How can I make the overlapping area of two sprites transparent in Unity?

Question

How can I make the overlapping area of two sprites transparent in Unity? Could you write a shader about it? After some research, I learned that I should use stencil buffer, but

Answer 1

There you go, keep in mind this is the first time I'm using stencil so I might have done something less than optimal. But it works with sprites as you requested.

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Sprites/Stencil"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)
        [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
    }

    SubShader
    {
        Tags
        { 
            "Queue"="Transparent" 
            "IgnoreProjector"="True" 
            "RenderType"="Transparent" 
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }

        Cull Off
        Lighting Off
        ZWrite Off
        Blend One OneMinusSrcAlpha



        Pass
        {
            Stencil {
                Ref 1
                Comp Greater
                Pass replace
                Fail Zero
            }

        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            struct appdata {
                float4 vertex : POSITION;
            };
            struct v2f {
                float4 pos : SV_POSITION;
            };
            v2f vert(appdata v) {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                return o;
            }
            half4 frag(v2f i) : SV_Target {
                return half4(0,0,0,0);
            }
        ENDCG
        }

        Pass
        {
            Stencil {
                Ref 1
                Comp equal
                Pass keep 
            }

        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile _ PIXELSNAP_ON
            #include "UnityCG.cginc"

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
            };

            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                float2 texcoord  : TEXCOORD0;
            };

            fixed4 _Color;

            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = UnityObjectToClipPos(IN.vertex);
                OUT.texcoord = IN.texcoord;
                OUT.color = IN.color * _Color;
                #ifdef PIXELSNAP_ON
                OUT.vertex = UnityPixelSnap (OUT.vertex);
                #endif

                return OUT;
            }

            sampler2D _MainTex;
            sampler2D _AlphaTex;
            float _AlphaSplitEnabled;

            fixed4 SampleSpriteTexture (float2 uv)
            {
                fixed4 color = tex2D (_MainTex, uv);

#if UNITY_TEXTURE_ALPHASPLIT_ALLOWED
                if (_AlphaSplitEnabled)
                    color.a = tex2D (_AlphaTex, uv).r;
#endif //UNITY_TEXTURE_ALPHASPLIT_ALLOWED

                return color;
            }

            fixed4 frag(v2f IN) : SV_Target
            {
                fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
                c.rgb *= c.a;
                return c;
            }
        ENDCG
        }
    }
}