RenderTask

[JMS55]

Objective

• Reduce boilerplate for render nodes, building on my experience writing SSAO, TAA, virtual geometry, Solari, etc
• Provide the missing low-level render API helper:
  • High level - Material and FullscreenMaterial
  • Mid level - Phase stuff
  • Low level - Missing until now

Solution

• Provide a new RenderTask trait to handle all the boilerplate you would otherwise have to write manually:
  • Checking GPU features/limits when setting up the plugin
  • Setting up a render graph node and edge ordering
  • Preparing and caching textures and buffers
  • Preparing and caching pipelines
  • Preparing and caching bind groups/layouts
  • Setting up wgpu compute/render passes and setting state between dispatches/draws
  • Inserting profiling spans

Testing

• Did you test these changes? If so, how?
• Are there any parts that need more testing?
• How can other people (reviewers) test your changes? Is there anything specific they need to know?
• If relevant, what platforms did you test these changes on, and are there any important ones you can't test?

---

Showcase

impl RenderTask for SolariLighting {
    type RenderNodeLabel = node::graph::SolariLightingNode;
    type RenderNodeSubGraph = Core3d;
    fn render_node_ordering() -> impl IntoRenderNodeArray {
        (
            Node3d::EndPrepasses,
            node::graph::SolariLightingNode,
            Node3d::EndMainPass,
        )
    }

    fn encode_commands(&self, mut encoder: RenderTaskEncoder, entity: Entity, world: &World) {
        let Some((
            solari_lighting_resources,
            view_target,
            view_prepass_textures,
            view_uniform_offset,
            previous_view_uniform_offset,
        )) = world.entity(entity).get_components::<(
            &SolariLightingResources,
            &ViewTarget,
            &ViewPrepassTextures,
            &ViewUniformOffset,
            &PreviousViewUniformOffset,
        )>()
        else {
            return;
        };

        let frame_count = world.resource::<FrameCount>();
        let frame_index = frame_count.0.wrapping_mul(5782582);

        let push_constants = &[frame_index, self.reset as u32];

        encoder
            .compute_pass("presample_light_tiles")
            .shader(load_embedded_asset!(world, "presample_light_tiles.wgsl"))
            .push_constants(push_constants)
            .dispatch_1d(LIGHT_TILE_BLOCKS as u32);
    }
}

[torsteingrindvik]

Is ordering always (before, myself, after)? If so is it enough to specify before and after?

[JMS55]

Is ordering always (before, myself, after)? If so is it enough to specify before and after?

I suppose yeah, but before/after can be more than 1 thing.

[atlv24]

I think @torsteingrindvik was suggesting having

    type AfterNodeLabel = Node3d::EndPrepasses;
    type RenderNodeLabel = node::graph::SolariLightingNode;
    type BeforeNodeLabel = Node3d::EndMainPass;
    
    // this is the same for all RenderTasks
    fn render_node_ordering() -> impl IntoRenderNodeArray {
        (
            Self::AfterNodeLabel,
            Self::RenderNodeLabel,
            Self::BeforeNodeLabel,
        )
    }

[JMS55]

No yeah I get the idea. I just don't think we can do that because you could want more than 1 thing before/after.

[torsteingrindvik]

About the ordering I suppose

    // Ordering defined by a (before) tuple and an (after) tuple
    fn render_node_ordering() -> (impl IntoRenderNodeArray, impl IntoRenderNodeArray) {
        (
            (Node3d::Before0),
            (Node3d::After0, Node3d::After1),
        )
    }

could work, alternatively splitting it up

    fn render_nodes_before() -> impl IntoRenderNodeArray {
        Node3d::Before0
    }

    fn render_nodes_after() -> impl IntoRenderNodeArray {
        (Node3d::After0, Node3d::After1)
    }

not a huge ergonomics win but perhaps worth considering to not have to name the "self node" an extra time.

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