@vuemap/amap-xyz-layer/dist/index.mjs.map

高德地图 JSAPI v2.0 自定义瓦片图层，支持瓦片纠偏，支持海拔

{"version":3,"file":"index.mjs","sources":["../../node_modules/.pnpm/earcut@2.2.4/node_modules/earcut/src/earcut.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/lib/common.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/classes/base/math-array.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/lib/validators.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/common.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/vec2.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/lib/gl-matrix-extras.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/vec3.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/classes/base/matrix.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/mat3.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/classes/matrix3.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/mat4.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/vec4.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/classes/matrix4.js","../../node_modules/.pnpm/gl-matrix@3.4.3/node_modules/gl-matrix/cjs/quat.js","../../node_modules/.pnpm/@math.gl+core@3.6.3/node_modules/@math.gl/core/dist/esm/classes/euler.js","../../src/packages/support/coordConver.ts","../../src/packages/support/node-baidusdk.js","../../src/packages/support/transform-class-baidu.ts","../../src/packages/support/Util.js","../../src/packages/CustomXyzLayer/index.ts"],"sourcesContent":["'use strict';\n\nmodule.exports = earcut;\nmodule.exports.default = earcut;\n\nfunction earcut(data, holeIndices, dim) {\n\n    dim = dim || 2;\n\n    var hasHoles = holeIndices && holeIndices.length,\n        outerLen = hasHoles ? holeIndices[0] * dim : data.length,\n        outerNode = linkedList(data, 0, outerLen, dim, true),\n        triangles = [];\n\n    if (!outerNode || outerNode.next === outerNode.prev) return triangles;\n\n    var minX, minY, maxX, maxY, x, y, invSize;\n\n    if (hasHoles) outerNode = eliminateHoles(data, holeIndices, outerNode, dim);\n\n    // if the shape is not too simple, we'll use z-order curve hash later; calculate polygon bbox\n    if (data.length > 80 * dim) {\n        minX = maxX = data[0];\n        minY = maxY = data[1];\n\n        for (var i = dim; i < outerLen; i += dim) {\n            x = data[i];\n            y = data[i + 1];\n            if (x < minX) minX = x;\n            if (y < minY) minY = y;\n            if (x > maxX) maxX = x;\n            if (y > maxY) maxY = y;\n        }\n\n        // minX, minY and invSize are later used to transform coords into integers for z-order calculation\n        invSize = Math.max(maxX - minX, maxY - minY);\n        invSize = invSize !== 0 ? 32767 / invSize : 0;\n    }\n\n    earcutLinked(outerNode, triangles, dim, minX, minY, invSize, 0);\n\n    return triangles;\n}\n\n// create a circular doubly linked list from polygon points in the specified winding order\nfunction linkedList(data, start, end, dim, clockwise) {\n    var i, last;\n\n    if (clockwise === (signedArea(data, start, end, dim) > 0)) {\n        for (i = start; i < end; i += dim) last = insertNode(i, data[i], data[i + 1], last);\n    } else {\n        for (i = end - dim; i >= start; i -= dim) last = insertNode(i, data[i], data[i + 1], last);\n    }\n\n    if (last && equals(last, last.next)) {\n        removeNode(last);\n        last = last.next;\n    }\n\n    return last;\n}\n\n// eliminate colinear or duplicate points\nfunction filterPoints(start, end) {\n    if (!start) return start;\n    if (!end) end = start;\n\n    var p = start,\n        again;\n    do {\n        again = false;\n\n        if (!p.steiner && (equals(p, p.next) || area(p.prev, p, p.next) === 0)) {\n            removeNode(p);\n            p = end = p.prev;\n            if (p === p.next) break;\n            again = true;\n\n        } else {\n            p = p.next;\n        }\n    } while (again || p !== end);\n\n    return end;\n}\n\n// main ear slicing loop which triangulates a polygon (given as a linked list)\nfunction earcutLinked(ear, triangles, dim, minX, minY, invSize, pass) {\n    if (!ear) return;\n\n    // interlink polygon nodes in z-order\n    if (!pass && invSize) indexCurve(ear, minX, minY, invSize);\n\n    var stop = ear,\n        prev, next;\n\n    // iterate through ears, slicing them one by one\n    while (ear.prev !