Cesium-Prequel/Source/Scene/TileBoundingRegion.js

import BoundingSphere from "../Core/BoundingSphere.js";
import Cartesian3 from "../Core/Cartesian3.js";
import Cartographic from "../Core/Cartographic.js";
import Check from "../Core/Check.js";
import ColorGeometryInstanceAttribute from "../Core/ColorGeometryInstanceAttribute.js";
import defaultValue from "../Core/defaultValue.js";
import Ellipsoid from "../Core/Ellipsoid.js";
import GeometryInstance from "../Core/GeometryInstance.js";
import IntersectionTests from "../Core/IntersectionTests.js";
import Matrix4 from "../Core/Matrix4.js";
import OrientedBoundingBox from "../Core/OrientedBoundingBox.js";
import Plane from "../Core/Plane.js";
import Ray from "../Core/Ray.js";
import Rectangle from "../Core/Rectangle.js";
import RectangleOutlineGeometry from "../Core/RectangleOutlineGeometry.js";
import PerInstanceColorAppearance from "./PerInstanceColorAppearance.js";
import Primitive from "./Primitive.js";
import SceneMode from "./SceneMode.js";

/**
 * A tile bounding volume specified as a longitude/latitude/height region.
 * @alias TileBoundingRegion
 * @constructor
 *
 * @param {Object} options Object with the following properties:
 * @param {Rectangle} options.rectangle The rectangle specifying the longitude and latitude range of the region.
 * @param {Number} [options.minimumHeight=0.0] The minimum height of the region.
 * @param {Number} [options.maximumHeight=0.0] The maximum height of the region.
 * @param {Ellipsoid} [options.ellipsoid=Cesium.Ellipsoid.WGS84] The ellipsoid.
 * @param {Boolean} [options.computeBoundingVolumes=true] True to compute the {@link TileBoundingRegion#boundingVolume} and
 *                  {@link TileBoundingVolume#boundingSphere}. If false, these properties will be undefined.
 *
 * @private
 */
function TileBoundingRegion(options) {
  //>>includeStart('debug', pragmas.debug);
  Check.typeOf.object("options", options);
  Check.typeOf.object("options.rectangle", options.rectangle);
  //>>includeEnd('debug');

  this.rectangle = Rectangle.clone(options.rectangle);
  this.minimumHeight = defaultValue(options.minimumHeight, 0.0);
  this.maximumHeight = defaultValue(options.maximumHeight, 0.0);

  /**
   * The world coordinates of the southwest corner of the tile's rectangle.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.southwestCornerCartesian = new Cartesian3();

  /**
   * The world coordinates of the northeast corner of the tile's rectangle.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.northeastCornerCartesian = new Cartesian3();

  /**
   * A normal that, along with southwestCornerCartesian, defines a plane at the western edge of
   * the tile.  Any position above (in the direction of the normal) this plane is outside the tile.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.westNormal = new Cartesian3();

  /**
   * A normal that, along with southwestCornerCartesian, defines a plane at the southern edge of
   * the tile.  Any position above (in the direction of the normal) this plane is outside the tile.
   * Because points of constant latitude do not necessary lie in a plane, positions below this
   * plane are not necessarily inside the tile, but they are close.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.southNormal = new Cartesian3();

  /**
   * A normal that, along with northeastCornerCartesian, defines a plane at the eastern edge of
   * the tile.  Any position above (in the direction of the normal) this plane is outside the tile.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.eastNormal = new Cartesian3();

  /**
   * A normal that, along with northeastCornerCartesian, defines a plane at the eastern edge of
   * the tile.  Any position above (in the direction of the normal) this plane is outside the tile.
   * Because points of constant latitude do not necessary lie in a plane, positions below this
   * plane are not necessarily inside the tile, but they are close.
   *
   * @type {Cartesian3}
   * @default Cartesian3()
   */
  this.northNormal = new Cartesian3();

  var ellipsoid = defaultValue(options.ellipsoid, Ellipsoid.WGS84);
  computeBox(this, options.rectangle, ellipsoid);

  if (defaultValue(options.computeBoundingVolumes, true)) {
    // An oriented bounding box that encloses this tile's region.  This is used to calculate tile visibility.
    this._orientedBoundingBox = OrientedBoundingBox.fromRectangle(
      this.rectangle,
      this.minimumHeight,
      this.maximumHeight,
      ellipsoid
    );

    this._boundingSphere = BoundingSphere.fromOrientedBoundingBox(
      this._orientedBoundingBox
    );
  }
}

