mapbox-gl
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A WebGL interactive maps library
1,217 lines (1,035 loc) • 84.5 kB
JavaScript
// @flow
import LngLat from './lng_lat.js';
import LngLatBounds from './lng_lat_bounds.js';
import MercatorCoordinate, {mercatorXfromLng, mercatorYfromLat, mercatorZfromAltitude, latFromMercatorY, MAX_MERCATOR_LATITUDE, circumferenceAtLatitude} from './mercator_coordinate.js';
import {getProjection} from './projection/index.js';
import {tileAABB} from '../geo/projection/tile_transform.js';
import Point from '@mapbox/point-geometry';
import {wrap, clamp, pick, radToDeg, degToRad, getAABBPointSquareDist, furthestTileCorner, warnOnce, deepEqual} from '../util/util.js';
import {number as interpolate} from '../style-spec/util/interpolate.js';
import EXTENT from '../data/extent.js';
import {vec4, mat4, mat2, vec3, quat} from 'gl-matrix';
import {Frustum, Ray} from '../util/primitives.js';
import EdgeInsets from './edge_insets.js';
import {FreeCamera, FreeCameraOptions, orientationFromFrame} from '../ui/free_camera.js';
import assert from 'assert';
import getProjectionAdjustments, {getProjectionAdjustmentInverted, getScaleAdjustment} from './projection/adjustments.js';
import {getPixelsToTileUnitsMatrix} from '../source/pixels_to_tile_units.js';
import {UnwrappedTileID, OverscaledTileID, CanonicalTileID} from '../source/tile_id.js';
import {calculateGlobeMatrix} from '../geo/projection/globe_util.js';
import type Projection from '../geo/projection/projection.js';
import type {Elevation} from '../terrain/elevation.js';
import type {PaddingOptions} from './edge_insets.js';
import type Tile from '../source/tile.js';
import type {ProjectionSpecification} from '../style-spec/types.js';
import type {FeatureDistanceData} from '../style-spec/feature_filter/index.js';
import type {Vec3, Vec4, Quat} from 'gl-matrix';
const NUM_WORLD_COPIES = 3;
const DEFAULT_MIN_ZOOM = 0;
type RayIntersectionResult = { p0: Vec4, p1: Vec4, t: number};
type ElevationReference = "sea" | "ground";
/**
* A single transform, generally used for a single tile to be
* scaled, rotated, and zoomed.
* @private
*/
class Transform {
tileSize: number;
tileZoom: number;
maxBounds: ?LngLatBounds;
// 2^zoom (worldSize = tileSize * scale)
scale: number;
// Map viewport size (not including the pixel ratio)
width: number;
height: number;
// Bearing, radians, in [-pi, pi]
angle: number;
// 2D rotation matrix in the horizontal plane, as a function of bearing
rotationMatrix: Float32Array;
// Zoom, modulo 1
zoomFraction: number;
// The scale factor component of the conversion from pixels ([0, w] x [h, 0]) to GL
// NDC ([1, -1] x [1, -1]) (note flipped y)
pixelsToGLUnits: [number, number];
// Distance from camera to the center, in screen pixel units, independent of zoom
cameraToCenterDistance: number;
// Projection from mercator coordinates ([0, 0] nw, [1, 1] se) to GL clip coordinates
mercatorMatrix: Array<number>;
// Translate points in mercator coordinates to be centered about the camera, with units chosen
// for screen-height-independent scaling of fog. Not affected by orientation of camera.
mercatorFogMatrix: Float32Array;
// Projection from world coordinates (mercator scaled by worldSize) to clip coordinates
projMatrix: Array<number>;
invProjMatrix: Float64Array;
// Same as projMatrix, pixel-aligned to avoid fractional pixels for raster tiles
alignedProjMatrix: Float64Array;
// From world coordinates to screen pixel coordinates (projMatrix premultiplied by labelPlaneMatrix)
pixelMatrix: Float64Array;
pixelMatrixInverse: Float64Array;
worldToFogMatrix: Float64Array;
skyboxMatrix: Float32Array;
// Transform from screen coordinates to GL NDC, [0, w] x [h, 0] --> [-1, 1] x [-1, 1]
// Roughly speaking, applies pixelsToGLUnits scaling with a translation
glCoordMatrix: Float32Array;
// Inverse of glCoordMatrix, from NDC to screen coordinates, [-1, 1] x [-1, 1] --> [0, w] x [h, 0]
labelPlaneMatrix: Float32Array;
// globe coordinate transformation matrix
globeMatrix: Float64Array;
inverseAdjustmentMatrix: Array<number>;
minLng: number;
maxLng: number;
minLat: number;
maxLat: number;
worldMinX: number;
worldMaxX: number;
worldMinY: number;
worldMaxY: number;
freezeTileCoverage: boolean;
cameraElevationReference: ElevationReference;
fogCullDistSq: ?number;
_averageElevation: number;
projectionOptions: ProjectionSpecification;
projection: Projection;
_elevation: ?Elevation;
_fov: number;
_pitch: number;
_zoom: number;
_seaLevelZoom: ?number;
_unmodified: boolean;
_renderWorldCopies: boolean;
_minZoom: number;
_maxZoom: number;
_minPitch: number;
_maxPitch: number;
_center: LngLat;
_edgeInsets: EdgeInsets;
_constraining: boolean;
_projMatrixCache: {[_: number]: Float32Array};
_alignedProjMatrixCache: {[_: number]: Float32Array};
_pixelsToTileUnitsCache: {[_: number]: Float32Array};
_fogTileMatrixCache: {[_: number]: Float32Array};
_distanceTileDataCache: {[_: number]: FeatureDistanceData};
_camera: FreeCamera;
_centerAltitude: number;
_centerAltitudeValidForExaggeration: number;
_horizonShift: number;
_projectionScaler: number;
_nearZ: number;
_farZ: number;
constructor(minZoom: ?number, maxZoom: ?number, minPitch: ?number, maxPitch: ?number, renderWorldCopies: boolean | void, projection?: ?ProjectionSpecification, bounds: ?LngLatBounds) {
this.tileSize = 512; // constant
this._renderWorldCopies = renderWorldCopies === undefined ? true : renderWorldCopies;
this._minZoom = minZoom || DEFAULT_MIN_ZOOM;
this._maxZoom = maxZoom || 22;
this._minPitch = (minPitch === undefined || minPitch === null) ? 0 : minPitch;
this._maxPitch = (maxPitch === undefined || maxPitch === null) ? 60 : maxPitch;
this.setProjection(projection);
this.setMaxBounds(bounds);
this.width = 0;
this.height = 0;
this._center = new LngLat(0, 0);
this.zoom = 0;
this.angle = 0;
this._fov = 0.6435011087932844;
this._pitch = 0;
this._nearZ = 0;
this._farZ = 0;
this._unmodified = true;
this._edgeInsets = new EdgeInsets();
this._projMatrixCache = {};
this._alignedProjMatrixCache = {};
this._fogTileMatrixCache = {};
this._distanceTileDataCache = {};
this._camera = new FreeCamera();
this._centerAltitude = 0;
this._centerAltitudeValidForExaggeration = 0;
this._averageElevation = 0;
this.cameraElevationReference = "ground";
this._projectionScaler = 1.0;
// Move the horizon closer to the center. 0 would not shift the horizon. 1 would put the horizon at the center.
