UnityShader如何实现新手引导遮罩镂空效果
1、圆形镂空shader代码：
//计算片元世界坐标和目标中心位置的距离float dis = distance(IN.worldPosition.xy, _Center.xy);//过滤掉距离小于（半径-过渡范围）的片元clip(dis - (_Radius - _TransitionRange));//优化if条件判断，如果距离小于半径则执行下一步，等于if(dis < _Radius)fixed tmp = step(dis, _Radius);//计算过渡范围内的alpha值color.a *= (1 - tmp) + tmp * (dis - (_Radius - _TransitionRange)) / _TransitionRange;
效果：忽略渐变的蒙版，随便找的图片
2、椭圆镂空shader代码：
//计算X轴方向距离float disX = distance(IN.worldPosition.x, _Center.x);//计算Y轴方向距离float disY = distance(IN.worldPosition.y, _Center.y);//运用椭圆方程计算片元的alpha值，_Ellipse为椭圆系数fixed factor = clamp(pow(abs(disX / _Width), _Ellipse) + pow(abs(disY / _Height), _Ellipse), 0.0, 1.0);//优化if条件判断fixed tmp = step(factor, 1.0f);//赋值椭圆外或椭圆内的alpha值color.a *= (1 - tmp) + tmp * factor;
效果：
3、圆形目标位置聚合动画shader代码：
//_StartTime为效果开始时间点，Unity中对应赋值material.SetFloat("_StartTime", Time.timeSinceLevelLoad);fixed processTime = _Time.y - _StartTime;//判断shader执行时长是否超过_TotalTimeclip(_TotalTime - processTime);//优化if条件判断fixed tmp = step(processTime, _ReduceTime);//计算当前时间点的圆形镂空半径float curRadius = (1 - tmp) * _Radius + tmp * (_MaxRadius - (_MaxRadius - _Radius) * processTime / _ReduceTime);float dis = distance(IN.worldPosition.xy, _Center.xy);//抛弃距离小于当前圆形镂空半径的片元clip(dis - curRadius);
效果：不知道为啥上传上来就有问题了，正常是没问题的
整个shader源码，在Unity UGUI 自带Default shader基础上添加：
// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)Shader "UI/Default_Mask"{ Properties { [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {} _Color ("Tint", Color) = (1,1,1,1) _StencilComp ("Stencil Comparison", Float) = 8 _Stencil ("Stencil ID", Float) = 0 _StencilOp ("Stencil Operation", Float) = 0 _StencilWriteMask ("Stencil Write Mask", Float) = 255 _StencilReadMask ("Stencil Read Mask", Float) = 255 _ColorMask ("Color Mask", Float) = 15 [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0 //-------------------add---------------------- _Center("Center", vector) = (0, 0, 0, 0) _Radius("Radius", Range(0,1000)) = 1000 // sliders _TransitionRange("Transition Range", Range(0, 100)) = 10 _Width("Width", Float) = 1 _Height("Height", Float) = 1 _Ellipse("Ellipse", Float) = 4 _ReduceTime("ReduceTime", Float) = 1 _TotalTime("TotalTime", Float) = 1 _StartTime("StartTime", Float) = 0 _MaxRadius("MaxRadius", Float) = 1500 [KeywordEnum(ROUND, ELLIPSE, DYNAMIC_ROUND)] _RoundMode("Mask mode", Float) = 0 //-------------------add---------------------- } SubShader { Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "PreviewType"="Plane" "CanUseSpriteAtlas"="True" } Stencil { Ref [_Stencil] Comp [_StencilComp] Pass [_StencilOp] ReadMask [_StencilReadMask] WriteMask [_StencilWriteMask] } Cull Off Lighting Off ZWrite Off ZTest [unity_GUIZTestMode] Blend SrcAlpha OneMinusSrcAlpha ColorMask [_ColorMask] Pass { Name "Default" CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma target 2.0 #include "UnityCG.cginc" #include "UnityUI.cginc" #pragma multi_compile __ UNITY_UI_CLIP_RECT #pragma multi_compile __ UNITY_UI_ALPHACLIP #pragma multi_compile _ROUNDMODE_ROUND _ROUNDMODE_ELLIPSE _ROUNDMODE_DYNAMIC_ROUND struct appdata_t { float4 vertex : POSITION; float4 color : COLOR; float2 texcoord : TEXCOORD0; UNITY_VERTEX_INPUT_INSTANCE_ID }; struct v2f { float4 vertex : SV_POSITION; fixed4 color : COLOR; float2 texcoord : TEXCOORD0; float4 worldPosition : TEXCOORD1; UNITY_VERTEX_OUTPUT_STEREO }; fixed4 _Color; fixed4 _TextureSampleAdd; float4 _ClipRect; //-------------------add---------------------- half _Radius; float2 _Center; half _TransitionRange; half _Width; half _Height; half _Ellipse; fixed _ReduceTime; half _TotalTime; float _StartTime; half _MaxRadius; //-------------------add---------------------- v2f vert(appdata_t v) { v2f OUT; UNITY_SETUP_INSTANCE_ID(v); UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT); OUT.worldPosition = v.vertex; OUT.vertex = UnityObjectToClipPos(OUT.worldPosition); OUT.texcoord = v.texcoord; OUT.color = v.color * _Color; return OUT; } sampler2D _MainTex; fixed4 frag(v2f IN) : SV_Target { half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color; #ifdef UNITY_UI_CLIP_RECT color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect); #endif #ifdef UNITY_UI_ALPHACLIP clip (color.a - 0.001); #endif //-------------------add----------------------#ifdef _ROUNDMODE_ROUND //计算片元世界坐标和目标中心位置的距离 float dis = distance(IN.worldPosition.xy, _Center.xy); //过滤掉距离小于（半径-过渡范围）的片元 clip(dis - (_Radius - _TransitionRange)); //优化if条件判断，如果距离小于半径则执行下一步，等于if(dis < _Radius) fixed tmp = step(dis, _Radius); //计算过渡范围内的alpha值 color.a *= (1 - tmp) + tmp * (dis - (_Radius - _TransitionRange)) / _TransitionRange;#elif _ROUNDMODE_ELLIPSE //计算X轴方向距离 float disX = distance(IN.worldPosition.x, _Center.x); //计算Y轴方向距离 float disY = distance(IN.worldPosition.y, _Center.y); //运用椭圆方程计算片元的alpha值，_Ellipse为椭圆系数 fixed factor = clamp(pow(abs(disX / _Width), _Ellipse) + pow(abs(disY / _Height), _Ellipse), 0.0, 1.0); //优化if条件判断 fixed tmp = step(factor, 1.0f); //赋值椭圆外或椭圆内的alpha值 color.a *= (1 - tmp) + tmp * factor;#else //_StartTime为效果开始时间点，Unity中对应赋值material.SetFloat("_StartTime", Time.timeSinceLevelLoad); fixed processTime = _Time.y - _StartTime; //判断shader执行时长是否超过_TotalTime clip(_TotalTime - processTime); //优化if条件判断 fixed tmp = step(processTime, _ReduceTime); //计算当前时间点的圆形镂空半径 float curRadius = (1 - tmp) * _Radius + tmp * (_MaxRadius - (_MaxRadius - _Radius) * processTime / _ReduceTime); float dis = distance(IN.worldPosition.xy, _Center.xy); //抛弃距离小于当前圆形镂空半径的片元 clip(dis - curRadius);#endif //-------------------add---------------------- return color; } ENDCG } }}