Gradient Character Shader

Applying gradient color to character shader to enhance foggy atmosphere (fake) feeling to blend with the scene better

Shader "Character/ToonLitVerticalFog" {
    Properties {
        _TopLine("Top Line Y", Float) = 0
        _BottomLine("Bottom Line Y", Float) = 0
        _OverTopColor ("OverTheTopColor", Color) = (1,1,1,1)
        _GradientTopColor ("GradientTopColor", Color) = (1,0,0,1)
        _GradientBottomColor ("GradientBottomColor", Color) = (0,1,0,0)
        _BelowBottomColor ("BelowTheBottomColor", Color) = (0,0,0,0)
        _Opacity ("Opacity", Float) = 1
        _ColorMult ("ColorMult", Float) = 1
        }

SubShader 
{
    Tags { "RenderType"="Transparent" "Queue"="Transparent"}
    LOD 100
    ZWrite Off
    Blend SrcAlpha OneMinusSrcAlpha
    
    Pass {  
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct appdata_t {
                float4 vertex : POSITION;
            };

            struct v2f {
                float4 vertex : SV_POSITION;
                float3 worldPos : TEXCOORD0;
            };

            fixed _TopLine;
            fixed _BottomLine;
            fixed4 _OverTopColor;
            fixed4 _BelowBottomColor;
            fixed4 _GradientTopColor;
            fixed4 _GradientBottomColor;
            fixed _Opacity;
            fixed _ColorMult;

            // remap value to 0-1 range
            float remap(float value, float minSource, float maxSource)
            {
                return (value-minSource)/(maxSource-minSource);
            }

            v2f vert (appdata_t v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
                return o;
            }
            
            fixed4 frag (v2f IN) : COLOR
            {
                fixed4 c = fixed4(0,0,0,0);
                // calculate gradient
                float v = remap(clamp(IN.worldPos.y,_BottomLine,_TopLine),_BottomLine,_TopLine);
                c = lerp(_GradientBottomColor,_GradientTopColor, v);
                if (IN.worldPos.y<_BottomLine) c=_BelowBottomColor; // set below the bottomline color
                if (IN.worldPos.y>_TopLine) c=_OverTopColor; // set over the topline color
                c = c * _ColorMult;
                c.a = c.a * _Opacity;
                return c;
            }
        ENDCG
    }
}
}