this._horizonShift = 0.1;
}
clone(): Transform {
const clone = new Transform(this._minZoom, this._maxZoom, this._minPitch, this.maxPitch, this._renderWorldCopies, this.getProjection());
clone._elevation = this._elevation;
clone._centerAltitude = this._centerAltitude;
clone._centerAltitudeValidForExaggeration = this._centerAltitudeValidForExaggeration;
clone.tileSize = this.tileSize;
clone.width = this.width;
clone.height = this.height;
clone.cameraElevationReference = this.cameraElevationReference;
clone._center = this._center;
clone._setZoom(this.zoom);
clone._seaLevelZoom = this._seaLevelZoom;
clone.angle = this.angle;
clone._fov = this._fov;
clone._pitch = this._pitch;
clone._nearZ = this._nearZ;
clone._farZ = this._farZ;
clone._averageElevation = this._averageElevation;
clone._unmodified = this._unmodified;
clone._edgeInsets = this._edgeInsets.clone();
clone._camera = this._camera.clone();
clone._calcMatrices();
clone.freezeTileCoverage = this.freezeTileCoverage;
return clone;
}
get elevation(): ?Elevation { return this._elevation; }
set elevation(elevation: ?Elevation) {
if (this._elevation === elevation) return;
this._elevation = elevation;
this._updateCameraOnTerrain();
this._calcMatrices();
}
updateElevation(constrainCameraOverTerrain: boolean) { // On render, no need for higher granularity on update reasons.
const centerAltitudeChanged = this._elevation && this._elevation.exaggeration() !== this._centerAltitudeValidForExaggeration;
if (this._seaLevelZoom == null || centerAltitudeChanged) {
this._updateCameraOnTerrain();
}
if (constrainCameraOverTerrain || centerAltitudeChanged) {
this._constrainCameraAltitude();
}
this._calcMatrices();
}
getProjection(): ProjectionSpecification {
return (pick(this.projection, ['name', 'center', 'parallels']): ProjectionSpecification);
}
// Returns the new projection if the projection changes, or null if no change.
setProjection(projection?: ?ProjectionSpecification): ProjectionSpecification | null {
if (projection === undefined || projection === null) projection = {name: 'mercator'};
this.projectionOptions = projection;
const oldProjection = this.projection ? this.getProjection() : undefined;
this.projection = getProjection(projection);
const newProjection = this.getProjection();
if (deepEqual(oldProjection, newProjection)) {
return null;
}
this._calcMatrices();
return newProjection;
}
get minZoom(): number { return this._minZoom; }
set minZoom(zoom: number) {
if (this._minZoom === zoom) return;
this._minZoom = zoom;
this.zoom = Math.max(this.zoom, zoom);
}
get maxZoom(): number { return this._maxZoom; }
set maxZoom(zoom: number) {
if (this._maxZoom === zoom) return;
this._maxZoom = zoom;
this.zoom = Math.min(this.zoom, zoom);
}
get minPitch(): number { return this._minPitch; }
set minPitch(pitch: number) {
if (this._minPitch === pitch) return;
this._minPitch = pitch;
this.pitch = Math.max(this.pitch, pitch);
}
get maxPitch(): number { return this._maxPitch; }
set maxPitch(pitch: number) {
if (this._maxPitch === pitch) return;
this._maxPitch = pitch;
this.pitch = Math.min(this.pitch, pitch);
}
get renderWorldCopies(): boolean {
return this._renderWorldCopies && this.projection.supportsWorldCopies === true;
}
set renderWorldCopies(renderWorldCopies?: ?boolean) {
if (renderWorldCopies === undefined) {
renderWorldCopies = true;
} else if (renderWorldCopies === null) {
renderWorldCopies = false;
}
this._renderWorldCopies = renderWorldCopies;
}
get worldSize(): number {
return this.tileSize * this.scale;
}
get cameraWorldSize(): number {
const distance = Math.max(this._camera.getDistanceToElevation(this._averageElevation), Number.EPSILON);
return this._worldSizeFromZoom(this._zoomFromMercatorZ(distance));
}
get pixelsPerMeter(): number {
return this.projection.pixelsPerMeter(this.center.lat, this.worldSize);
}
get cameraPixelsPerMeter(): number {
return this.projection.pixelsPerMeter(this.center.lat, this.cameraWorldSize);
}
get centerOffset(): Point {
return this.centerPoint._sub(this.size._div(2));
}
get size(): Point {
return new Point(this.width, this.height);
}
get bearing(): number {
return wrap(this.rotation, -180, 180);
}
set bearing(bearing: number) {
this.rotation = bearing;
}
get rotation(): number {
return -this.angle / Math.PI * 180;
}
set rotation(rotation: number) {
const b = -rotation * Math.PI / 180;
if (this.angle === b) return;
this._unmodified = false;
this.angle = b;
this._calcMatrices();
// 2x2 matrix for rotating points
this.rotationMatrix = mat2.create();
mat2.rotate(this.rotationMatrix, this.rotationMatrix, this.angle);
