package.src.geo.transform.js Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of mapbox-gl Show documentation
Show all versions of mapbox-gl Show documentation
A WebGL interactive maps library
The newest version!
// @flow
import LngLat from './lng_lat';
import LngLatBounds from './lng_lat_bounds';
import MercatorCoordinate, {mercatorXfromLng, mercatorYfromLat, mercatorZfromAltitude} from './mercator_coordinate';
import Point from '@mapbox/point-geometry';
import {wrap, clamp} from '../util/util';
import {number as interpolate} from '../style-spec/util/interpolate';
import EXTENT from '../data/extent';
import {vec4, mat4, mat2, vec2} from 'gl-matrix';
import {Aabb, Frustum} from '../util/primitives.js';
import EdgeInsets from './edge_insets';
import {UnwrappedTileID, OverscaledTileID, CanonicalTileID} from '../source/tile_id';
import type {PaddingOptions} from './edge_insets';
/**
* A single transform, generally used for a single tile to be
* scaled, rotated, and zoomed.
* @private
*/
class Transform {
tileSize: number;
tileZoom: number;
lngRange: ?[number, number];
latRange: ?[number, number];
maxValidLatitude: number;
scale: number;
width: number;
height: number;
angle: number;
rotationMatrix: Float64Array;
zoomFraction: number;
pixelsToGLUnits: [number, number];
cameraToCenterDistance: number;
mercatorMatrix: Array;
projMatrix: Float64Array;
invProjMatrix: Float64Array;
alignedProjMatrix: Float64Array;
pixelMatrix: Float64Array;
pixelMatrixInverse: Float64Array;
glCoordMatrix: Float32Array;
labelPlaneMatrix: Float32Array;
_fov: number;
_pitch: number;
_zoom: number;
_unmodified: boolean;
_renderWorldCopies: boolean;
_minZoom: number;
_maxZoom: number;
_minPitch: number;
_maxPitch: number;
_center: LngLat;
_edgeInsets: EdgeInsets;
_constraining: boolean;
_posMatrixCache: {[_: string]: Float32Array};
_alignedPosMatrixCache: {[_: string]: Float32Array};
constructor(minZoom: ?number, maxZoom: ?number, minPitch: ?number, maxPitch: ?number, renderWorldCopies: boolean | void) {
this.tileSize = 512; // constant
this.maxValidLatitude = 85.051129; // constant
this._renderWorldCopies = renderWorldCopies === undefined ? true : renderWorldCopies;
this._minZoom = minZoom || 0;
this._maxZoom = maxZoom || 22;
this._minPitch = (minPitch === undefined || minPitch === null) ? 0 : minPitch;
this._maxPitch = (maxPitch === undefined || maxPitch === null) ? 60 : maxPitch;
this.setMaxBounds();
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._unmodified = true;
this._edgeInsets = new EdgeInsets();
this._posMatrixCache = {};
this._alignedPosMatrixCache = {};
}
clone(): Transform {
const clone = new Transform(this._minZoom, this._maxZoom, this._minPitch, this.maxPitch, this._renderWorldCopies);
clone.tileSize = this.tileSize;
clone.latRange = this.latRange;
clone.width = this.width;
clone.height = this.height;
clone._center = this._center;
clone.zoom = this.zoom;
clone.angle = this.angle;
clone._fov = this._fov;
clone._pitch = this._pitch;
clone._unmodified = this._unmodified;
clone._edgeInsets = this._edgeInsets.clone();
clone._calcMatrices();
return clone;
}
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; }
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 centerOffset(): Point {
return this.centerPoint._sub(this.size._div(2));
}
get size(): Point {
return new Point(this.width, this.height);
}
get bearing(): number {
return -this.angle / Math.PI * 180;
}
set bearing(bearing: number) {
const b = -wrap(bearing, -180, 180) * 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 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._zoom = z;
this.scale = this.zoomScale(z);
this.tileZoom = Math.floor(z);
this.zoomFraction = z - this.tileZoom;
this._constrain();
this._calcMatrices();
}
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;
this._constrain();
this._calcMatrices();
}
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();
}
/**
* 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 if the padding params match
*
* @param {PaddingOptions} padding
* @returns {boolean}
* @memberof Transform
*/
isPaddingEqual(padding: PaddingOptions): boolean {
return this._edgeInsets.equals(padding);
}
/**
* Helper method to upadte edge-insets inplace
*
* @param {PaddingOptions} target
* @param {number} t
* @memberof Transform
*/
interpolatePadding(start: PaddingOptions, target: PaddingOptions, t: number) {
this._unmodified = false;
this._edgeInsets.interpolate(start, target, t);
this._constrain();
this._calcMatrices();
}
/**
* Return a zoom level that will cover all tiles the transform
* @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} zoom level An integer zoom level at which all tiles will be visible.
