struct Attributes
{
    float3 positionOS               : POSITION;
    float3 normalOS                 : NORMAL;
    UNITY_VERTEX_INPUT_INSTANCE_ID
};

struct Varyings
{
    float4 positionCS               : SV_POSITION;
    //UNITY_VERTEX_INPUT_INSTANCE_ID
};

//  Shadow caster specific input
float3 _LightDirection;
float3 _LightPosition;

Varyings ShadowPassVertex(Attributes input)
{
    Varyings output = (Varyings)0;
    UNITY_SETUP_INSTANCE_ID(input);

    float3 positionWS = TransformObjectToWorld(input.positionOS.xyz);
    float3 normalWS = TransformObjectToWorldDir(input.normalOS);

    #if _CASTING_PUNCTUAL_LIGHT_SHADOW
        float3 lightDirectionWS = normalize(_LightPosition - positionWS);
    #else
        float3 lightDirectionWS = _LightDirection;
    #endif

    output.positionCS = TransformWorldToHClip(ApplyShadowBias(positionWS, normalWS, lightDirectionWS));
    #if UNITY_REVERSED_Z
        output.positionCS.z = min(output.positionCS.z, UNITY_NEAR_CLIP_VALUE);
    #else
        output.positionCS.z = max(output.positionCS.z, UNITY_NEAR_CLIP_VALUE);
    #endif
    return output;
}

half4 ShadowPassFragment(Varyings input) : SV_TARGET
{
    #if defined(LOD_FADE_CROSSFADE) && !defined(SHADER_API_GLES)
        LODDitheringTransition(input.positionCS.xyz, unity_LODFade.x);
    #endif
    return 0;
}