#ifndef __LIGHTINGTEMPLATE_H__
#define __LIGHTINGTEMPLATE_H__


#include "UnityCG.cginc"
#include "UnityStandardBRDF.cginc"
#include "UnityStandardUtils.cginc"
#include "UnityPBSLighting.cginc"


uniform uint g_nNumDirLights;

//---------------------------------------------------------------------------------------------------------------------------------------------------------
// TODO:  clean up.. -va
#define MAX_SHADOW_LIGHTS 10
#define MAX_SHADOWMAP_PER_LIGHT 6
#define MAX_DIRECTIONAL_SPLIT  4

#define CUBEMAPFACE_POSITIVE_X 0
#define CUBEMAPFACE_NEGATIVE_X 1
#define CUBEMAPFACE_POSITIVE_Y 2
#define CUBEMAPFACE_NEGATIVE_Y 3
#define CUBEMAPFACE_POSITIVE_Z 4
#define CUBEMAPFACE_NEGATIVE_Z 5

CBUFFER_START(ShadowLightData)

float4 g_vShadow3x3PCFTerms0;
float4 g_vShadow3x3PCFTerms1;
float4 g_vShadow3x3PCFTerms2;
float4 g_vShadow3x3PCFTerms3;

float4 g_vDirShadowSplitSpheres[MAX_DIRECTIONAL_SPLIT];
float4x4 g_matWorldToShadow[MAX_SHADOW_LIGHTS * MAX_SHADOWMAP_PER_LIGHT];

CBUFFER_END
//---------------------------------------------------------------------------------------------------------------------------------------------------------


//UNITY_DECLARE_TEX2D(_LightTextureB0);
sampler2D _LightTextureB0;
UNITY_DECLARE_TEX2DARRAY(_spotCookieTextures);
UNITY_DECLARE_TEXCUBEARRAY(_pointCookieTextures);
		
StructuredBuffer<DirectionalLight> g_dirLightData;


#define VALVE_DECLARE_SHADOWMAP( tex ) Texture2D tex; SamplerComparisonState sampler##tex
#define VALVE_SAMPLE_SHADOW( tex, coord ) tex.SampleCmpLevelZero( sampler##tex, (coord).xy, (coord).z )

VALVE_DECLARE_SHADOWMAP(g_tShadowBuffer);

float ComputeShadow_PCF_3x3_Gaussian(float3 vPositionWs, float4x4 matWorldToShadow)
{
	float4 vPositionTextureSpace = mul(float4(vPositionWs.xyz, 1.0), matWorldToShadow);
	vPositionTextureSpace.xyz /= vPositionTextureSpace.w;

	float2 shadowMapCenter = vPositionTextureSpace.xy;

	if ((shadowMapCenter.x < 0.0f) || (shadowMapCenter.x > 1.0f) || (shadowMapCenter.y < 0.0f) || (shadowMapCenter.y > 1.0f))
		return 1.0f;

	float objDepth = saturate(257.0 / 256.0 - vPositionTextureSpace.z);

	float4 v20Taps;
	v20Taps.x = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms1.xy, objDepth)).x; //  1  1
	v20Taps.y = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms1.zy, objDepth)).x; // -1  1
	v20Taps.z = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms1.xw, objDepth)).x; //  1 -1
	v20Taps.w = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms1.zw, objDepth)).x; // -1 -1
	float flSum = dot(v20Taps.xyzw, float4(0.25, 0.25, 0.25, 0.25));
	if ((flSum == 0.0) || (flSum == 1.0))
		return flSum;
	flSum *= g_vShadow3x3PCFTerms0.x * 4.0;

	float4 v33Taps;
	v33Taps.x = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms2.xz, objDepth)).x; //  1  0
	v33Taps.y = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms3.xz, objDepth)).x; // -1  0
	v33Taps.z = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms3.zy, objDepth)).x; //  0 -1
	v33Taps.w = VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy + g_vShadow3x3PCFTerms2.zy, objDepth)).x; //  0  1
	flSum += dot(v33Taps.xyzw, g_vShadow3x3PCFTerms0.yyyy);

	flSum += VALVE_SAMPLE_SHADOW(g_tShadowBuffer, float3(shadowMapCenter.xy, objDepth)).x * g_vShadow3x3PCFTerms0.z;

