Struct PipelineCache

pub struct PipelineCache { /* private fields */ }

Cache for render and compute pipelines.

The cache stores existing render and compute pipelines allocated on the GPU, as well as pending creation. Pipelines inserted into the cache are identified by a unique ID, which can be used to retrieve the actual GPU object once it’s ready. The creation of the GPU pipeline object is deferred to the RenderSet::Render step, just before the render graph starts being processed, as this requires access to the GPU.

Note that the cache does not perform automatic deduplication of identical pipelines. It is up to the user not to insert the same pipeline twice to avoid wasting GPU resources.

Implementations

impl PipelineCache

pub fn pipelines(&self) -> impl Iterator<Item = &CachedPipeline>

Returns an iterator over the pipelines in the pipeline cache.

pub fn waiting_pipelines(&self) -> impl Iterator<Item = usize>

Returns a iterator of the IDs of all currently waiting pipelines.

Examples found in repository

examples/games/loading_screen.rs (line 301)

    fn update_pipelines_ready(mut main_world: ResMut<MainWorld>, pipelines: Res<PipelineCache>) {
        if let Some(mut pipelines_ready) = main_world.get_resource_mut::<PipelinesReady>() {
            pipelines_ready.0 = pipelines.waiting_pipelines().count() == 0;
        }
    }

pub fn new( device: RenderDevice, render_adapter: RenderAdapter, synchronous_pipeline_compilation: bool, ) -> PipelineCache

Create a new pipeline cache associated with the given render device.

pub fn get_render_pipeline_state( &self, id: CachedRenderPipelineId, ) -> &CachedPipelineState

Get the state of a cached render pipeline.

See PipelineCache::queue_render_pipeline().

pub fn get_compute_pipeline_state( &self, id: CachedComputePipelineId, ) -> &CachedPipelineState

Get the state of a cached compute pipeline.

See PipelineCache::queue_compute_pipeline().

Examples found in repository

examples/shader/compute_shader_game_of_life.rs (line 228)

    fn update(&mut self, world: &mut World) {
        let pipeline = world.resource::<GameOfLifePipeline>();
        let pipeline_cache = world.resource::<PipelineCache>();

        // if the corresponding pipeline has loaded, transition to the next stage
        match self.state {
            GameOfLifeState::Loading => {
                match pipeline_cache.get_compute_pipeline_state(pipeline.init_pipeline) {
                    CachedPipelineState::Ok(_) => {
                        self.state = GameOfLifeState::Init;
                    }
                    CachedPipelineState::Err(err) => {
                        panic!("Initializing assets/{SHADER_ASSET_PATH}:\n{err}")
                    }
                    _ => {}
                }
            }
            GameOfLifeState::Init => {
                if let CachedPipelineState::Ok(_) =
                    pipeline_cache.get_compute_pipeline_state(pipeline.update_pipeline)
                {
                    self.state = GameOfLifeState::Update(1);
                }
            }
            GameOfLifeState::Update(0) => {
                self.state = GameOfLifeState::Update(1);
            }
            GameOfLifeState::Update(1) => {
                self.state = GameOfLifeState::Update(0);
            }
            GameOfLifeState::Update(_) => unreachable!(),
        }
    }

pub fn get_render_pipeline_descriptor( &self, id: CachedRenderPipelineId, ) -> &RenderPipelineDescriptor

Get the render pipeline descriptor a cached render pipeline was inserted from.

See PipelineCache::queue_render_pipeline().

Note: Be careful calling this method. It will panic if called with a pipeline that has been queued but has not yet been processed by PipelineCache::process_queue().

pub fn get_compute_pipeline_descriptor( &self, id: CachedComputePipelineId, ) -> &ComputePipelineDescriptor

Get the compute pipeline descriptor a cached render pipeline was inserted from.

See PipelineCache::queue_compute_pipeline().

Note: Be careful calling this method. It will panic if called with a pipeline that has been queued but has not yet been processed by PipelineCache::process_queue().

pub fn get_render_pipeline( &self, id: CachedRenderPipelineId, ) -> Option<&RenderPipeline>

Try to retrieve a render pipeline GPU object from a cached ID.

Returns

This method returns a successfully created render pipeline if any, or None if the pipeline was not created yet or if there was an error during creation. You can check the actual creation state with PipelineCache::get_render_pipeline_state().

