高斯模糊后处理效果

使用 高斯核 对像素进行模糊处理

• 脚本

using System;
using UnityEngine;

public class GaussianBlur : PostEffectBase
{
    
    
    public Shader gaussianBlurShader;
    [Range(0.2f, 3f)] 
    public float blurSpread;
    [Range(1, 8)]
    public int downSample = 2;
    [Range(0, 4)]
    public int iterations = 3;
    

    private Material _gaussianBlurMaterial;

    public Material material
    {
    
    
        get
        {
    
    
            _gaussianBlurMaterial = CheckShaderAndCreateMaterial(gaussianBlurShader, _gaussianBlurMaterial);
            return _gaussianBlurMaterial;
        }
    }

    private void OnRenderImage(RenderTexture src, RenderTexture dest)
    {
    
    
        if (material != null)
        {
    
    
            int rtw = src.width / downSample;
            int rth = src.height / downSample;
            
            //Shader: Pass0 : 横线 Gx Pass : 垂直 Gy
            RenderTexture buffer0 = RenderTexture.GetTemporary(rtw, rth, 0);
            buffer0.filterMode = FilterMode.Bilinear;

            for (int i = 0; i < iterations; i++)
            {
    
    
                material.SetFloat("_BlurSize", 1.0f + i * blurSpread);

                RenderTexture buffer1 = RenderTexture.GetTemporary(rtw, rth, 0);
                
                Graphics.Blit(src, buffer1, material,  0);
                RenderTexture.ReleaseTemporary(buffer0);
                buffer0 = buffer1;
                buffer1 = RenderTexture.GetTemporary(rtw, rth, 0);
                
                Graphics.Blit(buffer0, buffer1, material, 1);
                RenderTexture.ReleaseTemporary(buffer0);
                buffer0 = buffer1;
            }
            
            Graphics.Blit(buffer0, dest);

            RenderTexture.ReleaseTemporary(buffer0);
        }
        else Graphics.Blit(src, dest);
    }
}

• shader

Shader "Hidden/GaussianBlur"
{
    
    
    Properties
    {
    
    
        _MainTex ("Texture", 2D) = "white" {
    
    }
        _BlurSize ("BlurSize", Float) = 1.0
    }
    SubShader
    {
    
    
        CGINCLUDE

        #include "UnityCG.cginc"

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

        struct v2f
        {
    
    
            float4 pos : SV_POSITION;
            float2 uv[5] : TEXCOORD0;
        };

        sampler2D _MainTex;
        half4 _MainTex_TexelSize;
        float _BlurSize;

        v2f vertBlurHorizontal (appdata v)
        {
    
    
            v2f o;
            o.pos = UnityObjectToClipPos(v.vertex);

            float2 uv = v.uv;
            o.uv[0] = uv + float2(0.0 * _MainTex_TexelSize.x, 0.0) * _BlurSize;
            o.uv[1] = uv + float2(1.0 * _MainTex_TexelSize.x, 0.0) * _BlurSize;
            o.uv[2] = uv + float2(-1.0 * _MainTex_TexelSize.x, 0.0) * _BlurSize;
            o.uv[3] = uv + float2(2.0 * _MainTex_TexelSize.x, 0.0) * _BlurSize;
            o.uv[4] = uv + float2(-2.0 * _MainTex_TexelSize.x, 0.0) * _BlurSize;
            return o;
        }

        v2f vertBlurVertical (appdata v)
        {
    
    
            v2f o;
            o.pos = UnityObjectToClipPos(v.vertex);

            float2 uv = v.uv;
            o.uv[0] = uv + float2(0.0, 0.0 * _MainTex_TexelSize.y) * _BlurSize;
            o.uv[1] = uv + float2(0.0, 1.0 * _MainTex_TexelSize.y) * _BlurSize;
            o.uv[2] = uv + float2(0.0, -1.0 * _MainTex_TexelSize.y) * _BlurSize;
            o.uv[3] = uv + float2(0.0, 2.0 * _MainTex_TexelSize.y) * _BlurSize;
            o.uv[4] = uv + float2(0.0, -2.0 * _MainTex_TexelSize.y) * _BlurSize;
            return o;
        }
        
        

        fixed4 fragBlur (v2f i) : SV_Target
        {
    
    
            float weight[3] = {
    
    0.4026, 0.2442, 0.0545};

            fixed3 color = tex2D(_MainTex, i.uv[0]).rgb * weight[0];
            for (int it = 1; it < 3; it++)
            {
    
    
                color += tex2D(_MainTex, i.uv[2 * it - 1]).rgb * weight[it];
                color += tex2D(_MainTex, i.uv[2 * it]).rgb * weight[it];
            }

            return fixed4(color, 1.0);
        }
        
        ENDCG
        
        // No culling or depth
        Cull Off ZWrite Off ZTest Always

        Pass
        {
    
    
            NAME "GAUSSIANBLUR_HORIZONTAL"
            
            CGPROGRAM
            
            #pragma vertex vertBlurHorizontal
            #pragma fragment fragBlur
            
            ENDCG
        }
        
        Pass
        {
    
    
            NAME "GAUSSIANBLUR_VERTICAL"
            
            CGPROGRAM
            
            #pragma vertex vertBlurVertical
            #pragma fragment fragBlur
            
            ENDCG
        }
    }
    
    FallBack Off
}