// Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.  

CCEffect %{
  techniques:
  - passes:
    - vert: vs
      frag: fs
      blendState:
        targets:
        - blend: true
      rasterizerState:
        cullMode: none
      properties:
        texture: { value: white }
        alphaThreshold: { value: 0.5 }
}%


CCProgram vs %{
  precision highp float;

  #include <cc-global>
  #include <cc-local>

  in vec3 a_position;
  in vec4 a_color;
  out vec4 v_color;

  #if USE_TEXTURE
  in vec2 a_uv0;
  out vec2 v_uv0;
  #endif

  void main () {
    vec4 pos = vec4(a_position, 1);

    #if CC_USE_MODEL
    pos = cc_matViewProj * cc_matWorld * pos;
    #else
    pos = cc_matViewProj * pos;
    #endif

    #if USE_TEXTURE
    v_uv0 = a_uv0;
    #endif

    v_color = a_color;

    gl_Position = pos;
  }
}%


CCProgram fs %{
  precision highp float;
  
  #include <cc-global>
  #include <alpha-test>
  #include <texture>

  in vec4 v_color;

  #if USE_TEXTURE
  in vec2 v_uv0;
  uniform sampler2D texture;
  #endif
  

  vec2 getSt(){
    vec4 o = vec4(1, 1, 1, 1);

    #if USE_TEXTURE
      CCTexture(texture, v_uv0, o);
    #endif

    o *= v_color;

    ALPHA_TEST(o);

    return v_uv0;
  }

  float Hash( vec2 p, in float s)
  {
    vec3 p2 = vec3(p.xy,27.0 * abs(sin(s)));
    return fract(sin(dot(p2,vec3(27.1,61.7, 12.4)))*273758.5453123);
  }

  float noise(in vec2 p, in float s)
  {
    vec2 i = floor(p);
    vec2 f = fract(p);
    f *= f * (3.0-2.0*f);
  
    return mix(mix(Hash(i + vec2(0.,0.), s), Hash(i + vec2(1.,0.), s),f.x),
    mix(Hash(i + vec2(0.,1.), s), Hash(i + vec2(1.,1.), s),f.x),f.y) * s;
  }

  float fbm(vec2 p)
  {
    float v = 0.0;
    v += noise(p*2., 0.25);
    v += noise(p*8., 0.0625);
    return v;
  }

  const float thickness = 100.0;// 闪电粗细值，值越小，闪电越粗
  const float offset = 0.4; // 闪电的偏移值
  const vec3 color = vec3(0.68, 0.85, 1.0);//此处可以修改 闪电的颜色
  const float rang = 0.45; // 闪电范围参数，一定范围内（小于1.0），值越大闪电边缘光越小
  
  void main () {
    vec2 st = getSt();
    vec2 position = vec2(offset) - st;

    float t = abs(0.5/ ((position.x + fbm(position + cc_time.x)) * thickness));
    vec3 finalColor =  t / color;
    float absv = abs(finalColor.x) + abs(finalColor.y) + abs(finalColor.z);

    gl_FragColor = vec4( finalColor,smoothstep(rang,1.0,absv));
  }
}%