Shader "Zhanyou/Effect/RadialBlur"
{
    Properties 
    {
        [PerRendererData] _MainTex ("Texture", 2D) = "white" {}
		_BlurFactor("BlurFactor", Range(0, 1)) = 0.12
		_BlurRatio("BlurRatio", Range(0, 1)) = 0
    }

    SubShader 
    {
        Pass 
        {       
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            #pragma fragmentoption ARB_precision_hint_fastest

			#include "UnityCG.cginc"

			uniform sampler2D _MainTex;
			uniform float _BlurFactor;
			uniform float _BlurRatio;

			half4 blur(sampler2D mainTex, float2 uv, float blurFactor)
			{
				float2 delta = 0.5 - uv;
				float4 uv01 = uv.xyxy + blurFactor * delta.xyxy * float4(0.5, 0.5, 1.0, 1.0);
				float4 uv23 = uv.xyxy + blurFactor * delta.xyxy * float4(1.5, 1.5, 2.0, 2.0);
				float4 uv45 = uv.xyxy + blurFactor * delta.xyxy * float4(2.5, 2.5, 3.0, 3.0);
				float4 uv67 = uv.xyxy + blurFactor * delta.xyxy * float4(3.5, 3.5, 4.0, 4.0);

				half4 color = 0.0;
				color += 0.225 * tex2D(mainTex, uv);
				color += 0.150 * tex2D(mainTex, uv01.xy);
				color += 0.150 * tex2D(mainTex, uv01.zw);
				color += 0.110 * tex2D(mainTex, uv23.xy);
				color += 0.110 * tex2D(mainTex, uv23.zw);
				color += 0.075 * tex2D(mainTex, uv45.xy);
				color += 0.075 * tex2D(mainTex, uv45.zw);
				color += 0.0525 * tex2D(mainTex, uv67.xy);
				color += 0.0525 * tex2D(mainTex, uv67.zw);
				return color;
			}

            fixed4 frag (v2f_img i) : SV_Target
            {
				return blur(_MainTex, i.uv, _BlurFactor * _BlurRatio);
            }
            ENDCG
        }
    }
}