Struct Tick 

pub struct Tick { /* private fields */ }

A value that tracks when a system ran relative to other systems. This is used to power change detection.

Note that a system that hasn’t been run yet has a Tick of 0.

Implementations

impl Tick

pub const MAX: Tick

The maximum relative age for a change tick. The value of this is equal to MAX_CHANGE_AGE.

Since change detection will not work for any ticks older than this, ticks are periodically scanned to ensure their relative values are below this.

pub const fn new(tick: u32) -> Tick

Creates a new Tick wrapping the given value.

pub const fn get(self) -> u32

Gets the value of this change tick.

Examples found in repository

examples/shader_advanced/custom_phase_item.rs (line 250)

fn queue_custom_phase_item(
    pipeline_cache: Res<PipelineCache>,
    mut pipeline: ResMut<CustomPhasePipeline>,
    mut opaque_render_phases: ResMut<ViewBinnedRenderPhases<Opaque3d>>,
    opaque_draw_functions: Res<DrawFunctions<Opaque3d>>,
    views: Query<(&ExtractedView, &RenderVisibleEntities, &Msaa)>,
    mut next_tick: Local<Tick>,
) {
    let draw_custom_phase_item = opaque_draw_functions
        .read()
        .id::<DrawCustomPhaseItemCommands>();

    // Render phases are per-view, so we need to iterate over all views so that
    // the entity appears in them. (In this example, we have only one view, but
    // it's good practice to loop over all views anyway.)
    for (view, view_visible_entities, msaa) in views.iter() {
        let Some(opaque_phase) = opaque_render_phases.get_mut(&view.retained_view_entity) else {
            continue;
        };

        // Find all the custom rendered entities that are visible from this
        // view.
        for &entity in view_visible_entities.get::<CustomRenderedEntity>().iter() {
            // Ordinarily, the [`SpecializedRenderPipeline::Key`] would contain
            // some per-view settings, such as whether the view is HDR, but for
            // simplicity's sake we simply hard-code the view's characteristics,
            // with the exception of number of MSAA samples.
            let Ok(pipeline_id) = pipeline
                .variants
                .specialize(&pipeline_cache, CustomPhaseKey(*msaa))
            else {
                continue;
            };

            // Bump the change tick in order to force Bevy to rebuild the bin.
            let this_tick = next_tick.get() + 1;
            next_tick.set(this_tick);

            // Add the custom render item. We use the
            // [`BinnedRenderPhaseType::NonMesh`] type to skip the special
            // handling that Bevy has for meshes (preprocessing, indirect
            // draws, etc.)
            //
            // The asset ID is arbitrary; we simply use [`AssetId::invalid`],
            // but you can use anything you like. Note that the asset ID need
            // not be the ID of a [`Mesh`].
            opaque_phase.add(
                Opaque3dBatchSetKey {
                    draw_function: draw_custom_phase_item,
                    pipeline: pipeline_id,
                    material_bind_group_index: None,
                    lightmap_slab: None,
                    vertex_slab: default(),
                    index_slab: None,
                },
                Opaque3dBinKey {
                    asset_id: AssetId::<Mesh>::invalid().untyped(),
                },
                entity,
                InputUniformIndex::default(),
                BinnedRenderPhaseType::NonMesh,
                *next_tick,
            );
        }
    }
}

examples/shader_advanced/specialized_mesh_pipeline.rs (line 338)

fn queue_custom_mesh_pipeline(
    pipeline_cache: Res<PipelineCache>,
    custom_mesh_pipeline: Res<CustomMeshPipeline>,
    (mut opaque_render_phases, opaque_draw_functions): (
        ResMut<ViewBinnedRenderPhases<Opaque3d>>,
        Res<DrawFunctions<Opaque3d>>,
    ),
    mut specialized_mesh_pipelines: ResMut<SpecializedMeshPipelines<CustomMeshPipeline>>,
    views: Query<(&RenderVisibleEntities, &ExtractedView, &Msaa)>,
    (render_meshes, render_mesh_instances): (
        Res<RenderAssets<RenderMesh>>,
        Res<RenderMeshInstances>,
    ),
    mut change_tick: Local<Tick>,
    mesh_allocator: Res<MeshAllocator>,
    gpu_preprocessing_support: Res<GpuPreprocessingSupport>,
) {
    // Get the id for our custom draw function
    let draw_function = opaque_draw_functions
        .read()
        .id::<DrawSpecializedPipelineCommands>();

