Shader "Custom/DissolveWithNoise" {
    Properties {
        _MainTex ("Sprite Texture", 2D) = "white" {}
        _NoiseTex ("Noise Texture", 2D) = "white" {}
        _DissolveAmount ("Dissolve Amount", Range(0, 1)) = 0.5
        _Threshold ("Threshold", Range(0, 1)) = 0.5
    }

    SubShader {
        Tags {"Queue"="Transparent" "RenderType"="Transparent"}
        LOD 100

        Pass {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct appdata {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            sampler2D _NoiseTex;
            float _DissolveAmount;
            float _Threshold;

            v2f vert (appdata v) {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target {
                fixed4 col = tex2D(_MainTex, i.uv);
                fixed4 noise = tex2D(_NoiseTex, i.uv);
                col.a = col.a * step(noise.r, _Threshold) * _DissolveAmount;
                return col;
            }
            ENDCG
        }
    }
    FallBack "Diffuse"
}