/**
 * WebGL Gradient Shader
 *
 * Canvas Texture 없이 GLSL uniform만으로 linear / circular gradient를 렌더링합니다.
 * 최대 8개 color stop 지원. SDF border-radius 및 ellipse 클리핑 내장.
 * GLSL ES 1.00 호환 (constant index only).
 */
export declare const gradientVertex = "\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 gradientFragment = "\n  precision highp float;\n\n  #define PI 3.14159265358979323846\n\n  uniform int   uStopCount;\n  uniform vec4  uStopColors0;\n  uniform vec4  uStopColors1;\n  uniform vec4  uStopColors2;\n  uniform vec4  uStopColors3;\n  uniform vec4  uStopColors4;\n  uniform vec4  uStopColors5;\n  uniform vec4  uStopColors6;\n  uniform vec4  uStopColors7;\n  uniform float uStopOffset0;\n  uniform float uStopOffset1;\n  uniform float uStopOffset2;\n  uniform float uStopOffset3;\n  uniform float uStopOffset4;\n  uniform float uStopOffset5;\n  uniform float uStopOffset6;\n  uniform float uStopOffset7;\n  uniform float uDirection;\n  uniform int   uType;\n\n  uniform vec2  uSize;\n  uniform vec4  uBorderRadius;\n  uniform float uIsEllipse;\n  uniform float uOpacity;\n\n  varying vec2 vUV;\n\n  float sdRoundedBox(vec2 p, vec2 b, vec4 r) {\n    float rx = (p.x > 0.0)\n      ? ((p.y > 0.0) ? r.y : r.z)\n      : ((p.y > 0.0) ? r.x : r.w);\n    vec2 q = abs(p) - b + rx;\n    return min(max(q.x, q.y), 0.0) + length(max(q, 0.0)) - rx;\n  }\n\n  vec4 getColor(int i) {\n    if (i == 0) return uStopColors0;\n    if (i == 1) return uStopColors1;\n    if (i == 2) return uStopColors2;\n    if (i == 3) return uStopColors3;\n    if (i == 4) return uStopColors4;\n    if (i == 5) return uStopColors5;\n    if (i == 6) return uStopColors6;\n    return uStopColors7;\n  }\n\n  float getOffset(int i) {\n    if (i == 0) return uStopOffset0;\n    if (i == 1) return uStopOffset1;\n    if (i == 2) return uStopOffset2;\n    if (i == 3) return uStopOffset3;\n    if (i == 4) return uStopOffset4;\n    if (i == 5) return uStopOffset5;\n    if (i == 6) return uStopOffset6;\n    return uStopOffset7;\n  }\n\n  vec4 evalStops(float t) {\n    if (t <= uStopOffset0) return uStopColors0;\n    vec4 result = uStopColors0;\n    for (int i = 0; i < 7; i++) {\n      int next = i + 1;\n      if (next >= uStopCount) break;\n      float s0 = getOffset(i);\n      float s1 = getOffset(next);\n      if (t >= s0 && t <= s1) {\n        float localT = (s1 > s0) ? (t - s0) / (s1 - s0) : 0.0;\n        result = mix(getColor(i), getColor(next), localT);\n        break;\n      }\n      result = getColor(next);\n    }\n    return result;\n  }\n\n  void main() {\n    vec2 p = (vUV - 0.5) * uSize;\n\n    if (uIsEllipse > 0.5) {\n      vec2 pN = vUV * 2.0 - 1.0;\n      if (dot(pN, pN) > 1.0) discard;\n    } else {\n      float d = sdRoundedBox(p, uSize * 0.5, uBorderRadius);\n      if (d > 0.0) discard;\n    }\n\n    float t;\n    if (uType == 1) {\n      vec2 pNorm = vUV * 2.0 - 1.0;\n      t = clamp(length(pNorm), 0.0, 1.0);\n    } else {\n      float rad = (uDirection - 90.0) * PI / 180.0;\n      vec2 dir = vec2(cos(rad), -sin(rad));\n      t = clamp(dot(vUV - 0.5, dir) + 0.5, 0.0, 1.0);\n    }\n\n    vec4 color = evalStops(t);\n    float a = color.a * uOpacity;\n    gl_FragColor = vec4(color.rgb * a, a);\n  }\n";