== ear.next) {\n        prev = ear.prev;\n        next = ear.next;\n\n        if (invSize ? isEarHashed(ear, minX, minY, invSize) : isEar(ear)) {\n            // cut off the triangle\n            triangles.push(prev.i / dim | 0);\n            triangles.push(ear.i / dim | 0);\n            triangles.push(next.i / dim | 0);\n\n            removeNode(ear);\n\n            // skipping the next vertex leads to less sliver triangles\n            ear = next.next;\n            stop = next.next;\n\n            continue;\n        }\n\n        ear = next;\n\n        // if we looped through the whole remaining polygon and can't find any more ears\n        if (ear === stop) {\n            // try filtering points and slicing again\n            if (!pass) {\n                earcutLinked(filterPoints(ear), triangles, dim, minX, minY, invSize, 1);\n\n            // if this didn't work, try curing all small self-intersections locally\n            } else if (pass === 1) {\n                ear = cureLocalIntersections(filterPoints(ear), triangles, dim);\n                earcutLinked(ear, triangles, dim, minX, minY, invSize, 2);\n\n            // as a last resort, try splitting the remaining polygon into two\n            } else if (pass === 2) {\n                splitEarcut(ear, triangles, dim, minX, minY, invSize);\n            }\n\n            break;\n        }\n    }\n}\n\n// check whether a polygon node forms a valid ear with adjacent nodes\nfunction isEar(ear) {\n    var a = ear.prev,\n        b = ear,\n        c = ear.next;\n\n    if (area(a, b, c) >= 0) return false; // reflex, can't be an ear\n\n    // now make sure we don't have other points inside the potential ear\n    var ax = a.x, bx = b.x, cx = c.x, ay = a.y, by = b.y, cy = c.y;\n\n    // triangle bbox; min & max are calculated like this for speed\n    var x0 = ax < bx ? (ax < cx ? ax : cx) : (bx < cx ? bx : cx),\n        y0 = ay < by ? (ay < cy ? ay : cy) : (by < cy ? by : cy),\n        x1 = ax > bx ? (ax > cx ? ax : cx) : (bx > cx ? bx : cx),\n        y1 = ay > by ? (ay > cy ? ay : cy) : (by > cy ? by : cy);\n\n    var p = c.next;\n    while (p !== a) {\n        if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 &&\n            pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) &&\n            area(p.prev, p, p.next) >= 0) return false;\n        p = p.next;\n    }\n\n    return true;\n}\n\nfunction isEarHashed(ear, minX, minY, invSize) {\n    var a = ear.prev,\n        b = ear,\n        c = ear.next;\n\n    if (area(a, b, c) >= 0) return false; // reflex, can't be an ear\n\n    var ax = a.x, bx = b.x, cx = c.x, ay = a.y, by = b.y, cy = c.y;\n\n    // triangle bbox; min & max are calculated like this for speed\n    var x0 = ax < bx ? (ax < cx ? ax : cx) : (bx < cx ? bx : cx),\n        y0 = ay < by ? (ay < cy ? ay : cy) : (by < cy ? by : cy),\n        x1 = ax > bx ? (ax > cx ? ax : cx) : (bx > cx ? bx : cx),\n        y1 = ay > by ? (ay > cy ? ay : cy) : (by > cy ? by : cy);\n\n    // z-order range for the current triangle bbox;\n    var minZ = zOrder(x0, y0, minX, minY, invSize),\n        maxZ = zOrder(x1, y1, minX, minY, invSize);\n\n    var p = ear.prevZ,\n        n = ear.nextZ;\n\n    // look for points inside the triangle in both directions\n    while (p && p.z >= minZ && n && n.z <= maxZ) {\n        if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 && p !== a && p !== c &&\n            pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) && area(p.prev, p, p.next) >= 0) return false;\n        p = p.prevZ;\n\n        if (n.x >= x0 && n.x <= x1 && n.y >= y0 && n.y <= y1 && n !== a && n !== c &&\n            pointInTriangle(ax, ay, bx, by, cx, cy, n.x, n.y) && area(n.prev, n, n.next) >= 0) return false;\n        n = n.nextZ;\n    }\n\n    // look for remaining points in decreasing z-order\n    while (p && p.z >= minZ) {\n        if (p.x >= x0 && p.x <= x1 && p.y >= y0 && p.y <= y1 && p !== a && p !== c &&\n            pointInTriangle(ax, ay, bx, by, cx, cy, p.x, p.y) && area(p.prev, p, p.next) >= 0) return false;\n        p = p.prevZ;\n    }\n\n    // look for remaining points in increasing z-order\n    while (n && n.z <= maxZ) {\n        if (n.x >= x0 && n.x <= x1 && n.y >= y0 && n.y <= y1 && n !== a && n !== c &&\n            pointInTriangle(ax, ay, bx, by, cx, cy, n.x, n.y) && area(n.prev, n, n.next) >= 0) return false;\n        n = n.nextZ;\n    }\n\n    return true;\n}\n\n// go through all polygon nodes and cure small local self-intersections\nfunction cureLocalIntersections(start, triangles, dim) {\n    var p = start;\n    do {\n        var a = p.prev,\n            b = p.next.next;\n\n        if (!equals(a, b) && intersects(a, p, p.next, b) && locallyInside(a, b) && locallyInside(b, a)) {\n\n            triangles.push(a.i / dim | 0);\n            triangles.push(p.i / dim | 0);\n            triangles.push(b.i / dim | 0);\n\n            // remove two nodes involved\n            removeNode(p);\n            removeNode(p.next);\n\n            p = start = b;\n        }\n        p = p.next;\n    } while (p !== start);\n\n    return filterPoints(p);\n}\n\n// try splitting polygon into two and triangulate them independently\nfunction splitEarcut(start, triangles, dim, minX, minY, invSize) {\n    // look for a valid diagonal that divides the polygon into two\n    var a = start;\n    do {\n        var b = a.next.next;\n        while (b !== a.prev) {\n            if (a.i !