*/
coveringZoomLevel(options: {roundZoom?: boolean, tileSize: 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) {
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
* @param {boolean} options.renderWorldCopies
* @returns {Array} OverscaledTileIDs
* @private
*/
coveringTiles(
options: {
tileSize: number,
minzoom?: number,
maxzoom?: number,
roundZoom?: boolean,
reparseOverscaled?: boolean,
renderWorldCopies?: boolean
}
): Array {
let z = this.coveringZoomLevel(options);
const actualZ = z;
if (options.minzoom !== undefined && z < options.minzoom) return [];
if (options.maxzoom !== undefined && z > options.maxzoom) z = options.maxzoom;
const centerCoord = MercatorCoordinate.fromLngLat(this.center);
const numTiles = Math.pow(2, z);
const centerPoint = [numTiles * centerCoord.x, numTiles * centerCoord.y, 0];
const cameraFrustum = Frustum.fromInvProjectionMatrix(this.invProjMatrix, this.worldSize, z);
// 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
let minZoom = options.minzoom || 0;
// Use 0.1 as an epsilon to avoid for explicit == 0.0 floating point checks
if (this.pitch <= 60.0 && this._edgeInsets.top < 0.1)
minZoom = z;
// There should always be a certain number of maximum zoom level tiles surrounding the center location
const radiusOfMaxLvlLodInTiles = 3;
const newRootTile = (wrap: number): any => {
return {
// All tiles are on zero elevation plane => z difference is zero
aabb: new Aabb([wrap * numTiles, 0, 0], [(wrap + 1) * numTiles, numTiles, 0]),
zoom: 0,
x: 0,
y: 0,
wrap,
fullyVisible: false
};
};
// Do a depth-first traversal to find visible tiles and proper levels of detail
const stack = [];
const result = [];
const maxZoom = z;
const overscaledZ = options.reparseOverscaled ? actualZ : z;
if (this._renderWorldCopies) {
// Render copy of the globe thrice on both sides
for (let i = 1; i <= 3; 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 if fully inside the frustum
if (!fullyVisible) {
const intersectResult = it.aabb.intersects(cameraFrustum);
if (intersectResult === 0)
continue;
fullyVisible = intersectResult === 2;
}
const distanceX = it.aabb.distanceX(centerPoint);
const distanceY = it.aabb.distanceY(centerPoint);
const longestDim = Math.max(Math.abs(distanceX), Math.abs(distanceY));
// We're using distance based heuristics to determine if a tile should be split into quadrants or not.
// radiusOfMaxLvlLodInTiles defines that there's always a certain number of maxLevel tiles next to the map center.
