void DoClipTestToTargetAlphaValue(half alpha) 
{
    // iOS上编译该shader出了点问题
    /*
    if(_UseAlphaClipping)
    {   
        clip(alpha - _Cutoff);
    }
    */

    // 并非最佳方案，尽量使用GPU原生特性
    clip(alpha - _Cutoff + (1.0001-_UseAlphaClipping));
}

// this function will be used by all direct lights (directional/point/spot)
half3 ShadeSingleLightDefaultMethod(SurfaceData surfaceData, LightingData lightingData, Light light)
{
    half3 N = lightingData.normalWS;
    half3 L = light.direction;
    half3 V = lightingData.viewDirectionWS;
    half3 H = normalize(L+V);

    half NoL = dot(N,L);

    half lightAttenuation = 1;

    // light's shadow map. If you prefer hard shadow, you can smoothstep() light.shadowAttenuation to make it sharp.
    lightAttenuation *= lerp(1,light.shadowAttenuation,_ReceiveShadowMappingAmount);

    // light's distance & angle fade for point light & spot light (see GetAdditionalPerObjectLight() in Lighting.hlsl)
    // Lighting.hlsl -> https://github.com/Unity-Technologies/Graphics/blob/master/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl
    lightAttenuation *= min(2,light.distanceAttenuation); //max intensity = 2, prevent over bright if light too close, can expose this float to editor if you wish to

    // N dot L
    // simplest 1 line cel shade, you can always replace this line by your own better method !
    lightAttenuation *= smoothstep(_CelShadeMidPoint-_CelShadeSoftness,_CelShadeMidPoint+_CelShadeSoftness, NoL);

    // don't want direct lighting becomes too bright for toon lit characters? set this value to a lower value 
    lightAttenuation *= _DirectLightMultiplier;

    return surfaceData.albedo * light.color * lightAttenuation;
}