== b.i && isValidDiagonal(a, b)) {\n                // split the polygon in two by the diagonal\n                var c = splitPolygon(a, b);\n\n                // filter colinear points around the cuts\n                a = filterPoints(a, a.next);\n                c = filterPoints(c, c.next);\n\n                // run earcut on each half\n                earcutLinked(a, triangles, dim, minX, minY, invSize, 0);\n                earcutLinked(c, triangles, dim, minX, minY, invSize, 0);\n                return;\n            }\n            b = b.next;\n        }\n        a = a.next;\n    } while (a !== start);\n}\n\n// link every hole into the outer loop, producing a single-ring polygon without holes\nfunction eliminateHoles(data, holeIndices, outerNode, dim) {\n    var queue = [],\n        i, len, start, end, list;\n\n    for (i = 0, len = holeIndices.length; i < len; i++) {\n        start = holeIndices[i] * dim;\n        end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;\n        list = linkedList(data, start, end, dim, false);\n        if (list === list.next) list.steiner = true;\n        queue.push(getLeftmost(list));\n    }\n\n    queue.sort(compareX);\n\n    // process holes from left to right\n    for (i = 0; i < queue.length; i++) {\n        outerNode = eliminateHole(queue[i], outerNode);\n    }\n\n    return outerNode;\n}\n\nfunction compareX(a, b) {\n    return a.x - b.x;\n}\n\n// find a bridge between vertices that connects hole with an outer ring and and link it\nfunction eliminateHole(hole, outerNode) {\n    var bridge = findHoleBridge(hole, outerNode);\n    if (!bridge) {\n        return outerNode;\n    }\n\n    var bridgeReverse = splitPolygon(bridge, hole);\n\n    // filter collinear points around the cuts\n    filterPoints(bridgeReverse, bridgeReverse.next);\n    return filterPoints(bridge, bridge.next);\n}\n\n// David Eberly's algorithm for finding a bridge between hole and outer polygon\nfunction findHoleBridge(hole, outerNode) {\n    var p = outerNode,\n        hx = hole.x,\n        hy = hole.y,\n        qx = -Infinity,\n        m;\n\n    // find a segment intersected by a ray from the hole's leftmost point to the left;\n    // segment's endpoint with lesser x will be potential connection point\n    do {\n        if (hy <= p.y && hy >= p.next.y && p.next.y !== p.y) {\n            var x = p.x + (hy - p.y) * (p.next.x - p.x) / (p.next.y - p.y);\n            if (x <= hx && x > qx) {\n                qx = x;\n                m = p.x < p.next.x ? p : p.next;\n                if (x === hx) return m; // hole touches outer segment; pick leftmost endpoint\n            }\n        }\n        p = p.next;\n    } while (p !== outerNode);\n\n    if (!m) return null;\n\n    // look for points inside the triangle of hole point, segment intersection and endpoint;\n    // if there are no points found, we have a valid connection;\n    // otherwise choose the point of the minimum angle with the ray as connection point\n\n    var stop = m,\n        mx = m.x,\n        my = m.y,\n        tanMin = Infinity,\n        tan;\n\n    p = m;\n\n    do {\n        if (hx >= p.x && p.x >= mx && hx !== p.x &&\n                pointInTriangle(hy < my ? hx : qx, hy, mx, my, hy < my ? qx : hx, hy, p.x, p.y)) {\n\n            tan = Math.abs(hy - p.y) / (hx - p.x); // tangential\n\n            if (locallyInside(p, hole) &&\n                (tan < tanMin || (tan === tanMin && (p.x > m.x || (p.x === m.x && sectorContainsSector(m, p)))))) {\n                m = p;\n                tanMin = tan;\n            }\n        }\n\n        p = p.next;\n    } while (p !== stop);\n\n    return m;\n}\n\n// whether sector in vertex m contains sector in vertex p in the same coordinates\nfunction sectorContainsSector(m, p) {\n    return area(m.prev, m, p.prev) < 0 && area(p.next, m, m.next) < 0;\n}\n\n// interlink polygon nodes in z-order\nfunction indexCurve(start, minX, minY, invSize) {\n    var p = start;\n    do {\n        if (p.z === 0) p.z = zOrder(p.x, p.y, minX, minY, invSize);\n        p.prevZ = p.prev;\n        p.nextZ = p.next;\n        p = p.next;\n    } while (p !== start);\n\n    p.prevZ.nextZ = null;\n    p.prevZ = null;\n\n    sortLinked(p);\n}\n\n// Simon Tatham's linked list merge sort algorithm\n// http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html\nfunction sortLinked(list) {\n    var i, p, q, e, tail, numMerges, pSize, qSize,\n        inSize = 1;\n\n    do {\n        p = list;\n        list = null;\n        tail = null;\n        numMerges = 0;\n\n        while (p) {\n            numMerges++;\n            q = p;\n            pSize = 0;\n            for (i = 0; i < inSize; i++) {\n                pSize++;\n                q = q.nextZ;\n                if (!q) break;\n            }\n            qSize = inSize;\n\n            while (pSize > 0 || (qSize > 0 && q)) {\n\n                if (pSize !