Examples found in repository

examples/shader/custom_post_processing.rs (line 159)

    fn run(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext,
        (view_target, _post_process_settings, settings_index): QueryItem<Self::ViewQuery>,
        world: &World,
    ) -> Result<(), NodeRunError> {
        // Get the pipeline resource that contains the global data we need
        // to create the render pipeline
        let post_process_pipeline = world.resource::<PostProcessPipeline>();

        // The pipeline cache is a cache of all previously created pipelines.
        // It is required to avoid creating a new pipeline each frame,
        // which is expensive due to shader compilation.
        let pipeline_cache = world.resource::<PipelineCache>();

        // Get the pipeline from the cache
        let Some(pipeline) = pipeline_cache.get_render_pipeline(post_process_pipeline.pipeline_id)
        else {
            return Ok(());
        };

        // Get the settings uniform binding
        let settings_uniforms = world.resource::<ComponentUniforms<PostProcessSettings>>();
        let Some(settings_binding) = settings_uniforms.uniforms().binding() else {
            return Ok(());
        };

        // This will start a new "post process write", obtaining two texture
        // views from the view target - a `source` and a `destination`.
        // `source` is the "current" main texture and you _must_ write into
        // `destination` because calling `post_process_write()` on the
        // [`ViewTarget`] will internally flip the [`ViewTarget`]'s main
        // texture to the `destination` texture. Failing to do so will cause
        // the current main texture information to be lost.
        let post_process = view_target.post_process_write();

        // The bind_group gets created each frame.
        //
        // Normally, you would create a bind_group in the Queue set,
        // but this doesn't work with the post_process_write().
        // The reason it doesn't work is because each post_process_write will alternate the source/destination.
        // The only way to have the correct source/destination for the bind_group
        // is to make sure you get it during the node execution.
        let bind_group = render_context.render_device().create_bind_group(
            "post_process_bind_group",
            &post_process_pipeline.layout,
            // It's important for this to match the BindGroupLayout defined in the PostProcessPipeline
            &BindGroupEntries::sequential((
                // Make sure to use the source view
                post_process.source,
                // Use the sampler created for the pipeline
                &post_process_pipeline.sampler,
                // Set the settings binding
                settings_binding.clone(),
            )),
        );

        // Begin the render pass
        let mut render_pass = render_context.begin_tracked_render_pass(RenderPassDescriptor {
            label: Some("post_process_pass"),
            color_attachments: &[Some(RenderPassColorAttachment {
                // We need to specify the post process destination view here
                // to make sure we write to the appropriate texture.
                view: post_process.destination,
                resolve_target: None,
                ops: Operations::default(),
            })],
            depth_stencil_attachment: None,
            timestamp_writes: None,
            occlusion_query_set: None,
        });

        // This is mostly just wgpu boilerplate for drawing a fullscreen triangle,
        // using the pipeline/bind_group created above
        render_pass.set_render_pipeline(pipeline);
        // By passing in the index of the post process settings on this view, we ensure
        // that in the event that multiple settings were sent to the GPU (as would be the
        // case with multiple cameras), we use the correct one.
        render_pass.set_bind_group(0, &bind_group, &[settings_index.index()]);
        render_pass.draw(0..3, 0..1);

        Ok(())
    }

pub fn block_on_render_pipeline(&mut self, id: CachedRenderPipelineId)

Wait for a render pipeline to finish compiling.

pub fn get_compute_pipeline( &self, id: CachedComputePipelineId, ) -> Option<&ComputePipeline>

Try to retrieve a compute pipeline GPU object from a cached ID.

Returns

This method returns a successfully created compute pipeline if any, or None if the pipeline was not created yet or if there was an error during creation. You can check the actual creation state with PipelineCache::get_compute_pipeline_state().