}
get pitch(): number {
return this._pitch / Math.PI * 180;
}
set pitch(pitch: number) {
const p = clamp(pitch, this.minPitch, this.maxPitch) / 180 * Math.PI;
if (this._pitch === p) return;
this._unmodified = false;
this._pitch = p;
this._calcMatrices();
}
get fov(): number {
return this._fov / Math.PI * 180;
}
set fov(fov: number) {
fov = Math.max(0.01, Math.min(60, fov));
if (this._fov === fov) return;
this._unmodified = false;
this._fov = fov / 180 * Math.PI;
this._calcMatrices();
}
get averageElevation(): number {
return this._averageElevation;
}
set averageElevation(averageElevation: number) {
this._averageElevation = averageElevation;
this._calcFogMatrices();
this._distanceTileDataCache = {};
}
get zoom(): number { return this._zoom; }
set zoom(zoom: number) {
const z = Math.min(Math.max(zoom, this.minZoom), this.maxZoom);
if (this._zoom === z) return;
this._unmodified = false;
this._setZoom(z);
this._updateSeaLevelZoom();
this._constrain();
this._calcMatrices();
}
_setZoom(z: number) {
this._zoom = z;
this.scale = this.zoomScale(z);
this.tileZoom = Math.floor(z);
this.zoomFraction = z - this.tileZoom;
}
_updateCameraOnTerrain() {
if (!this._elevation || !this._elevation.isDataAvailableAtPoint(this.locationCoordinate(this.center))) {
// Elevation data not loaded yet, reset
this._centerAltitude = 0;
this._seaLevelZoom = null;
this._centerAltitudeValidForExaggeration = 0;
return;
}
const elevation: Elevation = this._elevation;
this._centerAltitude = elevation.getAtPointOrZero(this.locationCoordinate(this.center));
this._centerAltitudeValidForExaggeration = elevation.exaggeration();
this._updateSeaLevelZoom();
}
_updateSeaLevelZoom() {
if (this._centerAltitudeValidForExaggeration === 0) {
return;
}
const height = this.cameraToCenterDistance;
const terrainElevation = this.pixelsPerMeter * this._centerAltitude;
const mercatorZ = (terrainElevation + height) / this.worldSize;
// MSL (Mean Sea Level) zoom describes the distance of the camera to the sea level (altitude).
// It is used only for manipulating the camera location. The standard zoom (this._zoom)
// defines the camera distance to the terrain (height). Its behavior and conceptual
// meaning in determining which tiles to stream is same with or without the terrain.
this._seaLevelZoom = this._zoomFromMercatorZ(mercatorZ);
}
sampleAverageElevation(): number {
if (!this._elevation) return 0;
const elevation: Elevation = this._elevation;
const elevationSamplePoints = [
[0.5, 0.2],
[0.3, 0.5],
[0.5, 0.5],
[0.7, 0.5],
[0.5, 0.8]
];
const horizon = this.horizonLineFromTop();
let elevationSum = 0.0;
let weightSum = 0.0;
for (let i = 0; i < elevationSamplePoints.length; i++) {
const pt = new Point(
elevationSamplePoints[i][0] * this.width,
horizon + elevationSamplePoints[i][1] * (this.height - horizon)
);
const hit = elevation.pointCoordinate(pt);
if (!hit) continue;
const distanceToHit = Math.hypot(hit[0] - this._camera.position[0], hit[1] - this._camera.position[1]);
const weight = 1 / distanceToHit;
elevationSum += hit[3] * weight;
weightSum += weight;
}
if (weightSum === 0) return NaN;
return elevationSum / weightSum;
}
get center(): LngLat { return this._center; }
set center(center: LngLat) {
if (center.lat === this._center.lat && center.lng === this._center.lng) return;
this._unmodified = false;
this._center = center;
if (this._terrainEnabled()) {
if (this.cameraElevationReference === "ground") {
this._updateCameraOnTerrain();
} else {
this._updateZoomFromElevation();
}
}
this._constrain();
this._calcMatrices();
}
_updateZoomFromElevation() {
if (this._seaLevelZoom == null || !this._elevation)
return;
// Compute zoom level from the height of the camera relative to the terrain
const seaLevelZoom: number = this._seaLevelZoom;
const elevationAtCenter = this._elevation.getAtPointOrZero(this.locationCoordinate(this.center));
const mercatorElevation = this.pixelsPerMeter / this.worldSize * elevationAtCenter;
const altitude = this._mercatorZfromZoom(seaLevelZoom);
const minHeight = this._mercatorZfromZoom(this._maxZoom);
const height = Math.max(altitude - mercatorElevation, minHeight);
this._setZoom(this._zoomFromMercatorZ(height));
}
get padding(): PaddingOptions { return this._edgeInsets.toJSON(); }
set padding(padding: PaddingOptions) {
if (this._edgeInsets.equals(padding)) return;
this._unmodified = false;
//Update edge-insets inplace
this._edgeInsets.interpolate(this._edgeInsets, padding, 1);
this._calcMatrices();
}
/**
* Computes a zoom value relative to a map plane that goes through the provided mercator position.
