Forest_Client/Forest/Assets/Scripts/Shader/UI_GaussianBlur.shader

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2024-06-12 15:01:54 +08:00
Shader "NLD_URP/NLD_UI_GaussianBlur"
{
Properties
{
[PerRendererData] _MainTex("MainTex", 2D) = "white" {}
//值越大,正态分布图像越扁,距离远的像素的权重越高,颗粒感越明显
_Color("Color", color) = (1,1,1,1)
_Sigma("Sigma", Range(1, 30)) = 20
//多少倍的Sigma值越大采样越多越细腻会循环(2n+1)(2n+1)次,所以这个值不要太大,太大也没用
_Ratio("Sigma Ratio", Range(1, 4)) = 2
}
SubShader
{
Cull Off
Lighting Off
ZWrite Off
Blend One OneMinusSrcAlpha
Tags
{
"Queue" = "Transparent"
"IgnoreProjector" = "True"
"RenderType" = "Transparent"
"PreviewType" = "Plane"
"CanUseSpriteAtlas" = "True"
}
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile _ PIXELSNAP_ON
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
fixed4 _Color;
float4 _MainTex_ST;
float4 _MainTex_TexelSize;
float _Sigma;
float _Ratio;
// 计算高斯权重
float computerBluGauss(float x, float sigma)
{
return 0.39894 * exp(-0.5 * x * x / (0.20 * sigma)) / sigma * sigma;
}
v2f vert(appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float sum = 0;
fixed4 col = fixed4(0, 0, 0, 0);
for (float j = -_Ratio * _Sigma; j <= _Ratio * _Sigma; j += _Sigma)
{
for (float k = -_Ratio * _Sigma; k <= _Ratio * _Sigma; k += _Sigma)
{
float2 _offset = float2(j, k) * _MainTex_TexelSize.xy;
float2 blurUV = i.uv + _offset;
if(blurUV.x >= 0 && blurUV.x <= 1 && blurUV.y >= 0 && blurUV.y <= 1)
{
//二维正态分布公式G(x,y)=exp(-(x²+y²)/(2σ²))/(2πσ²)
float weight = exp((_offset.x * _offset.x + _offset.y * _offset.y)/(-2 * _Sigma * _Sigma))/(6.2831852 * _Sigma * _Sigma);
col += tex2D(_MainTex, blurUV) * weight;
sum += weight;
}
}
}
return (col / sum) * _Color;
}
ENDCG
}
}
}