== 0 && (qSize === 0 || !q || p.z <= q.z)) {\n                    e = p;\n                    p = p.nextZ;\n                    pSize--;\n                } else {\n                    e = q;\n                    q = q.nextZ;\n                    qSize--;\n                }\n\n                if (tail) tail.nextZ = e;\n                else list = e;\n\n                e.prevZ = tail;\n                tail = e;\n            }\n\n            p = q;\n        }\n\n        tail.nextZ = null;\n        inSize *= 2;\n\n    } while (numMerges > 1);\n\n    return list;\n}\n\n// z-order of a point given coords and inverse of the longer side of data bbox\nfunction zOrder(x, y, minX, minY, invSize) {\n    // coords are transformed into non-negative 15-bit integer range\n    x = (x - minX) * invSize | 0;\n    y = (y - minY) * invSize | 0;\n\n    x = (x | (x << 8)) & 0x00FF00FF;\n    x = (x | (x << 4)) & 0x0F0F0F0F;\n    x = (x | (x << 2)) & 0x33333333;\n    x = (x | (x << 1)) & 0x55555555;\n\n    y = (y | (y << 8)) & 0x00FF00FF;\n    y = (y | (y << 4)) & 0x0F0F0F0F;\n    y = (y | (y << 2)) & 0x33333333;\n    y = (y | (y << 1)) & 0x55555555;\n\n    return x | (y << 1);\n}\n\n// find the leftmost node of a polygon ring\nfunction getLeftmost(start) {\n    var p = start,\n        leftmost = start;\n    do {\n        if (p.x < leftmost.x || (p.x === leftmost.x && p.y < leftmost.y)) leftmost = p;\n        p = p.next;\n    } while (p !== start);\n\n    return leftmost;\n}\n\n// check if a point lies within a convex triangle\nfunction pointInTriangle(ax, ay, bx, by, cx, cy, px, py) {\n    return (cx - px) * (ay - py) >= (ax - px) * (cy - py) &&\n           (ax - px) * (by - py) >= (bx - px) * (ay - py) &&\n           (bx - px) * (cy - py) >= (cx - px) * (by - py);\n}\n\n// check if a diagonal between two polygon nodes is valid (lies in polygon interior)\nfunction isValidDiagonal(a, b) {\n    return a.next.i !== b.i && a.prev.i !== b.i && !intersectsPolygon(a, b) && // dones't intersect other edges\n           (locallyInside(a, b) && locallyInside(b, a) && middleInside(a, b) && // locally visible\n            (area(a.prev, a, b.prev) || area(a, b.prev, b)) || // does not create opposite-facing sectors\n            equals(a, b) && area(a.prev, a, a.next) > 0 && area(b.prev, b, b.next) > 0); // special zero-length case\n}\n\n// signed area of a triangle\nfunction area(p, q, r) {\n    return (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);\n}\n\n// check if two points are equal\nfunction equals(p1, p2) {\n    return p1.x === p2.x && p1.y === p2.y;\n}\n\n// check if two segments intersect\nfunction intersects(p1, q1, p2, q2) {\n    var o1 = sign(area(p1, q1, p2));\n    var o2 = sign(area(p1, q1, q2));\n    var o3 = sign(area(p2, q2, p1));\n    var o4 = sign(area(p2, q2, q1));\n\n    if (o1 !== o2 && o3 !== o4) return true; // general case\n\n    if (o1 === 0 && onSegment(p1, p2, q1)) return true; // p1, q1 and p2 are collinear and p2 lies on p1q1\n    if (o2 === 0 && onSegment(p1, q2, q1)) return true; // p1, q1 and q2 are collinear and q2 lies on p1q1\n    if (o3 === 0 && onSegment(p2, p1, q2)) return true; // p2, q2 and p1 are collinear and p1 lies on p2q2\n    if (o4 === 0 && onSegment(p2, q1, q2)) return true; // p2, q2 and q1 are collinear and q1 lies on p2q2\n\n    return false;\n}\n\n// for collinear points p, q, r, check if point q lies on segment pr\nfunction onSegment(p, q, r) {\n    return q.x <= Math.max(p.x, r.x) && q.x >= Math.min(p.x, r.x) && q.y <= Math.max(p.y, r.y) && q.y >= Math.min(p.y, r.y);\n}\n\nfunction sign(num) {\n    return num > 0 ? 1 : num < 0 ? -1 : 0;\n}\n\n// check if a polygon diagonal intersects any polygon segments\nfunction intersectsPolygon(a, b) {\n    var p = a;\n    do {\n        if (p.i !== a.i && p.next.i !== a.i && p.i !== b.i && p.next.i !== b.i &&\n                intersects(p, p.next, a, b)) return true;\n        p = p.next;\n    } while (p !== a);\n\n    return false;\n}\n\n// check if a polygon diagonal is locally inside the polygon\nfunction locallyInside(a, b) {\n    return area(a.prev, a, a.next) < 0 ?\n        area(a, b, a.next) >= 0 && area(a, a.prev, b) >= 0 :\n        area(a, b, a.prev) < 0 || area(a, a.next, b) < 0;\n}\n\n// check if the middle point of a polygon diagonal is inside the polygon\nfunction middleInside(a, b) {\n    var p = a,\n        inside = false,\n        px = (a.x + b.x) / 2,\n        py = (a.y + b.y) / 2;\n    do {\n        if (((p.y > py) !== (p.next.y > py)) && p.next.y !== p.y &&\n                (px < (p.next.x - p.x) * (py - p.y) / (p.next.y - p.y) + p.x))\n            inside = !inside;\n        p = p.next;\n    } while (p !