    // Render phases are per-view, so we need to iterate over all views so that
    // the entity appears in them. (In this example, we have only one view, but
    // it's good practice to loop over all views anyway.)
    for (view_visible_entities, view, msaa) in views.iter() {
        let Some(opaque_phase) = opaque_render_phases.get_mut(&view.retained_view_entity) else {
            continue;
        };

        // Create the key based on the view. In this case we only care about MSAA and HDR
        let view_key = MeshPipelineKey::from_msaa_samples(msaa.samples())
            | MeshPipelineKey::from_hdr(view.hdr);

        // Find all the custom rendered entities that are visible from this
        // view.
        for &(render_entity, visible_entity) in
            view_visible_entities.get::<CustomRenderedEntity>().iter()
        {
            // Get the mesh instance
            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(visible_entity)
            else {
                continue;
            };

            // Get the mesh data
            let Some(mesh) = render_meshes.get(mesh_instance.mesh_asset_id) else {
                continue;
            };

            let (vertex_slab, index_slab) = mesh_allocator.mesh_slabs(&mesh_instance.mesh_asset_id);

            // Specialize the key for the current mesh entity
            // For this example we only specialize based on the mesh topology
            // but you could have more complex keys and that's where you'd need to create those keys
            let mut mesh_key = view_key;
            mesh_key |= MeshPipelineKey::from_primitive_topology(mesh.primitive_topology());

            // Finally, we can specialize the pipeline based on the key
            let pipeline_id = specialized_mesh_pipelines
                .specialize(
                    &pipeline_cache,
                    &custom_mesh_pipeline,
                    mesh_key,
                    &mesh.layout,
                )
                // This should never happen with this example, but if your pipeline
                // specialization can fail you need to handle the error here
                .expect("Failed to specialize mesh pipeline");

            // Bump the change tick so that Bevy is forced to rebuild the bin.
            let next_change_tick = change_tick.get() + 1;
            change_tick.set(next_change_tick);

            // Add the mesh with our specialized pipeline
            opaque_phase.add(
                Opaque3dBatchSetKey {
                    draw_function,
                    pipeline: pipeline_id,
                    material_bind_group_index: None,
                    vertex_slab: vertex_slab.unwrap_or_default(),
                    index_slab,
                    lightmap_slab: None,
                },
                // For this example we can use the mesh asset id as the bin key,
                // but you can use any asset_id as a key
                Opaque3dBinKey {
                    asset_id: mesh_instance.mesh_asset_id.into(),
                },
                (render_entity, visible_entity),
                mesh_instance.current_uniform_index,
                // This example supports batching and multi draw indirect,
                // but if your pipeline doesn't support it you can use
                // `BinnedRenderPhaseType::UnbatchableMesh`
                BinnedRenderPhaseType::mesh(
                    mesh_instance.should_batch(),
                    &gpu_preprocessing_support,
                ),
                *change_tick,
            );
        }
    }
}

pub fn set(&mut self, tick: u32)

Sets the value of this change tick.

Examples found in repository

examples/shader_advanced/custom_phase_item.rs (line 251)

fn queue_custom_phase_item(
    pipeline_cache: Res<PipelineCache>,
    mut pipeline: ResMut<CustomPhasePipeline>,
    mut opaque_render_phases: ResMut<ViewBinnedRenderPhases<Opaque3d>>,
    opaque_draw_functions: Res<DrawFunctions<Opaque3d>>,
    views: Query<(&ExtractedView, &RenderVisibleEntities, &Msaa)>,
    mut next_tick: Local<Tick>,
) {
    let draw_custom_phase_item = opaque_draw_functions
        .read()
        .id::<DrawCustomPhaseItemCommands>();

    // Render phases are per-view, so we need to iterate over all views so that
    // the entity appears in them. (In this example, we have only one view, but
    // it's good practice to loop over all views anyway.)
    for (view, view_visible_entities, msaa) in views.iter() {
        let Some(opaque_phase) = opaque_render_phases.get_mut(&view.retained_view_entity) else {
            continue;
        };

        // Find all the custom rendered entities that are visible from this
        // view.
        for &entity in view_visible_entities.get::<CustomRenderedEntity>().iter() {
            // Ordinarily, the [`SpecializedRenderPipeline::Key`] would contain
            // some per-view settings, such as whether the view is HDR, but for
            // simplicity's sake we simply hard-code the view's characteristics,
            // with the exception of number of MSAA samples.
            let Ok(pipeline_id) = pipeline
                .variants
                .specialize(&pipeline_cache, CustomPhaseKey(*msaa))
            else {
                continue;
            };