*
* @param {MercatorCoordinate} position A position defining the altitude of the the map plane.
* @returns {number} The zoom value.
*/
computeZoomRelativeTo(position: MercatorCoordinate): number {
// Find map center position on the target plane by casting a ray from screen center towards the plane.
// Direct distance to the target position is used if the target position is above camera position.
const centerOnTargetAltitude = this.rayIntersectionCoordinate(this.pointRayIntersection(this.centerPoint, position.toAltitude()));
let targetPosition: ?Vec3;
if (position.z < this._camera.position[2]) {
targetPosition = [centerOnTargetAltitude.x, centerOnTargetAltitude.y, centerOnTargetAltitude.z];
} else {
targetPosition = [position.x, position.y, position.z];
}
const distToTarget = vec3.length(vec3.sub([], this._camera.position, targetPosition));
return clamp(this._zoomFromMercatorZ(distToTarget), this._minZoom, this._maxZoom);
}
setFreeCameraOptions(options: FreeCameraOptions) {
if (!this.height)
return;
if (!options.position && !options.orientation)
return;
// Camera state must be up-to-date before accessing its getters
this._updateCameraState();
let changed = false;
if (options.orientation && !quat.exactEquals(options.orientation, this._camera.orientation)) {
changed = this._setCameraOrientation(options.orientation);
}
if (options.position) {
const newPosition = [options.position.x, options.position.y, options.position.z];
if (!vec3.exactEquals(newPosition, this._camera.position)) {
this._setCameraPosition(newPosition);
changed = true;
}
}
if (changed) {
this._updateStateFromCamera();
this.recenterOnTerrain();
}
}
getFreeCameraOptions(): FreeCameraOptions {
this._updateCameraState();
const pos = this._camera.position;
const options = new FreeCameraOptions();
options.position = new MercatorCoordinate(pos[0], pos[1], pos[2]);
options.orientation = this._camera.orientation;
options._elevation = this.elevation;
options._renderWorldCopies = this.renderWorldCopies;
return options;
}
_setCameraOrientation(orientation: Quat): boolean {
// zero-length quaternions are not valid
if (!quat.length(orientation))
return false;
quat.normalize(orientation, orientation);
// The new orientation must be sanitized by making sure it can be represented
// with a pitch and bearing. Roll-component must be removed and the camera can't be upside down
const forward = vec3.transformQuat([], [0, 0, -1], orientation);
const up = vec3.transformQuat([], [0, -1, 0], orientation);
if (up[2] < 0.0)
return false;
const updatedOrientation = orientationFromFrame(forward, up);
if (!updatedOrientation)
return false;
this._camera.orientation = updatedOrientation;
return true;
}
_setCameraPosition(position: Vec3) {
// Altitude must be clamped to respect min and max zoom
const minWorldSize = this.zoomScale(this.minZoom) * this.tileSize;
const maxWorldSize = this.zoomScale(this.maxZoom) * this.tileSize;
const distToCenter = this.cameraToCenterDistance;
position[2] = clamp(position[2], distToCenter / maxWorldSize, distToCenter / minWorldSize);
this._camera.position = position;
}
/**
* The center of the screen in pixels with the top-left corner being (0,0)
* and +y axis pointing downwards. This accounts for padding.
*
* @readonly
* @type {Point}
* @memberof Transform
*/
get centerPoint(): Point {
return this._edgeInsets.getCenter(this.width, this.height);
}
/**
* Returns the vertical half-fov, accounting for padding, in radians.
*
* @readonly
* @type {number}
* @private
*/
get fovAboveCenter(): number {
return this._fov * (0.5 + this.centerOffset.y / this.height);
}
/**
* Returns true if the padding options are equal.
*
* @param {PaddingOptions} padding The padding options to compare.
* @returns {boolean} True if the padding options are equal.
* @memberof Transform
*/
isPaddingEqual(padding: PaddingOptions): boolean {
return this._edgeInsets.equals(padding);
}
/**
* Helper method to update edge-insets inplace.
*
* @param {PaddingOptions} start The initial padding options.
* @param {PaddingOptions} target The target padding options.
* @param {number} t The interpolation variable.
* @memberof Transform
*/
interpolatePadding(start: PaddingOptions, target: PaddingOptions, t: number) {
this._unmodified = false;
this._edgeInsets.interpolate(start, target, t);
this._constrain();
this._calcMatrices();
}
/**
* Return the highest zoom level that fully includes all tiles within the transform's boundaries.
* @param {Object} options Options.
* @param {number} options.tileSize Tile size, expressed in screen pixels.
* @param {boolean} options.roundZoom Target zoom level. If true, the value will be rounded to the closest integer. Otherwise the value will be floored.
* @returns {number} An integer zoom level at which all tiles will be visible.
*/
coveringZoomLevel(options: {roundZoom?: boolean, tileSize: number}): number {
const z = (options.roundZoom ? Math.round : Math.floor)(
this.zoom + this.scaleZoom(this.tileSize / options.tileSize)
);
// At negative zoom levels load tiles from z0 because negative tile zoom levels don't exist.
return Math.max(0, z);
}
/**
* Return any "wrapped" copies of a given tile coordinate that are visible
* in the current view.
*
* @private
*/
getVisibleUnwrappedCoordinates(tileID: CanonicalTileID): Array<UnwrappedTileID> {
const result = [new UnwrappedTileID(0, tileID)];
if (this.renderWorldCopies) {
const utl = this.pointCoordinate(new Point(0, 0));
const utr = this.pointCoordinate(new Point(this.width, 0));
const ubl = this.pointCoordinate(new Point(this.width, this.height));
const ubr = this.pointCoordinate(new Point(0, this.height));
const w0 = Math.floor(Math.min(utl.x, utr.x, ubl.x, ubr.x));
const w1 = Math.floor(Math.max(utl.x, utr.x, ubl.x, ubr.x));
// Add an extra copy of the world on each side to properly render ImageSources and CanvasSources.
