            ComponentCloneBehavior::Default,
                            None,
                        )
                    });
                    let Some(info) = world.components().get_info(id) else {
                        return;
                    };
                    component_names.insert(name.to_string(), id);
                    component_info.insert(id, info.clone());
                    println!("Component {} created with id: {}", name, id.index());
                });
            }
            "s" => {
                let mut to_insert_ids = Vec::new();
                let mut to_insert_data = Vec::new();
                rest.split(',').for_each(|component| {
                    let mut component = component.split_whitespace();
                    let Some(name) = component.next() else {
                        return;
                    };

                    // Get the id for the component with the given name
                    let Some(&id) = component_names.get(name) else {
                        println!("Component {name} does not exist");
                        return;
                    };

                    // Calculate the length for the array based on the layout created for this component id
                    let info = world.components().get_info(id).unwrap();
                    let len = info.layout().size() / size_of::<u64>();
                    let mut values: Vec<u64> = component
                        .take(len)
                        .filter_map(|value| value.parse::<u64>().ok())
                        .collect();
                    values.resize(len, 0);

                    // Collect the id and array to be inserted onto our entity
                    to_insert_ids.push(id);
                    to_insert_data.push(values);
                });

                let mut entity = world.spawn_empty();

                // Construct an `OwningPtr` for each component in `to_insert_data`
                let to_insert_ptr = to_owning_ptrs(&mut to_insert_data);

                // SAFETY:
                // - Component ids have been taken from the same world
                // - Each array is created to the layout specified in the world
                unsafe {
                    entity.insert_by_ids(&to_insert_ids, to_insert_ptr.into_iter());
                }

                println!("Entity spawned with id: {}", entity.id());
            }
            "q" => {
                let mut builder = QueryBuilder::<FilteredEntityMut>::new(&mut world);
                parse_query(rest, &mut builder, &component_names);
                let mut query = builder.build();
                query.iter_mut(&mut world).for_each(|filtered_entity| {
                    let terms = filtered_entity
                        .access()
                        .try_iter_access()
                        .unwrap()
                        .map(|component_access| {
                            let id = *component_access.index();
                            let ptr = filtered_entity.get_by_id(id).unwrap();
                            let info = component_info.get(&id).unwrap();
                            let len = info.layout().size() / size_of::<u64>();

                            // SAFETY:
                            // - All components are created with layout [u64]
                            // - len is calculated from the component descriptor
                            let data = unsafe {
                                std::slice::from_raw_parts_mut(
                                    ptr.assert_unique().as_ptr().cast::<u64>(),
                                    len,
                                )
                            };

                            // If we have write access, increment each value once
                            if matches!(component_access, ComponentAccessKind::Exclusive(_)) {
                                data.iter_mut().for_each(|data| {
                                    *data += 1;
                                });
                            }

                            format!("{}: {:?}", info.name(), data[0..len].to_vec())
                        })
                        .collect::<Vec<_>>()
                        .join(", ");

                    println!("{}: {}", filtered_entity.id(), terms);
                });
            }
            "e" => {
                rest.split(',').for_each(|event| {
                    let name = event.trim();
                    if name.is_empty() {
                        return;
                    }

                    // Register a ComponentId for this event, no Rust type needed.
                    // SAFETY: ZST with no drop
                    let event_component_id = world.register_component_with_descriptor(unsafe {
                        ComponentDescriptor::new_with_layout(
                            format!("event:{name}"),
                            StorageType::Table,
                            Layout::new::<()>(),
                            None,
                            false,
                            ComponentCloneBehavior::Ignore,
                            None,
                        )
                    });
                    // SAFETY: event_component_id was just registered for this event
                    let event_key = unsafe { EventKey::new(event_component_id) };
                    event_names.insert(name.to_string(), event_key);

                    // Build a dynamic observer that prints when the event fires.
                    let runner: ObserverRunner = |mut world, _observer, ctx, _event, _trigger| {
                        println!("  Observer fired!");
                        if let Some(mut counts) = world.get_resource_mut::<EventFireCount>() {
                            *counts.0.entry(ctx.event_key).or_insert(0) += 1;
                        }
                    };

                    // SAFETY: event_key was just registered, runner ignores pointers
                    let observer =
                        unsafe { Observer::with_dynamic_runner(runner).with_event_key(event_key) };
                    world.spawn(observer);

                    println!(
                        "Event '{name}' registered (key: {}) with a dynamic observer",
                        event_component_id.index()
                    );
                });

