RGB Separation Shader (Unity)

RGBSplit.shader

/*
RGB split shader
Built-inシェーダのvert_imgなどはここを参照のこと。
http://wiki.unity3d.com/index.php/Shader_Code
uvなどは頂点シェーダで計算したほうが軽くなりそう。
*/

Shader "Custom/RGBSplit" {

	Properties {
		_MainTex("MainTex", 2D) = ""{}
		_Strength("Strength", Range(0, 1)) = 0
		_Area("Area", Vector) = (0, 0, 1, 1)
		_Red("Red", Vector) = (0, 0, 0, 0)
		_Green("Green", Vector) = (0, 0, 0, 0)
		_Blue("Blue", Vector) = (0, 0, 0, 0)
	}

	SubShader {
		Pass {
			CGPROGRAM

			#include "UnityCG.cginc"

			#pragma vertex vert_img
			#pragma fragment frag

			sampler2D _MainTex;
			float _Strength;
			half4 _Area;
			half4 _Red, _Green, _Blue;

			fixed4 frag(v2f_img i) : COLOR {
				half2 uv = i.uv;
				fixed4 c;

				int inX = ((uv.x - _Area.x) * (_Area.z - uv.x)) >= 0;
				int inY = ((uv.y - _Area.y) * (_Area.w - uv.y)) >= 0;

				int isIn = inX * inY;

				half2 r = uv - _Red.xy * isIn;
				c.r = tex2D(_MainTex, r).r;

				half2 g = uv - _Green.xy * isIn;
				c.g = tex2D(_MainTex, g).g;

				half2 b = uv - _Blue.xy * isIn;
				c.b = tex2D(_MainTex, b).b;

				return c;
			}

			ENDCG
		}
	}
}

RGBSplitEffect.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// 特定の領域にだけRGBOffsetを掛けるための制御スクリプト
/// </summary>
public class RGBSplitEffect : MonoBehaviour {

	/// <summary>
	/// スプリットの定義
	/// </summary>
	[System.Serializable]
	public class SplitDefine
	{
		public Vector4 area;
		public Vector4 red;
		public Vector4 green;
		public Vector4 blue;
	}

	public Material rgbOffset;

	public SplitDefine splitDefine;

	private void OnRenderImage(RenderTexture source, RenderTexture destination)
	{
		BlitRGBOffset(splitDefine, source, destination);
	}

	private void BlitRGBOffset(SplitDefine define, RenderTexture src, RenderTexture dst)
	{
		rgbOffset.SetVector("_Area", define.area);
		rgbOffset.SetVector("_Red", define.red);
		rgbOffset.SetVector("_Green", define.green);
		rgbOffset.SetVector("_Blue", define.blue);

		Graphics.Blit(src, dst, rgbOffset);
	}

}