1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
// flatmap.js — flat world maps (Equal Earth, plate carrée): GPU-reprojected texture, pan/zoom, picking
import * as THREE from 'three';
import { project, unproject, EE_XMAX, EE_YMAX, PC_XMAX, PC_YMAX } from './geo.js';
import { densify, flatSegments } from './overlay_geom.js';
import { LineSet } from './lines.js';
import { BACKGROUND } from './globe.js';
import { SHADE_GLSL, shadeUniforms, applyOver, applySun } from './shading.js';
import { MAX_ZOOM } from './limits.js';
import { Touches } from './gestures.js';
export { MAX_ZOOM };
const EXTENT = { equal_earth: [EE_XMAX, EE_YMAX, 1], plate_carree: [PC_XMAX, PC_YMAX, 0] };
const VERT = /* glsl */ `
varying vec2 vXY;
void main() {
vXY = position.xy;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}`;
// Inverse projection per pixel, same maths as geo.js / mapgen/projections.py (Equal Earth: Newton on t).
const FRAG = /* glsl */ `${SHADE_GLSL}
uniform int proj;
varying vec2 vXY;
const float A1 = 1.340264, A2 = -0.081106, A3 = 0.000893, A4 = 0.003796;
const float M = 0.8660254037844386, PI = 3.141592653589793;
void main() {
float lat = vXY.y, lon = vXY.x;
if (proj == 1) {
float t = vXY.y / A1;
for (int i = 0; i < 12; i++) {
float t2 = t * t, t6 = t2 * t2 * t2;
t -= (t * (A1 + A2 * t2 + A3 * t6 + A4 * t6 * t2) - vXY.y) / (A1 + 3.0 * A2 * t2 + 7.0 * A3 * t6 + 9.0 * A4 * t6 * t2);
}
float t2 = t * t, t6 = t2 * t2 * t2;
float s = sin(t) / M;
lon = 3.0 * vXY.x * (A1 + 3.0 * A2 * t2 + 7.0 * A3 * t6 + 9.0 * A4 * t6 * t2) / (2.0 * sqrt(3.0) * cos(t));
if (abs(s) > 1.000001 || abs(lon) > PI) discard;
lat = asin(clamp(s, -1.0, 1.0));
}
vec3 n = vec3(cos(lat) * cos(lon), sin(lat), -cos(lat) * sin(lon)); // scene convention, as geo.toVec
gl_FragColor = vec4(shadeColor(vec2(lon / (2.0 * PI) + 0.5, lat / PI + 0.5), n, 1.0), 1.0);
}`;
export class FlatView {
constructor(renderer, kind, onChange) {
const [xmax, ymax, proj] = EXTENT[kind];
Object.assign(this, { renderer, kind, onChange, xmax, ymax, cx: 0, cy: 0, zoom: 1, w: 1, h: 1, active: false });
this.scene = new THREE.Scene();
this.scene.background = new THREE.Color(BACKGROUND);
this.camera = new THREE.OrthographicCamera(-1, 1, 1, -1, 0.1, 10);
this.camera.position.z = 5;
this.shade = shadeUniforms();
this.material = new THREE.ShaderMaterial({ vertexShader: VERT, fragmentShader: FRAG,
uniforms: { ...this.shade, proj: { value: proj } } });
this.scene.add(new THREE.Mesh(new THREE.PlaneGeometry(2 * xmax, 2 * ymax), this.material));
this.lines = new LineSet(this.scene);
this.#bind(renderer.domElement);
}
activate() { this.active = true; }
deactivate() { this.active = false; }
resize(w, h) {
this.w = w;
this.h = h;
this.#apply();
}
#half() { // half width/height of the visible area in projection units; zoom 1 fits the whole map
const hh = (Math.max(this.ymax, (this.xmax * this.h) / this.w) * 1.04) / this.zoom;
return [(hh * this.w) / this.h, hh];
}
#apply() {
this.cy = Math.max(-this.ymax, Math.min(this.ymax, this.cy));
const edge = this.kind === 'equal_earth' // keep the centre on the map, so its lat/lon is exact
? project(this.kind, unproject(this.kind, 0, this.cy).lat, 180).x : this.xmax;
this.cx = Math.max(-edge, Math.min(edge, this.cx));
const [hw, hh] = this.#half();
Object.assign(this.camera, { left: -hw, right: hw, top: hh, bottom: -hh }); // camera follows the centre:
this.camera.position.set(this.cx, this.cy, 5); // small offsets keep float precision
this.camera.updateProjectionMatrix();
}
toWorld(x, y) {
const [hw, hh] = this.#half();
return { X: this.cx + ((x / this.w) * 2 - 1) * hw, Y: this.cy + (1 - (y / this.h) * 2) * hh };