                // Ensure the counter resource exists.
                world.init_resource::<EventFireCount>();
            }
            "t" => {
                let name = rest.trim();
                let Some(&event_key) = event_names.get(name) else {
                    println!(
                        "Event '{name}' does not exist. Register it first with 'event {name}'"
                    );
                    continue;
                };

                let mut event_data = ();
                let mut trigger_data = ();
                // SAFETY: event_key was registered in this world, both pointers are valid ZSTs
                unsafe {
                    world.trigger_dynamic(
                        event_key,
                        PtrMut::from(&mut event_data),
                        PtrMut::from(&mut trigger_data),
                    );
                }

                let count = world
                    .get_resource::<EventFireCount>()
                    .map_or(0, |c| c.0.get(&event_key).copied().unwrap_or(0));
                println!("Event '{name}' triggered ({count} fires)");
            }
            _ => continue,
        }
    }
}

pub fn get_mut_by_id( &mut self, component_id: ComponentId, ) -> Option<MutUntyped<'_>>

Gets a MutUntyped of the component of the given ComponentId from the entity.

You should prefer to use the typed API Self::get_mut where possible and only use this in cases where the actual component types are not known at compile time.

Unlike FilteredEntityMut::get_mut, this returns a raw pointer to the component, which is only valid while the FilteredEntityMut is alive.

Examples found in repository

examples/stress_tests/many_components.rs (line 66)

fn base_system(access_components: In<Vec<ComponentId>>, mut query: Query<FilteredEntityMut>) {
    #[cfg(feature = "trace")]
    let _span = tracing::info_span!("base_system", components = ?access_components.0, count = query.iter().len()).entered();

    for mut filtered_entity in &mut query {
        // We calculate Faulhaber's formula mod 256 with n = value and p = exponent.
        // See https://en.wikipedia.org/wiki/Faulhaber%27s_formula
        // The time is takes to compute this depends on the number of entities and the values in
        // each entity. This is to ensure that each system takes a different amount of time.
        let mut total: Wrapping<u8> = Wrapping(0);
        for (exponent, component_id) in (1_u32..).zip(access_components.0.iter()) {
            // find the value of the component
            let ptr = filtered_entity.get_by_id(*component_id).unwrap();

            // SAFETY: All components have a u8 layout
            let value: u8 = unsafe { *ptr.deref::<u8>() };

            for i in 0..=value {
                let mut product = Wrapping(1);
                for _ in 1..=exponent {
                    product *= Wrapping(i);
                }
                total += product;
            }
        }

        // we assign this value to all the components we can write to
        for component_id in &access_components.0 {
            if let Some(ptr) = filtered_entity.get_mut_by_id(*component_id) {
                // SAFETY: All components have a u8 layout
                unsafe {
                    let mut value = ptr.with_type::<u8>();
                    *value = total.0;
                }
            }
        }
    }
}

pub unsafe fn get_mut_by_id_unchecked( &self, component_id: ComponentId, ) -> Option<MutUntyped<'_>>

Gets a MutUntyped of the component of the given ComponentId from the entity.

You should prefer to use the typed API Self::get_mut where possible and only use this in cases where the actual component types are not known at compile time.

Unlike FilteredEntityMut::get_mut, this returns a raw pointer to the component, which is only valid while the FilteredEntityMut is alive.

This only requires &self, and so may be used to get mutable access to multiple components.

Safety

No other references to the same component may exist at the same time as the returned reference.

See also

• get_mut_by_id for the safe version.

pub fn spawned_by(&self) -> MaybeLocation

Returns the source code location from which this entity has last been spawned.

pub fn spawn_tick(&self) -> Tick

Returns the Tick at which this entity has been spawned.

Trait Implementations

impl ArchetypeQueryData for FilteredEntityMut<'_, '_>

impl ContainsEntity for FilteredEntityMut<'_, '_>

fn entity(&self) -> Entity

Returns the contained entity.

impl EntityEquivalent for FilteredEntityMut<'_, '_>

impl Eq for FilteredEntityMut<'_, '_>

impl<'a> From<&'a mut EntityMut<'_>> for FilteredEntityMut<'a, 'static>

fn from(entity: &'a mut EntityMut<'_>) -> FilteredEntityMut<'a, 'static>

Converts to this type from the input type.

impl<'a> From<&'a mut EntityWorldMut<'_>> for FilteredEntityMut<'a, 'static>

fn from(entity: &'a mut EntityWorldMut<'_>) -> FilteredEntityMut<'a, 'static>

Converts to this type from the input type.

impl<'w, 's> From<&'w FilteredEntityMut<'_, 's>> for FilteredEntityRef<'w, 's>

fn from(entity: &'w FilteredEntityMut<'_, 's>) -> FilteredEntityRef<'w, 's>

Converts to this type from the input type.

