CCEffect %{
  techniques:
  - passes:
    - vert: cover-vs:vert
      frag: cover-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:
        uvTransform: { value: [1, 1, 0.5, 0.5] }
        cornerRadii: { value: [20, 20, 20, 20], editor: { tooltip: "圆角半径（节点单位）：x左上、y右上、z右下、w左下；0为直角" } }
        nodeInfo: { value: [207, 412, 1, 0], editor: { tooltip: "xy节点宽高（脚本同步），z边缘柔化宽度" } }
        nodeUVRowX: { value: [1, 0, 0, 0], editor: { visible: false } }
        nodeUVRowY: { value: [0, -1, 1, 0], editor: { visible: false } }
}%

CCProgram cover-vs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>
  #if USE_LOCAL
    #include <builtin/uniforms/cc-local>
  #endif
  in vec3 a_position;
  in vec2 a_texCoord;
  in vec4 a_color;
  out vec2 v_uv;
  out vec4 v_color;
  vec4 vert () {
    vec4 pos = vec4(a_position, 1.0);
    #if USE_LOCAL
      pos = cc_matWorld * pos;
    #endif
    v_uv = a_texCoord;
    v_color = a_color;
    return cc_matViewProj * pos;
  }
}%

CCProgram cover-fs %{
  precision highp float;
  #include <builtin/internal/embedded-alpha>
  in vec2 v_uv;
  in vec4 v_color;
  #pragma builtin(local)
  layout(set = 2, binding = 11) uniform sampler2D cc_spriteTexture;
  uniform CoverParams {
    vec4 uvTransform;
    vec4 cornerRadii;
    vec4 nodeInfo;
    vec4 nodeUVRowX;
    vec4 nodeUVRowY;
  };
  vec4 frag () {
    // Geometry stays inside the node rectangle; only the sampled region shrinks.
    vec2 uv = (v_uv - uvTransform.zw) * uvTransform.xy + uvTransform.zw;
    vec4 color = CCSampleWithAlphaSeparated(cc_spriteTexture, uv) * v_color;

    // Use the original, uncropped UV to recover node coordinates. The two
    // rows also account for SpriteFrames stored in a rotated atlas rectangle.
    vec3 sourceUV = vec3(v_uv, 1.0);
    vec2 nodeUV = vec2(dot(nodeUVRowX.xyz, sourceUV), dot(nodeUVRowY.xyz, sourceUV));
    vec2 halfSize = max(nodeInfo.xy, vec2(0.001)) * 0.5;
    vec2 p = (nodeUV - 0.5) * nodeInfo.xy;
    float radius = p.y >= 0.0
      ? (p.x < 0.0 ? cornerRadii.x : cornerRadii.y)
      : (p.x < 0.0 ? cornerRadii.w : cornerRadii.z);
    radius = clamp(radius, 0.0, min(halfSize.x, halfSize.y));
    vec2 q = abs(p) - halfSize + vec2(radius);
    float distanceToEdge = length(max(q, vec2(0.0)))
      + min(max(q.x, q.y), 0.0) - radius;
    color.a *= 1.0 - smoothstep(-max(nodeInfo.z, 0.001), 0.0, distanceToEdge);
    return color;
  }
}%