(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports);
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports);
    global.HueSaturationShader = mod.exports;
  }
})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports) {
  "use strict";

  Object.defineProperty(_exports, "__esModule", {
    value: true
  });
  _exports.HueSaturationShader = void 0;

  /**
   * Hue and saturation adjustment
   * https://github.com/evanw/glfx.js
   * hue: -1 to 1 (-1 is 180 degrees in the negative direction, 0 is no change, etc.
   * saturation: -1 to 1 (-1 is solid gray, 0 is no change, and 1 is maximum contrast)
   */
  var HueSaturationShader = {
    uniforms: {
      'tDiffuse': {
        value: null
      },
      'hue': {
        value: 0
      },
      'saturation': {
        value: 0
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvUv = uv;\n\n\t\t\tgl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t\t}",
    fragmentShader:
    /* glsl */
    "\n\n\t\tuniform sampler2D tDiffuse;\n\t\tuniform float hue;\n\t\tuniform float saturation;\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tgl_FragColor = texture2D( tDiffuse, vUv );\n\n\t\t\t// hue\n\t\t\tfloat angle = hue * 3.14159265;\n\t\t\tfloat s = sin(angle), c = cos(angle);\n\t\t\tvec3 weights = (vec3(2.0 * c, -sqrt(3.0) * s - c, sqrt(3.0) * s - c) + 1.0) / 3.0;\n\t\t\tfloat len = length(gl_FragColor.rgb);\n\t\t\tgl_FragColor.rgb = vec3(\n\t\t\t\tdot(gl_FragColor.rgb, weights.xyz),\n\t\t\t\tdot(gl_FragColor.rgb, weights.zxy),\n\t\t\t\tdot(gl_FragColor.rgb, weights.yzx)\n\t\t\t);\n\n\t\t\t// saturation\n\t\t\tfloat average = (gl_FragColor.r + gl_FragColor.g + gl_FragColor.b) / 3.0;\n\t\t\tif (saturation > 0.0) {\n\t\t\t\tgl_FragColor.rgb += (average - gl_FragColor.rgb) * (1.0 - 1.0 / (1.001 - saturation));\n\t\t\t} else {\n\t\t\t\tgl_FragColor.rgb += (average - gl_FragColor.rgb) * (-saturation);\n\t\t\t}\n\n\t\t}"
  };
  _exports.HueSaturationShader = HueSaturationShader;
});