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This commit is contained in:
Vladimir Agafonkin
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31
debug.js
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31
debug.js
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var flatbush = require('./');
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var N = 1000000;
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var hilbertOrder = 16;
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console.time('gen data');
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var coords = [];
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var spaceSize = 100;
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var boxSize = 1;
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for (var i = 0; i < N; i++) {
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var x = Math.random() * (spaceSize - boxSize);
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var y = Math.random() * (spaceSize - boxSize);
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var x2 = x + Math.random() * boxSize;
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var y2 = y + Math.random() * boxSize;
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coords.push(x, y, x2, y2);
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}
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console.timeEnd('gen data');
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console.time('flatbush');
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var index = flatbush(N);
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for (var i = 0; i < coords.length; i += 4) {
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index.add(
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coords[i],
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coords[i + 1],
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coords[i + 2],
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coords[i + 3]);
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}
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index.finish();
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// console.log(index.data);
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console.timeEnd('flatbush');
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175
index.js
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175
index.js
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'use strict';
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module.exports = flatbush;
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function flatbush(numItems, nodeSize, hilbertOrder) {
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return new Flatbush(numItems, nodeSize, hilbertOrder);
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}
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function Flatbush(numItems, nodeSize, hilbertOrder) {
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this._numItems = numItems;
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this._nodeSize = nodeSize || 16;
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this._hilbertOrder = hilbertOrder || 16;
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// calculate the total number of nodes in the R-tree to allocate space for
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var n = numItems;
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var numNodes = n;
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do {
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n = Math.ceil(n / this._nodeSize);
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numNodes += n;
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} while (n !== 1);
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this.data = new Float64Array(numNodes * 5);
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this._hilbertValues = new Uint32Array(numItems);
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this._numAdded = 0;
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this._pos = 0;
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this._minX = Infinity;
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this._minY = Infinity;
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this._maxX = -Infinity;
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this._maxY = -Infinity;
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}
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Flatbush.prototype = {
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add: function (minX, minY, maxX, maxY) {
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this.data[this._pos++] = this._numAdded++;
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this.data[this._pos++] = minX;
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this.data[this._pos++] = minY;
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this.data[this._pos++] = maxX;
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this.data[this._pos++] = maxY;
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if (minX < this._minX) this._minX = minX;
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if (minY < this._minY) this._minY = minY;
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if (maxX > this._maxX) this._maxX = maxX;
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if (maxY > this._maxY) this._maxY = maxY;
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},
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finish: function () {
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if (this._numAdded !== this._numItems) {
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throw new Error('The number of items added does not match the number in the constructor.')
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}
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var width = this._maxX - this._minX;
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var height = this._maxY - this._minY;
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var hilbertMax = Math.pow(2, this._hilbertOrder) - 1;
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for (var i = 0; i < this._numItems; i++) {
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var x = Math.floor(hilbertMax * this.data[5 * i + 1] / width);
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var y = Math.floor(hilbertMax * this.data[5 * i + 2] / height);
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this._hilbertValues[i] = hilbert(this._hilbertOrder, x, y);
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}
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// sort boxes by hilbert value
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sort(this._hilbertValues, this.data, 0, this._numItems - 1);
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// TODO generate remaining nodes
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}
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};
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function sort(values, boxes, left, right) {
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if (left >= right) return;
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var i = left + 1;
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var j = right;
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swap(values, boxes, (left + right) >> 1, i);
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if (values[left] > values[right]) swap(values, boxes, left, right);
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if (values[i] > values[right]) swap(values, boxes, i, right);
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if (values[left] > values[i]) swap(values, boxes, left, i);
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var temp = values[i];
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while (true) {
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do i++; while (values[i] < temp);
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do j--; while (values[j] > temp);
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if (j < i) break;
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swap(values, boxes, i, j);
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}
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values[left + 1] = values[j];
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values[j] = temp;
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if (right - i + 1 >= j - left) {
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sort(values, boxes, i, right);
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sort(values, boxes, left, j - 1);
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} else {
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sort(values, boxes, left, j - 1);
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sort(values, boxes, i, right);
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}
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}
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function swap(values, boxes, i, j) {
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var temp = values[i];
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values[i] = values[j];
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values[j] = temp;
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var k = 5 * i;
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var m = 5 * j;
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var a = boxes[k];
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var b = boxes[k + 1];
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var c = boxes[k + 2];
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var d = boxes[k + 3];
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var e = boxes[k + 4];
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boxes[k] = boxes[m];
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boxes[k + 1] = boxes[m + 1];
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boxes[k + 2] = boxes[m + 2];
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boxes[k + 3] = boxes[m + 3];
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boxes[k + 4] = boxes[m + 4];
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boxes[m] = a;
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boxes[m + 1] = b;
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boxes[m + 2] = c;
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boxes[m + 3] = d;
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boxes[m + 4] = e;
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}
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// Fast Hilbert curve algorithm by http://threadlocalmutex.com/
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// Ported from C++ https://github.com/rawrunprotected/hilbert_curves (public domain)
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function hilbert(n, x, y) {
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x = x << (16 - n);
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y = y << (16 - n);
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var a = x ^ y;
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var b = 0xFFFF ^ a;
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var c = 0xFFFF ^ (x | y);
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var d = x & (y ^ 0xFFFF);
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var A = a | (b >> 1);
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var B = (a >> 1) ^ a;
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var C = ((c >> 1) ^ (b & (d >> 1))) ^ c;
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var D = ((a & (c >> 1)) ^ (d >> 1)) ^ d;
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a = A; b = B; c = C; d = D;
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A = ((a & (a >> 2)) ^ (b & (b >> 2)));
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B = ((a & (b >> 2)) ^ (b & ((a ^ b) >> 2)));
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C ^= ((a & (c >> 2)) ^ (b & (d >> 2)));
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D ^= ((b & (c >> 2)) ^ ((a ^ b) & (d >> 2)));
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a = A; b = B; c = C; d = D;
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A = ((a & (a >> 4)) ^ (b & (b >> 4)));
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B = ((a & (b >> 4)) ^ (b & ((a ^ b) >> 4)));
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C ^= ((a & (c >> 4)) ^ (b & (d >> 4)));
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D ^= ((b & (c >> 4)) ^ ((a ^ b) & (d >> 4)));
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a = A; b = B; c = C; d = D;
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C ^= ((a & (c >> 8)) ^ (b & (d >> 8)));
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D ^= ((b & (c >> 8)) ^ ((a ^ b) & (d >> 8)));
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a = C ^ (C >> 1);
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b = D ^ (D >> 1);
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var i0 = x ^ y;
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var i1 = b | (0xFFFF ^ (i0 | a));
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i0 = (i0 | (i0 << 8)) & 0x00FF00FF;
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i0 = (i0 | (i0 << 4)) & 0x0F0F0F0F;
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i0 = (i0 | (i0 << 2)) & 0x33333333;
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i0 = (i0 | (i0 << 1)) & 0x55555555;
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i1 = (i1 | (i1 << 8)) & 0x00FF00FF;
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i1 = (i1 | (i1 << 4)) & 0x0F0F0F0F;
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i1 = (i1 | (i1 << 2)) & 0x33333333;
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i1 = (i1 | (i1 << 1)) & 0x55555555;
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return (((i1 << 1) | i0) >> (32 - 2 * n)) >>> 0;
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}
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