cesiumDemo/Source/Core/PlaneOutlineGeometry.js

import BoundingSphere from './BoundingSphere.js';
import Cartesian3 from './Cartesian3.js';
import Check from './Check.js';
import ComponentDatatype from './ComponentDatatype.js';
import defined from './defined.js';
import Geometry from './Geometry.js';
import GeometryAttribute from './GeometryAttribute.js';
import GeometryAttributes from './GeometryAttributes.js';
import PrimitiveType from './PrimitiveType.js';

    /**
     * Describes geometry representing the outline of a plane centered at the origin, with a unit width and length.
     *
     * @alias PlaneOutlineGeometry
     * @constructor
     *
     */
    function PlaneOutlineGeometry() {
        this._workerName = 'createPlaneOutlineGeometry';
    }

    /**
     * The number of elements used to pack the object into an array.
     * @type {Number}
     */
    PlaneOutlineGeometry.packedLength = 0;

    /**
     * Stores the provided instance into the provided array.
     *
     * @param {PlaneOutlineGeometry} value The value to pack.
     * @param {Number[]} array The array to pack into.
     *
     * @returns {Number[]} The array that was packed into
     */
    PlaneOutlineGeometry.pack = function(value, array) {
        //>>includeStart('debug', pragmas.debug);
        Check.defined('value', value);
        Check.defined('array', array);
        //>>includeEnd('debug');

        return array;
    };

    /**
     * Retrieves an instance from a packed array.
     *
     * @param {Number[]} array The packed array.
     * @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
     * @param {PlaneOutlineGeometry} [result] The object into which to store the result.
     * @returns {PlaneOutlineGeometry} The modified result parameter or a new PlaneOutlineGeometry instance if one was not provided.
     */
    PlaneOutlineGeometry.unpack = function(array, startingIndex, result) {
        //>>includeStart('debug', pragmas.debug);
        Check.defined('array', array);
        //>>includeEnd('debug');

        if (!defined(result)) {
            return new PlaneOutlineGeometry();
        }

        return result;
    };

    var min = new Cartesian3(-0.5, -0.5, 0.0);
    var max = new Cartesian3( 0.5,  0.5, 0.0);

    /**
     * Computes the geometric representation of an outline of a plane, including its vertices, indices, and a bounding sphere.
     *
     * @returns {Geometry|undefined} The computed vertices and indices.
     */
    PlaneOutlineGeometry.createGeometry = function() {
        var attributes = new GeometryAttributes();
        var indices = new Uint16Array(4 * 2);
        var positions = new Float64Array(4 * 3);

        positions[0] = min.x;
        positions[1] = min.y;
        positions[2] = min.z;
        positions[3] = max.x;
        positions[4] = min.y;
        positions[5] = min.z;
        positions[6] = max.x;
        positions[7] = max.y;
        positions[8] = min.z;
        positions[9] = min.x;
        positions[10] = max.y;
        positions[11] = min.z;

        attributes.position = new GeometryAttribute({
            componentDatatype : ComponentDatatype.DOUBLE,
            componentsPerAttribute : 3,
            values : positions
        });

        indices[0] = 0;
        indices[1] = 1;
        indices[2] = 1;
        indices[3] = 2;
        indices[4] = 2;
        indices[5] = 3;
        indices[6] = 3;
        indices[7] = 0;

        return new Geometry({
            attributes : attributes,
            indices : indices,
            primitiveType : PrimitiveType.LINES,
            boundingSphere : new BoundingSphere(Cartesian3.ZERO, Math.sqrt(2.0))
        });
    };
export default PlaneOutlineGeometry;