如何在Unity中使两个精灵的重叠区域变得透明？

Shader "Custom/TransparentOverlap" {
    Properties {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader {
        Tags { "Queue"="Transparent" "RenderType"="Transparent" }
        Pass {
            Blend SrcAlpha OneMinusSrcAlpha
            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;
            float4 _MainTex_ST;

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

            fixed4 frag (v2f i) : SV_Target {
                fixed4 col = tex2D(_MainTex, i.uv);
                col.a = 0.5; // 设置重叠区域的透明度，可根据需求调整
                return col;
            }
            ENDCG
        }
    }
}