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

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

  function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

  function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }

  function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

  function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } Object.defineProperty(subClass, "prototype", { value: Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }), writable: false }); if (superClass) _setPrototypeOf(subClass, superClass); }

  function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

  function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }

  function _possibleConstructorReturn(self, call) { if (call && (typeof call === "object" || typeof call === "function")) { return call; } else if (call !== void 0) { throw new TypeError("Derived constructors may only return object or undefined"); } return _assertThisInitialized(self); }

  function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }

  function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Boolean.prototype.valueOf.call(Reflect.construct(Boolean, [], function () {})); return true; } catch (e) { return false; } }

  function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }

  var Refractor = /*#__PURE__*/function (_Mesh) {
    _inherits(Refractor, _Mesh);

    var _super = _createSuper(Refractor);

    function Refractor(geometry) {
      var _this;

      var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};

      _classCallCheck(this, Refractor);

      _this = _super.call(this, geometry);
      _this.type = 'Refractor';

      var scope = _assertThisInitialized(_this);

      var color = options.color !== undefined ? new _three.Color(options.color) : new _three.Color(0x7F7F7F);
      var textureWidth = options.textureWidth || 512;
      var textureHeight = options.textureHeight || 512;
      var clipBias = options.clipBias || 0;
      var shader = options.shader || Refractor.RefractorShader; //

      var virtualCamera = new _three.PerspectiveCamera();
      virtualCamera.matrixAutoUpdate = false;
      virtualCamera.userData.refractor = true; //

      var refractorPlane = new _three.Plane();
      var textureMatrix = new _three.Matrix4(); // render target

      var parameters = {
        minFilter: _three.LinearFilter,
        magFilter: _three.LinearFilter,
        format: _three.RGBFormat
      };
      var renderTarget = new _three.WebGLRenderTarget(textureWidth, textureHeight, parameters);

      if (!_three.MathUtils.isPowerOfTwo(textureWidth) || !_three.MathUtils.isPowerOfTwo(textureHeight)) {
        renderTarget.texture.generateMipmaps = false;
      } // material


      _this.material = new _three.ShaderMaterial({
        uniforms: _three.UniformsUtils.clone(shader.uniforms),
        vertexShader: shader.vertexShader,
        fragmentShader: shader.fragmentShader,
        transparent: true // ensures, refractors are drawn from farthest to closest

      });
      _this.material.uniforms['color'].value = color;
      _this.material.uniforms['tDiffuse'].value = renderTarget.texture;
      _this.material.uniforms['textureMatrix'].value = textureMatrix; // functions

      var visible = function () {
        var refractorWorldPosition = new _three.Vector3();
        var cameraWorldPosition = new _three.Vector3();
        var rotationMatrix = new _three.Matrix4();
        var view = new _three.Vector3();
        var normal = new _three.Vector3();
        return function visible(camera) {
          refractorWorldPosition.setFromMatrixPosition(scope.matrixWorld);
          cameraWorldPosition.setFromMatrixPosition(camera.matrixWorld);
          view.subVectors(refractorWorldPosition, cameraWorldPosition);
          rotationMatrix.extractRotation(scope.matrixWorld);
          normal.set(0, 0, 1);
          normal.applyMatrix4(rotationMatrix);
          return view.dot(normal) < 0;
        };
      }();

      var updateRefractorPlane = function () {
        var normal = new _three.Vector3();
        var position = new _three.Vector3();
        var quaternion = new _three.Quaternion();
        var scale = new _three.Vector3();
        return function updateRefractorPlane() {
          scope.matrixWorld.decompose(position, quaternion, scale);
          normal.set(0, 0, 1).applyQuaternion(quaternion).normalize(); // flip the normal because we want to cull everything above the plane

          normal.negate();
          refractorPlane.setFromNormalAndCoplanarPoint(normal, position);
        };
      }();

      var updateVirtualCamera = function () {
        var clipPlane = new _three.Plane();
        var clipVector = new _three.Vector4();
        var q = new _three.Vector4();
        return function updateVirtualCamera(camera) {
          virtualCamera.matrixWorld.copy(camera.matrixWorld);
          virtualCamera.matrixWorldInverse.copy(virtualCamera.matrixWorld).invert();
          virtualCamera.projectionMatrix.copy(camera.projectionMatrix);
          virtualCamera.far = camera.far; // used in WebGLBackground
          // The following code creates an oblique view frustum for clipping.
          // see: Lengyel, Eric. “Oblique View Frustum Depth Projection and Clipping”.
          // Journal of Game Development, Vol. 1, No. 2 (2005), Charles River Media, pp. 5–16