// Using the fact that a parent node in quadtree is twice the size of its children (per dimension)
// we can define distance thresholds for each relative level:
// f(k) = offset + 2 + 4 + 8 + 16 + ... + 2^k. This is the same as "offset+2^(k+1)-2"
const distToSplit = radiusOfMaxLvlLodInTiles + (1 << (maxZoom - it.zoom)) - 2;
// Have we reached the target depth or is the tile too far away to be any split further?
if (it.zoom === maxZoom || (longestDim > distToSplit && it.zoom >= minZoom)) {
result.push({
tileID: new OverscaledTileID(it.zoom === maxZoom ? overscaledZ : it.zoom, it.wrap, it.zoom, x, y),
distanceSq: vec2.sqrLen([centerPoint[0] - 0.5 - x, centerPoint[1] - 0.5 - y])
});
continue;
}
for (let i = 0; i < 4; i++) {
const childX = (x << 1) + (i % 2);
const childY = (y << 1) + (i >> 1);
stack.push({aabb: it.aabb.quadrant(i), zoom: it.zoom + 1, x: childX, y: childY, wrap: it.wrap, fullyVisible});
}
}
return result.sort((a, b) => a.distanceSq - b.distanceSq).map(a => a.tileID);
}
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) { return Math.pow(2, zoom); }
scaleZoom(scale: number) { return Math.log(scale) / Math.LN2; }
project(lnglat: LngLat) {
const lat = clamp(lnglat.lat, -this.maxValidLatitude, this.maxValidLatitude);
return new Point(
mercatorXfromLng(lnglat.lng) * this.worldSize,
mercatorYfromLat(lat) * this.worldSize);
}
unproject(point: Point): LngLat {
return new MercatorCoordinate(point.x / this.worldSize, point.y / this.worldSize).toLngLat();
}
get point(): Point { return this.project(this.center); }
setLocationAtPoint(lnglat: LngLat, point: Point) {
const a = this.pointCoordinate(point);
const b = this.pointCoordinate(this.centerPoint);
const loc = this.locationCoordinate(lnglat);
const newCenter = new MercatorCoordinate(
loc.x - (a.x - b.x),
loc.y - (a.y - b.y));
this.center = this.coordinateLocation(newCenter);
if (this._renderWorldCopies) {
this.center = this.center.wrap();
}
}
/**
* Given a location, return the screen point that corresponds to it
* @param {LngLat} lnglat location
* @returns {Point} screen point
* @private
*/
locationPoint(lnglat: LngLat) {
return this.coordinatePoint(this.locationCoordinate(lnglat));
}
/**
* Given a point on screen, return its lnglat
* @param {Point} p screen point
* @returns {LngLat} lnglat location
* @private
*/
pointLocation(p: Point) {
return this.coordinateLocation(this.pointCoordinate(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) {
return MercatorCoordinate.fromLngLat(lnglat);
}
/**
* Given a Coordinate, return its geographical position.
* @param {Coordinate} coord
* @returns {LngLat} lnglat
* @private
*/
coordinateLocation(coord: MercatorCoordinate) {
return coord.toLngLat();
}
pointCoordinate(p: Point) {
const targetZ = 0;
// 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 coord0 = [p.x, p.y, 0, 1];
const coord1 = [p.x, p.y, 1, 1];
vec4.transformMat4(coord0, coord0, this.pixelMatrixInverse);
vec4.transformMat4(coord1, coord1, this.pixelMatrixInverse);
const w0 = coord0[3];
const w1 = coord1[3];
const x0 = coord0[0] / w0;
const x1 = coord1[0] / w1;
const y0 = coord0[1] / w0;
const y1 = coord1[1] / w1;
const z0 = coord0[2] / w0;
const z1 = coord1[2] / w1;
const t = z0 === z1 ? 0 : (targetZ - z0) / (z1 - z0);
return new MercatorCoordinate(
interpolate(x0, x1, t) / this.worldSize,
interpolate(y0, y1, t) / this.worldSize);
}
/**
* Given a coordinate, return the screen point that corresponds to it
* @param {Coordinate} coord
* @returns {Point} screen point
* @private
*/
coordinatePoint(coord: MercatorCoordinate) {
const p = [coord.x * this.worldSize, coord.y * this.worldSize, 0, 1];
vec4.transformMat4(p, p, this.pixelMatrix);
return new Point(p[0] / p[3], p[1] / p[3]);
}
/**
* Returns the map's geographical bounds. When the bearing or pitch is non-zero, the visible region is not
* an axis-aligned rectangle, and the result is the smallest bounds that encompasses the visible region.
