模糊shader总结（均值模糊，高斯模糊）

作者: 星易乾川 | 来源:发表于2020-12-02 22:29 被阅读0次

image.png
效果排序高斯+降采样>高斯>均值
CommandBuff的实现效果好，效率可控，但缺点是无法用在UI上
UI上用模糊好像只能是GrabPass，其他方法暂时没想到
参考了一些文章，下面是连接，在他们基础上做了些修改，仅作为个人学习使用
高斯模糊：
https://blog.csdn.net/pz789as/article/details/79050631
https://blog.csdn.net/puppet_master/article/details/52783179
http://www.ruanyifeng.com/blog/2012/11/gaussian_blur.html
基于CommandBuff的高斯模糊：
https://www.gameres.com/844940.html
均值模糊：
https://blog.csdn.net/puppet_master/article/details/52547442
https://zhuanlan.zhihu.com/p/145463708

_MainTexture_TexelSize
{TextureName}_TexelSize - a float4 property contains texture size information:

x contains 1.0/width
y contains 1.0/height
z contains width
w contains height

均值模糊代码：

Shader "UI/BlurUI_SimpleBlur"
{
    Properties
    {
        _Color("Color", COLOR) = (1,1,1,1)
        _Radius("Blur Radius", Range(0, 4)) = 1
        _Size("Blur Size", Range(0, 5)) = 1
    }

        SubShader
    {
        Tags{ "Queue" = "Transparent"}

        //GrabPass {}

    GrabPass{}
        Pass
        {
        //Blend SrcAlpha OneMinusSrcAlpha

        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        #include "UnityCG.cginc"

        struct appdata
        {
            float4 vertex : POSITION;
            float2 uv : TEXCOORD0;
        };

        struct v2f
        {
            float4 vertex : SV_POSITION;
            float4 screenPos : TEXCOORD0;
            float4 grabPos : TEXCOORD1;
        };

        sampler2D _GrabTexture;
        float4 _GrabTexture_TexelSize;

        float4 _Color;
        int _Radius;
        float _Size;
        v2f vert(appdata v)
        {
            v2f o;
            o.vertex = UnityObjectToClipPos(v.vertex);
            o.screenPos = ComputeScreenPos(o.vertex);
            o.grabPos = ComputeGrabScreenPos(o.vertex);
            return o;
        }

        half4 frag(v2f i) : SV_TARGET
        {

            float4 result = tex2Dproj(_GrabTexture, i.screenPos);
            i.grabPos.zw = i.screenPos.zw;
            for (int range = 1; range <= _Radius; range++)
            {
                //对
                float2 w1 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * 0, _GrabTexture_TexelSize.y * range * _Size);
                i.grabPos.xy = w1;
                result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);//用屏幕坐标+偏移，这里没搞懂，但是实测效果确实好

                float2 w2 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * 0, _GrabTexture_TexelSize.y * -range * _Size);
                i.grabPos.xy = w2;
                result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);
            }

            result /= _Radius * 2 + 1;      //除以_Radius*2取均值

            return result;
        }
        ENDCG
    }

        GrabPass{}
        Pass
        {

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4 vertex : SV_POSITION;
                float4 screenPos : TEXCOORD0;
                float4 grabPos : TEXCOORD1;
            };

            sampler2D _GrabTexture;
            float4 _GrabTexture_TexelSize;

            float4 _Color;
            int _Radius;
            float _Size;
            v2f vert(appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.screenPos = ComputeScreenPos(o.vertex);
                o.grabPos = ComputeGrabScreenPos(o.vertex);
                return o;
            }

            half4 frag(v2f i) : SV_TARGET
            {

                float4 result = tex2Dproj(_GrabTexture, i.screenPos);
                i.grabPos.zw = i.screenPos.zw;
                for (int range = 1; range <= _Radius; range++)
                {
                    float2 w3 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * range * _Size, _GrabTexture_TexelSize.y * 0);
                    i.grabPos.xy = w3;
                    result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);

                    float2 w4 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * -range * _Size, _GrabTexture_TexelSize.y * 0);
                    i.grabPos.xy = w4;
                    result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);

                }

                result /= _Radius * 2 + 1;
                float4 col = half4(_Color.a * _Color.rgb + (1 - _Color.a) * result.rgb, 1.0f);
                return col;
            }
            ENDCG

        }
    }

}

高斯模糊代码：

Shader "UI/BlurUI_GaussianBlur"
{
    Properties
    {
        _Color("Color", COLOR) = (1,1,1,1)
        //_Radius("Blur Radius", Range(0, 4)) = 1
        _Size("Blur Size", Range(0, 5)) = 1
    }