Object.defineProperties(TileBoundingRegion.prototype, {
  /**
   * The underlying bounding volume
   *
   * @memberof TileBoundingRegion.prototype
   *
   * @type {Object}
   * @readonly
   */
  boundingVolume: {
    get: function () {
      return this._orientedBoundingBox;
    },
  },
  /**
   * The underlying bounding sphere
   *
   * @memberof TileBoundingRegion.prototype
   *
   * @type {BoundingSphere}
   * @readonly
   */
  boundingSphere: {
    get: function () {
      return this._boundingSphere;
    },
  },
});

var cartesian3Scratch = new Cartesian3();
var cartesian3Scratch2 = new Cartesian3();
var cartesian3Scratch3 = new Cartesian3();
var eastWestNormalScratch = new Cartesian3();
var westernMidpointScratch = new Cartesian3();
var easternMidpointScratch = new Cartesian3();
var cartographicScratch = new Cartographic();
var planeScratch = new Plane(Cartesian3.UNIT_X, 0.0);
var rayScratch = new Ray();

function computeBox(tileBB, rectangle, ellipsoid) {
  ellipsoid.cartographicToCartesian(
    Rectangle.southwest(rectangle),
    tileBB.southwestCornerCartesian
  );
  ellipsoid.cartographicToCartesian(
    Rectangle.northeast(rectangle),
    tileBB.northeastCornerCartesian
  );

  // The middle latitude on the western edge.
  cartographicScratch.longitude = rectangle.west;
  cartographicScratch.latitude = (rectangle.south + rectangle.north) * 0.5;
  cartographicScratch.height = 0.0;
  var westernMidpointCartesian = ellipsoid.cartographicToCartesian(
    cartographicScratch,
    westernMidpointScratch
  );

  // Compute the normal of the plane on the western edge of the tile.
  var westNormal = Cartesian3.cross(
    westernMidpointCartesian,
    Cartesian3.UNIT_Z,
    cartesian3Scratch
  );
  Cartesian3.normalize(westNormal, tileBB.westNormal);

  // The middle latitude on the eastern edge.
  cartographicScratch.longitude = rectangle.east;
  var easternMidpointCartesian = ellipsoid.cartographicToCartesian(
    cartographicScratch,
    easternMidpointScratch
  );

  // Compute the normal of the plane on the eastern edge of the tile.
  var eastNormal = Cartesian3.cross(
    Cartesian3.UNIT_Z,
    easternMidpointCartesian,
    cartesian3Scratch
  );
  Cartesian3.normalize(eastNormal, tileBB.eastNormal);

  // Compute the normal of the plane bounding the southern edge of the tile.
  var westVector = Cartesian3.subtract(
    westernMidpointCartesian,
    easternMidpointCartesian,
    cartesian3Scratch
  );
  var eastWestNormal = Cartesian3.normalize(westVector, eastWestNormalScratch);

  var south = rectangle.south;
  var southSurfaceNormal;

  if (south > 0.0) {
    // Compute a plane that doesn't cut through the tile.
    cartographicScratch.longitude = (rectangle.west + rectangle.east) * 0.5;
    cartographicScratch.latitude = south;
    var southCenterCartesian = ellipsoid.cartographicToCartesian(
      cartographicScratch,
      rayScratch.origin
    );
    Cartesian3.clone(eastWestNormal, rayScratch.direction);
    var westPlane = Plane.fromPointNormal(
      tileBB.southwestCornerCartesian,
      tileBB.westNormal,
      planeScratch
    );
    // Find a point that is on the west and the south planes
    IntersectionTests.rayPlane(
      rayScratch,
      westPlane,
      tileBB.southwestCornerCartesian
    );
    southSurfaceNormal = ellipsoid.geodeticSurfaceNormal(
      southCenterCartesian,
      cartesian3Scratch2
    );
  } else {
    southSurfaceNormal = ellipsoid.geodeticSurfaceNormalCartographic(
      Rectangle.southeast(rectangle),
      cartesian3Scratch2
    );
  }
  var southNormal = Cartesian3.cross(
    southSurfaceNormal,
    westVector,
    cartesian3Scratch3
  );
  Cartesian3.normalize(southNormal, tileBB.southNormal);

