DistanceDisplayConditionGeometryInstanceAttribute.js

define([
        './ComponentDatatype',
        './defaultValue',
        './defined',
        './defineProperties',
        './DeveloperError'
    ], function(
        ComponentDatatype,
        defaultValue,
        defined,
        defineProperties,
        DeveloperError) {
    'use strict';

    /**
     * Value and type information for per-instance geometry attribute that determines if the geometry instance has a distance display condition.
     *
     * @alias DistanceDisplayConditionGeometryInstanceAttribute
     * @constructor
     *
     * @param {Number} [near=0.0] The near distance.
     * @param {Number} [far=Number.MAX_VALUE] The far distance.
     *
     * @exception {DeveloperError} far must be greater than near.
     *
     * @example
     * var instance = new Cesium.GeometryInstance({
     *   geometry : new Cesium.BoxGeometry({
     *     vertexFormat : Cesium.VertexFormat.POSITION_AND_NORMAL,
     *     minimum : new Cesium.Cartesian3(-250000.0, -250000.0, -250000.0),
     *     maximum : new Cesium.Cartesian3(250000.0, 250000.0, 250000.0)
     *   }),
     *   modelMatrix : Cesium.Matrix4.multiplyByTranslation(Cesium.Transforms.eastNorthUpToFixedFrame(
     *     Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883)), new Cesium.Cartesian3(0.0, 0.0, 1000000.0), new Cesium.Matrix4()),
     *   id : 'box',
     *   attributes : {
     *     show : new Cesium.DistanceDisplayConditionGeometryInstanceAttribute(100.0, 10000.0)
     *   }
     * });
     *
     * @see GeometryInstance
     * @see GeometryInstanceAttribute
     */
    function DistanceDisplayConditionGeometryInstanceAttribute(near, far) {
        near = defaultValue(near, 0.0);
        far = defaultValue(far, Number.MAX_VALUE);

        //>>includeStart('debug', pragmas.debug);
        if (far <= near) {
            throw new DeveloperError('far distance must be greater than near distance.');
        }
        //>>includeEnd('debug');

        /**
         * The values for the attributes stored in a typed array.
         *
         * @type Float32Array
         *
         * @default [0.0, 0.0, Number.MAX_VALUE]
         */
        this.value = new Float32Array([near, far]);
    }

    defineProperties(DistanceDisplayConditionGeometryInstanceAttribute.prototype, {
        /**
         * The datatype of each component in the attribute, e.g., individual elements in
         * {@link DistanceDisplayConditionGeometryInstanceAttribute#value}.
         *
         * @memberof DistanceDisplayConditionGeometryInstanceAttribute.prototype
         *
         * @type {ComponentDatatype}
         * @readonly
         *
         * @default {@link ComponentDatatype.FLOAT}
         */
        componentDatatype : {
            get : function() {
                return ComponentDatatype.FLOAT;
            }
        },

        /**
         * The number of components in the attributes, i.e., {@link DistanceDisplayConditionGeometryInstanceAttribute#value}.
         *
         * @memberof DistanceDisplayConditionGeometryInstanceAttribute.prototype
         *
         * @type {Number}
         * @readonly
         *
         * @default 3
         */
        componentsPerAttribute : {
            get : function() {
                return 2;
            }
        },

        /**
         * 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.
         *
         * @memberof DistanceDisplayConditionGeometryInstanceAttribute.prototype
         *
         * @type {Boolean}
         * @readonly
         *
         * @default false
         */
        normalize : {
            get : function() {
                return false;
            }
        }
    });

    /**
     * Creates a new {@link DistanceDisplayConditionGeometryInstanceAttribute} instance given the provided an enabled flag and {@link DistanceDisplayCondition}.
     *
     * @param {DistanceDisplayCondition} distanceDisplayCondition The distance display condition.
     * @returns {DistanceDisplayConditionGeometryInstanceAttribute} The new {@link DistanceDisplayConditionGeometryInstanceAttribute} instance.
     *
     * @exception {DeveloperError} distanceDisplayCondition.far must be greater than distanceDisplayCondition.near
     *
     * @example
     * var instance = new Cesium.GeometryInstance({
     *   geometry : geometry,
     *   attributes : {
     *     color : Cesium.DistanceDisplayConditionGeometryInstanceAttribute.fromDistanceDisplayCondition(distanceDisplayCondition),
     *   }
     * });
     */
    DistanceDisplayConditionGeometryInstanceAttribute.fromDistanceDisplayCondition = function(distanceDisplayCondition) {
        //>>includeStart('debug', pragmas.debug);
        if (!defined(distanceDisplayCondition)) {
            throw new DeveloperError('distanceDisplayCondition is required.');
        }
        if (distanceDisplayCondition.far <= distanceDisplayCondition.near) {
            throw new DeveloperError('distanceDisplayCondition.far distance must be greater than distanceDisplayCondition.near distance.');
        }
        //>>includeEnd('debug');

        return new DistanceDisplayConditionGeometryInstanceAttribute(distanceDisplayCondition.near, distanceDisplayCondition.far);
    };

    /**
     * Converts a distance display condition to a typed array that can be used to assign a distance display condition attribute.
     *
     * @param {DistanceDisplayCondition} distanceDisplayCondition The distance display condition value.
     * @param {Float32Array} [result] The array to store the result in, if undefined a new instance will be created.
     * @returns {Float32Array} The modified result parameter or a new instance if result was undefined.
     *
     * @example
     * var attributes = primitive.getGeometryInstanceAttributes('an id');
     * attributes.distanceDisplayCondition = Cesium.DistanceDisplayConditionGeometryInstanceAttribute.toValue(distanceDisplayCondition, attributes.distanceDisplayCondition);
     */
    DistanceDisplayConditionGeometryInstanceAttribute.toValue = function(distanceDisplayCondition, result) {
        //>>includeStart('debug', pragmas.debug);
        if (!defined(distanceDisplayCondition)) {
            throw new DeveloperError('distanceDisplayCondition is required.');
        }
        //>>includeEnd('debug');

        if (!defined(result)) {
            return new Float32Array([distanceDisplayCondition.near, distanceDisplayCondition.far]);
        }
        result[0] = distanceDisplayCondition.near;
        result[1] = distanceDisplayCondition.far;
        return result;
    };

    return DistanceDisplayConditionGeometryInstanceAttribute;
});