// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.
CCEffect %{
techniques:
  - passes:
      - vert: sprite-vs:vert
        frag: circle-hole-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 }
          circles: { value: [0.5, 0.5, 0.5, 0.5], editor: { type: array } }
          maskColor: { value: [0.5, 0.5, 0.5, 0.5], editor: { type: color } }
          textureSize: { value: [300, 300] }

}%

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 circle-hole-fs %{
precision highp float;
#include <builtin/internal/embedded-alpha>
#include <builtin/internal/alpha-test>

in vec4 color;
in vec2 uv0;

#pragma builtin(local)
layout(set = 2, binding = 12)uniform sampler2D cc_spriteTexture;

uniform ufs {
  vec4 circles[20]; // 存储多个圆的信息，每个元素包含圆心坐标、半径、渐变宽度
  vec4 maskColor;
  vec2 textureSize;
};

vec4 frag() {
  vec4 o = maskColor;
  
  // 遍历每个圆的信息来判断像素是否在孔洞内并应用效果  
  for(int i = 0; i < 10; ++ i) { // 同样这里10根据实际设置的最大圆数量来定，可优化成根据circles实际传入的有效数量来循环
    
    float radius = circles[i].z;
    radius = circles[i].z / max(textureSize.x, textureSize.y);
    float dis = distance(uv0, circles[i].xy);
    
    if (dis < radius) {
      float gradient = smoothstep(radius - circles[i].w , radius, dis);
      o.a = min(gradient * maskColor.a, o.a); // 取多个圆作用后的最小透明度，可根据需求调整合成方式
    }
    
  }
  
  #if USE_TEXTURE
    o *= texture(cc_spriteTexture, uv0);
  #endif
  
  o *= color;
  ALPHA_TEST(o);
  return o;
}
}%