根据模型的Height进行颜色的渐变 （Shader相关）

有个Shader需求：
1.根据模型的Height进行颜色的渐变
2.a值读取给定的皮肤Texture
自己写了个，基本满足：



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

// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'

Shader "Test/Shader_HeightColorLocalSpace"
{
 Properties 
    {
         _Color("SourceColor", Color) = (1,0,0,1)
        _Color2("DestColor2", Color) = (1,1,1,1)
        _ButtonY("ModelHeight", Range(0.1,1000)) = 1
         _Glossiness("Smoothness", Range(0,1)) = 0.5
        _Metallic("Metallic", Range(0,1)) = 0.0
        _MainTex("MainTex",2D)= "white" {}
    }
    SubShader 
    {
      Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
      Fog { Mode Off }
      Blend SrcAlpha OneMinusSrcAlpha
      ZWrite Off
      Cull Off
      

          Pass {
            ColorMaterial AmbientAndDiffuse
            SetTexture [_MainTex] {
                Combine texture * primary
            }
        }

        Pass 
        {        
            Offset 1, 1
            
            Fog { Mode Off }
            ZWrite On
            ZTest LEqual
            Cull Off
            Lighting Off
               CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #pragma multi_compile __ ENABLE_SPLITALPHA
            
            #include "UnityCG.cginc"
                
            fixed4 _Color;
            fixed4 _Color2;
            float _ButtonY;
               sampler2D _MainTex;

            
             struct appdata_t
            {
                float4 vertex : POSITION;
                half4 color : COLOR;
                float2 texcoord : TEXCOORD0;
            };

            struct v2f
            {
                float4 vertex : POSITION;
                  float2  uv : TEXCOORD1;
                half4 color : COLOR;
            };

            v2f o;
            uniform float4 _MainTex_ST;
            v2f vert (appdata_t v)
            {
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                o.color =  (lerp(_Color, _Color2, o.vertex.y / _ButtonY));
                return o;
            }

            half4 frag (v2f IN) : COLOR
            {
                half4 col;
                col.rgb = IN.color;
              
                 fixed4 texcol = tex2D(_MainTex, IN.uv);
                col.a = texcol.a;
               // col.a = 1;
                 return col;
            }

            ENDCG
        }
    }
}