            // Bump the change tick in order to force Bevy to rebuild the bin.
            let this_tick = next_tick.get() + 1;
            next_tick.set(this_tick);

            // Add the custom render item. We use the
            // [`BinnedRenderPhaseType::NonMesh`] type to skip the special
            // handling that Bevy has for meshes (preprocessing, indirect
            // draws, etc.)
            //
            // The asset ID is arbitrary; we simply use [`AssetId::invalid`],
            // but you can use anything you like. Note that the asset ID need
            // not be the ID of a [`Mesh`].
            opaque_phase.add(
                Opaque3dBatchSetKey {
                    draw_function: draw_custom_phase_item,
                    pipeline: pipeline_id,
                    material_bind_group_index: None,
                    lightmap_slab: None,
                    vertex_slab: default(),
                    index_slab: None,
                },
                Opaque3dBinKey {
                    asset_id: AssetId::<Mesh>::invalid().untyped(),
                },
                entity,
                InputUniformIndex::default(),
                BinnedRenderPhaseType::NonMesh,
                *next_tick,
            );
        }
    }
}

examples/shader_advanced/specialized_mesh_pipeline.rs (line 339)

fn queue_custom_mesh_pipeline(
    pipeline_cache: Res<PipelineCache>,
    custom_mesh_pipeline: Res<CustomMeshPipeline>,
    (mut opaque_render_phases, opaque_draw_functions): (
        ResMut<ViewBinnedRenderPhases<Opaque3d>>,
        Res<DrawFunctions<Opaque3d>>,
    ),
    mut specialized_mesh_pipelines: ResMut<SpecializedMeshPipelines<CustomMeshPipeline>>,
    views: Query<(&RenderVisibleEntities, &ExtractedView, &Msaa)>,
    (render_meshes, render_mesh_instances): (
        Res<RenderAssets<RenderMesh>>,
        Res<RenderMeshInstances>,
    ),
    mut change_tick: Local<Tick>,
    mesh_allocator: Res<MeshAllocator>,
    gpu_preprocessing_support: Res<GpuPreprocessingSupport>,
) {
    // Get the id for our custom draw function
    let draw_function = opaque_draw_functions
        .read()
        .id::<DrawSpecializedPipelineCommands>();

    // Render phases are per-view, so we need to iterate over all views so that
    // the entity appears in them. (In this example, we have only one view, but
    // it's good practice to loop over all views anyway.)
    for (view_visible_entities, view, msaa) in views.iter() {
        let Some(opaque_phase) = opaque_render_phases.get_mut(&view.retained_view_entity) else {
            continue;
        };

        // Create the key based on the view. In this case we only care about MSAA and HDR
        let view_key = MeshPipelineKey::from_msaa_samples(msaa.samples())
            | MeshPipelineKey::from_hdr(view.hdr);

        // Find all the custom rendered entities that are visible from this
        // view.
        for &(render_entity, visible_entity) in
            view_visible_entities.get::<CustomRenderedEntity>().iter()
        {
            // Get the mesh instance
            let Some(mesh_instance) = render_mesh_instances.render_mesh_queue_data(visible_entity)
            else {
                continue;
            };

            // Get the mesh data
            let Some(mesh) = render_meshes.get(mesh_instance.mesh_asset_id) else {
                continue;
            };

            let (vertex_slab, index_slab) = mesh_allocator.mesh_slabs(&mesh_instance.mesh_asset_id);

            // Specialize the key for the current mesh entity
            // For this example we only specialize based on the mesh topology
            // but you could have more complex keys and that's where you'd need to create those keys
            let mut mesh_key = view_key;
            mesh_key |= MeshPipelineKey::from_primitive_topology(mesh.primitive_topology());

            // Finally, we can specialize the pipeline based on the key
            let pipeline_id = specialized_mesh_pipelines
                .specialize(
                    &pipeline_cache,
                    &custom_mesh_pipeline,
                    mesh_key,
                    &mesh.layout,
                )
                // This should never happen with this example, but if your pipeline
                // specialization can fail you need to handle the error here
                .expect("Failed to specialize mesh pipeline");

            // Bump the change tick so that Bevy is forced to rebuild the bin.
            let next_change_tick = change_tick.get() + 1;
            change_tick.set(next_change_tick);

