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unity屏幕高斯模糊

屏幕高斯模糊(Gaussian Blur)后期特效的实现

Gaussian Blur Post Effect


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cs代码:

using UnityEngine; 
using System.Collections; 
//设置在编辑模式下也执行该脚本 

[ExecuteInEditMode]

//添加选项到菜单中 

[AddComponentMenu("Learning Unity Shader/Lecture 15/RapidBlurEffect")]

public class RapidBlurEffect : MonoBehaviour 

{

//-------------------变量声明部分------------------- 

#region Variables

//指定Shader名称 

private string ShaderName = "Learning Unity Shader/Lecture 15/RapidBlurEffect";

//着色器和材质实例 

public Shader CurShader;

private Material CurMaterial;

//几个用于调节参数的中间变量 

public static int ChangeValue;

public static float ChangeValue2;

public static int ChangeValue3;

//降采样次数 

[Range(0, 6), Tooltip("[降采样次数]向下采样的次数。此值越大,则采样间隔越大,需要处理的像素点越少,运行速度越快。")]

public int DownSampleNum = 2;

//模糊扩散度 

[Range(0.0f, 20.0f), Tooltip("[模糊扩散度]进行高斯模糊时,相邻像素点的间隔。此值越大相邻像素间隔越远,图像越模糊。但过大的值会导致失真。")]

public float BlurSpreadSize = 3.0f;

//迭代次数 

[Range(0, 8), Tooltip("[迭代次数]此值越大,则模糊操作的迭代次数越多,模糊效果越好,但消耗越大。")]

public int BlurIterations = 3;

#endregion

//-------------------------材质的get&set---------------------------- 

#region MaterialGetAndSet

Material material

{

get 

{

if (CurMaterial == null)

{

CurMaterial = new Material(CurShader);

CurMaterial.hideFlags = HideFlags.HideAndDontSave;

}

return CurMaterial;

}

}

#endregion

#region Functions

//-----------------------------------------【Start()函数】---------------------------------------------  

// 说明:此函数仅在Update函数第一次被调用前被调用 

//-------------------------------------------------------------------------------------------------------- 

void Start()

{

//依次赋值 

ChangeValue = DownSampleNum;

ChangeValue2 = BlurSpreadSize;

ChangeValue3 = BlurIterations;

//找到当前的Shader文件 

CurShader = Shader.Find(ShaderName);

//判断当前设备是否支持屏幕特效 

if (!SystemInfo.supportsImageEffects)

{

enabled = false;

return;

}

}

//-------------------------------------【OnRenderImage()函数】------------------------------------  

// 说明:此函数在当完成所有渲染图片后被调用,用来渲染图片后期效果 

//-------------------------------------------------------------------------------------------------------- 

void OnRenderImage(RenderTexture sourceTexture, RenderTexture destTexture)

{

//着色器实例不为空,就进行参数设置 

if (CurShader != null)

{

//【0】参数准备 

//根据向下采样的次数确定宽度系数。用于控制降采样后相邻像素的间隔 

float widthMod = 1.0f / (1.0f * (1 << DownSampleNum));

//Shader的降采样参数赋值 

material.SetFloat("_DownSampleValue", BlurSpreadSize * widthMod);

//设置渲染模式:双线性 

sourceTexture.filterMode = FilterMode.Bilinear;

//通过右移,准备长、宽参数值 

int renderWidth = sourceTexture.width >> DownSampleNum;

int renderHeight = sourceTexture.height >> DownSampleNum;

// 【1】处理Shader的通道0,用于降采样 ||Pass 0,for down sample 

//准备一个缓存renderBuffer,用于准备存放最终数据 

RenderTexture renderBuffer = RenderTexture.GetTemporary(renderWidth, renderHeight, 0, sourceTexture.format);

//设置渲染模式:双线性 

renderBuffer.filterMode = FilterMode.Bilinear;

//拷贝sourceTexture中的渲染数据到renderBuffer,并仅绘制指定的pass0的纹理数据 

Graphics.Blit(sourceTexture, renderBuffer, material, 0);

//【2】根据BlurIterations(迭代次数),来进行指定次数的迭代操作 

for (int i = 0; i < BlurIterations; i++)

{

//【2.1】Shader参数赋值 

//迭代偏移量参数 

float iterationOffs = (i * 1.0f);

//Shader的降采样参数赋值 

material.SetFloat("_DownSampleValue", BlurSpreadSize * widthMod + iterationOffs);

// 【2.2】处理Shader的通道1,垂直方向模糊处理 || Pass1,for vertical blur 

// 定义一个临时渲染的缓存tempBuffer 

RenderTexture tempBuffer = RenderTexture.GetTemporary(renderWidth, renderHeight, 0, sourceTexture.format);

// 拷贝renderBuffer中的渲染数据到tempBuffer,并仅绘制指定的pass1的纹理数据 

Graphics.Blit(renderBuffer, tempBuffer, material, 1);

//  清空renderBuffer 

RenderTexture.ReleaseTemporary(renderBuffer);

// 将tempBuffer赋给renderBuffer,此时renderBuffer里面pass0和pass1的数据已经准备好 

renderBuffer = tempBuffer;

