Shader "Custom/DirectionalWipeHardCut"
{
    Properties
    {
        _MainTex("Main Texture", 2D) = "white" {}
        _Color("Color Tint", Color) = (1,1,1,1)
        _Cutoff("Cutoff (0=全隐, 1=全显)", Range(0,1)) = 0
        _Axis("Axis (0=X,1=Y,2=Z)", Range(0,2)) = 1
        _Direction("Direction (1=正向,-1=反向)", Float) = 1
        _WipeMin("Wipe Range Min", Float) = -1
        _WipeMax("Wipe Range Max", Float) = 1
    }

        SubShader
        {
            Tags { "Queue" = "AlphaTest" "RenderType" = "TransparentCutout" }
            LOD 200
            ZWrite On
            Cull Off   // 关键点：关闭剔除，支持双面
            AlphaToMask On
            Blend Off     // 不使用透明混合

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

                sampler2D _MainTex;
                float4 _Color;
                float _Cutoff;
                float _Axis;
                float _Direction;
                float _WipeMin;
                float _WipeMax;

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

                struct v2f
                {
                    float2 uv : TEXCOORD0;
                    float4 vertex : SV_POSITION;
                    float3 localPos : TEXCOORD1;
                };

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

                fixed4 frag(v2f i) : SV_Target
                {
                    float3 dir = (_Axis < 0.5) ? float3(1,0,0) : (_Axis < 1.5 ? float3(0,1,0) : float3(0,0,1));
                    dir *= _Direction;

                    float proj = dot(i.localPos, dir);
                    float wipeCoord = (proj - _WipeMin) / (_WipeMax - _WipeMin);

                    float revCutoff = 1.0 - _Cutoff;
                    clip(wipeCoord - revCutoff); // 直接硬切

                    fixed4 col = tex2D(_MainTex, i.uv) * _Color;
                    return col;
                }
                ENDCG
            }
        }
}