// 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:
        rows: {value: 4}
        columns: {value: 8}
        sizeExpand: {value: 0.6}
        radius: {value: 0.15}
}%

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 "../chunks/sdf2d"
  uniform Const {
    float rows;
    float columns;
    float sizeExpand;
    float radius;
  };
  in vec4 color;
  in vec2 uv0;
  
  float smin(float a,float b,float k){
      float h = clamp(0.5+0.5*(a-b)/k,0.0,1.0);
      return mix(a,b,h)-k*h*(1.0-h);
  }
  float smax(float a,float b,float k){
      return -smin(-a,-b,k);
  }
  float isOdd(float x) {
    return fract(x/2.0) * 2.0;
  }
  #pragma builtin(local)
  layout(set = 2, binding = 12) uniform sampler2D cc_spriteTexture;


  vec4 frag () {
    vec4 o = vec4(1, 1, 1, 1);      

    vec2 id = floor(uv0 * vec2(columns, rows));
    vec2 uv_center = (id + 0.5) / vec2(columns, rows);

    float exp = sizeExpand + 1.0;
    vec2 uv = (uv0 - uv_center) * vec2(columns, rows) * exp;
    o *= CCSampleWithAlphaSeparated(cc_spriteTexture, (uv0 - uv_center) * exp + uv_center);
    float d = sdBox(uv, vec2(0.5, 0.5));

    float rad = radius;
    float dd = 0.1;
    float odd = isOdd(id.x + id.y);
    float s = sign(odd - 0.5);

    float dc_top = sdCircle(uv + vec2(0, 0.5 - dd * s), rad);
    float dc_bottom = sdCircle(uv + vec2(0, -0.5 + dd * s), rad);
    float dc_left = sdCircle(uv + vec2(0.5 + dd * s, 0), rad);
    float dc_right = sdCircle(uv + vec2(-0.5 - dd * s, 0), rad);

    float k = 0.02;
    float nOdd = 1.0 - odd;

    float dt = smax(d, -dc_top, k) * odd + smin(d, dc_top , k) * nOdd;
    float edge = step(id.y, 0.5);
    d = dt * (1.0 - edge) + d * edge;

    float db = smax(d, -dc_bottom, k) * odd + smin(d, dc_bottom, k) * nOdd;
    edge = step(rows - 1.5, id.y);
    d = db * (1.0 - edge) + d * edge;

    float dl = smin(d, dc_left, k) * odd + smax(d, -dc_left, k) * nOdd;
    edge = step(id.x, 0.5);
    d = dl * (1.0 - edge) + d * edge;

    float dr = smin(d, dc_right, k) * odd + smax(d, -dc_right, k) * nOdd;
    edge = step(columns - 1.5, id.x);
    d = dr * (1.0 - edge) + d * edge;

    float c = smoothstep(0.01, -0.01, d);
    o *= c;
    return o;
  }
}%