== a);\n\n    return inside;\n}\n\n// link two polygon vertices with a bridge; if the vertices belong to the same ring, it splits polygon into two;\n// if one belongs to the outer ring and another to a hole, it merges it into a single ring\nfunction splitPolygon(a, b) {\n    var a2 = new Node(a.i, a.x, a.y),\n        b2 = new Node(b.i, b.x, b.y),\n        an = a.next,\n        bp = b.prev;\n\n    a.next = b;\n    b.prev = a;\n\n    a2.next = an;\n    an.prev = a2;\n\n    b2.next = a2;\n    a2.prev = b2;\n\n    bp.next = b2;\n    b2.prev = bp;\n\n    return b2;\n}\n\n// create a node and optionally link it with previous one (in a circular doubly linked list)\nfunction insertNode(i, x, y, last) {\n    var p = new Node(i, x, y);\n\n    if (!last) {\n        p.prev = p;\n        p.next = p;\n\n    } else {\n        p.next = last.next;\n        p.prev = last;\n        last.next.prev = p;\n        last.next = p;\n    }\n    return p;\n}\n\nfunction removeNode(p) {\n    p.next.prev = p.prev;\n    p.prev.next = p.next;\n\n    if (p.prevZ) p.prevZ.nextZ = p.nextZ;\n    if (p.nextZ) p.nextZ.prevZ = p.prevZ;\n}\n\nfunction Node(i, x, y) {\n    // vertex index in coordinates array\n    this.i = i;\n\n    // vertex coordinates\n    this.x = x;\n    this.y = y;\n\n    // previous and next vertex nodes in a polygon ring\n    this.prev = null;\n    this.next = null;\n\n    // z-order curve value\n    this.z = 0;\n\n    // previous and next nodes in z-order\n    this.prevZ = null;\n    this.nextZ = null;\n\n    // indicates whether this is a steiner point\n    this.steiner = false;\n}\n\n// return a percentage difference between the polygon area and its triangulation area;\n// used to verify correctness of triangulation\nearcut.deviation = function (data, holeIndices, dim, triangles) {\n    var hasHoles = holeIndices && holeIndices.length;\n    var outerLen = hasHoles ? holeIndices[0] * dim : data.length;\n\n    var polygonArea = Math.abs(signedArea(data, 0, outerLen, dim));\n    if (hasHoles) {\n        for (var i = 0, len = holeIndices.length; i < len; i++) {\n            var start = holeIndices[i] * dim;\n            var end = i < len - 1 ? holeIndices[i + 1] * dim : data.length;\n            polygonArea -= Math.abs(signedArea(data, start, end, dim));\n        }\n    }\n\n    var trianglesArea = 0;\n    for (i = 0; i < triangles.length; i += 3) {\n        var a = triangles[i] * dim;\n        var b = triangles[i + 1] * dim;\n        var c = triangles[i + 2] * dim;\n        trianglesArea += Math.abs(\n            (data[a] - data[c]) * (data[b + 1] - data[a + 1]) -\n            (data[a] - data[b]) * (data[c + 1] - data[a + 1]));\n    }\n\n    return polygonArea === 0 && trianglesArea === 0 ? 0 :\n        Math.abs((trianglesArea - polygonArea) / polygonArea);\n};\n\nfunction signedArea(data, start, end, dim) {\n    var sum = 0;\n    for (var i = start, j = end - dim; i < end; i += dim) {\n        sum += (data[j] - data[i]) * (data[i + 1] + data[j + 1]);\n        j = i;\n    }\n    return sum;\n}\n\n// turn a polygon in a multi-dimensional array form (e.g. as in GeoJSON) into a form Earcut accepts\nearcut.flatten = function (data) {\n    var dim = data[0][0].length,\n        result = {vertices: [], holes: [], dimensions: dim},\n        holeIndex = 0;\n\n    for (var i = 0; i < data.length; i++) {\n        for (var j = 0; j < data[i].length; j++) {\n            for (var d = 0; d < dim; d++) result.vertices.push(data[i][j][d]);\n        }\n        if (i > 0) {\n            holeIndex += data[i - 1].length;\n            result.holes.push(holeIndex);\n        }\n    }\n    return result;\n};\n","import assert from './assert';\nconst RADIANS_TO_DEGREES = 1 / Math.PI * 180;\nconst DEGREES_TO_RADIANS = 1 / 180 * Math.PI;\nexport const config = {\n  EPSILON: 1e-12,\n  debug: false,\n  precision: 4,\n  printTypes: false,\n  printDegrees: false,\n  printRowMajor: true\n};\nexport function configure(options) {\n  for (const key in options) {\n    assert(key in config);\n    config[key] = options[key];\n  }\n\n  return config;\n}\nexport function formatValue(value, {\n  precision = config.precision\n} = {}) {\n  value = round(value);\n  return \"\".concat(parseFloat(value.toPrecision(precision)));\n}\nexport function isArray(value) {\n  return Array.isArray(value) || ArrayBuffer.isView(value) && !(value instanceof DataView);\n}\nexport function clone(array) {\n  return 'clone' in array ? array.clone() : array.slice();\n}\nexport function toRadians(degrees) {\n  return radians(degrees);\n}\nexport function toDegrees(radians) {\n  return degrees(radians);\n}\nexport function radians(degrees, result) {\n  return map(degrees, degrees => degrees * DEGREES_TO_RADIANS, result);\n}\nexport function degrees(radians, result) {\n  return map(radians, radians => radians * RADIANS_TO_DEGREES, result);\n}\nexport function sin(radians, result) {\n  return map(radians, angle => Math.sin(angle), result);\n}\nexport function cos(radians, result) {\n  return map(radians, angle => Math.cos(angle), result);\n}\nexport function tan(radians, result) {\n  return map(radians, angle => Math.tan(angle), result);\n}\nexport function asin(radians, result) {\n  return map(radians, angle => Math.asin(angle), result);\n}\nexport function acos(radians, result) {\n  return map(radians, angle => Math.acos(angle), result);\n}\nexport function atan(radians, result) {\n  return map(radians, angle => Math.atan(angle), result);\n}\nexport function clamp(value, min, max) {\n  return map(value, value => Math.max(min, Math.min(max, value)));\n}\nexport function lerp(a, b, t) {\n  if (isArray(a)) {\n    return a.map((ai, i) => lerp(ai, b[i], t));\n  }\n\n  return t * b + (1 - t) * a;\n}\nexport function equals(a, b, epsilon) {\n  const oldEpsilon = config.EPSILON;\n\n  if (epsilon) {\n    config.EPSILON = epsilon;\n  }\n\n  try {\n    if (a === b) {\n      return true;\n    }\n\n    if (isArray(a) && isArray(b)) {\n      if (a.length !