// 【2.3】处理Shader的通道2,竖直方向模糊处理 || Pass2,for horizontal blur 

// 获取临时渲染纹理 

tempBuffer = RenderTexture.GetTemporary(renderWidth, renderHeight, 0, sourceTexture.format);

// 拷贝renderBuffer中的渲染数据到tempBuffer,并仅绘制指定的pass2的纹理数据 

Graphics.Blit(renderBuffer, tempBuffer, CurMaterial, 2);

//【2.4】得到pass0、pass1和pass2的数据都已经准备好的renderBuffer 

// 再次清空renderBuffer 

RenderTexture.ReleaseTemporary(renderBuffer);

// 再次将tempBuffer赋给renderBuffer,此时renderBuffer里面pass0、pass1和pass2的数据都已经准备好 

renderBuffer = tempBuffer;

}

//拷贝最终的renderBuffer到目标纹理,并绘制所有通道的纹理到屏幕 

Graphics.Blit(renderBuffer, destTexture);

//清空renderBuffer 

RenderTexture.ReleaseTemporary(renderBuffer);

}

//着色器实例为空,直接拷贝屏幕上的效果。此情况下是没有实现屏幕特效的 

else 

{

//直接拷贝源纹理到目标渲染纹理 

Graphics.Blit(sourceTexture, destTexture);

}

}

//-----------------------------------------【OnValidate()函数】--------------------------------------  

// 说明:此函数在编辑器中该脚本的某个值发生了改变后被调用 

//-------------------------------------------------------------------------------------------------------- 

void OnValidate()

{

//将编辑器中的值赋值回来,确保在编辑器中值的改变立刻让结果生效 

ChangeValue = DownSampleNum;

ChangeValue2 = BlurSpreadSize;

ChangeValue3 = BlurIterations;

}

//-----------------------------------------【Update()函数】--------------------------------------  

// 说明:此函数每帧都会被调用 

//-------------------------------------------------------------------------------------------------------- 

void Update()

{

//若程序在运行,进行赋值 

if (Application.isPlaying)

{

//赋值 

DownSampleNum = ChangeValue;

BlurSpreadSize = ChangeValue2;

BlurIterations = ChangeValue3;

}

//若程序没有在运行,去寻找对应的Shader文件 

#if UNITY_EDITOR 

if (Application.isPlaying != true)

{

CurShader = Shader.Find(ShaderName);

}

#endif

}

//-----------------------------------------【OnDisable()函数】---------------------------------------  

// 说明:当对象变为不可用或非激活状态时此函数便被调用  

//-------------------------------------------------------------------------------------------------------- 

void OnDisable()

{

if (CurMaterial)

{

//立即销毁材质实例 

DestroyImmediate(CurMaterial);

}

}

#endregion

}


shader代码:


