GeometryInstanceAttribute.js

/*global define*/
define([
        './defaultValue',
        './defined',
        './DeveloperError'
    ], function(
        defaultValue,
        defined,
        DeveloperError) {
    "use strict";

    /**
     * Values and type information for per-instance geometry attributes.
     *
     * @alias GeometryInstanceAttribute
     * @constructor
     *
     * @param {Object} options Object with the following properties:
     * @param {ComponentDatatype} [options.componentDatatype] The datatype of each component in the attribute, e.g., individual elements in values.
     * @param {Number} [options.componentsPerAttribute] A number between 1 and 4 that defines the number of components in an attributes.
     * @param {Boolean} [options.normalize=false] When <code>true</code> and <code>componentDatatype</code> is an integer format, indicate that the components should be mapped to the range [0, 1] (unsigned) or [-1, 1] (signed) when they are accessed as floating-point for rendering.
     * @param {Number[]} [options.value] The value for the attribute.
     *
     * @exception {DeveloperError} options.componentsPerAttribute must be between 1 and 4.
     *
     * @see ColorGeometryInstanceAttribute
     * @see ShowGeometryInstanceAttribute
     *
     * @example
     * var instance = new Cesium.GeometryInstance({
     *   geometry : new Cesium.BoxGeometry({
     *     dimensions : new Cesium.Cartesian3(1000000.0, 1000000.0, 500000.0)
     *   }),
     *   modelMatrix : Cesium.Matrix4.multiplyByTranslation(Cesium.Transforms.eastNorthUpToFixedFrame(
     *     Cesium.Cartesian3.fromDegrees(0.0, 0.0)), new Cesium.Cartesian3(0.0, 0.0, 1000000.0), new Cesium.Matrxi4()),
     *   id : 'box',
     *   attributes : {
     *     color : new Cesium.GeometryInstanceAttribute({
     *       componentDatatype : Cesium.ComponentDatatype.UNSIGNED_BYTE,
     *       componentsPerAttribute : 4,
     *       normalize : true,
     *       value : [255, 255, 0 255]
     *     }
     *   }
     * });
     */
    var GeometryInstanceAttribute = function(options) {
        options = defaultValue(options, defaultValue.EMPTY_OBJECT);

        //>>includeStart('debug', pragmas.debug);
        if (!defined(options.componentDatatype)) {
            throw new DeveloperError('options.componentDatatype is required.');
        }
        if (!defined(options.componentsPerAttribute)) {
            throw new DeveloperError('options.componentsPerAttribute is required.');
        }
        if (options.componentsPerAttribute < 1 || options.componentsPerAttribute > 4) {
            throw new DeveloperError('options.componentsPerAttribute must be between 1 and 4.');
        }
        if (!defined(options.value)) {
            throw new DeveloperError('options.value is required.');
        }
        //>>includeEnd('debug');

        /**
         * The datatype of each component in the attribute, e.g., individual elements in
         * {@link GeometryInstanceAttribute#value}.
         *
         * @type ComponentDatatype
         *
         * @default undefined
         */
        this.componentDatatype = options.componentDatatype;

        /**
         * A number between 1 and 4 that defines the number of components in an attributes.
         * For example, a position attribute with x, y, and z components would have 3 as
         * shown in the code example.
         *
         * @type Number
         *
         * @default undefined
         *
         * @example
         * show : new Cesium.GeometryInstanceAttribute({
         *   componentDatatype : Cesium.ComponentDatatype.UNSIGNED_BYTE,
         *   componentsPerAttribute : 1,
         *   normalize : true,
         *   value : 1.0
         * }
         */
        this.componentsPerAttribute = options.componentsPerAttribute;

        /**
         * When <code>true</code> and <code>componentDatatype</code> is an integer format,
         * indicate that the components should be mapped to the range [0, 1] (unsigned)
         * or [-1, 1] (signed) when they are accessed as floating-point for rendering.
         * <p>
         * This is commonly used when storing colors using {@link ComponentDatatype.UNSIGNED_BYTE}.
         * </p>
         *
         * @type Boolean
         *
         * @default false
         *
         * @example
         * attribute.componentDatatype : Cesium.ComponentDatatype.UNSIGNED_BYTE,
         * attribute.componentsPerAttribute : 4,
         * attribute.normalize = true;
         * attribute.value = [
         *   Cesium.Color.floatToByte(color.red)
         *   Cesium.Color.floatToByte(color.green)
         *   Cesium.Color.floatToByte(color.blue)
         *   Cesium.Color.floatToByte(color.alpha)
         * ];
         */
        this.normalize = defaultValue(options.normalize, false);

        /**
         * The values for the attributes stored in a typed array.  In the code example,
         * every three elements in <code>values</code> defines one attributes since
         * <code>componentsPerAttribute</code> is 3.
         *
         * @default undefined
         *
         * @example
         * show : new Cesium.GeometryInstanceAttribute({
         *   componentDatatype : Cesium.ComponentDatatype.UNSIGNED_BYTE,
         *   componentsPerAttribute : 1,
         *   normalize : true,
         *   value : [1.0]
         * }
         */
        this.value = options.value;
    };

    return GeometryInstanceAttribute;
});