3D模型的描边漫天飞，通过法线计算就行，但是2D还是虽然也有，但不是自己想要的，毕竟只是想调一下颜色，阈值，边缘大小就行。

之前是做图像处理的，用的波门处理，计算一个像素点与周围的梯度值差异，大于阈值的就是边缘点。求的边缘点与边缘色混合，再与原色混合输出就可以。直接上代码：

在这里插入代码片
Shader "UIEffect/Outline" {Properties {// [NoScaleOffset] _MainTex ("Main Texture", 2D) = "black" {}_OutlineWidth("Outline Width", Range(0, 10)) = 3.0_OutlineColor("Outline Color", Color) = (1,1,0,1)_ThresholdEnd("Outline Threshold", Range(0, 1)) = 0.25_OutlineSmoothness("Outline Smoothness", Range(0, 1)) = 1.0}SubShader {Tags { 	"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }Cull OffZWrite OffLighting OffBlend One OneMinusSrcAlphaPass {Name "Outline"CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;float4 color : Color;};struct v2f{float2 uv : TEXCOORD0;float4 vertex : SV_POSITION;float vertexAlpha : Color;};v2f vert (appdata v){v2f o = (v2f)0;o.uv = v.uv;o.vertex = UnityObjectToClipPos(v.vertex);o.vertexAlpha = v.color.a;return o;}sampler2D _MainTex;float _OutlineWidth;float4 _OutlineColor;float4 _MainTex_TexelSize;float _ThresholdEnd;float _OutlineSmoothness;fixed4 frag (v2f i) : SV_Target{float4 mainCol = tex2D(_MainTex, i.uv);// 使用自己的alpha数值， 不然计算之后的颜色的alpha值也会加进来mainCol.rgb *= mainCol.a;// 计算中心像素的alpha ，通过比较周围4个像素点的alpha，判断是不是边缘点float xOffset = _MainTex_TexelSize.x * _OutlineWidth / (1024 * _MainTex_TexelSize.x);float yOffset = _MainTex_TexelSize.y * _OutlineWidth / (1024 * _MainTex_TexelSize.x);float pixelCenter = tex2D(_MainTex, i.uv).a;float4 centerLod = float4(i.uv, 0, 0);float pixelTop = tex2Dlod(_MainTex, centerLod + float4(0,  yOffset, 0, 0)).a;float pixelBottom = tex2Dlod(_MainTex, centerLod + float4(0, -yOffset, 0, 0)).a;float pixelLeft = tex2Dlod(_MainTex, centerLod + float4(-xOffset, 0, 0, 0)).a;float pixelRight = tex2Dlod(_MainTex, centerLod + float4(xOffset, 0, 0, 0)).a;float numSamples = 1;float average = (pixelTop + pixelBottom + pixelLeft + pixelRight) * i.vertexAlpha / numSamples;float thresholdStart = _ThresholdEnd * (1.0 - _OutlineSmoothness);float outlineAlpha = saturate((average - thresholdStart) / (_ThresholdEnd - thresholdStart)) - pixelCenter;mainCol.rgba = lerp(mainCol, _OutlineColor, outlineAlpha);return mainCol;}ENDCG}}}

效果图不贴了，不会粘贴，直接复制代码就能使用。创建一个材质球，材质球放在Image组件的material里面即可。想要发光效果的，需要对边缘色模糊处理，就是2D的边缘泛光。