// Both sources draw outside the tile boundaries of the tile that "contains them" so we need
// to add extra copies on both sides in case offscreen tiles need to draw into on-screen ones.
const extraWorldCopy = 1;
for (let w = w0 - extraWorldCopy; w <= w1 + extraWorldCopy; w++) {
if (w === 0) continue;
result.push(new UnwrappedTileID(w, tileID));
}
}
return result;
}
/**
* Return all coordinates that could cover this transform for a covering
* zoom level.
* @param {Object} options
* @param {number} options.tileSize
* @param {number} options.minzoom
* @param {number} options.maxzoom
* @param {boolean} options.roundZoom
* @param {boolean} options.reparseOverscaled
* @returns {Array<OverscaledTileID>} OverscaledTileIDs
* @private
*/
coveringTiles(
options: {
tileSize: number,
minzoom?: number,
maxzoom?: number,
roundZoom?: boolean,
reparseOverscaled?: boolean,
renderWorldCopies?: boolean,
isTerrainDEM?: boolean
}
): Array<OverscaledTileID> {
let z = this.coveringZoomLevel(options);
const actualZ = z;
const useElevationData = this.elevation && !options.isTerrainDEM;
const isMercator = this.projection.name === 'mercator';
if (options.minzoom !== undefined && z < options.minzoom) return [];
if (options.maxzoom !== undefined && z > options.maxzoom) z = options.maxzoom;
const centerCoord = this.locationCoordinate(this.center);
const centerLatitude = this.center.lat;
const numTiles = 1 << z;
const centerPoint = [numTiles * centerCoord.x, numTiles * centerCoord.y, 0];
const isGlobe = this.projection.name === 'globe';
const zInMeters = !isGlobe;
const cameraFrustum = Frustum.fromInvProjectionMatrix(this.invProjMatrix, this.worldSize, z, zInMeters);
const cameraCoord = isGlobe ? this._camera.mercatorPosition : this.pointCoordinate(this.getCameraPoint());
const meterToTile = numTiles * mercatorZfromAltitude(1, this.center.lat);
const cameraAltitude = this._camera.position[2] / mercatorZfromAltitude(1, this.center.lat);
const cameraPoint = [numTiles * cameraCoord.x, numTiles * cameraCoord.y, cameraAltitude * (zInMeters ? 1 : meterToTile)];
// Let's consider an example for !roundZoom: e.g. tileZoom 16 is used from zoom 16 all the way to zoom 16.99.
// This would mean that the minimal distance to split would be based on distance from camera to center of 16.99 zoom.
// The same is already incorporated in logic behind roundZoom for raster (so there is no adjustment needed in following line).
// 0.02 added to compensate for precision errors, see "coveringTiles for terrain" test in transform.test.js.
const zoomSplitDistance = this.cameraToCenterDistance / options.tileSize * (options.roundZoom ? 1 : 0.502);
// No change of LOD behavior for pitch lower than 60 and when there is no top padding: return only tile ids from the requested zoom level
const minZoom = this.pitch <= 60.0 && this._edgeInsets.top <= this._edgeInsets.bottom && !this._elevation && !this.projection.isReprojectedInTileSpace ? z : 0;
// When calculating tile cover for terrain, create deep AABB for nodes, to ensure they intersect frustum: for sources,
// other than DEM, use minimum of visible DEM tiles and center altitude as upper bound (pitch is always less than 90°).
const maxRange = options.isTerrainDEM && this._elevation ? this._elevation.exaggeration() * 10000 : this._centerAltitude;
const minRange = options.isTerrainDEM ? -maxRange : this._elevation ? this._elevation.getMinElevationBelowMSL() : 0;
const scaleAdjustment = this.projection.isReprojectedInTileSpace ? getScaleAdjustment(this) : 1.0;
const relativeScaleAtMercatorCoord = mc => {
// Calculate how scale compares between projected coordinates and mercator coordinates.
// Returns a length. The units don't matter since the result is only
// used in a ratio with other values returned by this function.
// Construct a small square in Mercator coordinates.
const offset = 1 / 40000;
const mcEast = new MercatorCoordinate(mc.x + offset, mc.y, mc.z);
const mcSouth = new MercatorCoordinate(mc.x, mc.y + offset, mc.z);
// Convert the square to projected coordinates.
const ll = mc.toLngLat();
const llEast = mcEast.toLngLat();
const llSouth = mcSouth.toLngLat();
const p = this.locationCoordinate(ll);
const pEast = this.locationCoordinate(llEast);
const pSouth = this.locationCoordinate(llSouth);
// Calculate the size of each edge of the reprojected square
const dx = Math.hypot(pEast.x - p.x, pEast.y - p.y);
const dy = Math.hypot(pSouth.x - p.x, pSouth.y - p.y);
// Calculate the size of a projected square that would have the
// same area as the reprojected square.
return Math.sqrt(dx * dy) * scaleAdjustment / offset;
};
const newRootTile = (wrap: number): any => {
const max = maxRange;
const min = minRange;
return {
// With elevation, this._elevation provides z coordinate values. For 2D:
// All tiles are on zero elevation plane => z difference is zero
aabb: tileAABB(this, numTiles, 0, 0, 0, wrap, min, max, this.projection),
zoom: 0,
x: 0,
y: 0,
minZ: min,
maxZ: max,
wrap,
fullyVisible: false
};
};
// Do a depth-first traversal to find visible tiles and proper levels of detail
const stack = [];
let result = [];
const maxZoom = z;
const overscaledZ = options.reparseOverscaled ? actualZ : z;
const square = a => a * a;
const cameraHeightSqr = square((cameraAltitude - this._centerAltitude) * meterToTile); // in tile coordinates.
