Pass
{
	Tags{"LightMode" = "LightweightForward"}
	${Tags}
	${Blending}
	${Culling}
	${ZTest}
	${ZWrite}

	HLSLPROGRAM
    // Required to compile gles 2.0 with standard srp library
    #pragma prefer_hlslcc gles
	#pragma target 3.0

    // -------------------------------------
    // Lightweight Pipeline keywords
    // We have no good approach exposed to skip shader variants, e.g, ideally we would like to skip _CASCADE for all puctual lights
    // Lightweight combines light classification and shadows keywords to reduce shader variants.
    // Lightweight shader library declares defines based on these keywords to avoid having to check them in the shaders
    // Core.hlsl defines _MAIN_LIGHT_DIRECTIONAL and _MAIN_LIGHT_SPOT (point lights can't be main light)
    // Shadow.hlsl defines _SHADOWS_ENABLED, _SHADOWS_SOFT, _SHADOWS_CASCADE, _SHADOWS_PERSPECTIVE
    #pragma multi_compile _ _MAIN_LIGHT_DIRECTIONAL_SHADOW _MAIN_LIGHT_DIRECTIONAL_SHADOW_CASCADE _MAIN_LIGHT_DIRECTIONAL_SHADOW_SOFT _MAIN_LIGHT_DIRECTIONAL_SHADOW_CASCADE_SOFT _MAIN_LIGHT_SPOT_SHADOW _MAIN_LIGHT_SPOT_SHADOW_SOFT
    #pragma multi_compile _ _MAIN_LIGHT_COOKIE
    #pragma multi_compile _ _ADDITIONAL_LIGHTS
    #pragma multi_compile _ _VERTEX_LIGHTS
    #pragma multi_compile _ _MIXED_LIGHTING_SUBTRACTIVE
    #pragma multi_compile _ FOG_LINEAR FOG_EXP2

    // -------------------------------------
    // Unity defined keywords
    #pragma multi_compile _ UNITY_SINGLE_PASS_STEREO STEREO_INSTANCING_ON STEREO_MULTIVIEW_ON
    #pragma multi_compile _ DIRLIGHTMAP_COMBINED LIGHTMAP_ON

    //--------------------------------------
    // GPU Instancing
    #pragma multi_compile_instancing

    // LW doesn't support dynamic GI. So we save 30% shader variants if we assume
    // LIGHTMAP_ON when DIRLIGHTMAP_COMBINED is set
    #ifdef DIRLIGHTMAP_COMBINED
    #define LIGHTMAP_ON
    #endif

    #pragma vertex vert
	#pragma fragment frag

	${Defines}

	#include "LWRP/ShaderLibrary/Core.hlsl"
	#include "LWRP/ShaderLibrary/Lighting.hlsl"
	#include "CoreRP/ShaderLibrary/Color.hlsl"
	#include "CoreRP/ShaderLibrary/UnityInstancing.hlsl"
	#include "ShaderGraphLibrary/Functions.hlsl"

	${Graph}

	struct GraphVertexOutput
    {
        float4 clipPos                : SV_POSITION;
        float4 lightmapUVOrVertexSH   : TEXCOORD0;
		half4 fogFactorAndVertexLight : TEXCOORD1; // x: fogFactor, yzw: vertex light
    	float4 shadowCoord            : TEXCOORD2;
        ${Interpolators}
        UNITY_VERTEX_INPUT_INSTANCE_ID
    };

    GraphVertexOutput vert (GraphVertexInput v)
	{
	    v = PopulateVertexData(v);

        GraphVertexOutput o = (GraphVertexOutput)0;

        UNITY_SETUP_INSTANCE_ID(v);
    	UNITY_TRANSFER_INSTANCE_ID(v, o);

        ${VertexShader}

		float3 lwWNormal = TransformObjectToWorldNormal(v.normal);
		float3 lwWorldPos = TransformObjectToWorld(v.vertex.xyz);
		float4 clipPos = TransformWorldToHClip(lwWorldPos);

 		// We either sample GI from lightmap or SH. lightmap UV and vertex SH coefficients
	    // are packed in lightmapUVOrVertexSH to save interpolator.
	    // The following funcions initialize
	    OUTPUT_LIGHTMAP_UV(v.texcoord1, unity_LightmapST, o.lightmapUVOrVertexSH);
	    OUTPUT_SH(lwWNormal, o.lightmapUVOrVertexSH);

	    half3 vertexLight = VertexLighting(lwWorldPos, lwWNormal);
	    half fogFactor = ComputeFogFactor(clipPos.z);
	    o.fogFactorAndVertexLight = half4(fogFactor, vertexLight);
	    o.clipPos = clipPos;

#if defined(_SHADOWS_ENABLED) && !defined(_SHADOWS_CASCADE)
	    o.shadowCoord = ComputeShadowCoord(lwWorldPos);
#else
		o.shadowCoord = float4(0, 0, 0, 0);
#endif

		return o;
	}

	half4 frag (GraphVertexOutput IN) : SV_Target
    {
    	UNITY_SETUP_INSTANCE_ID(IN);

    	${LocalPixelShader}

        SurfaceInputs surfaceInput = (SurfaceInputs)0;
        ${SurfaceInputs}

        SurfaceDescription surf = PopulateSurfaceData(surfaceInput);

		float3 Albedo = float3(0.5, 0.5, 0.5);
		float3 Specular = float3(0, 0, 0);
		float Metallic = 1;
		float3 Normal = float3(0, 0, 1);
		float3 Emission = 0;
		float Smoothness = 0.5;
		float Occlusion = 1;
		float Alpha = 1;
		float AlphaClipThreshold = 0;

        ${SurfaceOutputRemap}

		InputData inputData;
		inputData.positionWS = WorldSpacePosition;

#ifdef _NORMALMAP
	    inputData.normalWS = TangentToWorldNormal(Normal, WorldSpaceTangent, WorldSpaceBiTangent, WorldSpaceNormal);
#else
	    inputData.normalWS = normalize(WorldSpaceNormal);
#endif

#ifdef SHADER_API_MOBILE
	    // viewDirection should be normalized here, but we avoid doing it as it's close enough and we save some ALU.
	    inputData.viewDirectionWS = WorldSpaceViewDirection;
#else
	    inputData.viewDirectionWS = normalize(WorldSpaceViewDirection);
#endif

#ifdef _SHADOWS_ENABLED
	    inputData.shadowCoord = IN.shadowCoord;
#else
	    inputData.shadowCoord = float4(0, 0, 0, 0);
#endif

	    inputData.fogCoord = IN.fogFactorAndVertexLight.x;
	    inputData.vertexLighting = IN.fogFactorAndVertexLight.yzw;
	    inputData.bakedGI = SampleGI(IN.lightmapUVOrVertexSH, inputData.normalWS);

		half4 color = LightweightFragmentPBR(
			inputData, 
			Albedo, 
			Metallic, 
			Specular, 
			Smoothness, 
			Occlusion, 
			Emission, 
			Alpha);

		// Computes fog factor per-vertex
    	ApplyFog(color.rgb, IN.fogFactorAndVertexLight.x);

#if _AlphaClip
		clip(Alpha - AlphaClipThreshold);
#endif
		return color;
    }

	ENDHLSL
}