SoftMaskForUGUI/Shaders/Resources/SoftMask.shader

Shader "Hidden/SoftMask" {

	SubShader {
		Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
		LOD 100
		
		Cull Off
		ZWrite Off
		Blend SrcAlpha One
		ColorMask [_ColorMask]

		Pass {  
			CGPROGRAM
			#pragma vertex vert_img
			#pragma fragment frag
			#pragma target 2.0
			
			#include "UnityCG.cginc"

			sampler2D _MainTex;
			float _Softness;
			float _Alpha;

			fixed4 frag (v2f_img i) : SV_Target
			{
			    half softness = max(_Softness, 0.0001f);
				return saturate(tex2D(_MainTex, i.uv).a/softness) * _Alpha;
			}
			ENDCG
		}
	}

}