impl<'w, 's, B> From<&'w mut EntityMutExcept<'_, 's, B>> for FilteredEntityMut<'w, 's>

where B: Bundle,

fn from(entity: &'w mut EntityMutExcept<'_, 's, B>) -> FilteredEntityMut<'w, 's>

Converts to this type from the input type.

impl<'w, 's> From<&'w mut FilteredEntityMut<'_, 's>> for FilteredEntityMut<'w, 's>

fn from(entity: &'w mut FilteredEntityMut<'_, 's>) -> FilteredEntityMut<'w, 's>

Converts to this type from the input type.

impl<'a> From<EntityMut<'a>> for FilteredEntityMut<'a, 'static>

fn from(entity: EntityMut<'a>) -> FilteredEntityMut<'a, 'static>

Converts to this type from the input type.

impl<'w, 's, B> From<EntityMutExcept<'w, 's, B>> for FilteredEntityMut<'w, 's>

where B: Bundle,

fn from(entity: EntityMutExcept<'w, 's, B>) -> FilteredEntityMut<'w, 's>

Converts to this type from the input type.

impl<'a> From<EntityWorldMut<'a>> for FilteredEntityMut<'a, 'static>

fn from(entity: EntityWorldMut<'a>) -> FilteredEntityMut<'a, 'static>

Converts to this type from the input type.

impl<'w, 's> From<FilteredEntityMut<'w, 's>> for FilteredEntityRef<'w, 's>

fn from(entity: FilteredEntityMut<'w, 's>) -> FilteredEntityRef<'w, 's>

Converts to this type from the input type.

impl Hash for FilteredEntityMut<'_, '_>

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl IterQueryData for FilteredEntityMut<'_, '_>

impl Ord for FilteredEntityMut<'_, '_>

fn cmp(&self, other: &FilteredEntityMut<'_, '_>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for FilteredEntityMut<'_, '_>

fn eq(&self, other: &FilteredEntityMut<'_, '_>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for FilteredEntityMut<'_, '_>

fn partial_cmp(&self, other: &FilteredEntityMut<'_, '_>) -> Option<Ordering>

FilteredEntityMut’s comparison trait implementations match the underlying Entity, and cannot discern between different worlds.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, 'b> QueryData for FilteredEntityMut<'a, 'b>

const IS_READ_ONLY: bool = false

True if this query is read-only and may not perform mutable access.

const IS_ARCHETYPAL: bool = true

Returns true if (and only if) this query data relies strictly on archetypes to limit which entities are accessed by the Query.

type ReadOnly = FilteredEntityRef<'a, 'b>

The read-only variant of this QueryData, which satisfies the ReadOnlyQueryData trait.

type Item<'w, 's> = FilteredEntityMut<'w, 's>

The item returned by this WorldQuery This will be the data retrieved by the query, and is visible to the end user when calling e.g. Query<Self>::get.

fn shrink<'wlong, 'wshort, 's>( item: <FilteredEntityMut<'a, 'b> as QueryData>::Item<'wlong, 's>, ) -> <FilteredEntityMut<'a, 'b> as QueryData>::Item<'wshort, 's>

where 'wlong: 'wshort,

This function manually implements subtyping for the query items.

fn provide_extra_access( state: &mut <FilteredEntityMut<'a, 'b> as WorldQuery>::State, access: &mut Access, available_access: &Access, )

Offers additional access above what we requested in update_component_access. Implementations may add additional access that is a subset of available_access and does not conflict with anything in access, and must update access to include that access.

unsafe fn fetch<'w, 's>( access: &'s <FilteredEntityMut<'a, 'b> as WorldQuery>::State, fetch: &mut <FilteredEntityMut<'a, 'b> as WorldQuery>::Fetch<'w>, entity: Entity, _table_row: TableRow, ) -> Option<<FilteredEntityMut<'a, 'b> as QueryData>::Item<'w, 's>>

Fetch Self::Item for either the given entity in the current Table, or for the given entity in the current Archetype. This must always be called after WorldQuery::set_table with a table_row in the range of the current Table or after WorldQuery::set_archetype with an entity in the current archetype. Accesses components registered in WorldQuery::update_component_access.

fn iter_access( state: &<FilteredEntityMut<'a, 'b> as WorldQuery>::State, ) -> impl Iterator<Item = EcsAccessType<'_>>

Returns an iterator over the access needed by QueryData::fetch. Access conflicts are usually checked in WorldQuery::update_component_access, but in certain cases this method can be useful to implement a way of checking for access conflicts in a non-allocating way.

impl SingleEntityQueryData for FilteredEntityMut<'_, '_>

impl<'a> TryFrom<&'a FilteredEntityMut<'_, '_>> for EntityRef<'a>

type Error = TryFromFilteredError

The type returned in the event of a conversion error.

