假设我想根据细节层次算法和非常高分辨率的卫星纹理（即 32.768x32.768px）创建一个动态地形。最终，我根据级别从这张图片中创建了图块：
level1 4 tiles
level2 16 tiles
level3 64 tiles
level4 256 tiles
level5 1024 tiles
All these tiles are 1024x1024
我附上了一个非常基本的片段，它已经根据相机位置划分了平面（THREE.BufferGeometry）。
Mapbox 的 Delaunator 工作得非常快，但是我不知道如何将纹理放置到平面上，如下图所示：
我敢打赌它必须用着色器完成，但不知道如何去做。将这些图块合并到一个大纹理会导致我们达到 32.768x32.768，所以这是死胡同。
是的，它可以使用 THREE.MeshFaceMaterial(materials) 进行多重纹理化，并将每种材质（平铺）分配给某些顶点。但是，我正在寻找能够处理至少 512x512、更好的 1024x1024 的 ~60-65 纹理的直接 GLSL 解决方案。
PS：是的，我已经有这个单平面被分割成小平面的版本，但是我正在寻找单平面的方法，因为瓷砖接头上有裂缝，类似于本文所述，图 8。
PS：请忽略四叉树算法。我要求为一个几何体渲染 60-70 个纹理的通用解决方案。
//https://hofk.de/main/discourse.threejs/2018/Triangulation/Triangulation.html
////by Mapbox https://github.com/mapbox/delaunator
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global.Delaunator = factory());
}(this, (function () { 'use strict';
var EPSILON = Math.pow(2, -52);
var Delaunator = function Delaunator(coords) {
var this$1 = this;
var n = coords.length >> 1;
if (n > 0 && typeof coords[0] !== 'number') { throw new Error('Expected coords to contain numbers.'); }
this.coords = coords;
var maxTriangles = 2 * n - 5;
var triangles = this.triangles = new Uint32Array(maxTriangles * 3);
var halfedges = this.halfedges = new Int32Array(maxTriangles * 3);
this._hashSize = Math.ceil(Math.sqrt(n));
var hullPrev = this.hullPrev = new Uint32Array(n);
var hullNext = this.hullNext = new Uint32Array(n);
var hullTri = this.hullTri = new Uint32Array(n);
var hullHash = new Int32Array(this._hashSize).fill(-1);
var ids = new Uint32Array(n);
var minX = Infinity;
var minY = Infinity;
var maxX = -Infinity;
var maxY = -Infinity;
for (var i = 0; i < n; i++) {
var x = coords[2 * i];
var y = coords[2 * i + 1];
if (x < minX) { minX = x; }
if (y < minY) { minY = y; }
if (x > maxX) { maxX = x; }
if (y > maxY) { maxY = y; }
ids[i] = i;
}
var cx = (minX + maxX) / 2;
var cy = (minY + maxY) / 2;
var minDist = Infinity;
var i0, i1, i2;
for (var i$1 = 0; i$1 < n; i$1++) {
var d = dist(cx, cy, coords[2 * i$1], coords[2 * i$1 + 1]);
if (d < minDist) {
i0 = i$1;
minDist = d;
}
}
var i0x = coords[2 * i0];
var i0y = coords[2 * i0 + 1];
minDist = Infinity;
for (var i$2 = 0; i$2 < n; i$2++) {
if (i$2 === i0) { continue; }
var d$1 = dist(i0x, i0y, coords[2 * i$2], coords[2 * i$2 + 1]);
if (d$1 < minDist && d$1 > 0) {
i1 = i$2;
minDist = d$1;
}
}
var i1x = coords[2 * i1];
var i1y = coords[2 * i1 + 1];
var minRadius = Infinity;
for (var i$3 = 0; i$3 < n; i$3++) {
if (i$3 === i0 || i$3 === i1) { continue; }
var r = circumradius(i0x, i0y, i1x, i1y, coords[2 * i$3], coords[2 * i$3 + 1]);
if (r < minRadius) {
i2 = i$3;
minRadius = r;
}
}
var i2x = coords[2 * i2];
var i2y = coords[2 * i2 + 1];
if (minRadius === Infinity) {
throw new Error('No Delaunay triangulation exists for this input.');
}
if (orient(i0x, i0y, i1x, i1y, i2x, i2y)) {
var i$4 = i1;
var x$1 = i1x;
var y$1 = i1y;
i1 = i2;
i1x = i2x;
i1y = i2y;
i2 = i$4;
i2x = x$1;
i2y = y$1;
}
var center = circumcenter(i0x, i0y, i1x, i1y, i2x, i2y);
this._cx = center.x;
this._cy = center.y;
var dists = new Float64Array(n);
for (var i$5 = 0; i$5 < n; i$5++) {
dists[i$5] = dist(coords[2 * i$5], coords[2 * i$5 + 1], center.x, center.y);
