URP Shader How to smooth ramp with smoothstep function

Questions & Answers
1

I write a urp shader, step the N Dot L, but result have aliasing.

How to smooth the ramp with smoothstep function and not use FXAA like?

This my code

Shader "test"
{
    Properties
    {
         _Step ("_Step", Float) = 2
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" "RenderPipeline"="UniversalRenderPipeline" "Queue"="Geometry"}

        Pass
        {
            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

            struct Attributes
            {
                float4 positionOS   : POSITION;
                float3 normalOS : NORMAL;
            };

            struct Varyings
            {
                float4 positionHCS  : SV_POSITION;
                float3 normalWS : TEXCOORD0;
                float3 viewWS : TEXCOORD1;
            };

            CBUFFER_START(UnityPerMaterial)
            half _Step;
            CBUFFER_END

            Varyings vert(Attributes IN)
            {
                Varyings OUT;

                float3 positionWS = TransformObjectToWorld(IN.positionOS.xyz);
                OUT.positionHCS = TransformWorldToHClip(positionWS);
                OUT.normalWS = TransformObjectToWorldNormal(IN.normalOS);
                OUT.viewWS = GetWorldSpaceViewDir(positionWS);
                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                Light light = GetMainLight();
                half3 lightColor = light.color * light.distanceAttenuation;
                half3 normalWS = normalize(IN.normalWS);
                half3 viewWS =  SafeNormalize(IN.viewWS);

                half NdotL = saturate(dot(normalWS, light.direction));
                half ramp = ceil(NdotL * 3) / 3;

                half4 totalColor = half4(ramp.xxx,1);
                return totalColor;
            }

            ENDHLSL
        }
    }
}

But result have Aliasing
199269-screenshot-20220829-002626.png

2

try into looking “partial derivatives” using functions like DDX , DDY, fWidth(note that this one is weirdly implemented in shadergrapgh).

there are several videos on youtube where gradients are smoothly broken with the aid of these values.