const getAABBFromElevation = (it) => {
assert(this._elevation);
if (!this._elevation || !it.tileID || !isMercator) return; // To silence flow.
const minmax = this._elevation.getMinMaxForTile(it.tileID);
const aabb = it.aabb;
if (minmax) {
aabb.min[2] = minmax.min;
aabb.max[2] = minmax.max;
aabb.center[2] = (aabb.min[2] + aabb.max[2]) / 2;
} else {
it.shouldSplit = shouldSplit(it);
if (!it.shouldSplit) {
// At final zoom level, while corresponding DEM tile is not loaded yet,
// assume center elevation. This covers ground to horizon and prevents
// loading unnecessary tiles until DEM cover is fully loaded.
aabb.min[2] = aabb.max[2] = aabb.center[2] = this._centerAltitude;
}
}
};
// Scale distance to split for acute angles.
// dzSqr: z component of camera to tile distance, square.
// dSqr: 3D distance of camera to tile, square.
const distToSplitScale = (dzSqr, dSqr) => {
// When the angle between camera to tile ray and tile plane is smaller
// than acuteAngleThreshold, scale the distance to split. Scaling is adaptive: smaller
// the angle, the scale gets lower value. Although it seems early to start at 45,
// it is not: scaling kicks in around 60 degrees pitch.
const acuteAngleThresholdSin = 0.707; // Math.sin(45)
const stretchTile = 1.1;
// Distances longer than 'dz / acuteAngleThresholdSin' gets scaled
// following geometric series sum: every next dz length in distance can be
// 'stretchTile times' longer. It is further, the angle is sharper. Total,
// adjusted, distance would then be:
// = dz / acuteAngleThresholdSin + (dz * stretchTile + dz * stretchTile ^ 2 + ... + dz * stretchTile ^ k),
// where k = (d - dz / acuteAngleThresholdSin) / dz = d / dz - 1 / acuteAngleThresholdSin;
// = dz / acuteAngleThresholdSin + dz * ((stretchTile ^ (k + 1) - 1) / (stretchTile - 1) - 1)
// or put differently, given that k is based on d and dz, tile on distance d could be used on distance scaled by:
// 1 / acuteAngleThresholdSin + (stretchTile ^ (k + 1) - 1) / (stretchTile - 1) - 1
if (dSqr * square(acuteAngleThresholdSin) < dzSqr) return 1.0; // Early return, no scale.
const r = Math.sqrt(dSqr / dzSqr);
const k = r - 1 / acuteAngleThresholdSin;
return r / (1 / acuteAngleThresholdSin + (Math.pow(stretchTile, k + 1) - 1) / (stretchTile - 1) - 1);
};
const shouldSplit = (it) => {
if (it.zoom < minZoom) {
return true;
} else if (it.zoom === maxZoom) {
return false;
}
if (it.shouldSplit != null) {
return it.shouldSplit;
}
const dx = it.aabb.distanceX(cameraPoint);
const dy = it.aabb.distanceY(cameraPoint);
let dzSqr = cameraHeightSqr;
let tileScaleAdjustment = 1;
if (isGlobe) {
dzSqr = square(it.aabb.distanceZ(cameraPoint));
// Compensate physical sizes of the tiles when determining which zoom level to use.
// In practice tiles closer to poles should use more aggressive LOD as their
// physical size is already smaller than size of tiles near the equator.
const tilesAtZoom = Math.pow(2, it.zoom);
const minLat = latFromMercatorY((it.y + 1) / tilesAtZoom);
const maxLat = latFromMercatorY((it.y) / tilesAtZoom);
const closestLat = Math.min(Math.max(centerLatitude, minLat), maxLat);
const scale = circumferenceAtLatitude(closestLat) / circumferenceAtLatitude(centerLatitude);
tileScaleAdjustment = Math.min(scale, 1.0);
} else {
assert(zInMeters);
if (useElevationData) {
dzSqr = square(it.aabb.distanceZ(cameraPoint) * meterToTile);
}
if (this.projection.isReprojectedInTileSpace && actualZ <= 5) {
// In other projections, not all tiles are the same size.
// Account for the tile size difference by adjusting the distToSplit.
// Adjust by the ratio of the area at the tile center to the area at the map center.
// Adjustments are only needed at lower zooms where tiles are not similarly sized.
const numTiles = Math.pow(2, it.zoom);
const relativeScale = relativeScaleAtMercatorCoord(new MercatorCoordinate((it.x + 0.5) / numTiles, (it.y + 0.5) / numTiles));
// Fudge the ratio slightly so that all tiles near the center have the same zoom level.
tileScaleAdjustment = relativeScale > 0.85 ? 1 : relativeScale;
}
}
const distanceSqr = dx * dx + dy * dy + dzSqr;
const distToSplit = (1 << maxZoom - it.zoom) * zoomSplitDistance * tileScaleAdjustment;
const distToSplitSqr = square(distToSplit * distToSplitScale(Math.max(dzSqr, cameraHeightSqr), distanceSqr));
return distanceSqr < distToSplitSqr;
};
if (this.renderWorldCopies) {
// Render copy of the globe thrice on both sides
for (let i = 1; i <= NUM_WORLD_COPIES; i++) {
stack.push(newRootTile(-i));
stack.push(newRootTile(i));
}
}
stack.push(newRootTile(0));
while (stack.length > 0) {
const it = stack.pop();
const x = it.x;
const y = it.y;
let fullyVisible = it.fullyVisible;
// Visibility of a tile is not required if any of its ancestor is fully inside the frustum
if (!fullyVisible) {
const intersectResult = it.aabb.intersects(cameraFrustum);
if (intersectResult === 0)
continue;
fullyVisible = intersectResult === 2;
}
// Have we reached the target depth or is the tile too far away to be any split further?