== b.length) {\n        return false;\n      }\n\n      for (let i = 0; i < a.length; ++i) {\n        if (!equals(a[i], b[i])) {\n          return false;\n        }\n      }\n\n      return true;\n    }\n\n    if (a && a.equals) {\n      return a.equals(b);\n    }\n\n    if (b && b.equals) {\n      return b.equals(a);\n    }\n\n    if (typeof a === 'number' && typeof b === 'number') {\n      return Math.abs(a - b) <= config.EPSILON * Math.max(1, Math.abs(a), Math.abs(b));\n    }\n\n    return false;\n  } finally {\n    config.EPSILON = oldEpsilon;\n  }\n}\nexport function exactEquals(a, b) {\n  if (a === b) {\n    return true;\n  }\n\n  if (a && typeof a === 'object' && b && typeof b === 'object') {\n    if (a.constructor !== b.constructor) {\n      return false;\n    }\n\n    if (a.exactEquals) {\n      return a.exactEquals(b);\n    }\n  }\n\n  if (isArray(a) && isArray(b)) {\n    if (a.length !== b.length) {\n      return false;\n    }\n\n    for (let i = 0; i < a.length; ++i) {\n      if (!exactEquals(a[i], b[i])) {\n        return false;\n      }\n    }\n\n    return true;\n  }\n\n  return false;\n}\nexport function withEpsilon(epsilon, func) {\n  const oldPrecision = config.EPSILON;\n  config.EPSILON = epsilon;\n  let value;\n\n  try {\n    value = func();\n  } finally {\n    config.EPSILON = oldPrecision;\n  }\n\n  return value;\n}\n\nfunction round(value) {\n  return Math.round(value / config.EPSILON) * config.EPSILON;\n}\n\nfunction duplicateArray(array) {\n  return array.clone ? array.clone() : new Array(array.length);\n}\n\nfunction map(value, func, result) {\n  if (isArray(value)) {\n    const array = value;\n    result = result || duplicateArray(array);\n\n    for (let i = 0; i < result.length && i < array.length; ++i) {\n      result[i] = func(value[i], i, result);\n    }\n\n    return result;\n  }\n\n  return func(value);\n}\n//# sourceMappingURL=common.js.map","function _extendableBuiltin(cls) {\n  function ExtendableBuiltin() {\n    var instance = Reflect.construct(cls, Array.from(arguments));\n    Object.setPrototypeOf(instance, Object.getPrototypeOf(this));\n    return instance;\n  }\n\n  ExtendableBuiltin.prototype = Object.create(cls.prototype, {\n    constructor: {\n      value: cls,\n      enumerable: false,\n      writable: true,\n      configurable: true\n    }\n  });\n\n  if (Object.setPrototypeOf) {\n    Object.setPrototypeOf(ExtendableBuiltin, cls);\n  } else {\n    ExtendableBuiltin.__proto__ = cls;\n  }\n\n  return ExtendableBuiltin;\n}\n\nimport { config, formatValue, equals, isArray } from '../../lib/common';\nexport default class MathArray extends _extendableBuiltin(Array) {\n  clone() {\n    return new this.constructor().copy(this);\n  }\n\n  fromArray(array, offset = 0) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = array[i + offset];\n    }\n\n    return this.check();\n  }\n\n  toArray(targetArray = [], offset = 0) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      targetArray[offset + i] = this[i];\n    }\n\n    return targetArray;\n  }\n\n  from(arrayOrObject) {\n    return Array.isArray(arrayOrObject) ? this.copy(arrayOrObject) : this.fromObject(arrayOrObject);\n  }\n\n  to(arrayOrObject) {\n    if (arrayOrObject === this) {\n      return this;\n    }\n\n    return isArray(arrayOrObject) ? this.toArray(arrayOrObject) : this.toObject(arrayOrObject);\n  }\n\n  toTarget(target) {\n    return target ? this.to(target) : this;\n  }\n\n  toFloat32Array() {\n    return new Float32Array(this);\n  }\n\n  toString() {\n    return this.formatString(config);\n  }\n\n  formatString(opts) {\n    let string = '';\n\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      string += (i > 0 ? ', ' : '') + formatValue(this[i], opts);\n    }\n\n    return \"\".concat(opts.printTypes ? this.constructor.name : '', \"[\").concat(string, \"]\");\n  }\n\n  equals(array) {\n    if (!array || this.length !== array.length) {\n      return false;\n    }\n\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      if (!equals(this[i], array[i])) {\n        return false;\n      }\n    }\n\n    return true;\n  }\n\n  exactEquals(array) {\n    if (!array || this.length !== array.length) {\n      return false;\n    }\n\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      if (this[i] !