        SubShader
    {
        Tags{ "Queue" = "Transparent"}

        //GrabPass {}

    GrabPass{}
        Pass
        {
        //Blend SrcAlpha OneMinusSrcAlpha

        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        #include "UnityCG.cginc"

        struct appdata
        {
            float4 vertex : POSITION;
            float2 uv : TEXCOORD0;
        };

        struct v2f
        {
            float4 vertex : SV_POSITION;
            float4 screenPos : TEXCOORD0;
            float4 grabPos : TEXCOORD1;
        };

        sampler2D _GrabTexture;
        float4 _GrabTexture_TexelSize;

        float4 _Color;
        int _Radius;
        float _Size;
        v2f vert(appdata v)
        {
            v2f o;
            o.vertex = UnityObjectToClipPos(v.vertex);
            o.screenPos = ComputeScreenPos(o.vertex);
            o.grabPos = ComputeGrabScreenPos(o.vertex);
            return o;
        }
        half4 GrabPixel(v2f i, float weight, float kernelx)
        {
            //float2 w1 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * 0, _GrabTexture_TexelSize.y * kernelx * _Size);
            //i.grabPos.xy = w1;
   //         return tex2Dproj(_GrabTexture, i.screenPos + i.grabPos) * weight;        
            return tex2Dproj(_GrabTexture, i.screenPos + UNITY_PROJ_COORD(float4(i.grabPos.x + _GrabTexture_TexelSize.x*kernelx*_Size, i.grabPos.y, i.grabPos.z, i.grabPos.w))) * weight;
        }

        half4 frag(v2f i) : SV_TARGET
        {

            //float4 result = tex2Dproj(_GrabTexture, i.screenPos/*UNITY_PROJ_COORD(i.grabPos)*/);
            //i.grabPos.zw = i.screenPos.zw;
            half4 sum = half4(0,0,0,0);                  
                sum += GrabPixel(i, 0.05, -4.0);
                sum += GrabPixel(i, 0.09, -3.0);
                sum += GrabPixel(i, 0.12, -2.0);
                sum += GrabPixel(i, 0.15, -1.0);
                sum += GrabPixel(i, 0.18,  0.0);
                sum += GrabPixel(i, 0.15, +1.0);
                sum += GrabPixel(i, 0.12, +2.0);
                sum += GrabPixel(i, 0.09, +3.0);
                sum += GrabPixel(i, 0.05, +4.0);
            //for (int range = 1; range <= _Radius; range++)
            //{
            //  //对
            //  float2 w1 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * 0, _GrabTexture_TexelSize.y * range * _Size);
            //  i.grabPos.xy = w1;
            //  result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);

            //  float2 w2 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * 0, _GrabTexture_TexelSize.y * -range * _Size);
            //  i.grabPos.xy = w2;
            //  result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);
            //}

            //result /= _Radius * 2 + 1;        //除以_Radius*2取均值

            return sum;
        }
        ENDCG
    }

        GrabPass{}
        Pass
        {

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4 vertex : SV_POSITION;
                float4 screenPos : TEXCOORD0;
                float4 grabPos : TEXCOORD1;
            };

            sampler2D _GrabTexture;
            float4 _GrabTexture_TexelSize;

            float4 _Color;
            int _Radius;
            float _Size;
            v2f vert(appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.screenPos = ComputeScreenPos(o.vertex);
                o.grabPos = ComputeGrabScreenPos(o.vertex);
                return o;
            }
            half4 GrabPixel(v2f i, float weight, float kernely)
        {
            //return tex2Dproj(_GrabTexture,i.screenPos + UNITY_PROJ_COORD(float4(i.grabPos.x, i.grabPos.y + _GrabTexture_TexelSize.y*kernely*_Size, i.grabPos.z, i.grabPos.w))) * weight;        
            return tex2Dproj(_GrabTexture,i.screenPos + UNITY_PROJ_COORD(float4(i.grabPos.x, i.grabPos.y + _GrabTexture_TexelSize.y*kernely*_Size, i.grabPos.z, i.grabPos.w))) * weight;
        }
            half4 frag(v2f i) : SV_TARGET
            {

                //float4 result = tex2Dproj(_GrabTexture, i.screenPos/*UNITY_PROJ_COORD(i.grabPos)*/);
                //i.grabPos.zw = i.screenPos.zw;
                half4 sum = half4(0,0,0,0);                  
                sum += GrabPixel(i, 0.05, -4.0);
                sum += GrabPixel(i, 0.09, -3.0);
                sum += GrabPixel(i, 0.12, -2.0);
                sum += GrabPixel(i, 0.15, -1.0);
                sum += GrabPixel(i, 0.18,  0.0);
                sum += GrabPixel(i, 0.15, +1.0);
                sum += GrabPixel(i, 0.12, +2.0);
                sum += GrabPixel(i, 0.09, +3.0);
                sum += GrabPixel(i, 0.05, +4.0);
                
