Unity blending shader prototype

BlendingSurfaceShader.shader

Shader "Custom/BlendingSurfaceShader" {
	Properties {
		[NoScaleOffset] _NoiseTex ("Noise", 2D) = "white" {}

		[NoScaleOffset] _BottomDiffuseTex ("Bottom diffuse", 2D) = "white" {}
		[NoScaleOffset] [Normal] _BottomNormalTex ("Bottom normal", 2D) = "bump" {}

		[NoScaleOffset] _MiddleDiffuseTex ("Middle diffuse", 2D) = "white" {}
		[NoScaleOffset] [Normal] _MiddleNormalTex ("Middle normal", 2D) = "bump" {}

		[NoScaleOffset] _TopDiffuseTex ("Top diffuse", 2D) = "white" {}
		[NoScaleOffset] [Normal] _TopNormalTex ("Top normal", 2D) = "bump" {}

		_MiddleThreshold ("Middle threshold", Range (0, 1)) = 0.4
		_BlendThreshold ("Blend threshold", Range (0, 1)) = 0.1

		_Intensity ("Intensity", Range(0, 5)) = 3.0

		_Glossiness ("Smoothness", Range(0,1)) = 0.5
		_Metallic ("Metallic", Range(0,1)) = 0.0
	}
	SubShader {
		Tags { "RenderType"="Opaque" }
		LOD 200
		
		CGPROGRAM
		#pragma surface surf Standard vertex:vert addshadow
		#pragma target 3.0

		sampler2D _NoiseTex;
		sampler2D _BottomDiffuseTex;
		sampler2D _BottomNormalTex;
		sampler2D _MiddleDiffuseTex;
		sampler2D _MiddleNormalTex;
		sampler2D _TopDiffuseTex;
		sampler2D _TopNormalTex;

		half _MiddleThreshold;
		half _BlendThreshold;

		half _Intensity;

		half _Glossiness;
		half _Metallic;

		struct Input {
			float2 uv_NoiseTex;
			float2 uv_BottomDiffuseTex;
			float2 uv_MiddleDiffuseTex;
			float2 uv_TopDiffuseTex;
		};

		float map(float value, float low1, float high1, float low2, float high2){
    		return(low2 + (high2 - low2) * (value - low1) / (high1 - low1));
		}

		void vert (inout appdata_full v) {
          v.vertex.y = tex2Dlod (_NoiseTex, float4(v.texcoord.xy,0,0)) * _Intensity;
          v.normal.y = v.vertex.y = tex2Dlod (_NoiseTex, float4(v.texcoord.xy,0,0)) * _Intensity;
      	}

		void surf (Input IN, inout SurfaceOutputStandard o) {
			fixed4 noiseTexColor = tex2D (_NoiseTex, IN.uv_NoiseTex);
			fixed4 bottomTexColor = tex2D (_BottomDiffuseTex, IN.uv_BottomDiffuseTex);
			fixed4 middleTexColor = tex2D (_MiddleDiffuseTex, IN.uv_MiddleDiffuseTex);
			fixed4 topTexColor = tex2D (_TopDiffuseTex, IN.uv_TopDiffuseTex);

			float middleBlendedThreshold1 = _MiddleThreshold + _BlendThreshold;
			float middleBlendedThreshold2 = _MiddleThreshold - _BlendThreshold;

			float blend1 = 0;
			float blend2 = 0;

			if (noiseTexColor.r < middleBlendedThreshold2) {
				blend1 = 0;
			} else if (noiseTexColor.r >= middleBlendedThreshold2 && noiseTexColor.r <= middleBlendedThreshold1) {
				blend1 = map(noiseTexColor.r, middleBlendedThreshold2, _MiddleThreshold, 0, 1);
			} else {
				blend1 = 1;
			}

			if (noiseTexColor.r < middleBlendedThreshold2) {
				blend2 = 0;
			} else if (noiseTexColor.r >= middleBlendedThreshold2 && noiseTexColor.r <= middleBlendedThreshold1) {
				blend2 = map(noiseTexColor.r, middleBlendedThreshold1, _MiddleThreshold, 1, 0);
			} else {
				blend2 = 1;
			}

			fixed4 finalColor = (0, 0, 0, 0);
			
			if (noiseTexColor.r < _MiddleThreshold) {
				finalColor = lerp(bottomTexColor, middleTexColor, blend1);
			} else {
				finalColor = lerp(middleTexColor, topTexColor, blend2);
			}

			o.Albedo = finalColor.rgb;
			o.Metallic = _Metallic;
			o.Smoothness = _Glossiness;
			o.Alpha = finalColor.a;
		}
		ENDCG
	}
	FallBack "Diffuse"
}