* @returns {LngLatBounds} Returns a {@link LngLatBounds} object describing the map's geographical bounds.
*/
getBounds(): LngLatBounds {
return new LngLatBounds()
.extend(this.pointLocation(new Point(0, 0)))
.extend(this.pointLocation(new Point(this.width, 0)))
.extend(this.pointLocation(new Point(this.width, this.height)))
.extend(this.pointLocation(new Point(0, this.height)));
}
/**
* Returns the maximum geographical bounds the map is constrained to, or `null` if none set.
* @returns {LngLatBounds} {@link LngLatBounds}
*/
getMaxBounds(): LngLatBounds | null {
if (!this.latRange || this.latRange.length !== 2 ||
!this.lngRange || this.lngRange.length !== 2) return null;
return new LngLatBounds([this.lngRange[0], this.latRange[0]], [this.lngRange[1], this.latRange[1]]);
}
/**
* Sets or clears the map's geographical constraints.
* @param {LngLatBounds} bounds A {@link LngLatBounds} object describing the new geographic boundaries of the map.
*/
setMaxBounds(bounds?: LngLatBounds) {
if (bounds) {
this.lngRange = [bounds.getWest(), bounds.getEast()];
this.latRange = [bounds.getSouth(), bounds.getNorth()];
this._constrain();
} else {
this.lngRange = null;
this.latRange = [-this.maxValidLatitude, this.maxValidLatitude];
}
}
/**
* Calculate the posMatrix that, given a tile coordinate, would be used to display the tile on a map.
* @param {UnwrappedTileID} unwrappedTileID;
* @private
*/
calculatePosMatrix(unwrappedTileID: UnwrappedTileID, aligned: boolean = false): Float32Array {
const posMatrixKey = unwrappedTileID.key;
const cache = aligned ? this._alignedPosMatrixCache : this._posMatrixCache;
if (cache[posMatrixKey]) {
return cache[posMatrixKey];
}
const canonical = unwrappedTileID.canonical;
const scale = this.worldSize / this.zoomScale(canonical.z);
const unwrappedX = canonical.x + Math.pow(2, canonical.z) * unwrappedTileID.wrap;
const posMatrix = mat4.identity(new Float64Array(16));
mat4.translate(posMatrix, posMatrix, [unwrappedX * scale, canonical.y * scale, 0]);
mat4.scale(posMatrix, posMatrix, [scale / EXTENT, scale / EXTENT, 1]);
mat4.multiply(posMatrix, aligned ? this.alignedProjMatrix : this.projMatrix, posMatrix);
cache[posMatrixKey] = new Float32Array(posMatrix);
return cache[posMatrixKey];
}
customLayerMatrix(): Array {
return this.mercatorMatrix.slice();
}
_constrain() {
if (!this.center || !this.width || !this.height || this._constraining) return;
this._constraining = true;
let minY = -90;
let maxY = 90;
let minX = -180;
let maxX = 180;
let sy, sx, x2, y2;
const size = this.size,
unmodified = this._unmodified;
if (this.latRange) {
const latRange = this.latRange;
minY = mercatorYfromLat(latRange[1]) * this.worldSize;
maxY = mercatorYfromLat(latRange[0]) * this.worldSize;
sy = maxY - minY < size.y ? size.y / (maxY - minY) : 0;
}
if (this.lngRange) {
const lngRange = this.lngRange;
minX = mercatorXfromLng(lngRange[0]) * this.worldSize;
maxX = mercatorXfromLng(lngRange[1]) * this.worldSize;
sx = maxX - minX < size.x ? size.x / (maxX - minX) : 0;
}
const point = this.point;
// how much the map should scale to fit the screen into given latitude/longitude ranges
const s = Math.max(sx || 0, sy || 0);
if (s) {
this.center = this.unproject(new Point(
sx ? (maxX + minX) / 2 : point.x,
sy ? (maxY + minY) / 2 : point.y));