fn try_from( entity: &'a FilteredEntityMut<'_, '_>, ) -> Result<EntityRef<'a>, <EntityRef<'a> as TryFrom<&'a FilteredEntityMut<'_, '_>>>::Error>

Performs the conversion.

impl<'a> TryFrom<&'a mut FilteredEntityMut<'_, '_>> for EntityMut<'a>

type Error = TryFromFilteredError

The type returned in the event of a conversion error.

fn try_from( entity: &'a mut FilteredEntityMut<'_, '_>, ) -> Result<EntityMut<'a>, <EntityMut<'a> as TryFrom<&'a mut FilteredEntityMut<'_, '_>>>::Error>

Performs the conversion.

impl<'a> TryFrom<FilteredEntityMut<'a, '_>> for EntityRef<'a>

type Error = TryFromFilteredError

The type returned in the event of a conversion error.

fn try_from( entity: FilteredEntityMut<'a, '_>, ) -> Result<EntityRef<'a>, <EntityRef<'a> as TryFrom<FilteredEntityMut<'a, '_>>>::Error>

Performs the conversion.

impl<'a> TryFrom<FilteredEntityMut<'a, '_>> for EntityMut<'a>

type Error = TryFromFilteredError

The type returned in the event of a conversion error.

fn try_from( entity: FilteredEntityMut<'a, '_>, ) -> Result<EntityMut<'a>, <EntityMut<'a> as TryFrom<FilteredEntityMut<'a, '_>>>::Error>

Performs the conversion.

impl WorldQuery for FilteredEntityMut<'_, '_>

const IS_DENSE: bool = true

Returns true if (and only if) every table of every archetype matched by this fetch contains all of the matched components.

type Fetch<'w> = EntityFetch<'w>

Per archetype/table state retrieved by this WorldQuery to compute Self::Item for each entity.

type State = Access

State used to construct a Self::Fetch. This will be cached inside QueryState, so it is best to move as much data / computation here as possible to reduce the cost of constructing Self::Fetch.

fn shrink_fetch<'wlong, 'wshort>( fetch: <FilteredEntityMut<'_, '_> as WorldQuery>::Fetch<'wlong>, ) -> <FilteredEntityMut<'_, '_> as WorldQuery>::Fetch<'wshort>

where 'wlong: 'wshort,

This function manually implements subtyping for the query fetches.

unsafe fn init_fetch<'w, 's>( world: UnsafeWorldCell<'w>, _state: &'s <FilteredEntityMut<'_, '_> as WorldQuery>::State, last_run: Tick, this_run: Tick, ) -> <FilteredEntityMut<'_, '_> as WorldQuery>::Fetch<'w>

Creates a new instance of Self::Fetch, by combining data from the World with the cached Self::State. Readonly accesses resources registered in WorldQuery::update_component_access.

unsafe fn set_archetype<'w, 's>( _fetch: &mut <FilteredEntityMut<'_, '_> as WorldQuery>::Fetch<'w>, _state: &'s <FilteredEntityMut<'_, '_> as WorldQuery>::State, _: &'w Archetype, _table: &Table, )

Adjusts internal state to account for the next Archetype. This will always be called on archetypes that match this WorldQuery.

unsafe fn set_table<'w, 's>( _fetch: &mut <FilteredEntityMut<'_, '_> as WorldQuery>::Fetch<'w>, _state: &'s <FilteredEntityMut<'_, '_> as WorldQuery>::State, _: &'w Table, )

Adjusts internal state to account for the next Table. This will always be called on tables that match this WorldQuery.

fn update_component_access( state: &<FilteredEntityMut<'_, '_> as WorldQuery>::State, filtered_access: &mut FilteredAccess, )

Adds any component accesses to the current entity used by this WorldQuery to access.

fn init_state( _world: &mut World, ) -> <FilteredEntityMut<'_, '_> as WorldQuery>::State

Creates and initializes a State for this WorldQuery type.

fn get_state( _components: &Components, ) -> Option<<FilteredEntityMut<'_, '_> as WorldQuery>::State>

Attempts to initialize a State for this WorldQuery type using read-only access to Components.

fn matches_component_set( _state: &<FilteredEntityMut<'_, '_> as WorldQuery>::State, _set_contains_id: &impl Fn(ComponentId) -> bool, ) -> bool

Returns true if this query matches a set of components. Otherwise, returns false.

fn init_nested_access( _state: &Self::State, _system_name: Option<&str>, _component_access_set: &mut FilteredAccessSet, _world: UnsafeWorldCell<'_>, )

Adds any component accesses to other entities used by this WorldQuery.

fn update_archetypes(_state: &mut Self::State, _world: UnsafeWorldCell<'_>)

Called when the query state is updating its archetype cache. This can be used by nested queries to update their internal archetype caches.