}
quicksort(ids, dists, 0, n - 1);
this.hullStart = i0;
var hullSize = 3;
hullNext[i0] = hullPrev[i2] = i1;
hullNext[i1] = hullPrev[i0] = i2;
hullNext[i2] = hullPrev[i1] = i0;
hullTri[i0] = 0;
hullTri[i1] = 1;
hullTri[i2] = 2;
hullHash[this._hashKey(i0x, i0y)] = i0;
hullHash[this._hashKey(i1x, i1y)] = i1;
hullHash[this._hashKey(i2x, i2y)] = i2;
this.trianglesLen = 0;
this._addTriangle(i0, i1, i2, -1, -1, -1);
for (var k = 0, xp = (void 0), yp = (void 0); k < ids.length; k++) {
var i$6 = ids[k];
var x$2 = coords[2 * i$6];
var y$2 = coords[2 * i$6 + 1];
if (k > 0 && Math.abs(x$2 - xp) <= EPSILON && Math.abs(y$2 - yp) <= EPSILON) { continue; }
xp = x$2;
yp = y$2;
if (i$6 === i0 || i$6 === i1 || i$6 === i2) { continue; }
var start = 0;
for (var j = 0, key = this._hashKey(x$2, y$2); j < this._hashSize; j++) {
start = hullHash[(key + j) % this$1._hashSize];
if (start !== -1 && start !== hullNext[start]) { break; }
}
start = hullPrev[start];
var e = start, q = (void 0);
while (q = hullNext[e], !orient(x$2, y$2, coords[2 * e], coords[2 * e + 1], coords[2 * q], coords[2 * q + 1])) {
e = q;
if (e === start) {
e = -1;
break;
}
}
if (e === -1) { continue; }
var t = this$1._addTriangle(e, i$6, hullNext[e], -1, -1, hullTri[e]);
hullTri[i$6] = this$1._legalize(t + 2);
hullTri[e] = t;
hullSize++;
var n$1 = hullNext[e];
while (q = hullNext[n$1], orient(x$2, y$2, coords[2 * n$1], coords[2 * n$1 + 1], coords[2 * q], coords[2 * q + 1])) {
t = this$1._addTriangle(n$1, i$6, q, hullTri[i$6], -1, hullTri[n$1]);
hullTri[i$6] = this$1._legalize(t + 2);
hullNext[n$1] = n$1;
hullSize--;
n$1 = q;
}
if (e === start) {
while (q = hullPrev[e], orient(x$2, y$2, coords[2 * q], coords[2 * q + 1], coords[2 * e], coords[2 * e + 1])) {
t = this$1._addTriangle(q, i$6, e, -1, hullTri[e], hullTri[q]);
this$1._legalize(t + 2);
hullTri[q] = t;
hullNext[e] = e;
hullSize--;
e = q;
}
}
this$1.hullStart = hullPrev[i$6] = e;
hullNext[e] = hullPrev[n$1] = i$6;
hullNext[i$6] = n$1;
hullHash[this$1._hashKey(x$2, y$2)] = i$6;
hullHash[this$1._hashKey(coords[2 * e], coords[2 * e + 1])] = e;
}
this.hull = new Uint32Array(hullSize);
for (var i$7 = 0, e$1 = this.hullStart; i$7 < hullSize; i$7++) {
this$1.hull[i$7] = e$1;
e$1 = hullNext[e$1];
}
this.hullPrev = this.hullNext = this.hullTri = null;
this.triangles = triangles.subarray(0, this.trianglesLen);
this.halfedges = halfedges.subarray(0, this.trianglesLen);
};
Delaunator.from = function from (points, getX, getY) {
if ( getX === void 0 ) getX = defaultGetX;
if ( getY === void 0 ) getY = defaultGetY;
var n = points.length;
var coords = new Float64Array(n * 2);
for (var i = 0; i < n; i++) {
var p = points[i];
coords[2 * i] = getX(p);
coords[2 * i + 1] = getY(p);
}
return new Delaunator(coords);
};
Delaunator.prototype._hashKey = function _hashKey (x, y) {
return Math.floor(pseudoAngle(x - this._cx, y - this._cy) * this._hashSize) % this._hashSize;
};
Delaunator.prototype._legalize = function _legalize (a) {
var this$1 = this;
var ref = this;
var triangles = ref.triangles;
var coords = ref.coords;
var halfedges = ref.halfedges;
var b = halfedges[a];
var a0 = a - a % 3;
var b0 = b - b % 3;
