TraceTransparentRays.urtshader

#define UNIFIED_RT_GROUP_SIZE_X 16
#define UNIFIED_RT_GROUP_SIZE_Y 8
#define UNIFIED_RT_PAYLOAD RayPayload
#define UNIFIED_RT_RAYGEN_FUNC RayGenExecute
#define UNIFIED_RT_CLOSESTHIT_FUNC ClosestHitExecute
#define UNIFIED_RT_ANYHIT_FUNC AnyHitExecute

struct RayPayload
{
    uint anyHits;
    int closestHit;
};

#include "Packages/com.unity.render-pipelines.core/Runtime/UnifiedRayTracing/TraceRay.hlsl"

int _AnyHitDecision;

uint AnyHitExecute(UnifiedRT::HitContext hitContext, inout RayPayload payload)
{
    payload.anyHits |= (1u << hitContext.InstanceID());

    return _AnyHitDecision;
}

void ClosestHitExecute(UnifiedRT::HitContext hitContext, inout RayPayload payload)
{
    payload.closestHit = hitContext.InstanceID();
}

UNIFIED_RT_DECLARE_ACCEL_STRUCT(_AccelStruct);

struct RayWithFlags
{
    float3 origin;
    float tMin;
    float3 direction;
    float tMax;
    uint culling;
    uint instanceMask;
    uint padding;
    uint padding2;
};

StructuredBuffer<RayWithFlags> _Rays;
RWStructuredBuffer<RayPayload> _Hits;


void RayGenExecute(UnifiedRT::DispatchInfo dispatchInfo)
{
    RayWithFlags rayWithFlags = _Rays[dispatchInfo.globalThreadIndex];
    UnifiedRT::Ray ray;
    ray.origin = rayWithFlags.origin;
    ray.direction = rayWithFlags.direction;
    ray.tMin = rayWithFlags.tMin;
    ray.tMax = rayWithFlags.tMax;

    UnifiedRT::RayTracingAccelStruct accelStruct = UNIFIED_RT_GET_ACCEL_STRUCT(_AccelStruct);

    RayPayload rayPayload = (RayPayload)0;
    rayPayload.closestHit = -1;
    UnifiedRT::TraceRay(dispatchInfo, accelStruct, 0xFFFFFFFF, ray, rayWithFlags.culling, rayPayload);

    _Hits[dispatchInfo.globalThreadIndex] = rayPayload;
}