Shader "Custom/UIShader"
{
    Properties
    {
        _Color("Tint", Color) = (1,1,1,1)
        _MainTex("AlphaTex", 2D) = "white" {}
    }
        SubShader
    {
        Tags { "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" }
        Blend SrcAlpha OneMinusSrcAlpha
        Cull Off ZWrite Off
        Lighting Off

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

            sampler2D _MainTex;
            fixed4 _Color;

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

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

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

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 tex = tex2D(_MainTex, i.uv);
                return fixed4(_Color.rgb, tex.a * _Color.a); // 只用透明度
            }
            ENDCG
        }
    }
}