学习完UnityShader入门精要的前5章，总算开始动手写shader，但是凭空让我写，我咋知道写什么呢。 还是看看项目的Shader，学习一下吧！
#####项目最常用的Shader就是ui界面的背景模糊:
Shader "_Aver3/20190710FastBlur"
{
Properties
{
_MainTex("Base (RGB)", 2D) = "white" {}
_blurSize ("Blur Size", Range(0,10)) = 1.0
}
SubShader
{
// 透明队列，在所有不透明的几何图形后绘制
Tags { "RenderType"="Transparent" }
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#pragma target 3.0
#include "UnityCG.cginc"
float _blurSize;
sampler2D _MainTex;
float4 _MainTex_ST;
float4 _MainTex_TexelSize;
struct a2v{
float2 uv : TEXCOORD0;
float4 vertex : POSITION;
};
struct v2f{
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float2 offsetuv[4] : TEXCOORD1;
};
v2f vert(a2v IN){
v2f o;
o.pos = UnityObjectToClipPos(IN.vertex);
// 处理UV的till和offset
o.uv = TRANSFORM_TEX(IN.uv, _MainTex);
// 为啥这个常量放在顶点函数外面效果差这么多？？？todo
float2 offsetWeight[4] = {
float2(0, 1),
float2(-1, 0),
float2(1, 0),
float2(0, -1)
};
// 取周围4个像素做模糊
o.offsetuv[0] = o.uv.xy + float2(offsetWeight[0].x, offsetWeight[0].y) * _MainTex_TexelSize * _blurSize;
o.offsetuv[1] = o.uv.xy + float2(offsetWeight[1].x, offsetWeight[1].y) * _MainTex_TexelSize * _blurSize;
o.offsetuv[2] = o.uv.xy + float2(offsetWeight[2].x, offsetWeight[2].y) * _MainTex_TexelSize * _blurSize;
o.offsetuv[3] = o.uv.xy + float2(offsetWeight[3].x, offsetWeight[3].y) * _MainTex_TexelSize * _blurSize;
return o;
}
fixed4 frag (v2f IN) : SV_Target
{
fixed4 col = fixed4(0, 0, 0, 0);
// 取样4个像素，然后*0.25 得出平均值
col += tex2D(_MainTex, IN.offsetuv[0]);
col += tex2D(_MainTex, IN.offsetuv[1]);
col += tex2D(_MainTex, IN.offsetuv[2]);
col += tex2D(_MainTex, IN.offsetuv[3]);
col *= 0.25;
col.a = 1;
// sample the texture
// fixed4 col = tex2D(_MainTex, i.uv);
// apply fog
UNITY_APPLY_FOG(i.fogCoord, col);
return col;
}
ENDCG
}
}
}
- 看了一下，就是取样周围4个像素做平均值模糊，这样的话，当模糊值大的时候，效果就很差。然后看了一下高斯模糊，学习了一下卷积的定义。后面再来填坑，搬砖搬砖
- 然后调用的地方，有点没看懂：
void BlurRender(RenderTexture sourceTexture) { int rtW = sourceTexture.width; int rtH = sourceTexture.height; RenderTexture temporary = RenderTexture.GetTemporary(rtW, rtH, 0, sourceTexture.format); // 为啥要调用2次 temporary.filterMode = FilterMode.Bilinear; temporary.Create(); temporary.filterMode = FilterMode.Bilinear; // float widthMod = 1.0f / (1.0f * (1 << DownSampleNum)); for (int i = 0; i < 2; i++) { float iterationOffs = i * 1.0f; BlurMaterial.SetFloat("_blurSize", BlurSize + iterationOffs); //垂直模糊 temporary.DiscardContents(); // 为啥要调用2次 Graphics.Blit(sourceTexture, temporary, BlurMaterial, 0); sourceTexture.DiscardContents(); Graphics.Blit(temporary, sourceTexture, BlurMaterial, 0); } RenderTexture.ReleaseTemporary(temporary); renderBuffer = sourceTexture; m_rawImage.texture = renderBuffer; }