                //for (int range = 1; range <= _Radius; range++)
                //{
                //  float2 w3 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * range * _Size, _GrabTexture_TexelSize.y * 0);
                //  i.grabPos.xy = w3;
                //  result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);

                //  float2 w4 = i.screenPos.xy + float2(_GrabTexture_TexelSize.x * -range * _Size, _GrabTexture_TexelSize.y * 0);
                //  i.grabPos.xy = w4;
                //  result += tex2Dproj(_GrabTexture, i.screenPos + i.grabPos);

                //}

                //result /= _Radius * 2 + 1;
                float4 col = half4(_Color.a * _Color.rgb + (1 - _Color.a) * sum.rgb, 1.0f);
                return col;
            }
            ENDCG

        }
    }

}

CommandBuff高斯模糊代码:
Shader
抓图做模糊用

Shader "Hidden/SeparableGlassBlur" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "" {}
    }

    CGINCLUDE
    
    #include "UnityCG.cginc"
    
    struct v2f {
        float4 pos : POSITION;
        float2 uv : TEXCOORD0;

        float4 uv01 : TEXCOORD1;
        float4 uv23 : TEXCOORD2;
        float4 uv45 : TEXCOORD3;
    };
    
    float4 offsets;
    
    sampler2D _MainTex;
    
    v2f vert (appdata_img v) {
        v2f o;
        o.pos = UnityObjectToClipPos(v.vertex);

        o.uv.xy = v.texcoord.xy;//正常uv
        //偏移值  沿左右上下进行偏移   六套UV，横竖12个偏移值
        o.uv01 =  v.texcoord.xyxy + offsets.xyxy * float4(1,1, -1,-1);
        o.uv23 =  v.texcoord.xyxy + offsets.xyxy * float4(1,1, -1,-1) * 2.0;
        o.uv45 =  v.texcoord.xyxy + offsets.xyxy * float4(1,1, -1,-1) * 3.0;


        return o;
    }
    
    half4 frag (v2f i) : COLOR {
        half4 color = float4 (0,0,0,0);
        //根据权重叠加偏移后的颜色
        color += 0.40 * tex2D (_MainTex, i.uv);
        color += 0.15 * tex2D (_MainTex, i.uv01.xy);
        color += 0.15 * tex2D (_MainTex, i.uv01.zw);
        color += 0.10 * tex2D (_MainTex, i.uv23.xy);
        color += 0.10 * tex2D (_MainTex, i.uv23.zw);
        color += 0.05 * tex2D (_MainTex, i.uv45.xy);
        color += 0.05 * tex2D (_MainTex, i.uv45.zw);
        
        return color;
    }

    ENDCG
    
Subshader {
 Pass {
      ZTest Always Cull Off ZWrite Off
      Fog { Mode off }

      CGPROGRAM
      #pragma fragmentoption ARB_precision_hint_fastest
      #pragma vertex vert
      #pragma fragment frag
      ENDCG
  }
}

Fallback off


} // shader

放在物体上

Shader "Effects/FrostedGlass"
{
    Properties
    {
        _FrostTex ("Fross Texture", 2D) = "white" {}
        _FrostIntensity ("Frost Intensity", Range(0.0, 1.0)) = 0.5
    }
    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue" = "Transparent" }
        LOD 100
        
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uvfrost : TEXCOORD0;
                float4 uvgrab : TEXCOORD1;  
                float4 vertex : SV_POSITION;
            };

            sampler2D _FrostTex;
            float4 _FrostTex_ST;

            float _FrostIntensity;

            sampler2D _GrabBlurTexture_0;
            sampler2D _GrabBlurTexture_1;
            sampler2D _GrabBlurTexture_2;
            sampler2D _GrabBlurTexture_3;
            
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uvfrost = TRANSFORM_TEX(v.uv, _FrostTex);
                o.uvgrab = ComputeGrabScreenPos(o.vertex);
                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
                float surfSmooth = 1-tex2D(_FrostTex, i.uvfrost) * _FrostIntensity;   //模糊强度贴图
                
                surfSmooth = clamp(0, 1, surfSmooth);//限制到0-1的区间

                half4 refraction;

                half4 ref00 = tex2Dproj(_GrabBlurTexture_0, i.uvgrab); //通过屏幕坐标采样抓到并模糊处理后的贴图
                half4 ref01 = tex2Dproj(_GrabBlurTexture_1, i.uvgrab);
                half4 ref02 = tex2Dproj(_GrabBlurTexture_2, i.uvgrab);
                half4 ref03 = tex2Dproj(_GrabBlurTexture_3, i.uvgrab);

                float step00 = smoothstep(0.75, 1.00, surfSmooth);//进行平滑过渡
                float step01 = smoothstep(0.5, 0.75, surfSmooth);
                float step02 = smoothstep(0.05, 0.5, surfSmooth);
                float step03 = smoothstep(0.00, 0.05, surfSmooth);

                refraction = lerp(ref03, lerp( lerp( lerp(ref03, ref02, step02), ref01, step01), ref00, step00), step03);
                
                return refraction;
            }
            ENDCG
        }
    }
}

using UnityEngine;
using UnityEngine.Rendering;

