// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.
CCEffect %{
  techniques:
  - passes:
    - vert: sprite-vs:vert
      frag: sprite-fs:frag
      depthStencilState:
        depthTest: false
        depthWrite: false
      blendState:
        targets:
        - blend: true
          blendSrc: src_alpha
          blendDst: one_minus_src_alpha
          blendDstAlpha: one_minus_src_alpha
      rasterizerState:
        cullMode: none
      properties:
        alphaThreshold: { value: 0.5 }
        texSize: {value: [500.0,500.0],editor: {tooltip: "节点尺寸"}}
        radius: {value: 0.0}
        texAlpha: {value: 1.0}
        x_count: {value: 1.0}
        y_count: {value: 1.0}
}%

CCProgram sprite-vs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>
  #if USE_LOCAL
    #include <builtin/uniforms/cc-local>
  #endif
  #if SAMPLE_FROM_RT
    #include <common/common-define>
  #endif
  in vec3 a_position;
  in vec2 a_texCoord;
  in vec4 a_color;

  out vec4 color;
  out vec2 uv0;

  vec4 vert () {
    vec4 pos = vec4(a_position, 1);

    #if USE_LOCAL
      pos = cc_matWorld * pos;
    #endif

    #if USE_PIXEL_ALIGNMENT
      pos = cc_matView * pos;
      pos.xyz = floor(pos.xyz);
      pos = cc_matProj * pos;
    #else
      pos = cc_matViewProj * pos;
    #endif

    uv0 = a_texCoord;
    #if SAMPLE_FROM_RT
      CC_HANDLE_RT_SAMPLE_FLIP(uv0);
    #endif
    color = a_color;

    return pos;
  }
}%

CCProgram sprite-fs %{
  precision highp float;
  #include <builtin/internal/embedded-alpha>
  #include <builtin/internal/alpha-test>
  #include <builtin/uniforms/cc-global>
  uniform ARGS {
    vec2 texSize;
    float radius;
    float texAlpha;
    float x_count;
    float y_count;
  };

    // 定义无理数
    #pragma define e 2.718281828459045

    // 定义标准方差值（方差值越大，越模糊，但是需要计算的高斯矩阵范围会变大，从而带来巨大的计算量
    #pragma define stDev 1.5

    // 定义π
    #pragma define pi 3.141592653589793
  in vec4 color;
  #if USE_TEXTURE
    in vec2 uv0;
    #pragma builtin(local)
    layout(set = 2, binding = 11) uniform sampler2D cc_spriteTexture;
  #endif

  /**
  * 获取权重(对应二维高斯函数公式，见 https://zh.wikipedia.org/wiki/%E9%AB%98%E6%96%AF%E6%A8%A1%E7%B3%8A )
  */
  float getWeight(float x, float y) {
    return (1.0 / (2.0 * pi * pow(stDev, 2.0))) * pow(1.0 / e, (pow(x, 2.0) + pow(y, 2.0)) / (2.0 * pow(stDev, 2.0)));
  }

   vec2 getUvMapPos() {
      float block_w = 1.0 / x_count;
      float block_x_idx = floor(uv0.x / block_w);

      float block_h = 1.0 / y_count;
      float block_y_idx = floor(uv0.y / block_h);

      return vec2(block_w * (block_x_idx + 0.5), block_h * (block_y_idx + 0.5));
    }
  vec4 frag () {
    vec4 o = vec4(0, 0, 0, 0);

    #if USE_TEXTURE
      o *= CCSampleWithAlphaSeparated(cc_spriteTexture, uv0);
      #if IS_GRAY
        float gray  = 0.2126 * o.r + 0.7152 * o.g + 0.0722 * o.b;
        o.r = o.g = o.b = gray;
      #endif
    #endif

    // o *= color;
    // ALPHA_TEST(o);

    // const mediump float rd = 10.0;
    vec4 col = vec4(0.);
    // float sum = 0.0;
   
  
    float circle = radius * radius;
    vec2 center = vec2(0.5);
    float rx = (uv0.x - center.x);
    float ry = uv0.y - center.y;
    float dis = rx * rx + ry * ry;
    // float a = smoothstep(dis, dis - 0.1, circle);
    if (dis <= circle) {
      discard;
    }
    
    // 根据高斯分布（也叫正态分布），在3个标准差范围内的分布比例占到99%的权重，因此我们只需要计算矩阵范围 [6 * stDev + 1, 6 * stDev +1] 上的权重

    const highp float size = floor(stDev * 6.0 + 1.0);
    const highp float halfSize = floor(size / 2.0);

      //计算高斯矩阵上所有权重的和

      // 原点
      float totalWeight = getWeight(0.0, 0.0);

      // X轴正方向上的权重 * 2.0 就是整个X轴上的权重
      for(float x = 1.0; x <= halfSize; x++) {
          totalWeight += getWeight(x, 0.0) * 2.0;
      } 
      // Y轴正方向上的权重 * 2.0 就是整个Y轴上的权重
      for(float y = 1.0; y <= halfSize; y++) {
          totalWeight += getWeight(0.0, y) * 2.0;
      } 
      // 第一象限的权重 * 4.0 就是4个象限的权重
      for(float x = 1.0; x <= halfSize; x++) {
        for (float y = 1.0; y<= halfSize; y++) {
          totalWeight += getWeight(x, y) * 4.0;
        }
      }

      // 采样周边像素并应用加权平均值，得出最终像素值
      vec4 finalColor = vec4(0.0, 0.0, 0.0, 0.0);
      // float divider = 0.01; 
      float onePxWidth = 1.0 / texSize.x;
      float onePxHeight = 1.0 / texSize.y;
      //  vec2 realPos = getUvMapPos();
      // o *= CCSampleWithAlphaSeparated(cc_spriteTexture, realPos);
      for(float x = -halfSize; x<= halfSize; x++) {
        for (float y = -halfSize; y<= halfSize; y++) {
          // 求出对应坐标的真正权重（对应权重矩阵）
          float weight = getWeight(x, y) / totalWeight;

          // 求出对应坐标像素颜色值的加权值
          finalColor += CCSampleWithAlphaSeparated(cc_spriteTexture, uv0 + vec2(onePxWidth * x, onePxHeight * y)) * weight;
        }
      }
     
      // o *= finalColor;
      o = finalColor;
      o.a *= texAlpha;
    // }
    // col.a = color.a;
    //  #if USE_TRAMSFORM
    // #endif
    return o;
  }
}%