//高斯模糊2

CCEffect %{
  techniques:
  - passes:
    - vert: vs
      frag: fs
      blendState:
        targets:
        - blend: true
      rasterizerState:
        cullMode: none
      properties:
        texture: { value: white }
        u_resolution: { value: [1280,720] }
}%

CCProgram vs %{
  #include <cc-global>
  precision highp float;	      // 定义float高精度
	in vec3 a_position;    // 顶点Shader 从渲染管道里面获取的顶点信息,使用attribute来修饰;
	in vec2 a_uv0;         // 纹理坐标;
	out vec2 uv0;             // 传递给着色Shader，varying 来修饰，进行插值
	void main () {
		vec4 pos = cc_matViewProj * vec4(a_position, 1);
		gl_Position = pos;
		uv0 = a_uv0;
	}
}%

CCProgram fs %{
  precision mediump float;
  in vec2 uv0;
  uniform sampler2D texture;
  uniform ARGS {
    vec2 u_resolution;
    float strength;
  };
  const float blurRadius = 7.0;
  void main()
  {
    vec2 unit = 1.0 / u_resolution; //单位坐标
    vec3 sumColor = vec3(0.0, 0.0, 0.0);
    float count = 0.0;
    vec4 col = vec4(0.0);
    for(float fy = -blurRadius; fy <= blurRadius; ++fy)
    {
      for(float fx = -blurRadius; fx <= blurRadius; ++fx)
      {   
        float weight = (blurRadius - abs(fx)) * (blurRadius - abs(fy)); //权重，p点的权重最高，向四周依次减少
        col += texture2D(texture, uv0 + vec2(fx * unit.x, fy * unit.y)) * weight;
        count += weight;
      }
    }
    col.a = texture2D(texture, uv0).a;
    gl_FragColor = vec4(col.rgb / count, col.a);
  }
}%