LOGO闪光效果Shader实现

Shader "Unlit/logo"
｛
Properties｛
_MainTex("Base (RGB)", 2D) = "white" ｛｝ //在属性面板上显示贴图
_FlashColor("Flash Color", Color) = (1,1,1,1)
//闪光的颜色
_Angle("Flash Angle", Range(0, 180)) = 45
//闪光的角度
_Width("Flash Width", Range(0, 1)) = 0.2
//闪光的宽度
_LoopTime("Loop Time", Float) = 1
//持续的时间
_Interval("Time Interval", Float) = 3
//每一次的间隔
       _BeginTime ("Begin Time", Float) = 2
//第一次开始的时间
｝
SubShader
｛
Tags｛ "Queue" = "Transparent" "RenderType" = "Transparent" ｝
//"Queue"表示渲染的顺序，"RenderType"表示渲染的类型
CGPROGRAM
#pragma surface surf Lambert alpha exclude_path:prepass noforwardadd
//surface表示采用哪种渲染类型，surf是定义的方法，与下文相对应
//alpha是混合，至于后面那个加与不加效果一样，反正我是没弄明白
#pragma target 3.0
//在shader中用面板的属性要从新进行一次定义，名字必须一致
sampler2D _MainTex;
float4 _FlashColor;
float _Angle;
float _Width;
float _LoopTime;
float _Interval;
        float _BeginTime;
//作为surf的输入
struct Input
｛
half2 uv_MainTex;
｝;
float inFlash(half2 uv)
｛
float brightness = 0;//亮度值
float angleInRad = 0.0174444 * _Angle;//倾斜角
float tanInverseInRad = 1.0 / tan(angleInRad);//_Angle在0~45°，tanInverseInRad>1;_Angle在45~90°,0<tanInverseInRad<1;
//_Angle在90~135°，-1<tanInverseInRad<0;_Angle在135~180°,-625<tanInverseInRad<-1,以后的又从头开始循环
            float currentTime = _Time.y - _BeginTime;//第一次开始的时间
float totalTime = _Interval + _LoopTime;//从第一次播放到第二次开始播放的间隔
float currentTurnStartTime = (int)((currentTime / totalTime)) * totalTime;
float currentTurnTimePassed = currentTime - currentTurnStartTime - _Interval;
bool onLeft = (tanInverseInRad > 0);
float xBottomFarLeft = onLeft ? 0.0 : tanInverseInRad;
float xBottomFarRight = onLeft ? (1.0 + tanInverseInRad) : 1.0;
float percent = currentTurnTimePassed / _LoopTime;
float xBottomRightBound = xBottomFarLeft + percent * (xBottomFarRight - xBottomFarLeft);
float xBottomLeftBound = xBottomRightBound - _Width;
float xProj = uv.x + uv.y * tanInverseInRad;
if (xProj > xBottomLeftBound && xProj < xBottomRightBound)
｛
brightness = 1.0 - abs(2.0 * xProj - (xBottomLeftBound + xBottomRightBound)) / _Width;
｝
return brightness;
｝
void surf(Input IN, inout SurfaceOutput o)
｛
half4 texCol = tex2D(_MainTex, IN.uv_MainTex);//根据uv取得每个像素的颜色
float brightness = inFlash(IN.uv_MainTex);//传进i.uv等参数，得到亮度值
o.Albedo = texCol.rgb + _FlashColor.rgb * brightness;//根据每个RGB进行叠加
o.Alpha = texCol.a;
｝
ENDCG
｝
FallBack "Unlit/Transparent"
｝