this.zoom += this.scaleZoom(s);
this._unmodified = unmodified;
this._constraining = false;
return;
}
if (this.latRange) {
const y = point.y,
h2 = size.y / 2;
if (y - h2 < minY) y2 = minY + h2;
if (y + h2 > maxY) y2 = maxY - h2;
}
if (this.lngRange) {
const x = point.x,
w2 = size.x / 2;
if (x - w2 < minX) x2 = minX + w2;
if (x + w2 > maxX) x2 = maxX - w2;
}
// pan the map if the screen goes off the range
if (x2 !== undefined || y2 !== undefined) {
this.center = this.unproject(new Point(
x2 !== undefined ? x2 : point.x,
y2 !== undefined ? y2 : point.y));
}
this._unmodified = unmodified;
this._constraining = false;
}
_calcMatrices() {
if (!this.height) return;
const halfFov = this._fov / 2;
const offset = this.centerOffset;
this.cameraToCenterDistance = 0.5 / Math.tan(halfFov) * this.height;
// Find the distance from the center point [width/2 + offset.x, height/2 + offset.y] to the
// center top point [width/2 + offset.x, 0] in Z units, using the law of sines.
// 1 Z unit is equivalent to 1 horizontal px at the center of the map
// (the distance between[width/2, height/2] and [width/2 + 1, height/2])
const groundAngle = Math.PI / 2 + this._pitch;
const fovAboveCenter = this._fov * (0.5 + offset.y / this.height);
const topHalfSurfaceDistance = Math.sin(fovAboveCenter) * this.cameraToCenterDistance / Math.sin(clamp(Math.PI - groundAngle - fovAboveCenter, 0.01, Math.PI - 0.01));
const point = this.point;
const x = point.x, y = point.y;
// Calculate z distance of the farthest fragment that should be rendered.
const furthestDistance = Math.cos(Math.PI / 2 - this._pitch) * topHalfSurfaceDistance + this.cameraToCenterDistance;
// Add a bit extra to avoid precision problems when a fragment's distance is exactly `furthestDistance`
const farZ = furthestDistance * 1.01;
// The larger the value of nearZ is
// - the more depth precision is available for features (good)
// - clipping starts appearing sooner when the camera is close to 3d features (bad)
//
// Smaller values worked well for mapbox-gl-js but deckgl was encountering precision issues
// when rendering it's layers using custom layers. This value was experimentally chosen and
// seems to solve z-fighting issues in deckgl while not clipping buildings too close to the camera.
const nearZ = this.height / 50;
// matrix for conversion from location to GL coordinates (-1 .. 1)
let m = new Float64Array(16);
mat4.perspective(m, this._fov, this.width / this.height, nearZ, farZ);
//Apply center of perspective offset
m[8] = -offset.x * 2 / this.width;
m[9] = offset.y * 2 / this.height;
mat4.scale(m, m, [1, -1, 1]);
mat4.translate(m, m, [0, 0, -this.cameraToCenterDistance]);
mat4.rotateX(m, m, this._pitch);
mat4.rotateZ(m, m, this.angle);
mat4.translate(m, m, [-x, -y, 0]);
// The mercatorMatrix can be used to transform points from mercator coordinates
// ([0, 0] nw, [1, 1] se) to GL coordinates.
this.mercatorMatrix = mat4.scale([], m, [this.worldSize, this.worldSize, this.worldSize]);
// scale vertically to meters per pixel (inverse of ground resolution):
mat4.scale(m, m, [1, 1, mercatorZfromAltitude(1, this.center.lat) * this.worldSize, 1]);
this.projMatrix = m;
this.invProjMatrix = mat4.invert([], this.projMatrix);
// Make a second projection matrix that is aligned to a pixel grid for rendering raster tiles.