  // Compute the normal of the plane bounding the northern edge of the tile.
  var north = rectangle.north;
  var northSurfaceNormal;
  if (north < 0.0) {
    // Compute a plane that doesn't cut through the tile.
    cartographicScratch.longitude = (rectangle.west + rectangle.east) * 0.5;
    cartographicScratch.latitude = north;
    var northCenterCartesian = ellipsoid.cartographicToCartesian(
      cartographicScratch,
      rayScratch.origin
    );
    Cartesian3.negate(eastWestNormal, rayScratch.direction);
    var eastPlane = Plane.fromPointNormal(
      tileBB.northeastCornerCartesian,
      tileBB.eastNormal,
      planeScratch
    );
    // Find a point that is on the east and the north planes
    IntersectionTests.rayPlane(
      rayScratch,
      eastPlane,
      tileBB.northeastCornerCartesian
    );
    northSurfaceNormal = ellipsoid.geodeticSurfaceNormal(
      northCenterCartesian,
      cartesian3Scratch2
    );
  } else {
    northSurfaceNormal = ellipsoid.geodeticSurfaceNormalCartographic(
      Rectangle.northwest(rectangle),
      cartesian3Scratch2
    );
  }
  var northNormal = Cartesian3.cross(
    westVector,
    northSurfaceNormal,
    cartesian3Scratch3
  );
  Cartesian3.normalize(northNormal, tileBB.northNormal);
}

var southwestCornerScratch = new Cartesian3();
var northeastCornerScratch = new Cartesian3();
var negativeUnitY = new Cartesian3(0.0, -1.0, 0.0);
var negativeUnitZ = new Cartesian3(0.0, 0.0, -1.0);
var vectorScratch = new Cartesian3();

/**
 * Gets the distance from the camera to the closest point on the tile.  This is used for level of detail selection.
 *
 * @param {FrameState} frameState The state information of the current rendering frame.
 * @returns {Number} The distance from the camera to the closest point on the tile, in meters.
 */
TileBoundingRegion.prototype.distanceToCamera = function (frameState) {
  //>>includeStart('debug', pragmas.debug);
  Check.defined("frameState", frameState);
  //>>includeEnd('debug');
  var camera = frameState.camera;
  var cameraCartesianPosition = camera.positionWC;
  var cameraCartographicPosition = camera.positionCartographic;

  var result = 0.0;
  if (!Rectangle.contains(this.rectangle, cameraCartographicPosition)) {
    var southwestCornerCartesian = this.southwestCornerCartesian;
    var northeastCornerCartesian = this.northeastCornerCartesian;
    var westNormal = this.westNormal;
    var southNormal = this.southNormal;
    var eastNormal = this.eastNormal;
    var northNormal = this.northNormal;

    if (frameState.mode !== SceneMode.SCENE3D) {
      southwestCornerCartesian = frameState.mapProjection.project(
        Rectangle.southwest(this.rectangle),
        southwestCornerScratch
      );
      southwestCornerCartesian.z = southwestCornerCartesian.y;
      southwestCornerCartesian.y = southwestCornerCartesian.x;
      southwestCornerCartesian.x = 0.0;
      northeastCornerCartesian = frameState.mapProjection.project(
        Rectangle.northeast(this.rectangle),
        northeastCornerScratch
      );
      northeastCornerCartesian.z = northeastCornerCartesian.y;
      northeastCornerCartesian.y = northeastCornerCartesian.x;
      northeastCornerCartesian.x = 0.0;
      westNormal = negativeUnitY;
      eastNormal = Cartesian3.UNIT_Y;
      southNormal = negativeUnitZ;
      northNormal = Cartesian3.UNIT_Z;
    }