[ExecuteInEditMode]
[ImageEffectAllowedInSceneView]
[RequireComponent(typeof(Camera))]
public class CommandBufferBlur : MonoBehaviour
{
    Shader _Shader;

    Material _Material = null;

    Camera _Camera = null;
    CommandBuffer _CommandBuffer = null;

    Vector2 _ScreenResolution = Vector2.zero;
    RenderTextureFormat _TextureFormat = RenderTextureFormat.ARGB32;

    public void Cleanup()
    {
        if (!Initialized)
            return;

        _Camera.RemoveCommandBuffer(CameraEvent.BeforeForwardAlpha, _CommandBuffer);
        _CommandBuffer = null;
        Object.DestroyImmediate(_Material);
    }

    public void OnEnable()
    {
        Cleanup();//先清理
        Initialize();//初始化
    }

    public void OnDisable()
    {
        Cleanup();
    }

    public bool Initialized
    {
        get { return _CommandBuffer != null; }
    }

    void Initialize()
    {
        if (Initialized)
            return;
        //根据shader创建材质球
        if (!_Shader)
        {
            _Shader = Shader.Find("Hidden/SeparableGlassBlur");

            if (!_Shader)
                throw new MissingReferenceException("Unable to find required shader \"Hidden/SeparableGlassBlur\"");
        }

        if (!_Material)
        {
            _Material = new Material(_Shader);
            _Material.hideFlags = HideFlags.HideAndDontSave;
        }
        //创建摄像机
        _Camera = GetComponent<Camera>();

        if (_Camera.allowHDR && SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.DefaultHDR))
            _TextureFormat = RenderTextureFormat.DefaultHDR;
        //创建commandbuffer
        _CommandBuffer = new CommandBuffer();
        _CommandBuffer.name = "Blur screen";

        int numIterations = 4;
        //屏幕尺寸
        Vector2[] sizes = {
            new Vector2(Screen.width, Screen.height),
            new Vector2(Screen.width / 2, Screen.height / 2),
            new Vector2(Screen.width / 4, Screen.height / 4),
            new Vector2(Screen.width / 8, Screen.height / 8),
        };

        for (int i = 0; i < numIterations; ++i)
        {
            int screenCopyID = Shader.PropertyToID("_ScreenCopyTexture");
            _CommandBuffer.GetTemporaryRT(screenCopyID, -1, -1, 0, FilterMode.Bilinear, _TextureFormat);
            //当前场景渲染到RT上
            _CommandBuffer.Blit(BuiltinRenderTextureType.CurrentActive, screenCopyID);

            int blurredID = Shader.PropertyToID("_Grab" + i + "_Temp1");
            int blurredID2 = Shader.PropertyToID("_Grab" + i + "_Temp2");
            //申请两个临时缓存RT
            _CommandBuffer.GetTemporaryRT(blurredID, (int)sizes[i].x, (int)sizes[i].y, 0, FilterMode.Bilinear, _TextureFormat);
            _CommandBuffer.GetTemporaryRT(blurredID2, (int)sizes[i].x, (int)sizes[i].y, 0, FilterMode.Bilinear, _TextureFormat);
            //降采样
            _CommandBuffer.Blit(screenCopyID, blurredID);
            _CommandBuffer.ReleaseTemporaryRT(screenCopyID);
            //横向偏移
            _CommandBuffer.SetGlobalVector("offsets", new Vector4(2.0f / sizes[i].x, 0, 0, 0));
            _CommandBuffer.Blit(blurredID, blurredID2, _Material);
            //纵向偏移
            _CommandBuffer.SetGlobalVector("offsets", new Vector4(0, 2.0f / sizes[i].y, 0, 0));
            _CommandBuffer.Blit(blurredID2, blurredID, _Material);
            //按照index输出RT
            _CommandBuffer.SetGlobalTexture("_GrabBlurTexture_" + i, blurredID);
        }
        //_Camera.AddCommandBuffer(CameraEvent.AfterForwardAlpha, _CommandBuffer);
        _Camera.AddCommandBuffer(CameraEvent.BeforeForwardAlpha, _CommandBuffer);

        _ScreenResolution = new Vector2(Screen.width, Screen.height);
    }

    void OnPreRender()
    {
        if (_ScreenResolution != new Vector2(Screen.width, Screen.height))
            Cleanup();

        Initialize();
    }
}

模糊shader总结（均值模糊，高斯模糊）

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