	return flSum;
}

//---------------------------------------------------------------------------------------------------------------------------------------------------------
/**
* Gets the cascade weights based on the world position of the fragment and the positions of the split spheres for each cascade.
* Returns an invalid split index if past shadowDistance (ie 4 is invalid for cascade)
*/
float GetSplitSphereIndexForDirshadows(float3 wpos)
{
	float3 fromCenter0 = wpos.xyz - g_vDirShadowSplitSpheres[0].xyz;
	float3 fromCenter1 = wpos.xyz - g_vDirShadowSplitSpheres[1].xyz;
	float3 fromCenter2 = wpos.xyz - g_vDirShadowSplitSpheres[2].xyz;
	float3 fromCenter3 = wpos.xyz - g_vDirShadowSplitSpheres[3].xyz;
	float4 distances2 = float4(dot(fromCenter0, fromCenter0), dot(fromCenter1, fromCenter1), dot(fromCenter2, fromCenter2), dot(fromCenter3, fromCenter3));

	float4 vDirShadowSplitSphereSqRadii;
	vDirShadowSplitSphereSqRadii.x = g_vDirShadowSplitSpheres[0].w;
	vDirShadowSplitSphereSqRadii.y = g_vDirShadowSplitSpheres[1].w;
	vDirShadowSplitSphereSqRadii.z = g_vDirShadowSplitSpheres[2].w;
	vDirShadowSplitSphereSqRadii.w = g_vDirShadowSplitSpheres[3].w;
	fixed4 weights = float4(distances2 < vDirShadowSplitSphereSqRadii);
	weights.yzw = saturate(weights.yzw - weights.xyz);
	return 4 - dot(weights, float4(4, 3, 2, 1));
}

float SampleShadow(uint type, float3 vPositionWs, float3 vPositionToLightDirWs, uint lightIndex)
{
	float flShadowScalar = 1.0;
	int shadowSplitIndex = 0;

	if (type == DIRECTIONAL_LIGHT)
	{
		shadowSplitIndex = GetSplitSphereIndexForDirshadows(vPositionWs);
	}

	else if (type == SPHERE_LIGHT)
	{
		float3 absPos = abs(vPositionToLightDirWs);
		shadowSplitIndex = (vPositionToLightDirWs.z > 0) ? CUBEMAPFACE_NEGATIVE_Z : CUBEMAPFACE_POSITIVE_Z;
		if (absPos.x > absPos.y)
		{
			if (absPos.x > absPos.z)
			{
				shadowSplitIndex = (vPositionToLightDirWs.x > 0) ? CUBEMAPFACE_NEGATIVE_X : CUBEMAPFACE_POSITIVE_X;
			}
		}
		else
		{
			if (absPos.y > absPos.z)
			{
				shadowSplitIndex = (vPositionToLightDirWs.y > 0) ? CUBEMAPFACE_NEGATIVE_Y : CUBEMAPFACE_POSITIVE_Y;
			}
		}
	}

	flShadowScalar = ComputeShadow_PCF_3x3_Gaussian(vPositionWs.xyz, g_matWorldToShadow[lightIndex * MAX_SHADOWMAP_PER_LIGHT + shadowSplitIndex]);
	return flShadowScalar;
}


float3 ExecuteLightList(uint start, uint numLights, float3 vP, float3 vPw, float3 Vworld)
{
	UnityIndirect ind;
	UNITY_INITIALIZE_OUTPUT(UnityIndirect, ind);
	ind.diffuse = 0;
	ind.specular = 0;


	float3 ints = 0;
	
	uint l=0;

	for (int i = 0; i < g_nNumDirLights; i++)
	{
		DirectionalLight lightData = g_dirLightData[i];
		float atten = 1;

		[branch]
		if (lightData.uShadowLightIndex != 0xffffffff)
		{
			float shadowScalar = SampleShadow(DIRECTIONAL_LIGHT, vPw, 0, lightData.uShadowLightIndex);
			atten *= shadowScalar;
		}

		UnityLight light;
		light.color.xyz = lightData.vCol.xyz * atten;
		light.dir.xyz = mul((float3x3) g_mViewToWorld, -lightData.vLaxisZ).xyz;

		ints += EvalMaterial(light, ind);
	}

	// we need this outer loop for when we cannot assume a wavefront is 64 wide
	// since in this case we cannot assume the lights will remain sorted by type
	// during processing in lightlist_cs.hlsl
#if !defined(XBONE) && !defined(PLAYSTATION4)
	while(l<numLights)
#endif
	{
		uint uIndex = l<numLights ? FetchIndex(start, l) : 0;
		uint uLgtType = l<numLights ? g_vLightData[uIndex].uLightType : 0;