            // Add the mesh with our specialized pipeline
            opaque_phase.add(
                Opaque3dBatchSetKey {
                    draw_function,
                    pipeline: pipeline_id,
                    material_bind_group_index: None,
                    vertex_slab: vertex_slab.unwrap_or_default(),
                    index_slab,
                    lightmap_slab: None,
                },
                // For this example we can use the mesh asset id as the bin key,
                // but you can use any asset_id as a key
                Opaque3dBinKey {
                    asset_id: mesh_instance.mesh_asset_id.into(),
                },
                (render_entity, visible_entity),
                mesh_instance.current_uniform_index,
                // This example supports batching and multi draw indirect,
                // but if your pipeline doesn't support it you can use
                // `BinnedRenderPhaseType::UnbatchableMesh`
                BinnedRenderPhaseType::mesh(
                    mesh_instance.should_batch(),
                    &gpu_preprocessing_support,
                ),
                *change_tick,
            );
        }
    }
}

pub fn is_newer_than(self, last_run: Tick, this_run: Tick) -> bool

Returns true if this Tick occurred since the system’s last_run.

this_run is the current tick of the system, used as a reference to help deal with wraparound.

pub fn check_tick(&mut self, check: CheckChangeTicks) -> bool

Wraps this change tick’s value if it exceeds Tick::MAX.

Returns true if wrapping was performed. Otherwise, returns false.

Trait Implementations

impl Clone for Tick

fn clone(&self) -> Tick

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Tick

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Tick

fn default() -> Tick

Returns the “default value” for a type.

impl FromArg for Tick

type This<'from_arg> = Tick

The type to convert into.

fn from_arg(arg: Arg<'_>) -> Result<<Tick as FromArg>::This<'_>, ArgError>

Creates an item from an argument.

impl FromReflect for Tick

fn from_reflect(reflect: &(dyn PartialReflect + 'static)) -> Option<Tick>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn PartialReflect>, ) -> Result<Self, Box<dyn PartialReflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl GetOwnership for Tick

fn ownership() -> Ownership

Returns the ownership of Self.

impl GetTypeRegistration for Tick

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl Hash for Tick

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 IntoReturn for Tick

fn into_return<'into_return>(self) -> Return<'into_return>

where Tick: 'into_return,

Converts Self into a Return value.

impl PartialEq for Tick

fn eq(&self, other: &Tick) -> 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 PartialReflect for Tick

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn try_apply( &mut self, value: &(dyn PartialReflect + 'static), ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<Tick>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<Tick>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.

fn try_as_reflect(&self) -> Option<&(dyn Reflect + 'static)>

Attempts to cast this type to a fully-reflected value.

fn try_as_reflect_mut(&mut self) -> Option<&mut (dyn Reflect + 'static)>

Attempts to cast this type to a mutable, fully-reflected value.

fn into_partial_reflect(self: Box<Tick>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &(dyn PartialReflect + 'static)

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut (dyn PartialReflect + 'static)

Casts this type to a mutable, reflected value.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

fn reflect_partial_eq( &self, value: &(dyn PartialReflect + 'static), ) -> Option<bool>

Returns a “partial equality” comparison result.

fn debug(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Debug formatter for the value.

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection.

fn apply(&mut self, value: &(dyn PartialReflect + 'static))

Applies a reflected value to this value.

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind.

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>

where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Reflect for Tick

fn into_any(self: Box<Tick>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<Tick>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.

fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a fully-reflected value.

fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable, fully-reflected value.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

impl Struct for Tick

fn field(&self, name: &str) -> Option<&(dyn PartialReflect + 'static)>

Returns a reference to the value of the field named name as a &dyn PartialReflect.

fn field_mut( &mut self, name: &str, ) -> Option<&mut (dyn PartialReflect + 'static)>

Returns a mutable reference to the value of the field named name as a &mut dyn PartialReflect.

fn field_at(&self, index: usize) -> Option<&(dyn PartialReflect + 'static)>

Returns a reference to the value of the field with index index as a &dyn PartialReflect.

fn field_at_mut( &mut self, index: usize, ) -> Option<&mut (dyn PartialReflect + 'static)>

Returns a mutable reference to the value of the field with index index as a &mut dyn PartialReflect.

fn name_at(&self, index: usize) -> Option<&str>

Returns the name of the field with index index.

fn field_len(&self) -> usize

Returns the number of fields in the struct.

fn iter_fields(&self) -> FieldIter<'_>

Returns an iterator over the values of the reflectable fields for this struct.

fn to_dynamic_struct(&self) -> DynamicStruct

Creates a new DynamicStruct from this struct.

fn get_represented_struct_info(&self) -> Option<&'static StructInfo>

Will return None if TypeInfo is not available.

impl TypePath for Tick

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for Tick

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl Copy for Tick

impl Eq for Tick

impl StructuralPartialEq for Tick