== array[i]) {\n        return false;\n      }\n    }\n\n    return true;\n  }\n\n  negate() {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = -this[i];\n    }\n\n    return this.check();\n  }\n\n  lerp(a, b, t) {\n    if (t === undefined) {\n      return this.lerp(this, a, b);\n    }\n\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      const ai = a[i];\n      this[i] = ai + t * (b[i] - ai);\n    }\n\n    return this.check();\n  }\n\n  min(vector) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = Math.min(vector[i], this[i]);\n    }\n\n    return this.check();\n  }\n\n  max(vector) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = Math.max(vector[i], this[i]);\n    }\n\n    return this.check();\n  }\n\n  clamp(minVector, maxVector) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = Math.min(Math.max(this[i], minVector[i]), maxVector[i]);\n    }\n\n    return this.check();\n  }\n\n  add(...vectors) {\n    for (const vector of vectors) {\n      for (let i = 0; i < this.ELEMENTS; ++i) {\n        this[i] += vector[i];\n      }\n    }\n\n    return this.check();\n  }\n\n  subtract(...vectors) {\n    for (const vector of vectors) {\n      for (let i = 0; i < this.ELEMENTS; ++i) {\n        this[i] -= vector[i];\n      }\n    }\n\n    return this.check();\n  }\n\n  scale(scale) {\n    if (typeof scale === 'number') {\n      for (let i = 0; i < this.ELEMENTS; ++i) {\n        this[i] *= scale;\n      }\n    } else {\n      for (let i = 0; i < this.ELEMENTS && i < scale.length; ++i) {\n        this[i] *= scale[i];\n      }\n    }\n\n    return this.check();\n  }\n\n  multiplyByScalar(scalar) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] *= scalar;\n    }\n\n    return this.check();\n  }\n\n  check() {\n    if (config.debug && !this.validate()) {\n      throw new Error(\"math.gl: \".concat(this.constructor.name, \" some fields set to invalid numbers'\"));\n    }\n\n    return this;\n  }\n\n  validate() {\n    let valid = this.length === this.ELEMENTS;\n\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      valid = valid && Number.isFinite(this[i]);\n    }\n\n    return valid;\n  }\n\n  sub(a) {\n    return this.subtract(a);\n  }\n\n  setScalar(a) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = a;\n    }\n\n    return this.check();\n  }\n\n  addScalar(a) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] += a;\n    }\n\n    return this.check();\n  }\n\n  subScalar(a) {\n    return this.addScalar(-a);\n  }\n\n  multiplyScalar(scalar) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] *= scalar;\n    }\n\n    return this.check();\n  }\n\n  divideScalar(a) {\n    return this.multiplyByScalar(1 / a);\n  }\n\n  clampScalar(min, max) {\n    for (let i = 0; i < this.ELEMENTS; ++i) {\n      this[i] = Math.min(Math.max(this[i], min), max);\n    }\n\n    return this.check();\n  }\n\n  get elements() {\n    return this;\n  }\n\n}\n//# sourceMappingURL=math-array.js.map","import { config } from './common';\nexport function validateVector(v, length) {\n  if (v.length !== length) {\n    return false;\n  }\n\n  for (let i = 0; i < v.length; ++i) {\n    if (!Number.isFinite(v[i])) {\n      return false;\n    }\n  }\n\n  return true;\n}\nexport function checkNumber(value) {\n  if (!Number.isFinite(value)) {\n    throw new Error(\"Invalid number \".concat(value));\n  }\n\n  return value;\n}\nexport function checkVector(v, length, callerName = '') {\n  if (config.debug && !validateVector(v, length)) {\n    throw new Error(\"math.gl: \".concat(callerName, \" some fields set to invalid numbers'\"));\n  }\n\n  return v;\n}\nconst map = {};\nexport function deprecated(method, version) {\n  if (!map[method]) {\n    map[method] = true;\n    console.warn(\"\".concat(method, \" has been removed in version \").concat(version, \", see upgrade guide for more information\"));\n  }\n}\n//# sourceMappingURL=validators.js.map","\"use strict\";\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\nexports.setMatrixArrayType = setMatrixArrayType;\nexports.toRadian = toRadian;\nexports.equals = equals;\nexports.RANDOM = exports.ARRAY_TYPE = exports.EPSILON = void 0;\n\n/**\n * Common utilities\n * @module glMatrix\n */\n// Configuration Constants\nvar EPSILON = 0.000001;\nexports.EPSILON = EPSILON;\nvar ARRAY_TYPE = typeof Float32Array !== 'undefined' ? Float32Array : Array;\nexports.ARRAY_TYPE = ARRAY_TYPE;\nvar RANDOM = Math.random;\n/**\n * Sets the type of array used when creating new vectors and matrices\n *\n * @param {Float32ArrayConstructor | ArrayConstructor} type Array type, such as Float32Array or Array\n */\n\nexports.RANDOM = RANDOM;\n\nfunction setMatrixArrayType(type) {\n  exports.ARRAY_TYPE = ARRAY_TYPE = type;\n}\n\nvar degree = Math.PI / 180;\n/**\n * Convert Degree To Radian\n *\n * @param {Number} a Angle in Degrees\n */\n\nfunction toRadian(a) {\n  return a * degree;\n}\n/**\n * Tests whether or not the arguments have approximately the same value, within an absolute\n * or relative tolerance of glMatrix.EPSILON (an absolute tolerance is used for values less\n * than or equal to 1.0, and a relative tolerance is used for larger values)\n *\n * @param {Number} a The first number to test.