		// specialized loop for spot lights
		while(l<numLights && uLgtType==SPOT_LIGHT)
		{
			SFiniteLightData lgtDat = g_vLightData[uIndex];	
			float3 vLp = lgtDat.vLpos.xyz;

			float3 toLight  = vLp - vP;
			float dist = length(toLight);
			float3 vL = toLight / dist;
			
			float attLookUp = dist*lgtDat.fRecipRange; attLookUp *= attLookUp;
			float atten = tex2Dlod(_LightTextureB0, float4(attLookUp.rr, 0.0, 0.0)).UNITY_ATTEN_CHANNEL;
					
			// spot attenuation
			const float fProjVec = -dot(vL, lgtDat.vLaxisZ.xyz);		// spotDir = lgtDat.vLaxisZ.xyz
			float2 cookCoord = (-lgtDat.cotan)*float2( dot(vL, lgtDat.vLaxisX.xyz), dot(vL, lgtDat.vLaxisY.xyz) ) / fProjVec;

			const bool bHasCookie = (lgtDat.flags&IS_CIRCULAR_SPOT_SHAPE)==0;		// all square spots have cookies
			float d0 = 0.65;
			float4 angularAtt = float4(1,1,1,smoothstep(0.0, 1.0-d0, 1.0-length(cookCoord)));
			[branch]if(bHasCookie)
			{
				cookCoord = cookCoord*0.5 + 0.5;
				angularAtt = UNITY_SAMPLE_TEX2DARRAY_LOD(_spotCookieTextures, float3(cookCoord, lgtDat.iSliceIndex), 0.0);
			}
			atten *= angularAtt.w*(fProjVec>0.0);                           // finally apply this to the dist att.
			
			const bool bHasShadow = (lgtDat.flags&HAS_SHADOW)!=0;
			[branch]if(bHasShadow)
			{
				float shadowScalar = SampleShadow(SPOT_LIGHT, vPw, 0, lgtDat.uShadowLightIndex);
				atten *= shadowScalar;
			}

			UnityLight light;
			light.color.xyz = lgtDat.vCol.xyz*atten*angularAtt.xyz;
			light.dir.xyz = mul((float3x3) g_mViewToWorld, vL).xyz;		//unity_CameraToWorld

			ints += EvalMaterial(light, ind);

			++l; uIndex = l<numLights ? FetchIndex(start, l) : 0;
			uLgtType = l<numLights ? g_vLightData[uIndex].uLightType : 0;
		}
		
		// specialized loop for sphere lights
		while(l<numLights && uLgtType==SPHERE_LIGHT)
		{
			SFiniteLightData lgtDat = g_vLightData[uIndex];	
			float3 vLp = lgtDat.vLpos.xyz;

			float3 toLight  = vLp - vP; 
			float dist = length(toLight);
			float3 vL = toLight / dist;
			float3 vLw = mul((float3x3) g_mViewToWorld, vL).xyz;		//unity_CameraToWorld

			float attLookUp = dist*lgtDat.fRecipRange; attLookUp *= attLookUp;
			float atten = tex2Dlod(_LightTextureB0, float4(attLookUp.rr, 0.0, 0.0)).UNITY_ATTEN_CHANNEL;

			float4 cookieColor = float4(1,1,1,1);
			
			const bool bHasCookie = (lgtDat.flags&HAS_COOKIE_TEXTURE)!=0;
			[branch]if(bHasCookie)
			{
				float3 cookieCoord = -float3(dot(vL, lgtDat.vLaxisX.xyz), dot(vL, lgtDat.vLaxisY.xyz), dot(vL, lgtDat.vLaxisZ.xyz));	// negate to make vL a fromLight vector
				cookieColor = UNITY_SAMPLE_TEXCUBEARRAY_LOD(_pointCookieTextures, float4(cookieCoord, lgtDat.iSliceIndex), 0.0);
				atten *= cookieColor.w;
			}
			
			const bool bHasShadow = (lgtDat.flags&HAS_SHADOW)!=0;
			[branch]if(bHasShadow)
			{
				float shadowScalar = SampleShadow(SPHERE_LIGHT, vPw, vLw, lgtDat.uShadowLightIndex);
				atten *= shadowScalar;
			}

			UnityLight light;
			light.color.xyz = lgtDat.vCol.xyz*atten*cookieColor.xyz;
			light.dir.xyz = vLw;
					
			ints += EvalMaterial(light, ind);
					
			++l; uIndex = l<numLights ? FetchIndex(start, l) : 0;
			uLgtType = l<numLights ? g_vLightData[uIndex].uLightType : 0;
		}

#if !defined(XBONE) && !defined(PLAYSTATION4)
		//if(uLgtType>=MAX_TYPES) ++l;
		if(uLgtType!=SPOT_LIGHT && uLgtType!=SPHERE_LIGHT) ++l;
#endif
	}

	return ints;
}





#endif