Examples found in repository

examples/shader/gpu_readback.rs (line 207)

    fn run(
        &self,
        _graph: &mut render_graph::RenderGraphContext,
        render_context: &mut RenderContext,
        world: &World,
    ) -> Result<(), render_graph::NodeRunError> {
        let pipeline_cache = world.resource::<PipelineCache>();
        let pipeline = world.resource::<ComputePipeline>();
        let bind_group = world.resource::<GpuBufferBindGroup>();

        if let Some(init_pipeline) = pipeline_cache.get_compute_pipeline(pipeline.pipeline) {
            let mut pass =
                render_context
                    .command_encoder()
                    .begin_compute_pass(&ComputePassDescriptor {
                        label: Some("GPU readback compute pass"),
                        ..default()
                    });

            pass.set_bind_group(0, &bind_group.0, &[]);
            pass.set_pipeline(init_pipeline);
            pass.dispatch_workgroups(BUFFER_LEN as u32, 1, 1);
        }
        Ok(())
    }

examples/shader/compute_shader_game_of_life.rs (line 274)

    fn run(
        &self,
        _graph: &mut render_graph::RenderGraphContext,
        render_context: &mut RenderContext,
        world: &World,
    ) -> Result<(), render_graph::NodeRunError> {
        let bind_groups = &world.resource::<GameOfLifeImageBindGroups>().0;
        let pipeline_cache = world.resource::<PipelineCache>();
        let pipeline = world.resource::<GameOfLifePipeline>();

        let mut pass = render_context
            .command_encoder()
            .begin_compute_pass(&ComputePassDescriptor::default());

        // select the pipeline based on the current state
        match self.state {
            GameOfLifeState::Loading => {}
            GameOfLifeState::Init => {
                let init_pipeline = pipeline_cache
                    .get_compute_pipeline(pipeline.init_pipeline)
                    .unwrap();
                pass.set_bind_group(0, &bind_groups[0], &[]);
                pass.set_pipeline(init_pipeline);
                pass.dispatch_workgroups(SIZE.0 / WORKGROUP_SIZE, SIZE.1 / WORKGROUP_SIZE, 1);
            }
            GameOfLifeState::Update(index) => {
                let update_pipeline = pipeline_cache
                    .get_compute_pipeline(pipeline.update_pipeline)
                    .unwrap();
                pass.set_bind_group(0, &bind_groups[index], &[]);
                pass.set_pipeline(update_pipeline);
                pass.dispatch_workgroups(SIZE.0 / WORKGROUP_SIZE, SIZE.1 / WORKGROUP_SIZE, 1);
            }
        }

        Ok(())
    }

pub fn queue_render_pipeline( &self, descriptor: RenderPipelineDescriptor, ) -> CachedRenderPipelineId

Insert a render pipeline into the cache, and queue its creation.

The pipeline is always inserted and queued for creation. There is no attempt to deduplicate it with an already cached pipeline.

Returns

This method returns the unique render shader ID of the cached pipeline, which can be used to query the caching state with get_render_pipeline_state() and to retrieve the created GPU pipeline once it’s ready with get_render_pipeline().

Examples found in repository

examples/shader/custom_post_processing.rs (lines 266-290)

    fn from_world(world: &mut World) -> Self {
        let render_device = world.resource::<RenderDevice>();

        // We need to define the bind group layout used for our pipeline
        let layout = render_device.create_bind_group_layout(
            "post_process_bind_group_layout",
            &BindGroupLayoutEntries::sequential(
                // The layout entries will only be visible in the fragment stage
                ShaderStages::FRAGMENT,
                (
                    // The screen texture
                    texture_2d(TextureSampleType::Float { filterable: true }),
                    // The sampler that will be used to sample the screen texture
                    sampler(SamplerBindingType::Filtering),
                    // The settings uniform that will control the effect
                    uniform_buffer::<PostProcessSettings>(true),
                ),
            ),
        );

        // We can create the sampler here since it won't change at runtime and doesn't depend on the view
        let sampler = render_device.create_sampler(&SamplerDescriptor::default());