    var vectorFromSouthwestCorner = Cartesian3.subtract(
      cameraCartesianPosition,
      southwestCornerCartesian,
      vectorScratch
    );
    var distanceToWestPlane = Cartesian3.dot(
      vectorFromSouthwestCorner,
      westNormal
    );
    var distanceToSouthPlane = Cartesian3.dot(
      vectorFromSouthwestCorner,
      southNormal
    );

    var vectorFromNortheastCorner = Cartesian3.subtract(
      cameraCartesianPosition,
      northeastCornerCartesian,
      vectorScratch
    );
    var distanceToEastPlane = Cartesian3.dot(
      vectorFromNortheastCorner,
      eastNormal
    );
    var distanceToNorthPlane = Cartesian3.dot(
      vectorFromNortheastCorner,
      northNormal
    );

    if (distanceToWestPlane > 0.0) {
      result += distanceToWestPlane * distanceToWestPlane;
    } else if (distanceToEastPlane > 0.0) {
      result += distanceToEastPlane * distanceToEastPlane;
    }

    if (distanceToSouthPlane > 0.0) {
      result += distanceToSouthPlane * distanceToSouthPlane;
    } else if (distanceToNorthPlane > 0.0) {
      result += distanceToNorthPlane * distanceToNorthPlane;
    }
  }

  var cameraHeight;
  var minimumHeight;
  var maximumHeight;
  if (frameState.mode === SceneMode.SCENE3D) {
    cameraHeight = cameraCartographicPosition.height;
    minimumHeight = this.minimumHeight;
    maximumHeight = this.maximumHeight;
  } else {
    cameraHeight = cameraCartesianPosition.x;
    minimumHeight = 0.0;
    maximumHeight = 0.0;
  }

  if (cameraHeight > maximumHeight) {
    var distanceAboveTop = cameraHeight - maximumHeight;
    result += distanceAboveTop * distanceAboveTop;
  } else if (cameraHeight < minimumHeight) {
    var distanceBelowBottom = minimumHeight - cameraHeight;
    result += distanceBelowBottom * distanceBelowBottom;
  }

  return Math.sqrt(result);
};

/**
 * Determines which side of a plane this box is located.
 *
 * @param {Plane} plane The plane to test against.
 * @returns {Intersect} {@link Intersect.INSIDE} if the entire box is on the side of the plane
 *                      the normal is pointing, {@link Intersect.OUTSIDE} if the entire box is
 *                      on the opposite side, and {@link Intersect.INTERSECTING} if the box
 *                      intersects the plane.
 */
TileBoundingRegion.prototype.intersectPlane = function (plane) {
  //>>includeStart('debug', pragmas.debug);
  Check.defined("plane", plane);
  //>>includeEnd('debug');
  return this._orientedBoundingBox.intersectPlane(plane);
};

/**
 * Creates a debug primitive that shows the outline of the tile bounding region.
 *
 * @param {Color} color The desired color of the primitive's mesh
 * @return {Primitive}
 *
 * @private
 */
TileBoundingRegion.prototype.createDebugVolume = function (color) {
  //>>includeStart('debug', pragmas.debug);
  Check.defined("color", color);
  //>>includeEnd('debug');

  var modelMatrix = new Matrix4.clone(Matrix4.IDENTITY);
  var geometry = new RectangleOutlineGeometry({
    rectangle: this.rectangle,
    height: this.minimumHeight,
    extrudedHeight: this.maximumHeight,
  });
  var instance = new GeometryInstance({
    geometry: geometry,
    id: "outline",
    modelMatrix: modelMatrix,
    attributes: {
      color: ColorGeometryInstanceAttribute.fromColor(color),
    },
  });

  return new Primitive({
    geometryInstances: instance,
    appearance: new PerInstanceColorAppearance({
      translucent: false,
      flat: true,
    }),
    asynchronous: false,
  });
};
export default TileBoundingRegion;