cesium/Source/ThirdParty/kdbush.js

CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.

/* This file is automatically rebuilt by the Cesium build process. */
function sortKD(ids, coords, nodeSize, left, right, depth) {
    if (right - left <= nodeSize) return;

    const m = (left + right) >> 1;

    select(ids, coords, m, left, right, depth % 2);

    sortKD(ids, coords, nodeSize, left, m - 1, depth + 1);
    sortKD(ids, coords, nodeSize, m + 1, right, depth + 1);
}

function select(ids, coords, k, left, right, inc) {

    while (right > left) {
        if (right - left > 600) {
            const n = right - left + 1;
            const m = k - left + 1;
            const z = Math.log(n);
            const s = 0.5 * Math.exp(2 * z / 3);
            const sd = 0.5 * Math.sqrt(z * s * (n - s) / n) * (m - n / 2 < 0 ? -1 : 1);
            const newLeft = Math.max(left, Math.floor(k - m * s / n + sd));
            const newRight = Math.min(right, Math.floor(k + (n - m) * s / n + sd));
            select(ids, coords, k, newLeft, newRight, inc);
        }

        const t = coords[2 * k + inc];
        let i = left;
        let j = right;

        swapItem(ids, coords, left, k);
        if (coords[2 * right + inc] > t) swapItem(ids, coords, left, right);

        while (i < j) {
            swapItem(ids, coords, i, j);
            i++;
            j--;
            while (coords[2 * i + inc] < t) i++;
            while (coords[2 * j + inc] > t) j--;
        }

        if (coords[2 * left + inc] === t) swapItem(ids, coords, left, j);
        else {
            j++;
            swapItem(ids, coords, j, right);
        }

        if (j <= k) left = j + 1;
        if (k <= j) right = j - 1;
    }
}

function swapItem(ids, coords, i, j) {
    swap(ids, i, j);
    swap(coords, 2 * i, 2 * j);
    swap(coords, 2 * i + 1, 2 * j + 1);
}

function swap(arr, i, j) {
    const tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
}

function range(ids, coords, minX, minY, maxX, maxY, nodeSize) {
    const stack = [0, ids.length - 1, 0];
    const result = [];
    let x, y;

    while (stack.length) {
        const axis = stack.pop();
        const right = stack.pop();
        const left = stack.pop();

        if (right - left <= nodeSize) {
            for (let i = left; i <= right; i++) {
                x = coords[2 * i];
                y = coords[2 * i + 1];
                if (x >= minX && x <= maxX && y >= minY && y <= maxY) result.push(ids[i]);
            }
            continue;
        }

        const m = Math.floor((left + right) / 2);

        x = coords[2 * m];
        y = coords[2 * m + 1];

        if (x >= minX && x <= maxX && y >= minY && y <= maxY) result.push(ids[m]);

        const nextAxis = (axis + 1) % 2;

        if (axis === 0 ? minX <= x : minY <= y) {
            stack.push(left);
            stack.push(m - 1);
            stack.push(nextAxis);
        }
        if (axis === 0 ? maxX >= x : maxY >= y) {
            stack.push(m + 1);
            stack.push(right);
            stack.push(nextAxis);
        }
    }

    return result;
}

function within(ids, coords, qx, qy, r, nodeSize) {
    const stack = [0, ids.length - 1, 0];
    const result = [];
    const r2 = r * r;

    while (stack.length) {
        const axis = stack.pop();
        const right = stack.pop();
        const left = stack.pop();

        if (right - left <= nodeSize) {
            for (let i = left; i <= right; i++) {
                if (sqDist(coords[2 * i], coords[2 * i + 1], qx, qy) <= r2) result.push(ids[i]);
            }
            continue;
        }

        const m = Math.floor((left + right) / 2);

        const x = coords[2 * m];
        const y = coords[2 * m + 1];

        if (sqDist(x, y, qx, qy) <= r2) result.push(ids[m]);

        const nextAxis = (axis + 1) % 2;

        if (axis === 0 ? qx - r <= x : qy - r <= y) {
            stack.push(left);
            stack.push(m - 1);
            stack.push(nextAxis);
        }
        if (axis === 0 ? qx + r >= x : qy + r >= y) {
            stack.push(m + 1);
            stack.push(right);
            stack.push(nextAxis);
        }
    }

    return result;
}

function sqDist(ax, ay, bx, by) {
    const dx = ax - bx;
    const dy = ay - by;
    return dx * dx + dy * dy;
}

const defaultGetX = p => p[0];
const defaultGetY = p => p[1];

class KDBush {
    constructor(points, getX = defaultGetX, getY = defaultGetY, nodeSize = 64, ArrayType = Float64Array) {
        this.nodeSize = nodeSize;
        this.points = points;

        const IndexArrayType = points.length < 65536 ? Uint16Array : Uint32Array;

        const ids = this.ids = new IndexArrayType(points.length);
        const coords = this.coords = new ArrayType(points.length * 2);

        for (let i = 0; i < points.length; i++) {
            ids[i] = i;
            coords[2 * i] = getX(points[i]);
            coords[2 * i + 1] = getY(points[i]);
        }

        sortKD(ids, coords, nodeSize, 0, ids.length - 1, 0);
    }

    range(minX, minY, maxX, maxY) {
        return range(this.ids, this.coords, minX, minY, maxX, maxY, this.nodeSize);
    }

    within(x, y, r) {
        return within(this.ids, this.coords, x, y, r, this.nodeSize);
    }
}

export { KDBush as default };