        // Get the shader handle
        let shader = world.load_asset(SHADER_ASSET_PATH);

        let pipeline_id = world
            .resource_mut::<PipelineCache>()
            // This will add the pipeline to the cache and queue its creation
            .queue_render_pipeline(RenderPipelineDescriptor {
                label: Some("post_process_pipeline".into()),
                layout: vec![layout.clone()],
                // This will setup a fullscreen triangle for the vertex state
                vertex: fullscreen_shader_vertex_state(),
                fragment: Some(FragmentState {
                    shader,
                    shader_defs: vec![],
                    // Make sure this matches the entry point of your shader.
                    // It can be anything as long as it matches here and in the shader.
                    entry_point: "fragment".into(),
                    targets: vec![Some(ColorTargetState {
                        format: TextureFormat::bevy_default(),
                        blend: None,
                        write_mask: ColorWrites::ALL,
                    })],
                }),
                // All of the following properties are not important for this effect so just use the default values.
                // This struct doesn't have the Default trait implemented because not all fields can have a default value.
                primitive: PrimitiveState::default(),
                depth_stencil: None,
                multisample: MultisampleState::default(),
                push_constant_ranges: vec![],
                zero_initialize_workgroup_memory: false,
            });

        Self {
            layout,
            sampler,
            pipeline_id,
        }
    }

pub fn queue_compute_pipeline( &self, descriptor: ComputePipelineDescriptor, ) -> CachedComputePipelineId

Insert a compute pipeline into the cache, and queue its creation.

The pipeline is always inserted and queued for creation. There is no attempt to deduplicate it with an already cached pipeline.

Returns

This method returns the unique compute shader ID of the cached pipeline, which can be used to query the caching state with get_compute_pipeline_state() and to retrieve the created GPU pipeline once it’s ready with get_compute_pipeline().

Examples found in repository

examples/shader/gpu_readback.rs (lines 176-184)

    fn from_world(world: &mut World) -> Self {
        let render_device = world.resource::<RenderDevice>();
        let layout = render_device.create_bind_group_layout(
            None,
            &BindGroupLayoutEntries::sequential(
                ShaderStages::COMPUTE,
                (
                    storage_buffer::<Vec<u32>>(false),
                    texture_storage_2d(TextureFormat::R32Uint, StorageTextureAccess::WriteOnly),
                ),
            ),
        );
        let shader = world.load_asset(SHADER_ASSET_PATH);
        let pipeline_cache = world.resource::<PipelineCache>();
        let pipeline = pipeline_cache.queue_compute_pipeline(ComputePipelineDescriptor {
            label: Some("GPU readback compute shader".into()),
            layout: vec![layout.clone()],
            push_constant_ranges: Vec::new(),
            shader: shader.clone(),
            shader_defs: Vec::new(),
            entry_point: "main".into(),
            zero_initialize_workgroup_memory: false,
        });
        ComputePipeline { layout, pipeline }
    }

examples/shader/compute_shader_game_of_life.rs (lines 175-183)

    fn from_world(world: &mut World) -> Self {
        let render_device = world.resource::<RenderDevice>();
        let texture_bind_group_layout = render_device.create_bind_group_layout(
            "GameOfLifeImages",
            &BindGroupLayoutEntries::sequential(
                ShaderStages::COMPUTE,
                (
                    texture_storage_2d(TextureFormat::R32Float, StorageTextureAccess::ReadOnly),
                    texture_storage_2d(TextureFormat::R32Float, StorageTextureAccess::WriteOnly),
                ),
            ),
        );
        let shader = world.load_asset(SHADER_ASSET_PATH);
        let pipeline_cache = world.resource::<PipelineCache>();
        let init_pipeline = pipeline_cache.queue_compute_pipeline(ComputePipelineDescriptor {
            label: None,
            layout: vec![texture_bind_group_layout.clone()],
            push_constant_ranges: Vec::new(),
            shader: shader.clone(),
            shader_defs: vec![],
            entry_point: Cow::from("init"),
            zero_initialize_workgroup_memory: false,
        });
        let update_pipeline = pipeline_cache.queue_compute_pipeline(ComputePipelineDescriptor {
            label: None,
            layout: vec![texture_bind_group_layout.clone()],
            push_constant_ranges: Vec::new(),
            shader,
            shader_defs: vec![],
            entry_point: Cow::from("update"),
            zero_initialize_workgroup_memory: false,
        });

        GameOfLifePipeline {
            texture_bind_group_layout,
            init_pipeline,
            update_pipeline,
        }
    }

pub fn process_queue(&mut self)

Process the pipeline queue and create all pending pipelines if possible.

This is generally called automatically during the RenderSet::Render step, but can be called manually to force creation at a different time.

Trait Implementations

impl Resource for PipelineCache

where PipelineCache: Send + Sync + 'static,