AccelerationStructure Support for VividRP RenderGraph

April 7, 2026 · View on GitHub

Overview

VividRP's RenderGraph now includes full support for ray tracing acceleration structures through the serializable descriptor system. This enables declarative configuration of ray tracing resources in the graph editor.

New Components

RenderGraphAccelerationStructureDesc

Location: Runtime/RenderGraph/Resource/RenderGraphAccelerationStructureDesc.cs

A serializable descriptor class that mirrors Unity's RayTracingAccelerationStructureDesc but can be fully serialized in assets.

Properties:

Name - String identifier for debugging and profiling

Methods:

ToAccelerationStructureDesc() - Converts to Unity's RayTracingAccelerationStructureDesc
FromAccelerationStructureDesc(desc) - Creates from Unity's descriptor
Create(name) - Static factory method for creating new descriptors

RenderGraphAccelerationStructure

Location: Runtime/RenderGraph/Resource/RenderGraphAccelerationStructureDesc.cs

A serializable RenderGraph resource wrapper around Unity's RayTracingAccelerationStructure. It can lazily create a native acceleration structure from the serialized descriptor or wrap an externally managed one.

AccelerationStructureResourceNodeData

Location: Editor/RenderGraph/Nodes/AccelerationStructureResourceNodeData.cs

A dedicated resource node for authoring RTAS descriptors directly in the RenderGraph editor.

RTASBuildPass

Location: Runtime/RenderPass/Core/RTASBuildPass.cs

A compute pass that builds a scene RTAS into a RenderGraph resource without relying on SetGlobalRayTracingAccelerationStructure, so the resource can flow explicitly to downstream passes.

Integration with Existing System

The acceleration structure descriptor integrates seamlessly with the existing descriptor system:

Uses the same namespace (VividRP.Runtime) as other descriptors
Follows the same naming convention (RenderGraph[Type]Desc)
Provides conversion methods to/from Unity's native types
Includes factory methods for common use cases

Usage Patterns

Building an Acceleration Structure

Connect an AccelerationStructureResourceNodeData node to RTASBuildPass when you want an authored RTAS descriptor, or use the pass-owned default RTAS output directly and forward it to downstream ray tracing passes.

Using an Acceleration Structure for Ray Tracing

In a downstream pass, declare a [RenderGraphResource] RenderGraphAccelerationStructure field with AccessFlags.Read and bind it from RTASBuildPass through the graph. At record time, use the wrapped native object with SetRayTracingAccelerationStructure(...) or other ray tracing command buffer APIs.

Benefits

Explicit Dependencies - RTAS lifetime and ordering stay inside RenderGraph instead of hidden global state
Async Compute Friendly - RTAS build and consumer passes can use explicit resource edges
Serialization - Descriptor and node data are stored in graph assets
Integration - Works alongside existing texture, buffer, history, and render-list resources
Ray Tracing Ready - Downstream passes can consume the same RTAS resource directly

Future Enhancements

Scene Culling Controls - More authoring-time control over RTAS build scope and filtering
Ray Tracing Pass Templates - Prebuilt nodes for common ray tracing workflows
Inline Ray Tracing - Support for inline ray tracing in raster passes
RTAS Validation - Additional editor/runtime validation for unsupported hardware or pass layouts

Hardware Requirements

Ray tracing acceleration structures require:

DirectX 12 with DXR support (Windows)
Vulkan with ray tracing extensions (Windows, Linux)
Metal with ray tracing support (macOS, iOS)
Hardware with ray tracing capabilities (NVIDIA RTX, AMD RDNA 2+, Intel Arc, Apple Silicon)

Shader Integration

Example compute shader using acceleration structure:

#pragma kernel RayTraceMain

RWTexture2D<float4> _OutputTexture;
RaytracingAccelerationStructure _AccelStruct;

[numthreads(8, 8, 1)]
void RayTraceMain(uint3 id : SV_DispatchThreadID)
{
    // Setup ray
    RayDesc ray;
    ray.Origin = float3(0, 0, 0);
    ray.Direction = normalize(float3(id.xy, 1));
    ray.TMin = 0.001;
    ray.TMax = 1000.0;

    // Trace ray
    RayQuery<RAY_FLAG_NONE> query;
    query.TraceRayInline(_AccelStruct, RAY_FLAG_NONE, 0xFF, ray);
    query.Proceed();

    // Write result
    float4 color = query.CommittedStatus() == COMMITTED_TRIANGLE_HIT
        ? float4(1, 1, 1, 1)
        : float4(0, 0, 0, 1);
    _OutputTexture[id.xy] = color;
}