Unity3D Shader 高斯模糊

Shader "Hidden/GaussianBlur"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_BlurSize ("Blur Size", Float) = 0.1
}

CGINCLUDE

#include "UnityCG.cginc"

sampler2D _MainTex;
uniform half4 _MainTex_TexelSize;
uniform float _BlurSize;

static const half weight[4] = {0.0205, 0.0855, 0.232, 0.324};
static const half4 coordOffset = half4(1.0h,1.0h,-1.0h,-1.0h);

struct v2f_blurSGX
{
float4 pos:SV_POSITION;
half2 uv:TEXCOORD0;
half4 uvoff[3]:TEXCOORD1;
};

v2f_blurSGX vert_BlurHorizontal(appdata_img v)
{
v2f_blurSGX o;
o.pos = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = v.texcoord.xy;
half2 offs = _MainTex_TexelSize.xy*half2(1,0)*_BlurSize;
o.uvoff[0] = v.texcoord.xyxy+offs.xyxy*coordOffset*3;
o.uvoff[1] = v.texcoord.xyxy+offs.xyxy*coordOffset*2;
o.uvoff[2] = v.texcoord.xyxy+offs.xyxy*coordOffset;

return o;
}

v2f_blurSGX vert_BlurVertical(appdata_img v)
{
v2f_blurSGX o;
o.pos = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = v.texcoord.xy;

half2 offs = _MainTex_TexelSize.xy*half2(0,1)*_BlurSize;
o.uvoff[0] = v.texcoord.xyxy+offs.xyxy*coordOffset*3;
o.uvoff[1] = v.texcoord.xyxy+offs.xyxy*coordOffset*2;
o.uvoff[2] = v.texcoord.xyxy+offs.xyxy*coordOffset;

return o;
}

fixed4 frag_Blur(v2f_blurSGX i):SV_Target
{

fixed4 c = tex2D(_MainTex,i.uv)*weight[3];
for(int idx=0; idx<3; idx++)
{
c+=tex2D(_MainTex,i.uvoff[idx].xy)*weight[idx];
c+=tex2D(_MainTex,i.uvoff[idx].zw)*weight[idx];
}

return c;
}

ENDCG

SubShader
{
// No culling or depth
Cull Off ZWrite Off

Pass
{
ZTest Always
CGPROGRAM
#pragma vertex vert_BlurHorizontal
#pragma fragment frag_Blur

ENDCG
}

Pass
{
ZTest Always
CGPROGRAM
#pragma vertex vert_BlurVertical
#pragma fragment frag_Blur

ENDCG
}
}
}

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Camera))]
[ExecuteInEditMode]
public class Blur : MonoBehaviour {

public Material ma;

public float BlurSize =10;
public int interator = 2;

void OnRenderImage (RenderTexture sourceTexture, RenderTexture destTexture)
{

ma.SetFloat ("_BlurSize", BlurSize);
int rtW = sourceTexture.width/8;
int rtH = sourceTexture.height/8;

RenderTexture rtTempA = RenderTexture.GetTemporary (rtW, rtH, 0, sourceTexture.format);
rtTempA.filterMode = FilterMode.Bilinear;

RenderTexture rtTempB = RenderTexture.GetTemporary (rtW, rtH, 0, sourceTexture.format);
rtTempB.filterMode = FilterMode.Bilinear;

for (int i = 0; i < interator; i++) {
if (0 == i) {
Graphics.Blit (sourceTexture, rtTempA,ma,0);
Graphics.Blit (rtTempA, rtTempB, ma, 1);
} else {

Graphics.Blit (rtTempB, rtTempA, ma, 0);
Graphics.Blit (rtTempA, rtTempB,ma,1);
}

}

Graphics.Blit(rtTempB, destTexture);

RenderTexture.ReleaseTemporary(rtTempA);
RenderTexture.ReleaseTemporary(rtTempB);
}

}