cesiumDemo/Source/DataSources/ColorMaterialProperty.js

import Color from '../Core/Color.js';
import defined from '../Core/defined.js';
import defineProperties from '../Core/defineProperties.js';
import Event from '../Core/Event.js';
import createPropertyDescriptor from './createPropertyDescriptor.js';
import Property from './Property.js';

    /**
     * A {@link MaterialProperty} that maps to solid color {@link Material} uniforms.
     *
     * @param {Property} [color=Color.WHITE] The {@link Color} Property to be used.
     *
     * @alias ColorMaterialProperty
     * @constructor
     */
    function ColorMaterialProperty(color) {
        this._definitionChanged = new Event();
        this._color = undefined;
        this._colorSubscription = undefined;

        this.color = color;
    }

    defineProperties(ColorMaterialProperty.prototype, {
        /**
         * Gets a value indicating if this property is constant.  A property is considered
         * constant if getValue always returns the same result for the current definition.
         * @memberof ColorMaterialProperty.prototype
         *
         * @type {Boolean}
         * @readonly
         */
        isConstant : {
            get : function() {
                return Property.isConstant(this._color);
            }
        },

        /**
         * Gets the event that is raised whenever the definition of this property changes.
         * The definition is considered to have changed if a call to getValue would return
         * a different result for the same time.
         * @memberof ColorMaterialProperty.prototype
         *
         * @type {Event}
         * @readonly
         */
        definitionChanged : {
            get : function() {
                return this._definitionChanged;
            }
        },

        /**
         * Gets or sets the {@link Color} {@link Property}.
         * @memberof ColorMaterialProperty.prototype
         * @type {Property}
         * @default Color.WHITE
         */
        color : createPropertyDescriptor('color')
    });

    /**
     * Gets the {@link Material} type at the provided time.
     *
     * @param {JulianDate} time The time for which to retrieve the type.
     * @returns {String} The type of material.
     */
    ColorMaterialProperty.prototype.getType = function(time) {
        return 'Color';
    };

    /**
     * Gets the value of the property at the provided time.
     *
     * @param {JulianDate} time The time for which to retrieve the value.
     * @param {Object} [result] The object to store the value into, if omitted, a new instance is created and returned.
     * @returns {Object} The modified result parameter or a new instance if the result parameter was not supplied.
     */
    ColorMaterialProperty.prototype.getValue = function(time, result) {
        if (!defined(result)) {
            result = {};
        }
        result.color = Property.getValueOrClonedDefault(this._color, time, Color.WHITE, result.color);
        return result;
    };

    /**
     * Compares this property to the provided property and returns
     * <code>true</code> if they are equal, <code>false</code> otherwise.
     *
     * @param {Property} [other] The other property.
     * @returns {Boolean} <code>true</code> if left and right are equal, <code>false</code> otherwise.
     */
    ColorMaterialProperty.prototype.equals = function(other) {
        return this === other || //
               (other instanceof ColorMaterialProperty && //
                Property.equals(this._color, other._color));
    };
export default ColorMaterialProperty;