#include "/Engine/Private/Common.ush"
#include "/Engine/Private/RayTracing/RayTracingCommon.ush"
#include "/Engine/Private/RayTracing/RayTracingHitGroupCommon.ush"

RWTexture2D<float4> outTex;
RaytracingAccelerationStructure TLAS;

RAY_TRACING_ENTRY_RAYGEN(RayTraceTestRGS)
{
	// reconstruct camera direction with a small (far) device z
	uint2 PixelCoord = DispatchRaysIndex().xy + View.ViewRectMin.xy;
	float3 WorldPosition;
	float3 CameraDirection;
	ReconstructTranslatedWorldPositionAndCameraDirectionFromDeviceZ(PixelCoord, 0.1f, WorldPosition, CameraDirection);

	// setup ray, simply shoot a long distance
	FRayDesc Ray;
	Ray.Origin = WorldPosition;
	Ray.Direction = CameraDirection;
	Ray.TMin = 0.0f;
	Ray.TMax = 9999;

	// SETTINGS
	//const uint InstanceInclusionMask = RAY_TRACING_MASK_OPAQUE;
	const uint InstanceInclusionMask = RAY_TRACING_MASK_ALL;
	const bool bEnableSkyLightContribution = false;
	const bool bIgnoreTranslucentMaterials = false;
	//uint RayFlags = RAY_FLAG_FORCE_OPAQUE | RAY_FLAG_CULL_BACK_FACING_TRIANGLES;
	uint RayFlags = RAY_FLAG_CULL_BACK_FACING_TRIANGLES;
	FRayCone RayCone = (FRayCone)0;


	//Payload Struct
    	FPackedMaterialClosestHitPayload Payload = (FPackedMaterialClosestHitPayload) 0;
	FMaterialClosestHitPayload UnpackedPayload = (FMaterialClosestHitPayload) 0;

        //TraceRay
	TraceMaterialRayPacked(
	Payload,
    	TLAS,
    	RayFlags,
    	InstanceInclusionMask,
    	Ray,
    	RayCone,
	bEnableSkyLightContribution);

	UnpackedPayload = UnpackRayTracingPayload(Payload, Ray);

	if (UnpackedPayload.IsHit())
        	outTex[PixelCoord] = UnpackedPayload.HitT * 0.001f);
	else
		outTex[PixelCoord] = 0.0f;
}

[shader("miss")]
void RayTraceTestMS(inout FPackedMaterialClosestHitPayload data)
{
	data.SetMiss();
}

RAY_TRACING_ENTRY_CLOSEST_HIT(RayTraceTestCHS,
    FPackedMaterialClosestHitPayload, Payload,
    FRayTracingIntersectionAttributes, Attributes)
{
    Payload.HitT = RayTCurrent();
}