Shader "Custom/Vector"
{
  Properties
  {
    _Color ("Color", Color) = (1, 1, 1, 1)
  }

  SubShader
  {
    Tags { "RenderType"="Opaque" }
    LOD 100

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

      struct appdata
      {
        float4 vertex : POSITION;
        float3 normal : NORMAL;
        UNITY_VERTEX_INPUT_INSTANCE_ID
      };

      struct v2f
      {
        float4 vertex : SV_POSITION;
        float4 worldPos : TEXCOORD1;
        float3 normal : TEXCOORD2;
        float4 color : COLOR;
        UNITY_VERTEX_INPUT_INSTANCE_ID // necessary only if you want to access instanced properties in fragment Shader.
      };

      UNITY_INSTANCING_BUFFER_START(Props)
      UNITY_DEFINE_INSTANCED_PROP(float4, _Color)
      UNITY_INSTANCING_BUFFER_END(Props)
      
      v2f vert(appdata v)
      {
        v2f o;

        UNITY_SETUP_INSTANCE_ID(v);
        UNITY_TRANSFER_INSTANCE_ID(v, o); // necessary only if you want to access instanced properties in the fragment Shader.

        o.vertex = UnityObjectToClipPos(v.vertex);
        o.worldPos = mul(unity_ObjectToWorld, v.vertex);
        o.normal = UnityObjectToWorldNormal(v.normal);
        
        o.color = float4(1,1,1,1);
        return o;
      }
      
      fixed4 frag(v2f i) : SV_Target
      {
        // UNITY_SETUP_INSTANCE_ID(i); // necessary only if any instanced properties are going to be accessed in the fragment Shader.
        // UNITY_ACCESS_INSTANCED_PROP(Props, _Color);

        float t = 1 + clamp(dot(normalize(UnityWorldSpaceViewDir(i.worldPos)), i.normal), -1, 1);
        t = t / 2;
        t = t - 0.8;
        // float t = abs(i.worldPos.x) + abs(i.worldPos.y) + abs(i.worldPos.z);
        // t = t / 1;
        return i.color * t;
      }
      ENDCG
    }
  }
}