          clipPlane.copy(refractorPlane);
          clipPlane.applyMatrix4(virtualCamera.matrixWorldInverse);
          clipVector.set(clipPlane.normal.x, clipPlane.normal.y, clipPlane.normal.z, clipPlane.constant); // calculate the clip-space corner point opposite the clipping plane and
          // transform it into camera space by multiplying it by the inverse of the projection matrix

          var projectionMatrix = virtualCamera.projectionMatrix;
          q.x = (Math.sign(clipVector.x) + projectionMatrix.elements[8]) / projectionMatrix.elements[0];
          q.y = (Math.sign(clipVector.y) + projectionMatrix.elements[9]) / projectionMatrix.elements[5];
          q.z = -1.0;
          q.w = (1.0 + projectionMatrix.elements[10]) / projectionMatrix.elements[14]; // calculate the scaled plane vector

          clipVector.multiplyScalar(2.0 / clipVector.dot(q)); // replacing the third row of the projection matrix

          projectionMatrix.elements[2] = clipVector.x;
          projectionMatrix.elements[6] = clipVector.y;
          projectionMatrix.elements[10] = clipVector.z + 1.0 - clipBias;
          projectionMatrix.elements[14] = clipVector.w;
        };
      }(); // This will update the texture matrix that is used for projective texture mapping in the shader.
      // see: http://developer.download.nvidia.com/assets/gamedev/docs/projective_texture_mapping.pdf


      function updateTextureMatrix(camera) {
        // this matrix does range mapping to [ 0, 1 ]
        textureMatrix.set(0.5, 0.0, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 1.0); // we use "Object Linear Texgen", so we need to multiply the texture matrix T
        // (matrix above) with the projection and view matrix of the virtual camera
        // and the model matrix of the refractor

        textureMatrix.multiply(camera.projectionMatrix);
        textureMatrix.multiply(camera.matrixWorldInverse);
        textureMatrix.multiply(scope.matrixWorld);
      } //


      function render(renderer, scene, camera) {
        scope.visible = false;
        var currentRenderTarget = renderer.getRenderTarget();
        var currentXrEnabled = renderer.xr.enabled;
        var currentShadowAutoUpdate = renderer.shadowMap.autoUpdate;
        renderer.xr.enabled = false; // avoid camera modification

        renderer.shadowMap.autoUpdate = false; // avoid re-computing shadows

        renderer.setRenderTarget(renderTarget);
        if (renderer.autoClear === false) renderer.clear();
        renderer.render(scene, virtualCamera);
        renderer.xr.enabled = currentXrEnabled;
        renderer.shadowMap.autoUpdate = currentShadowAutoUpdate;
        renderer.setRenderTarget(currentRenderTarget); // restore viewport

        var viewport = camera.viewport;

        if (viewport !== undefined) {
          renderer.state.viewport(viewport);
        }

        scope.visible = true;
      } //


      _this.onBeforeRender = function (renderer, scene, camera) {
        // Render
        renderTarget.texture.encoding = renderer.outputEncoding; // ensure refractors are rendered only once per frame

        if (camera.userData.refractor === true) return; // avoid rendering when the refractor is viewed from behind

        if (!visible(camera) === true) return; // update

        updateRefractorPlane();
        updateTextureMatrix(camera);
        updateVirtualCamera(camera);
        render(renderer, scene, camera);
      };

      _this.getRenderTarget = function () {
        return renderTarget;
      };

      return _this;
    }

    return _createClass(Refractor);
  }(_three.Mesh);

  _exports.Refractor = Refractor;
  Refractor.prototype.isRefractor = true;
  Refractor.RefractorShader = {
    uniforms: {
      'color': {
        value: null
      },
      'tDiffuse': {
        value: null
      },
      'textureMatrix': {
        value: null
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tuniform mat4 textureMatrix;\n\n\t\tvarying vec4 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvUv = textureMatrix * vec4( position, 1.0 );\n\t\t\tgl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t\t}",
    fragmentShader:
    /* glsl */
    "\n\n\t\tuniform vec3 color;\n\t\tuniform sampler2D tDiffuse;\n\n\t\tvarying vec4 vUv;\n\n\t\tfloat blendOverlay( float base, float blend ) {\n\n\t\t\treturn( base < 0.5 ? ( 2.0 * base * blend ) : ( 1.0 - 2.0 * ( 1.0 - base ) * ( 1.0 - blend ) ) );\n\n\t\t}\n\n\t\tvec3 blendOverlay( vec3 base, vec3 blend ) {\n\n\t\t\treturn vec3( blendOverlay( base.r, blend.r ), blendOverlay( base.g, blend.g ), blendOverlay( base.b, blend.b ) );\n\n\t\t}\n\n\t\tvoid main() {\n\n\t\t\tvec4 base = texture2DProj( tDiffuse, vUv );\n\t\t\tgl_FragColor = vec4( blendOverlay( base.rgb, color ), 1.0 );\n\n\t\t}"
  };
});