var al = a0 + (a + 1) % 3;
var ar = a0 + (a + 2) % 3;
var bl = b0 + (b + 2) % 3;
if (b === -1) { return ar; }
var p0 = triangles[ar];
var pr = triangles[a];
var pl = triangles[al];
var p1 = triangles[bl];
var illegal = inCircle(
coords[2 * p0], coords[2 * p0 + 1],
coords[2 * pr], coords[2 * pr + 1],
coords[2 * pl], coords[2 * pl + 1],
coords[2 * p1], coords[2 * p1 + 1]);
if (illegal) {
triangles[a] = p1;
triangles[b] = p0;
var hbl = halfedges[bl];
if (hbl === -1) {
var e = this.hullStart;
do {
if (this$1.hullTri[e] === bl) {
this$1.hullTri[e] = a;
break;
}
e = this$1.hullNext[e];
} while (e !== this.hullStart);
}
this._link(a, hbl);
this._link(b, halfedges[ar]);
this._link(ar, bl);
var br = b0 + (b + 1) % 3;
this._legalize(a);
return this._legalize(br);
}
return ar;
};
Delaunator.prototype._link = function _link (a, b) {
this.halfedges[a] = b;
if (b !== -1) { this.halfedges[b] = a; }
};
Delaunator.prototype._addTriangle = function _addTriangle (i0, i1, i2, a, b, c) {
var t = this.trianglesLen;
this.triangles[t] = i0;
this.triangles[t + 1] = i1;
this.triangles[t + 2] = i2;
this._link(t, a);
this._link(t + 1, b);
this._link(t + 2, c);
this.trianglesLen += 3;
return t;
};
function pseudoAngle(dx, dy) {
var p = dx / (Math.abs(dx) + Math.abs(dy));
return (dy > 0 ? 3 - p : 1 + p) / 4;
}
function dist(ax, ay, bx, by) {
var dx = ax - bx;
var dy = ay - by;
return dx * dx + dy * dy;
}
function orient(px, py, qx, qy, rx, ry) {
return (qy - py) * (rx - qx) - (qx - px) * (ry - qy) < 0;
}
function inCircle(ax, ay, bx, by, cx, cy, px, py) {
var dx = ax - px;
var dy = ay - py;
var ex = bx - px;
var ey = by - py;
var fx = cx - px;
var fy = cy - py;
var ap = dx * dx + dy * dy;
var bp = ex * ex + ey * ey;
var cp = fx * fx + fy * fy;
return dx * (ey * cp - bp * fy) -
dy * (ex * cp - bp * fx) +
ap * (ex * fy - ey * fx) < 0;
}
function circumradius(ax, ay, bx, by, cx, cy) {
var dx = bx - ax;
var dy = by - ay;
var ex = cx - ax;
var ey = cy - ay;
var bl = dx * dx + dy * dy;
var cl = ex * ex + ey * ey;
var d = 0.5 / (dx * ey - dy * ex);
var x = (ey * bl - dy * cl) * d;
var y = (dx * cl - ex * bl) * d;
return x * x + y * y;
}
function circumcenter(ax, ay, bx, by, cx, cy) {
var dx = bx - ax;
var dy = by - ay;
var ex = cx - ax;
var ey = cy - ay;
var bl = dx * dx + dy * dy;
var cl = ex * ex + ey * ey;
var d = 0.5 / (dx * ey - dy * ex);
var x = ax + (ey * bl - dy * cl) * d;
var y = ay + (dx * cl - ex * bl) * d;
return {x: x, y: y};
}
function quicksort(ids, dists, left, right) {
if (right - left <= 20) {
for (var i = left + 1; i <= right; i++) {
var temp = ids[i];
var tempDist = dists[temp];
var j = i - 1;
while (j >= left && dists[ids[j]] > tempDist) { ids[j + 1] = ids[j--]; }
ids[j + 1] = temp;
}
} else {
var median = (left + right) >> 1;
var i$1 = left + 1;
var j$1 = right;
swap(ids, median, i$1);
if (dists[ids[left]] > dists[ids[right]]) { swap(ids, left, right); }
if (dists[ids[i$1]] > dists[ids[right]]) { swap(ids, i$1, right); }
if (dists[ids[left]] > dists[ids[i$1]]) { swap(ids, left, i$1); }
var temp$1 = ids[i$1];
var tempDist$1 = dists[temp$1];
while (true) {
do { i$1++; } while (dists[ids[i$1]] < tempDist$1);
do { j$1--; } while (dists[ids[j$1]] > tempDist$1);