if (it.zoom === maxZoom || !shouldSplit(it)) {
const tileZoom = it.zoom === maxZoom ? overscaledZ : it.zoom;
if (!!options.minzoom && options.minzoom > tileZoom) {
// Not within source tile range.
continue;
}
const dx = centerPoint[0] - ((0.5 + x + (it.wrap << it.zoom)) * (1 << (z - it.zoom)));
const dy = centerPoint[1] - 0.5 - y;
const id = it.tileID ? it.tileID : new OverscaledTileID(tileZoom, it.wrap, it.zoom, x, y);
result.push({tileID: id, distanceSq: dx * dx + dy * dy});
continue;
}
for (let i = 0; i < 4; i++) {
const childX = (x << 1) + (i % 2);
const childY = (y << 1) + (i >> 1);
const aabb = isMercator ? it.aabb.quadrant(i) : tileAABB(this, numTiles, it.zoom + 1, childX, childY, it.wrap, it.minZ, it.maxZ, this.projection);
const child = {aabb, zoom: it.zoom + 1, x: childX, y: childY, wrap: it.wrap, fullyVisible, tileID: undefined, shouldSplit: undefined, minZ: it.minZ, maxZ: it.maxZ};
if (useElevationData && !isGlobe) {
child.tileID = new OverscaledTileID(it.zoom + 1 === maxZoom ? overscaledZ : it.zoom + 1, it.wrap, it.zoom + 1, childX, childY);
getAABBFromElevation(child);
}
stack.push(child);
}
}
if (this.fogCullDistSq) {
const fogCullDistSq = this.fogCullDistSq;
const horizonLineFromTop = this.horizonLineFromTop();
result = result.filter(entry => {
const min = [0, 0, 0, 1];
const max = [EXTENT, EXTENT, 0, 1];
const fogTileMatrix = this.calculateFogTileMatrix(entry.tileID.toUnwrapped());
vec4.transformMat4(min, min, fogTileMatrix);
vec4.transformMat4(max, max, fogTileMatrix);
const sqDist = getAABBPointSquareDist(min, max);
if (sqDist === 0) { return true; }
let overHorizonLine = false;
// Terrain loads at one zoom level lower than the raster data,
// so the following checks whether the terrain sits above the horizon and ensures that
// when mountains stick out above the fog (due to horizon-blend),
// we haven’t accidentally culled some of the raster tiles we need to draw on them.
// If we don’t do this, the terrain is default black color and may flash in and out as we move toward it.
const elevation = this._elevation;
if (elevation && sqDist > fogCullDistSq && horizonLineFromTop !== 0) {
const projMatrix = this.calculateProjMatrix(entry.tileID.toUnwrapped());
let minmax;
if (!options.isTerrainDEM) {
minmax = elevation.getMinMaxForTile(entry.tileID);
}
if (!minmax) { minmax = {min: minRange, max: maxRange}; }
// ensure that we want `this.rotation` instead of `this.bearing` here
const cornerFar = furthestTileCorner(this.rotation);
const farX = cornerFar[0] * EXTENT;
const farY = cornerFar[1] * EXTENT;
const worldFar = [farX, farY, minmax.max];
// World to NDC
vec3.transformMat4(worldFar, worldFar, projMatrix);
// NDC to Screen
const screenCoordY = (1 - worldFar[1]) * this.height * 0.5;
// Prevent cutting tiles crossing over the horizon line to
// prevent pop-in and out within the fog culling range
overHorizonLine = screenCoordY < horizonLineFromTop;
}
return sqDist < fogCullDistSq || overHorizonLine;
});
}
const cover = result.sort((a, b) => a.distanceSq - b.distanceSq).map(a => a.tileID);
// Relax the assertion on terrain, on high zoom we use distance to center of tile
// while camera might be closer to selected center of map.
assert(!cover.length || this.elevation || cover[0].overscaledZ === overscaledZ || !isMercator);
return cover;
}
resize(width: number, height: number) {
this.width = width;
this.height = height;
this.pixelsToGLUnits = [2 / width, -2 / height];
this._constrain();
this._calcMatrices();
}
get unmodified(): boolean { return this._unmodified; }
zoomScale(zoom: number): number { return Math.pow(2, zoom); }
scaleZoom(scale: number): number { return Math.log(scale) / Math.LN2; }
// Transform from LngLat to Point in world coordinates [-180, 180] x [90, -90] --> [0, this.worldSize] x [0, this.worldSize]
project(lnglat: LngLat): Point {
const lat = clamp(lnglat.lat, -MAX_MERCATOR_LATITUDE, MAX_MERCATOR_LATITUDE);
const projectedLngLat = this.projection.project(lnglat.lng, lat);
return new Point(
projectedLngLat.x * this.worldSize,
projectedLngLat.y * this.worldSize);
}
// Transform from Point in world coordinates to LngLat [0, this.worldSize] x [0, this.worldSize] --> [-180, 180] x [90, -90]
unproject(point: Point): LngLat {
return this.projection.unproject(point.x / this.worldSize, point.y / this.worldSize);
}
// Point at center in world coordinates.
get point(): Point { return this.project(this.center); }
setLocationAtPoint(lnglat: LngLat, point: Point) {
let x, y;
const centerPoint = this.centerPoint;
if (this.projection.name === 'globe') {
// Pixel coordinates are applied directly to the globe
const worldSize = this.worldSize;
x = (point.x - centerPoint.x) / worldSize;
y = (point.y - centerPoint.y) / worldSize;
} else {
const a = this.pointCoordinate(point);
const b = this.pointCoordinate(centerPoint);
x = a.x - b.x;
y = a.y - b.y;
}
const loc = this.locationCoordinate(lnglat);
this.setLocation(new MercatorCoordinate(loc.x - x, loc.y - y));
}
setLocation(location: MercatorCoordinate) {
this.center = this.coordinateLocation(location);
if (this.projection.wrap) {
this.center = this.center.wrap();
}
}
/**
* Given a location, return the screen point that corresponds to it. In 3D mode
* (with terrain) this behaves the same as in 2D mode.
