在法线连续的情况下效果凑合，目前项目着急，先用着，以后有时间慢慢改进。

Shader "ShenDong/SimpleSection"
{
	Properties
	{
		_MainTex("Texture", 2D) = "white" {}
		_UVMulti("UV Multi",float) = 1
	}
	SubShader
	{
		Tags { "RenderType" = "Opaque" }
		LOD 100
		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#include "UnityCG.cginc"
			struct appdata
			{
				float4 vertex : POSITION;
				float3 normal : NORMAL;
			};

			struct v2f
			{
				float3 normal : NORMAL;
				float4 vertex : TEXCOORD0;
				float4 screenvert : SV_POSITION;
			};

			sampler2D _MainTex;
			float4 _MainTex_ST;
			float _UVMulti;

			float2 hash22(float2 p) {
				p = float2(dot(p, float2(127.1, 311.7)), dot(p, float2(269.5, 183.3)));
				return -1.0 + 2.0 * frac(sin(p) * 43758.5453123);
			}

			float perlin_noise(float2 p) {
				float2 pi = floor(p);
				float2 pf = p - pi;
				float2 w = pf * pf * (3.0 - 2.0 * pf);
				return lerp(lerp(dot(hash22(pi + float2(0.0, 0.0)), pf - float2(0.0, 0.0)),
					dot(hash22(pi + float2(1.0, 0.0)), pf - float2(1.0, 0.0)), w.x),
					lerp(dot(hash22(pi + float2(0.0, 1.0)), pf - float2(0.0, 1.0)),
						dot(hash22(pi + float2(1.0, 1.0)), pf - float2(1.0, 1.0)), w.x), w.y);
			}

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

			fixed4 frag(v2f i) : SV_Target
			{
				float3 f3 = i.vertex.xyz;
				f3 *= _UVMulti;
				f3.x = frac(f3.x);
				f3.y = frac(f3.y);
				f3.z = frac(f3.z);
				fixed4 c0 = tex2D(_MainTex, f3.xy);
				fixed4 c1 = tex2D(_MainTex, f3.yz);
				fixed4 c2 = tex2D(_MainTex, f3.zx);
				return c0 * i.normal.z * i.normal.z + c1 * i.normal.x * i.normal.x + c2 * i.normal.y * i.normal.y;
			}
			ENDCG
		}
	}
}