Shader "Learning Unity Shader/Lecture 15/RapidBlurEffect"
{
//-----------------------------------【属性 || Properties】------------------------------------------  
Properties
{
//主纹理 
_MainTex("Base (RGB)", 2D) = "white" {}
}
//----------------------------------【子着色器 || SubShader】---------------------------------------  
SubShader
{
ZWrite Off
Blend Off
//---------------------------------------【通道0 || Pass 0】------------------------------------ 
//通道0:降采样通道 ||Pass 0: Down Sample Pass 
Pass
{
ZTest Off
Cull Off
CGPROGRAM
//指定此通道的顶点着色器为vert_DownSmpl 
 #pragma vertex vert_DownSmpl
//指定此通道的像素着色器为frag_DownSmpl 
 #pragma fragment frag_DownSmpl
ENDCG
}
//---------------------------------------【通道1 || Pass 1】------------------------------------ 
//通道1:垂直方向模糊处理通道 ||Pass 1: Vertical Pass 
Pass
{
ZTest Always
Cull Off
CGPROGRAM
//指定此通道的顶点着色器为vert_BlurVertical 
 #pragma vertex vert_BlurVertical
//指定此通道的像素着色器为frag_Blur 
 #pragma fragment frag_Blur
ENDCG
}
//---------------------------------------【通道2 || Pass 2】------------------------------------ 
//通道2:水平方向模糊处理通道 ||Pass 2: Horizontal Pass 
Pass
{
ZTest Always
Cull Off
CGPROGRAM
//指定此通道的顶点着色器为vert_BlurHorizontal 
 #pragma vertex vert_BlurHorizontal
//指定此通道的像素着色器为frag_Blur 
 #pragma fragment frag_Blur
ENDCG
}
}
//-------------------------CG着色语言声明部分 || Begin CG Include Part----------------------  
CGINCLUDE
//【1】头文件包含 || include 
#include "UnityCG.cginc"
//【2】变量声明 || Variable Declaration 
sampler2D _MainTex;
//UnityCG.cginc中内置的变量,纹理中的单像素尺寸|| it is the size of a texel of the texture 
uniform half4 _MainTex_TexelSize;
//C#脚本控制的变量 || Parameter 
uniform half _DownSampleValue;
//【3】顶点输入结构体 || Vertex Input Struct 
struct VertexInput
{
//顶点位置坐标 
float4 vertex : POSITION;
//一级纹理坐标 
half2 texcoord : TEXCOORD0;
};
//【4】降采样输出结构体 || Vertex Input Struct 
struct VertexOutput_DownSmpl
{
//像素位置坐标 
float4 pos : SV_POSITION;
//一级纹理坐标(右上) 
half2 uv20 : TEXCOORD0;
//二级纹理坐标(左下) 
half2 uv21 : TEXCOORD1;
//三级纹理坐标(右下) 
half2 uv22 : TEXCOORD2;
//四级纹理坐标(左上) 
half2 uv23 : TEXCOORD3;
};
//【5】准备高斯模糊权重矩阵参数7x4的矩阵 ||  Gauss Weight 
static const half4 GaussWeight[7] = 
{
half4(0.0205,0.0205,0.0205,0),
half4(0.0855,0.0855,0.0855,0),
half4(0.232,0.232,0.232,0),
half4(0.324,0.324,0.324,1),
half4(0.232,0.232,0.232,0),
half4(0.0855,0.0855,0.0855,0),
half4(0.0205,0.0205,0.0205,0)
};
//【6】顶点着色函数 || Vertex Shader Function 
VertexOutput_DownSmpl vert_DownSmpl(VertexInput v)
{
//【6.1】实例化一个降采样输出结构 
VertexOutput_DownSmpl o;
//【6.2】填充输出结构 
//将三维空间中的坐标投影到二维窗口  
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
//对图像的降采样:取像素上下左右周围的点,分别存于四级纹理坐标中 
o.uv20 = v.texcoord + _MainTex_TexelSize.xy* half2(0.5h, 0.5h);;
o.uv21 = v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h, -0.5h);
o.uv22 = v.texcoord + _MainTex_TexelSize.xy * half2(0.5h, -0.5h);
o.uv23 = v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h, 0.5h);
//【6.3】返回最终的输出结果 
return o;
}
//【7】片段着色函数 || Fragment Shader Function 
fixed4 frag_DownSmpl(VertexOutput_DownSmpl i) : SV_Target
{
//【7.1】定义一个临时的颜色值 
fixed4 color = (0,0,0,0);
//【7.2】四个相邻像素点处的纹理值相加 
color += tex2D(_MainTex, i.uv20);
color += tex2D(_MainTex, i.uv21);
color += tex2D(_MainTex, i.uv22);
color += tex2D(_MainTex, i.uv23);
//【7.3】返回最终的平均值 
return color / 4;
}
//【8】顶点输入结构体 || Vertex Input Struct 
struct VertexOutput_Blur
{
//像素坐标 
float4 pos : SV_POSITION;
//一级纹理(纹理坐标) 
half4 uv : TEXCOORD0;
//二级纹理(偏移量) 
half2 offset : TEXCOORD1;
};
//【9】顶点着色函数 || Vertex Shader Function 
VertexOutput_Blur vert_BlurHorizontal(VertexInput v)
{
//【9.1】实例化一个输出结构 
VertexOutput_Blur o;
//【9.2】填充输出结构 
//将三维空间中的坐标投影到二维窗口  
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
//纹理坐标 
o.uv = half4(v.texcoord.xy, 1, 1);
//计算X方向的偏移量 
o.offset = _MainTex_TexelSize.xy * half2(1.0, 0.0) * _DownSampleValue;
//【9.3】返回最终的输出结果 
return o;
}
//【10】顶点着色函数 || Vertex Shader Function 
VertexOutput_Blur vert_BlurVertical(VertexInput v)
{
//【10.1】实例化一个输出结构 
VertexOutput_Blur o;
//【10.2】填充输出结构 
//将三维空间中的坐标投影到二维窗口  
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
//纹理坐标 
o.uv = half4(v.texcoord.xy, 1, 1);
//计算Y方向的偏移量 
o.offset = _MainTex_TexelSize.xy * half2(0.0, 1.0) * _DownSampleValue;
//【10.3】返回最终的输出结果 
return o;
}
//【11】片段着色函数 || Fragment Shader Function 
half4 frag_Blur(VertexOutput_Blur i) : SV_Target
{
//【11.1】获取原始的uv坐标 
half2 uv = i.uv.xy;
//【11.2】获取偏移量 
half2 OffsetWidth = i.offset;
//从中心点偏移3个间隔,从最左或最上开始加权累加 
half2 uv_withOffset = uv - OffsetWidth * 3.0;
//【11.3】循环获取加权后的颜色值 
half4 color = 0;
for (int j = 0; j< 7; j++)
{
//偏移后的像素纹理值 
half4 texCol = tex2D(_MainTex, uv_withOffset);
//待输出颜色值+=偏移后的像素纹理值 x 高斯权重 
color += texCol * GaussWeight[j];
//移到下一个像素处,准备下一次循环加权 
uv_withOffset += OffsetWidth;
}
//【11.4】返回最终的颜色值 
return color;
}
//-------------------结束CG着色语言声明部分  || End CG Programming Part------------------  
ENDCG
FallBack Off
}

---

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