// Copyright (C) 2009-present, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#pragma anki technique RtMaterialFetch rgen

#include <AnKi/Shaders/RtMaterialFetch.hlsl>
#include <AnKi/Shaders/Include/GpuSceneTypes.h>

#define CHEAP 0

[shader("raygeneration")] void main()
{
	Vec2 outSize;
	g_colorAndPdfTex.GetDimensions(outSize.x, outSize.y);
	const Vec2 uv = Vec2(DispatchRaysIndex().xy) / outSize;

	const Vec4 v4 = mul(g_globalRendererConstants.m_matrices.m_invertedViewProjectionJitter, Vec4(uvToNdc(uv), 1.0, 1.0));
	const Vec3 worldPos = v4.xyz / v4.w;

	const Vec3 rayOrigin = g_globalRendererConstants.m_matrices.m_cameraTransform.getTranslationPart().xyz;
	const Vec3 rayDir = normalize(worldPos - rayOrigin);
	const F32 tMax = 1000.0;
	const F32 tMin = 0.1;
	constexpr U32 traceFlags = RAY_FLAG_FORCE_OPAQUE | RAY_FLAG_SKIP_PROCEDURAL_PRIMITIVES;
	Vec3 col;

#if !CHEAP
	const F32 texLod = 0.0;
	GBufferLight<F16> gbuffer = (GBufferLight<F16>)0;
	F32 rayT = 0.0;
	Bool backfacing = false;
	const Bool hit = materialRayTrace<F16>(rayOrigin, rayDir, tMin, tMax, texLod, gbuffer, rayT, backfacing, traceFlags);

	if(!hit)
	{
		col = Vec3(0.0, 0.0, 1.0);
	}
	else if(backfacing)
	{
		col = Vec3(1.0, 0.0, 1.0);
	}
	else
	{
		// col = gbuffer.m_diffuse * 1.0 + (gbuffer.m_worldNormal / 2.0 + 0.5) * 0.0 + rayT * 0.0 + gbuffer.m_emission * 0.0;
		col = directLighting(gbuffer, rayOrigin + rayDir * rayT, false, true, 100.0, true);
		col += gbuffer.m_diffuse * 0.3;

		// col = gbuffer.m_worldNormal / 2.0 + 0.5;
	}
#else
	RayQuery<RAY_FLAG_FORCE_OPAQUE> q;
	const U32 cullMask = 0xFFu;
	RayDesc ray;
	ray.Origin = rayOrigin;
	ray.TMin = tMin;
	ray.Direction = rayDir;
	ray.TMax = tMax;
	q.TraceRayInline(g_tlas, RAY_FLAG_FORCE_OPAQUE, cullMask, ray);
	while(q.Proceed())
	{
	}
	const Bool hit = q.CommittedStatus() == COMMITTED_TRIANGLE_HIT;

	Bool backfacing = false;
	if(hit)
	{
		backfacing = q.CommittedTriangleFrontFace();
	}

	if(!hit)
	{
		col = Vec3(0.0, 0.0, 1.0);
	}
	else if(backfacing)
	{
		col = Vec3(1.0, 0.0, 1.0);
	}
	else
	{
		UVec3 coloru = q.CommittedInstanceID();
		coloru >>= UVec3(16, 8, 0);
		coloru &= 0xFF;
		const Vec3 color = Vec3(coloru) / 255.0;

		const Vec3 positions[3] = spvRayQueryGetIntersectionTriangleVertexPositionsKHR(q, SpvRayQueryCommittedIntersectionKHR);
		const Vec3 vertNormal = normalize(cross(positions[1] - positions[0], positions[2] - positions[1]));

		const Vec3 worldNormal = normalize(mul(q.CommittedObjectToWorld3x4(), Vec4(vertNormal, 0.0)));

		GBufferLight<F16> gbuffer = (GBufferLight<F16>)0;
		gbuffer.m_diffuse = color;
		gbuffer.m_worldNormal = worldNormal;

		const F32 rayT = q.CommittedRayT();

		col = directLighting(gbuffer, rayOrigin + rayDir * rayT, false, true, 100.0, true);
		col += gbuffer.m_diffuse * 0.3;

		// col = worldNormal / 2.0 + 0.5;
		// col = frac(positions[0]);
	}
#endif

	g_colorAndPdfTex[DispatchRaysIndex().xy] = Vec4(col, 0.0);
}