?? 这个效果在很多LOGO及广告宣传中都会用到。商业开发的做法应该是拿一张闪光的图，对其做uv移动，然后和原图两张图混合，这样运算会小很多，需要储存的变量也会小很多。本讲不用图而完全通过计算得出闪光区域，主要是借此加深uv计算实现特殊效果的实现,以及计算uv的方法。代码注释配合图解已经比较详细了，跟着做就行，随便找一张半透明的图来做地图即可。

?

Shader "Custom/logo" {
??? Properties {
??? ??? _MainTex ("Texture", 2D) = "white" { }
??? }
??? SubShader
??? {
??? ??? AlphaTest Greater .2
??? ??? pass
??? ??? {
??? ??? ??? CGPROGRAM
??? ??? ??? #pragma vertex vert
??? ??? ??? #pragma fragment frag
??? ??? ??? #include "UnityCG.cginc"
??? ???
??? ??? ??? sampler2D _MainTex;
??? ??? ??? float4 _MainTex_ST;
??? ??? ???
??? ??? ??? struct v2f {
??? ??? ??? ??? float4? pos : SV_POSITION;
??? ??? ??? ??? float2? uv : TEXCOORD0;
??? ??? ??? };
??? ??? ???
??? ??? ??? //顶点函数没什么特别的，和常规一样
??? ??? ??? v2f vert (appdata_base v)
??? ??? ??? {
??? ??? ??? ??? v2f o;
??? ??? ??? ?? ??? o.pos = mul(UNITY_MATRIX_MVP,v.vertex);
??? ??? ??? ??? o.uv =??? TRANSFORM_TEX(v.texcoord,_MainTex);
??? ??? ??? ??? return o;
??? ??? ??? }
??? ??? ???
??? ??? ??? //必须放在使用其的 frag函数之前，否则无法识别。
??? ??? ??? //核心：计算函数，角度，uv,光带的x长度，间隔，开始时间，偏移，单次循环时间
??? ??? ??? float inFlash(float angle,float2 uv,float xLength,int interval,int beginTime, float offX, float loopTime )
??? ??? ??? {
??? ??? ??? ??? //亮度值
??? ??? ??? ??? float brightness =0;
??? ??? ??? ???
??? ??? ??? ??? //倾斜角
??? ??? ??? ??? float angleInRad = 0.0174444 * angle;
??? ??? ??? ???
??? ??? ??? ??? //当前时间
??? ??? ??? ??? float currentTime = _Time.y;
??? ??? ???
??? ??? ??? ??? //获取本次光照的起始时间
??? ??? ??? ??? int currentTimeInt = _Time.y/interval;
??? ??? ??? ??? currentTimeInt *=interval;
??? ??? ??? ???
??? ??? ??? ??? //获取本次光照的流逝时间 = 当前时间 - 起始时间
??? ??? ??? ??? float currentTimePassed = currentTime -currentTimeInt;
??? ??? ??? ??? if(currentTimePassed >beginTime)
??? ??? ??? ??? {
??? ??? ??? ??? ??? //底部左边界和右边界
??? ??? ??? ??? ??? float xBottomLeftBound;
??? ??? ??? ??? ??? float xBottomRightBound;

??? ??? ??? ??? ??? //此点边界
??? ??? ??? ??? ??? float xPointLeftBound;
??? ??? ??? ??? ??? float xPointRightBound;
??? ??? ??? ??? ???
??? ??? ??? ??? ??? float x0 = currentTimePassed-beginTime;
??? ??? ??? ??? ??? x0 /= loopTime;
??? ??? ???
??? ??? ??? ??? ??? //设置右边界
??? ??? ??? ??? ??? xBottomRightBound = x0;
??? ??? ??? ??? ???
??? ??? ??? ??? ??? //设置左边界
??? ??? ??? ??? ??? xBottomLeftBound = x0 - xLength;
??? ??? ??? ??? ???
??? ??? ??? ??? ??? //投影至x的长度 = y/ tan(angle)
??? ??? ??? ??? ??? float xProjL;
??? ??? ??? ??? ??? xProjL= (uv.y)/tan(angleInRad);

??? ??? ??? ??? ??? //此点的左边界 = 底部左边界 - 投影至x的长度
??? ??? ??? ??? ??? xPointLeftBound = xBottomLeftBound - xProjL;
??? ??? ??? ??? ??? //此点的右边界 = 底部右边界 - 投影至x的长度
??? ??? ??? ??? ??? xPointRightBound = xBottomRightBound - xProjL;
??? ??? ??? ??? ???
??? ??? ??? ??? ??? //边界加上一个偏移
??? ??? ??? ??? ??? xPointLeftBound += offX;
??? ??? ??? ??? ??? xPointRightBound += offX;
??? ??? ??? ??? ???
??? ??? ??? ??? ??? //如果该点在区域内
??? ??? ??? ??? ??? if(uv.x > xPointLeftBound && uv.x < xPointRightBound)
??? ??? ??? ??? ??? {
??? ??? ??? ??? ??? ??? //得到发光区域的中心点
??? ??? ??? ??? ??? ??? float midness = (xPointLeftBound + xPointRightBound)/2;
??? ??? ??? ??? ??? ???
??? ??? ??? ??? ??? ??? //趋近中心点的程度，0表示位于边缘，1表示位于中心点
??? ??? ??? ??? ??? ??? float rate= (xLength -2*abs(uv.x - midness))/ (xLength);
??? ??? ??? ??? ??? ??? brightness = rate;
??? ??? ??? ??? ??? }
??? ??? ??? ??? }
??? ??? ??? ??? brightness= max(brightness,0);
??? ??? ??? ???
??? ??? ??? ??? //返回颜色 = 纯白色 * 亮度
??? ??? ??? ??? float4 col = float4(1,1,1,1) *brightness;
??? ??? ??? ??? return brightness;
??? ??? ??? }
??? ??? ???
??? ??? ??? float4 frag (v2f i) : COLOR
??? ??? ??? {
??? ??? ??? ???? float4 outp;
??? ??? ??? ????
??? ??? ??? ???? //根据uv取得纹理颜色，和常规一样
??? ??? ??? ??? float4 texCol = tex2D(_MainTex,i.uv);
??? ???
??? ??? ??? ??? //传进i.uv等参数，得到亮度值
??? ??? ??? ??? float tmpBrightness;
??? ??? ??? ??? tmpBrightness =inFlash(75,i.uv,0.25f,5f,2f,0.15,0.7f);
??? ??? ???
??? ??? ??? ??? //图像区域，判定设置为 颜色的A > 0.5,输出为材质颜色+光亮值
??? ??? ??? ??? if(texCol.w >0.5)
??? ??? ??? ??? ??? ??? outp? =texCol+float4(1,1,1,1)*tmpBrightness;
??? ??? ??? ??? //空白区域，判定设置为 颜色的A <=0.5,输出空白
??? ??? ??? ??? else
??? ??? ??? ??? ??? outp =float4(0,0,0,0);

??? ??? ??? ??? return outp;
??? ??? ??? }
??? ??? ??? ENDCG
??? ??? }
??? }
}

转载自风宇冲Unity3D教程学院

[Shader]LOGO闪光效果