if (j$1 < i$1) { break; }
swap(ids, i$1, j$1);
}
ids[left + 1] = ids[j$1];
ids[j$1] = temp$1;
if (right - i$1 + 1 >= j$1 - left) {
quicksort(ids, dists, i$1, right);
quicksort(ids, dists, left, j$1 - 1);
} else {
quicksort(ids, dists, left, j$1 - 1);
quicksort(ids, dists, i$1, right);
}
}
}
function swap(arr, i, j) {
var tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;
}
function defaultGetX(p) {
return p[0];
}
function defaultGetY(p) {
return p[1];
}
return Delaunator;
})));
var folder = "17_50438_37354_50534_37450/satellite/";
var levels = [0x0B132B, 0x1C2541, 0x3A506B, 0x5BC0BE, 0x6FFFE9];
var mouseDown = false;
var renderer, scene, camera, controls, loader, terrain, glsl, uniforms, root, tree;
var colors = [0xFFFFFF, 0xFF0000, 0x00FF00, 0x0000FF, 0xFFFF00, 0xFF00FF];
class Node{
constructor(level_, index_, centerX_, centerY_, width_, height_, resolution_){
this.level = level_;
this.index = index_;
this.w = width_;
this.h = height_;
this.x = centerX_;
this.y = centerY_;
this.resolution = resolution_;
this.lifetime = 128;
this.edges = this.getEdges();
}
getEdges = function(){
return [
new THREE.Vector3(this.x - this.w / 2, 0, this.y - this.h / 2),
new THREE.Vector3(this.x + this.w / 2, 0, this.y - this.h / 2),
new THREE.Vector3(this.x - this.w / 2, 0, this.y + this.h / 2),
new THREE.Vector3(this.x + this.w / 2, 0, this.y + this.h / 2)
];
}
}
class Quadtree{
constructor(root_, levels_, distance_){
var this_ = this;
this.levels = levels_;
this.distance = distance_;
this.root = root_;
this.nodes = [];
this.nodes = this.splitNode(0, this.root, false);
this.generateLevels();
this.last = [...this.nodes];
this.tiles = {};
this.debug = {};
this.points = [];
}
generateLevels = function(){
for(var i = 0; i < this.levels; i++){
var tmpNodes = [];
for(var j = 0; j < this.nodes.length; j++){
tmpNodes.push(...this.splitNode(j, this.nodes[j], true));
}
this.nodes = tmpNodes;
}
}
update = function(){
var this_ = this;
this.nodes = [];
this.nodes = this.splitNode(0, this.root, false);
this.generateLevels();
this.debug = {};
this.last = [...this.nodes];
}
splitNode = function(index_, parent_, check_){
if((parent_.level < this.levels && this.sqrtDistance(parent_) < this.distance) || !check_){
var lt = new Node(parent_.level + 1, { x: parent_.index.x * 2, y: parent_.index.y * 2 }, parent_.x - parent_.w / 4, parent_.y - parent_.h / 4, parent_.w / 2, parent_.h / 2, parent_.resolution / 2);
var rt = new Node(parent_.level + 1, { x: parent_.index.x * 2, y: parent_.index.y * 2 + 1 }, parent_.x + parent_.w / 4, parent_.y - parent_.h / 4, parent_.w / 2, parent_.h / 2, parent_.resolution / 2);
var lb = new Node(parent_.level + 1, { x: parent_.index.x * 2 + 1, y: parent_.index.y * 2 }, parent_.x - parent_.w / 4, parent_.y + parent_.h / 4, parent_.w / 2, parent_.h / 2, parent_.resolution / 2);
var rb = new Node(parent_.level + 1, { x: parent_.index.x * 2 + 1, y: parent_.index.y * 2 + 1 }, parent_.x + parent_.w / 4, parent_.y + parent_.h / 4, parent_.w / 2, parent_.h / 2, parent_.resolution / 2);
return [lt, rt, lb, rb];
}
return [parent_];
}
sqrtDistance = function(node_){
