Struct bevy::render::renderer::RenderContext

pub struct RenderContext<'w> { /* private fields */ }

The context with all information required to interact with the GPU.

The RenderDevice is used to create render resources and the the CommandEncoder is used to record a series of GPU operations.

Implementations

impl<'w> RenderContext<'w>

pub fn new( render_device: RenderDevice, adapter_info: AdapterInfo ) -> RenderContext<'w>

Creates a new RenderContext from a RenderDevice.

pub fn render_device(&self) -> &RenderDevice

Gets the underlying RenderDevice.

Examples found in repository

examples/shader/post_processing.rs (line 179)

    fn run(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext,
        (view_target, _post_process_settings): 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);
        render_pass.set_bind_group(0, &bind_group, &[]);
        render_pass.draw(0..3, 0..1);

        Ok(())
    }

pub fn command_encoder(&mut self) -> &mut CommandEncoder

Gets the current CommandEncoder.

Examples found in repository

examples/shader/compute_shader_game_of_life.rs (line 217)

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

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

        pass.set_bind_group(0, texture_bind_group, &[]);

        // 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_pipeline(init_pipeline);
                pass.dispatch_workgroups(SIZE.0 / WORKGROUP_SIZE, SIZE.1 / WORKGROUP_SIZE, 1);
            }
            GameOfLifeState::Update => {
                let update_pipeline = pipeline_cache
                    .get_compute_pipeline(pipeline.update_pipeline)
                    .unwrap();
                pass.set_pipeline(update_pipeline);
                pass.dispatch_workgroups(SIZE.0 / WORKGROUP_SIZE, SIZE.1 / WORKGROUP_SIZE, 1);
            }
        }

        Ok(())
    }

pub fn begin_tracked_render_pass<'a>( &'a mut self, descriptor: RenderPassDescriptor<'a, '_> ) -> TrackedRenderPass<'a>

Creates a new TrackedRenderPass for the context, configured using the provided descriptor.

Examples found in repository

examples/shader/post_processing.rs (lines 194-206)

    fn run(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext,
        (view_target, _post_process_settings): 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);
        render_pass.set_bind_group(0, &bind_group, &[]);
        render_pass.draw(0..3, 0..1);

        Ok(())
    }

pub fn add_command_buffer(&mut self, command_buffer: CommandBuffer)

Append a CommandBuffer to the command buffer queue.

If present, this will flush the currently unflushed CommandEncoder into a CommandBuffer into the queue before appending the provided buffer.

pub fn add_command_buffer_generation_task( &mut self, task: impl FnOnce(RenderDevice) -> CommandBuffer + Send + 'w )

Append a function that will generate a CommandBuffer to the command buffer queue, to be ran later.

If present, this will flush the currently unflushed CommandEncoder into a CommandBuffer into the queue before appending the provided buffer.

pub fn finish(self) -> Vec<CommandBuffer>

Finalizes and returns the queue of CommandBuffers.

This function will wait until all command buffer generation tasks are complete by running them in parallel (where supported).