function ToneMappingPass() {
	    var _this;

	    var options = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

	    classCallCheck(this, ToneMappingPass);

	    _this = possibleConstructorReturn(this, getPrototypeOf$2(ToneMappingPass).call(this, "ToneMappingPass"));
	    /**
	     * The render target for the current luminosity.
	     *
	     * @type {WebGLRenderTarget}
	     * @private
	     * @todo Use RED format in WebGL 2.0.
	     */

	    _this.renderTargetLuminosity = new WebGLRenderTarget(1, 1, {
	      minFilter: LinearMipMapLinearFilter,
	      magFilter: LinearFilter,
	      format: RGBFormat,
	      stencilBuffer: false,
	      depthBuffer: false
	    });
	    _this.renderTargetLuminosity.texture.name = "ToneMapping.Luminosity";
	    /**
	     * The render target for adapted luminosity.
	     *
	     * @type {WebGLRenderTarget}
	     * @private
	     */

	    _this.renderTargetAdapted = _this.renderTargetLuminosity.clone();
	    _this.renderTargetAdapted.texture.name = "ToneMapping.AdaptedLuminosity";
	    _this.renderTargetAdapted.texture.generateMipmaps = false;
	    _this.renderTargetAdapted.texture.minFilter = LinearFilter;
	    /**
	     * A render target that holds a copy of the adapted limonosity.
	     *
	     * @type {WebGLRenderTarget}
	     * @private
	     */

	    _this.renderTargetPrevious = _this.renderTargetAdapted.clone();
	    _this.renderTargetPrevious.texture.name = "ToneMapping.PreviousLuminosity";
	    /**
	     * Copy shader material used for saving the luminance map.
	     *
	     * @type {CopyMaterial}
	     * @private
	     */

	    _this.copyMaterial = new CopyMaterial();
	    /**
	     * A luminosity shader material.
	     *
	     * @type {LuminosityMaterial}
	     * @private
	     */

	    _this.luminosityMaterial = new LuminosityMaterial();
	    _this.luminosityMaterial.uniforms.distinction.value = options.distinction !== undefined ? options.distinction : 1.0;
	    /**
	     * An adaptive luminance shader material.
	     *
	     * @type {AdaptiveLuminosityMaterial}
	     * @private
	     */

	    _this.adaptiveLuminosityMaterial = new AdaptiveLuminosityMaterial();
	    _this.resolution = options.resolution;
	    /**
	     * A tone mapping shader material.
	     *
	     * @type {ToneMappingMaterial}
	     * @private
	     */

	    _this.toneMappingMaterial = new ToneMappingMaterial();
	    _this.adaptive = options.adaptive;
	    return _this;
	  }
Constructs a new tone mapping pass.

@param {Object} [options] - The options.
@param {Boolean} [options.adaptive=true] - Whether the tone mapping should use an adaptive luminance map.
@param {Number} [options.resolution=256] - The render texture resolution.
@param {Number} [options.distinction=1.0] - A luminance distinction factor.