// We're rounding the (floating point) x/y values to achieve to avoid rendering raster images to fractional
// coordinates. Additionally, we adjust by half a pixel in either direction in case that viewport dimension
// is an odd integer to preserve rendering to the pixel grid. We're rotating this shift based on the angle
// of the transformation so that 0°, 90°, 180°, and 270° rasters are crisp, and adjust the shift so that
// it is always <= 0.5 pixels.
const xShift = (this.width % 2) / 2, yShift = (this.height % 2) / 2,
angleCos = Math.cos(this.angle), angleSin = Math.sin(this.angle),
dx = x - Math.round(x) + angleCos * xShift + angleSin * yShift,
dy = y - Math.round(y) + angleCos * yShift + angleSin * xShift;
const alignedM = new Float64Array(m);
mat4.translate(alignedM, alignedM, [ dx > 0.5 ? dx - 1 : dx, dy > 0.5 ? dy - 1 : dy, 0 ]);
this.alignedProjMatrix = alignedM;
m = mat4.create();
mat4.scale(m, m, [this.width / 2, -this.height / 2, 1]);
mat4.translate(m, m, [1, -1, 0]);
this.labelPlaneMatrix = m;
m = mat4.create();
mat4.scale(m, m, [1, -1, 1]);
mat4.translate(m, m, [-1, -1, 0]);
mat4.scale(m, m, [2 / this.width, 2 / this.height, 1]);
this.glCoordMatrix = m;
// matrix for conversion from location to screen coordinates
this.pixelMatrix = mat4.multiply(new Float64Array(16), this.labelPlaneMatrix, this.projMatrix);
// inverse matrix for conversion from screen coordinaes to location
m = mat4.invert(new Float64Array(16), this.pixelMatrix);
if (!m) throw new Error("failed to invert matrix");
this.pixelMatrixInverse = m;
this._posMatrixCache = {};
this._alignedPosMatrixCache = {};
}
maxPitchScaleFactor() {
// calcMatrices hasn't run yet
if (!this.pixelMatrixInverse) return 1;
const coord = this.pointCoordinate(new Point(0, 0));
const p = [coord.x * this.worldSize, coord.y * this.worldSize, 0, 1];
const topPoint = vec4.transformMat4(p, p, this.pixelMatrix);
return topPoint[3] / this.cameraToCenterDistance;
}
/*
* The camera looks at the map from a 3D (lng, lat, altitude) location. Let's use `cameraLocation`
* as the name for the location under the camera and on the surface of the earth (lng, lat, 0).
* `cameraPoint` is the projected position of the `cameraLocation`.
*
* This point is useful to us because only fill-extrusions that are between `cameraPoint` and
* the query point on the surface of the earth can extend and intersect the query.
*
* When the map is not pitched the `cameraPoint` is equivalent to the center of the map because
* the camera is right above the center of the map.
*/
getCameraPoint() {
const pitch = this._pitch;
const yOffset = Math.tan(pitch) * (this.cameraToCenterDistance || 1);
return this.centerPoint.add(new Point(0, yOffset));
}
/*
* When the map is pitched, some of the 3D features that intersect a query will not intersect
* the query at the surface of the earth. Instead the feature may be closer and only intersect
* the query because it extrudes into the air.
*
* This returns a geometry that includes all of the original query as well as all possible ares of the
* screen where the *base* of a visible extrusion could be.
* - For point queries, the line from the query point to the "camera point"
* - For other geometries, the envelope of the query geometry and the "camera point"
*/
getCameraQueryGeometry(queryGeometry: Array): Array {
const c = this.getCameraPoint();
if (queryGeometry.length === 1) {
return [queryGeometry[0], c];
} else {
let minX = c.x;
let minY = c.y;
let maxX = c.x;
let maxY = c.y;
for (const p of queryGeometry) {
minX = Math.min(minX, p.x);
minY = Math.min(minY, p.y);
maxX = Math.max(maxX, p.x);
maxY = Math.max(maxY, p.y);
}
return [
new Point(minX, minY),
new Point(maxX, minY),
new Point(maxX, maxY),
new Point(minX, maxY),
new Point(minX, minY)
];
}
}
}
export default Transform;