var target = new THREE.Vector2(camera.position.x, camera.position.z).lerp(new THREE.Vector2(controls.target.x, controls.target.z), 1.0);
var x1 = node_.x - node_.w / 2.0;
var y1 = node_.y - node_.h / 2.0;
var x2 = node_.x + node_.w / 2.0;
var y2 = node_.y + node_.h / 2.0;
var rx = (x1 + x2) / 2.0;
var ry = (y1 + y2) / 2.0;
var rwidth = node_.w;
var rheight = node_.h;
var dx = Math.max(Math.abs(target.x - rx) - rwidth / 2, 0);
var dy = Math.max(Math.abs(target.y - ry) - rheight / 2, 0);
return Math.sqrt(dx * dx + dy * dy);
}
}
renderer = new THREE.WebGLRenderer({
antialias: true
});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setClearColor(0x000000);
document.body.appendChild(renderer.domElement);
scene = new THREE.Scene();
loader = new THREE.TextureLoader();
loader.crossOrigin = "";
camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 51200);
camera.position.set(-2048, 2048, -2048);
controls = new THREE.OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.05;
controls.screenSpacePanning = false;
controls.minDistance = 8;
controls.maxDistance = 5120;
controls.maxPolarAngle = Math.PI / 2;
camera.position.set(208.48355078304965, 45.28894677815297, 310.34089790619583);
controls.target.set(233.437242880138, -1.1266992511037067e-14, 279.779814968453);
root = new Node(0, {x: 0, y: 0}, 0, 0, 2048, 2048, 64);
partition = new Quadtree(root, 5, 2048.0 / 16.0);
var points = [];
partition.nodes.forEach(function(node_){
points.push(...node_.edges);
});
var geometry = new THREE.BufferGeometry().setFromPoints(points);
var indexDelaunay = Delaunator.from(points.map(v => { return [v.x, v.z]; }) );
var meshIndex = [];
for (let i = 0; i < indexDelaunay.triangles.length; i++){ meshIndex.push(indexDelaunay.triangles[i]); }
geometry.setIndex(meshIndex);
geometry.computeVertexNormals();
var plane = new THREE.Mesh(geometry, new THREE.MeshNormalMaterial({ wireframe: true }));
scene.add(plane);
animate();
document.addEventListener("mousedown", function(){ mouseDown = true; }, false);
document.addEventListener("mouseup", function(){ mouseDown = false; }, false);
document.addEventListener("mousemove", onMouseUpdate, false);
renderer.domElement.addEventListener("wheel", onMouseUpdate, false);
function animate(){
controls.update();
renderer.render(scene, camera);
requestAnimationFrame(animate);
}
function onMouseUpdate(e_){
partition.update(new THREE.Vector2(camera.position.x, camera.position.y));
var points = [];
partition.nodes.forEach(function(node_){
points.push(...node_.edges);
});
var geometry = new THREE.BufferGeometry().setFromPoints(points);
var indexDelaunay = Delaunator.from(points.map(v => { return [v.x, v.z]; }) );
var meshIndex = [];
for (let i = 0; i < indexDelaunay.triangles.length; i++){ meshIndex.push(indexDelaunay.triangles[i]); }
geometry.setIndex(meshIndex);
geometry.computeVertexNormals();
plane.geometry = geometry;
}body { margin: 0; }<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>GLSL Intersection</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://unpkg.com/three@0.116.0/build/three.min.js"></script>
<script src="https://unpkg.com/three@0.116.0/examples/js/controls/OrbitControls.js"></script>
</head>
<body>
</body>
</html>