Simple Line Integral Convolution shader for Unity.

LIC.shader

Shader "Mattaz/LIC" {
	Properties {
		_VectorFieldTex 	("Vector Field Texture",	2D) 		= "white" {}
		_NoiseTex 		("Noise Texture", 		2D) 		= "white" {}
		_FlowLength		("Flow Length", 		int)		= 10
	}
	SubShader {
	
		Tags { "RenderType"="Opaque" }
		LOD 200
		
		CGINCLUDE
		
		#include "UnityCG.cginc"

		sampler2D _VectorFieldTex;
		float4 _VectorFieldTex_TexelSize;
		sampler2D _NoiseTex;
		int _FlowLength;
		
		float4 frag (v2f_img IN) : COLOR {
			float3 col = tex2D(_NoiseTex, IN.uv);
			int w = 0;
			
			float2 v = (tex2D(_VectorFieldTex, IN.uv).xy - 0.5) * 2;
			v.x *= _VectorFieldTex_TexelSize.x;
			v.y *= _VectorFieldTex_TexelSize.y;
			
			float2 st0 = IN.uv;
			for(int i = 0; i < _FlowLength; i++) {
				st0 += v;
				float3 n = tex2D(_NoiseTex, st0).rgb;
				col += n;
				w++;
			}
			
			float2 st1 = IN.uv;
			for(int i = 0; i < _FlowLength; i++) {
				st1 -= v;
				float3 n = tex2D(_NoiseTex, st1).rgb;
				col += n;
				w++;
			}
		
			col /= w;
		
			return float4(col, 1);
		}
	
		ENDCG
		
		Pass {
			CGPROGRAM
			#pragma vertex vert_img
			#pragma fragment frag
			ENDCG
		}
	} 
	FallBack "Diffuse"
}