}
getState() {
const c = unproject(this.kind, this.cx, this.cy) // centre may sit outside the outline
?? { lat: unproject(this.kind, 0, this.cy).lat, lon: Math.sign(this.cx) * 180 };
return { lat: c.lat, lon: c.lon, zoom: this.zoom };
}
setState({ lat, lon, zoom }) {
const p = project(this.kind, lat, lon);
this.cx = p.x;
this.cy = p.y;
this.zoom = Math.min(MAX_ZOOM, Math.max(1, Number.isFinite(zoom) ? zoom : this.zoom));
this.#apply();
this.onChange();
}
setTexture(tex) {
this.material.uniforms.map.value = tex;
this.material.uniforms.hasMap.value = tex ? 1 : 0;
}
setOver(tex, op) { applyOver(this.shade, tex, op); }
setSun(v) { applySun(this.shade, v); }
setLines(id, lines, color) { // densify: long legs (measure paths) follow the great circle, as on the globe
this.lines.set(id, flatSegments(densify(lines, 1), this.kind, 0.001), color);
}
removeLines(id) { this.lines.remove(id); }
pick(x, y) {
const { X, Y } = this.toWorld(x, y);
return unproject(this.kind, X, Y);
}
toScreen(lat, lon) {
const p = project(this.kind, lat, lon), [hw, hh] = this.#half();
return { x: (((p.x - this.cx) / hw + 1) / 2) * this.w, y: ((1 - (p.y - this.cy) / hh) / 2) * this.h };
}
render() { this.renderer.render(this.scene, this.camera); }
#zoomAt(x, y, f) { // zoom by f keeping the point under (x, y) in place
const before = this.toWorld(x, y);
this.zoom = Math.min(MAX_ZOOM, Math.max(1, this.zoom * f));
const after = this.toWorld(x, y);
this.cx += before.X - after.X;
this.cy += before.Y - after.Y;
}
#bind(canvas) {
let drag = null;
const touches = new Touches(), at = e => { const r = canvas.getBoundingClientRect(); return { x: e.clientX - r.left, y: e.clientY - r.top }; };
canvas.addEventListener('pointerdown', e => {
if (!this.active || e.button !== 0) return;
drag = { x: e.clientX, y: e.clientY, cx: this.cx, cy: this.cy, id: e.pointerId };
try { canvas.setPointerCapture(e.pointerId); } catch { /* a synthetic or already-ended pointer */ }
if (e.pointerType === 'touch') {
touches.down(e.pointerId, at(e));
if (touches.size >= 2) drag = null; // two fingers: pinch and pan together
}
});
canvas.addEventListener('pointermove', e => {
if (!this.active) return;
const g = e.pointerType === 'touch' ? touches.move(e.pointerId, at(e)) : null;
if (g) {
const k = (2 * this.#half()[1]) / this.h;
this.cx -= g.move.x * k;
this.cy += g.move.y * k;
this.#zoomAt(g.mid.x, g.mid.y, g.scale);
this.#apply();
this.onChange();
return;
}
if (!drag || e.pointerId !== drag.id) return;
const k = (2 * this.#half()[1]) / this.h; // projection units per CSS px
this.cx = drag.cx - (e.clientX - drag.x) * k;
this.cy = drag.cy + (e.clientY - drag.y) * k;
this.#apply();
this.onChange();
});
const end = e => {
drag = null;
if (e.pointerType !== 'touch') return;
const wasPair = touches.size >= 2;
touches.up(e.pointerId);
const rest = wasPair && touches.size === 1 ? touches.other(e.pointerId) : null;
if (rest) { // one finger left: it pans on from where it is
const r = canvas.getBoundingClientRect();
drag = { x: rest.at.x + r.left, y: rest.at.y + r.top, cx: this.cx, cy: this.cy, id: rest.id };
}
};
canvas.addEventListener('pointerup', end);
canvas.addEventListener('pointercancel', end);
canvas.addEventListener('wheel', e => {
if (!this.active) return;
e.preventDefault();
const r = canvas.getBoundingClientRect(), x = e.clientX - r.left, y = e.clientY - r.top;
const px = e.deltaY * (e.deltaMode === 1 ? 33 : e.deltaMode === 2 ? 400 : 1); // Firefox may send lines
this.#zoomAt(x, y, Math.exp(-px * 0.0015));
this.#apply();
this.onChange();
}, { passive: false });
}
}
|
