#include "$ENGINE$\LightGridCommon.bslinc"
#include "$ENGINE$\ReflectionCubemapCommon.bslinc"
#define USE_LIGHT_GRID_INDICES 1
#include "$ENGINE$\DirectLighting.bslinc"
#include "$ENGINE$\ImageBasedLighting.bslinc"

options
{
	forward = true;
};

mixin ForwardLighting
{
	mixin DirectLighting;
	mixin ReflectionCubemapCommon;
	mixin ImageBasedLighting;
	
	#if CLUSTERED
	mixin LightGridCommon;
	mixin LightAccumulatorIndexed;
	mixin ReflProbeAccumulatorIndexed;
	
	featureset = HighEnd;
	#else
	mixin LightAccumulatorDirect;
	mixin ReflProbeAccumulatorDirect;
	#endif
	
	variations
	{
		CLUSTERED = { true, false };
	};		

	code
	{
		#if CLUSTERED
		Buffer<uint4> gGridLightOffsetsAndSize;
		Buffer<uint2> gGridProbeOffsetsAndSize;
		#else
		[internal]
		cbuffer LightAndReflProbeParams
		{
			// Number of lights per type in the lights buffer
			// x - number of directional lights
			// y - offset to radial lights
			// z - offset to spot lights
			// w - total number of lights
			uint4 gLightOffsets;
			
			uint gReflProbeCount;
		}
		#endif

		float3 calcLighting(float3 worldPosition, float3 screenPosition, float2 uv, SurfaceData surfaceData)
		{
			#if CLUSTERED
			uint2 pixelPos = (uint2)screenPosition.xy;
			uint cellIdx = calcCellIdx(pixelPos, screenPosition.z);
			uint3 lightOffsetAndSize = gGridLightOffsetsAndSize[cellIdx].rgb;
			
			uint4 lightOffsets;
			lightOffsets.x = gLightCounts.x;
			lightOffsets.y = lightOffsetAndSize.x;
			lightOffsets.z = lightOffsets.y + lightOffsetAndSize.y;
			lightOffsets.w = lightOffsets.z + lightOffsetAndSize.z;
			
			uint2 reflProbeOffsetAndSize = gGridProbeOffsetsAndSize[cellIdx];
			#else
			uint4 lightOffsets = gLightOffsets;
			uint2 reflProbeOffsetAndSize = uint2(0, gReflProbeCount);			
			#endif
			
			float3 V = normalize(gViewOrigin - worldPosition);
			float3 N = surfaceData.worldNormal.xyz;
			float3 R = 2 * dot(V, N) * N - V;
			float3 specR = getSpecularDominantDir(N, R, surfaceData.roughness);
			
			float4 directLighting = getDirectLighting(worldPosition, V, specR, surfaceData, lightOffsets);
			float ao = gAmbientOcclusionTex.Sample(gAmbientOcclusionSamp, uv);
			float4 ssr = gSSRTex.Sample(gSSRSamp, uv);
			float3 imageBasedSpecular = getImageBasedSpecular(worldPosition, V, specR, surfaceData, ao, ssr,
				reflProbeOffsetAndSize.x, reflProbeOffsetAndSize.y);

			float3 totalLighting = directLighting.rgb;
			totalLighting.rgb += imageBasedSpecular;

			return totalLighting;
		}	
	};
};