[Unity3D]Shader编程之扫描显示2

上一篇使用的方式是对UV进行剪裁，如果用于模型的话，会出现一些问题。本片使用的方式是对模型进行模型空间的剪裁，可设置剪裁方向。效果如下：

设置界面如下：

mode用于设置剪裁方向。
clip用于设置剪裁值。

shader实现如下：

Shader "XM/ScanEffect2" 
{
    Properties {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0
        _Clip("Clip", float) = 0
        [KeywordEnum(None, Left, Up, Forward)]_Mode("Mode", Float) = 0
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard fullforwardshadows vertex:vert

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex;

        struct Input {
            float2 uv_MainTex;
            float4 localPos;
        };

        half _Glossiness;
        half _Metallic;
        fixed4 _Color;
        float _Clip;
        float _Mode;

        void vert(inout appdata_full i, out Input o)
        {
            UNITY_INITIALIZE_OUTPUT(Input, o);
            o.localPos = i.vertex;
        }

        void surf (Input i, inout SurfaceOutputStandard o) {

            if(i.localPos.x >= _Clip && _Mode == 1 || i.localPos.y >= _Clip && _Mode == 2|| i.localPos.z >= _Clip && _Mode == 3)
            {
                clip(-1);
            }

            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, i.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}