/**
 * 알파채널 경계 기반 Border + Outline 셰이더
 *
 * image/sprite 객체에서 style.borderColor, style.outlineColor 를
 * 이미지 사각형이 아닌 알파채널 외곽에 렌더링합니다.
 *
 * 동작 방식:
 *   - 확장 쿼드(expanded quad) 전체에서 실행됩니다.
 *     expandedW = drawW + 2 * (borderWidth + outlineWidth)
 *   - 불투명 픽셀(이미지 내부): discard → 별도 texture 패스에서 렌더됨
 *   - border 범위 내 픽셀: borderColor 렌더
 *   - outline 범위 내 픽셀: outlineColor 렌더
 *   - 범위 초과: discard
 *
 * 제한:
 *   - MAX_RADIUS = 16 → borderWidth + outlineWidth 합계 최대 16 world units
 *     더 큰 값이 필요하면 MAX_RADIUS 상수를 수정하십시오 (성능 비례 증가)
 */
export declare const alphaOutlineVertex = "\n  attribute vec2 position;\n  attribute vec2 uv;\n  uniform mat4 uModelMatrix;\n  uniform mat4 uViewMatrix;\n  uniform mat4 uProjectionMatrix;\n  varying vec2 vUV;\n\n  void main() {\n    vUV = uv;\n    gl_Position = uProjectionMatrix * uViewMatrix * uModelMatrix * vec4(position, 0.0, 1.0);\n  }\n";
export declare const alphaOutlineFragment = "\n  precision highp float;\n\n  uniform sampler2D uTexture;\n  uniform float uOpacity;\n  uniform float uAlphaThreshold;\n\n  uniform vec2 uUVOffset;\n  uniform vec2 uUVScale;\n\n  // \uD655\uC7A5 \uCFFC\uB4DC \u2192 \uC774\uBBF8\uC9C0 UV \uBCC0\uD658 \uD30C\uB77C\uBBF8\uD130\n  uniform vec2 uImageOffset; // \uD655\uC7A5 \uCFFC\uB4DC UV\uC5D0\uC11C \uC774\uBBF8\uC9C0 \uC2DC\uC791\uC810 (pad/expandedW)\n  uniform vec2 uImageScale;  // \uD655\uC7A5 \uCFFC\uB4DC UV\uC5D0\uC11C \uC774\uBBF8\uC9C0\uAC00 \uCC28\uC9C0\uD558\uB294 \uBE44\uC728 (drawW/expandedW)\n\n  // \uC774\uBBF8\uC9C0 UV \uACF5\uAC04\uC5D0\uC11C 1 world pixel \uD06C\uAE30 = vec2(1/drawW, 1/drawH)\n  uniform vec2 uTexelStep;\n\n  uniform float uBorderWidth;  // world pixels\n  uniform vec4  uBorderColor;  // premultiplied-ready RGBA\n  uniform float uOutlineWidth; // world pixels\n  uniform vec4  uOutlineColor; // premultiplied-ready RGBA\n\n  varying vec2 vUV;\n\n  #define MAX_RADIUS 16\n\n  void main() {\n    // 1. \uD655\uC7A5 \uCFFC\uB4DC UV \u2192 \uC774\uBBF8\uC9C0 UV \uBCC0\uD658\n    vec2 imageUV = (vUV - uImageOffset) / uImageScale;\n    bool inImage = imageUV.x >= 0.0 && imageUV.x <= 1.0\n                && imageUV.y >= 0.0 && imageUV.y <= 1.0;\n\n    // 2. \uC774\uBBF8\uC9C0 \uB0B4 \uBD88\uD22C\uBA85 \uD53D\uC140\uC740 main texture \uD328\uC2A4\uC5D0\uC11C \uB80C\uB354\uB428 \u2192 \uC5EC\uAE30\uC120 \uC81C\uC678\n    if (inImage) {\n      vec2 texUV = imageUV * uUVScale + uUVOffset;\n      if (texture2D(uTexture, texUV).a > uAlphaThreshold) {\n        discard;\n      }\n    }\n\n    // 3. \uC778\uC811 \uD53D\uC140 \uD0D0\uC0C9: \uBD88\uD22C\uBA85 \uD53D\uC140\uAE4C\uC9C0\uC758 \uCD5C\uC18C \uAC70\uB9AC(world pixels)\n    float searchR = uBorderWidth + uOutlineWidth;\n    float minDist = 99999.0;\n\n    for (int dx = -MAX_RADIUS; dx <= MAX_RADIUS; dx++) {\n      for (int dy = -MAX_RADIUS; dy <= MAX_RADIUS; dy++) {\n        float d = length(vec2(float(dx), float(dy)));\n        if (d > searchR) continue;\n        vec2 sUV = imageUV + vec2(float(dx), float(dy)) * uTexelStep;\n        if (sUV.x < 0.0 || sUV.x > 1.0 || sUV.y < 0.0 || sUV.y > 1.0) continue;\n        \n        vec2 sTexUV = sUV * uUVScale + uUVOffset;\n        if (texture2D(uTexture, sTexUV).a > uAlphaThreshold) {\n          if (d < minDist) minDist = d;\n        }\n      }\n    }\n\n    if (minDist > searchR) {\n      discard;\n    }\n\n    // 4. \uAC70\uB9AC \uAD6C\uAC04\uBCC4 \uC0C9\uC0C1 \uACB0\uC815 (border \u2192 outline \uC21C\uC11C)\n    if (uBorderWidth > 0.0 && minDist <= uBorderWidth) {\n      float a = uBorderColor.a * uOpacity;\n      gl_FragColor = vec4(uBorderColor.rgb * a, a);\n    } else if (uOutlineWidth > 0.0 && minDist <= searchR) {\n      float a = uOutlineColor.a * uOpacity;\n      gl_FragColor = vec4(uOutlineColor.rgb * a, a);\n    } else {\n      discard;\n    }\n  }\n";