OpenGL Shader实例分析（4）闪光效果

Shader "stalendp/imageShine" {
 Properties{
 _image("image", 2D) = "white" {}
 _percent("_percent", Range(-5, 5)) = 1
 _angle("angle", Range(0, 1)) = 0
 }
 
 CGINCLUDE
#include "UnityCG.cginc"    
 
 sampler2D _image;
 float _percent;
 float _angle;
 
 struct v2f {
 float4 pos:SV_POSITION;
 float2 uv : TEXCOORD0;
 };
 
 v2f vert(appdata_base v) {
 v2f o;
 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
 o.uv = v.texcoord.xy;
 return o;
 }
 
 fixed4 frag(v2f i) : COLOR0{
 // 计算圆角 
 float2 uv = i.uv.xy - float2(0.5,0.5);
 float rx = fmod(uv.x, 0.4);
 float ry = fmod(uv.y, 0.4);
 float mx = step(0.4, abs(uv.x));
 float my = step(0.4, abs(uv.y));
 float alpha = 1 - mx*my*step(0.1, length(half2(rx,ry)));
 
 fixed2x2 rotMat = fixed2x2(0.866,0.5,-0.5,0.866); // 旋转矩阵，旋转30度 
 
 fixed4 k = tex2D(_image, i.uv);
 //    k = fixed4(fixed3(k.r+k.g+k.b)/3, 1); //灰度设置 
 
 uv = i.uv - fixed2(0.5, 0.5); 
 _angle = 6.283*(_angle - 0.5);
 float hui = (2 - sign(_angle - atan2(uv.y, uv.x))) / 3; // 百分比计算 
 
 uv = (i.uv + fixed2(_percent, _percent)) * 2; // 缩放并位移 
 uv = mul(rotMat, uv); //旋转 
 
 fixed v = saturate(lerp(fixed(1), fixed(0), abs(uv.y)));
 k += fixed4(v,v,v,v); // 加上光线 
 k *= fixed4(fixed3(hui, hui, hui), alpha); // 圆角的运用 
 return k;
 }
 ENDCG
 
 SubShader {
 Tags{ "Queue" = "Transparent" }
 ZWrite Off
 Blend SrcAlpha OneMinusSrcAlpha
 Pass{
 CGPROGRAM
#pragma vertex vert  
#pragma fragment frag  
#pragma fragmentoption ARB_precision_hint_fastest  
 
 ENDCG
 }
 }
 FallBack Off
}