* This method is coupled with {@see pointLocation} in 3D mode to model map manipulation
* using flat plane approach to keep constant elevation above ground.
* @param {LngLat} lnglat location
* @returns {Point} screen point
* @private
*/
locationPoint(lnglat: LngLat): Point {
return this.projection.locationPoint(this, lnglat);
}
/**
* Given a location, return the screen point that corresponds to it
* In 3D mode (when terrain is enabled) elevation is sampled for the point before
* projecting it. In 2D mode, behaves the same locationPoint.
* @param {LngLat} lnglat location
* @returns {Point} screen point
* @private
*/
locationPoint3D(lnglat: LngLat): Point {
return this._coordinatePoint(this.locationCoordinate(lnglat), true);
}
/**
* Given a point on screen, return its lnglat
* @param {Point} p screen point
* @returns {LngLat} lnglat location
* @private
*/
pointLocation(p: Point): LngLat {
return this.coordinateLocation(this.pointCoordinate(p));
}
/**
* Given a point on screen, return its lnglat
* In 3D mode (map with terrain) returns location of terrain raycast point.
* In 2D mode, behaves the same as {@see pointLocation}.
* @param {Point} p screen point
* @returns {LngLat} lnglat location
* @private
*/
pointLocation3D(p: Point): LngLat {
return this.coordinateLocation(this.pointCoordinate3D(p));
}
/**
* Given a geographical lngLat, return an unrounded
* coordinate that represents it at this transform's zoom level.
* @param {LngLat} lngLat
* @returns {Coordinate}
* @private
*/
locationCoordinate(lngLat: LngLat, altitude?: number): MercatorCoordinate {
const z = altitude ?
mercatorZfromAltitude(altitude, lngLat.lat) :
undefined;
const projectedLngLat = this.projection.project(lngLat.lng, lngLat.lat);
return new MercatorCoordinate(
projectedLngLat.x,
projectedLngLat.y,
z);
}
/**
* Given a Coordinate, return its geographical position.
* @param {Coordinate} coord
* @returns {LngLat} lngLat
* @private
*/
coordinateLocation(coord: MercatorCoordinate): LngLat {
return this.projection.unproject(coord.x, coord.y);
}
/**
* Casts a ray from a point on screen and returns the Ray,
* and the extent along it, at which it intersects the map plane.
*
* @param {Point} p Viewport pixel co-ordinates.
* @param {number} z Optional altitude of the map plane, defaulting to elevation at center.
* @returns {{ p0: Vec4, p1: Vec4, t: number }} p0,p1 are two points on the ray.
* t is the fractional extent along the ray at which the ray intersects the map plane.
* @private
*/
pointRayIntersection(p: Point, z: ?number): RayIntersectionResult {
const targetZ = (z !== undefined && z !== null) ? z : this._centerAltitude;
// Since we don't know the correct projected z value for the point,
// unproject two points to get a line and then find the point on that
// line with z=0.
const p0 = [p.x, p.y, 0, 1];
const p1 = [p.x, p.y, 1, 1];
vec4.transformMat4(p0, p0, this.pixelMatrixInverse);
vec4.transformMat4(p1, p1, this.pixelMatrixInverse);
const w0 = p0[3];
const w1 = p1[3];
vec4.scale(p0, p0, 1 / w0);
vec4.scale(p1, p1, 1 / w1);
const z0 = p0[2];
const z1 = p1[2];
const t = z0 === z1 ? 0 : (targetZ - z0) / (z1 - z0);
return {p0, p1, t};
}
screenPointToMercatorRay(p: Point): Ray {
const p0 = [p.x, p.y, 0, 1];
const p1 = [p.x, p.y, 1, 1];
vec4.transformMat4(p0, p0, this.pixelMatrixInverse);
vec4.transformMat4(p1, p1, this.pixelMatrixInverse);
vec4.scale(p0, p0, 1 / p0[3]);
vec4.scale(p1, p1, 1 / p1[3]);
// Convert altitude from meters to pixels.
p0[2] = mercatorZfromAltitude(p0[2], this._center.lat) * this.worldSize;
p1[2] = mercatorZfromAltitude(p1[2], this._center.lat) * this.worldSize;
vec4.scale(p0, p0, 1 / this.worldSize);
vec4.scale(p1, p1, 1 / this.worldSize);
return new Ray([p0[0], p0[1], p0[2]], vec3.normalize([], vec3.sub([], p1, p0)));
}
/**
* Helper method to convert the ray intersection with the map plane to MercatorCoordinate.
*
* @param {RayIntersectionResult} rayIntersection
* @returns {MercatorCoordinate}
* @private
*/
rayIntersectionCoordinate(rayIntersection: RayIntersectionResult): MercatorCoordinate {
const {p0, p1, t} = rayIntersection;
const z0 = mercatorZfromAltitude(p0[2], this._center.lat);
const z1 = mercatorZfromAltitude(p1[2], this._center.lat);
return new MercatorCoordinate(
interpolate(p0[0], p1[0], t) / this.worldSize,
interpolate(p0[1], p1[1], t) / this.worldSize,
interpolate(z0, z1, t));
}
/**
* Given a point on screen, returns MercatorCoordinate.
* @param {Point} p Top left origin screen point, in pixels.
* @param {number} z Optional altitude of the map plane, defaulting to elevation at center.
* @private
*/
pointC