\n * @param {Number} b The second number to test.\n * @returns {Boolean} True if the numbers are approximately equal, false otherwise.\n */\n\n\nfunction equals(a, b) {\n  return Math.abs(a - b) <= EPSILON * Math.max(1.0, Math.abs(a), Math.abs(b));\n}\n\nif (!Math.hypot) Math.hypot = function () {\n  var y = 0,\n      i = arguments.length;\n\n  while (i--) {\n    y += arguments[i] * arguments[i];\n  }\n\n  return Math.sqrt(y);\n};","\"use strict\";\n\nfunction _typeof(obj) { \"@babel/helpers - typeof\"; if (typeof Symbol === \"function\" && typeof Symbol.iterator === \"symbol\") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === \"function\" && obj.constructor === Symbol && obj !== Symbol.prototype ? \"symbol\" : typeof obj; }; } return _typeof(obj); }\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\nexports.create = create;\nexports.clone = clone;\nexports.fromValues = fromValues;\nexports.copy = copy;\nexports.set = set;\nexports.add = add;\nexports.subtract = subtract;\nexports.multiply = multiply;\nexports.divide = divide;\nexports.ceil = ceil;\nexports.floor = floor;\nexports.min = min;\nexports.max = max;\nexports.round = round;\nexports.scale = scale;\nexports.scaleAndAdd = scaleAndAdd;\nexports.distance = distance;\nexports.squaredDistance = squaredDistance;\nexports.length = length;\nexports.squaredLength = squaredLength;\nexports.negate = negate;\nexports.inverse = inverse;\nexports.normalize = normalize;\nexports.dot = dot;\nexports.cross = cross;\nexports.lerp = lerp;\nexports.random = random;\nexports.transformMat2 = transformMat2;\nexports.transformMat2d = transformMat2d;\nexports.transformMat3 = transformMat3;\nexports.transformMat4 = transformMat4;\nexports.rotate = rotate;\nexports.angle = angle;\nexports.zero = zero;\nexports.str = str;\nexports.exactEquals = exactEquals;\nexports.equals = equals;\nexports.forEach = exports.sqrLen = exports.sqrDist = exports.dist = exports.div = exports.mul = exports.sub = exports.len = void 0;\n\nvar glMatrix = _interopRequireWildcard(require(\"./common.js\"));\n\nfunction _getRequireWildcardCache(nodeInterop) { if (typeof WeakMap !== \"function\") return null; var cacheBabelInterop = new WeakMap(); var cacheNodeInterop = new WeakMap(); return (_getRequireWildcardCache = function _getRequireWildcardCache(nodeInterop) { return nodeInterop ? cacheNodeInterop : cacheBabelInterop; })(nodeInterop); }\n\nfunction _interopRequireWildcard(obj, nodeInterop) { if (!nodeInterop && obj && obj.__esModule) { return obj; } if (obj === null || _typeof(obj) !== \"object\" && typeof obj !== \"function\") { return { \"default\": obj }; } var cache = _getRequireWildcardCache(nodeInterop); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (key !== \"default\" && Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj[\"default\"] = obj; if (cache) { cache.set(obj, newObj); } return newObj; }\n\n/**\n * 2 Dimensional Vector\n * @module vec2\n */\n\n/**\n * Creates a new, empty vec2\n *\n * @returns {vec2} a new 2D vector\n */\nfunction create() {\n  var out = new glMatrix.ARRAY_TYPE(2);\n\n  if (glMatrix.ARRAY_TYPE != Float32Array) {\n    out[0] = 0;\n    out[1] = 0;\n  }\n\n  return out;\n}\n/**\n * Creates a new vec2 initialized with values from an existing vector\n *\n * @param {ReadonlyVec2} a vector to clone\n * @returns {vec2} a new 2D vector\n */\n\n\nfunction clone(a) {\n  var out = new glMatrix.ARRAY_TYPE(2);\n  out[0] = a[0];\n  out[1] = a[1];\n  return out;\n}\n/**\n * Creates a new vec2 initialized with the given values\n *\n * @param {Number} x X component\n * @param {Number} y Y component\n * @returns {vec2} a new 2D vector\n */\n\n\nfunction fromValues(x, y) {\n  var out = new glMatrix.ARRAY_TYPE(2);\n  out[0] = x;\n  out[1] = y;\n  return out;\n}\n/**\n * Copy the values from one vec2 to another\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the source vector\n * @returns {vec2} out\n */\n\n\nfunction copy(out, a) {\n  out[0] = a[0];\n  out[1] = a[1];\n  return out;\n}\n/**\n * Set the components of a vec2 to the given values\n *\n * @param {vec2} out the receiving vector\n * @param {Number} x X component\n * @param {Number} y Y component\n * @returns {vec2} out\n */\n\n\nfunction set(out, x, y) {\n  out[0] = x;\n  out[1] = y;\n  return out;\n}\n/**\n * Adds two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction add(out, a, b) {\n  out[0] = a[0] + b[0];\n  out[1] = a[1] + b[1];\n  return out;\n}\n/**\n * Subtracts vector b from vector a\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction subtract(out, a, b) {\n  out[0] = a[0] - b[0];\n  out[1] = a[1] - b[1];\n  return out;\n}\n/**\n * Multiplies two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction multiply(out, a, b) {\n  out[0] = a[0] * b[0];\n  out[1] = a[1] * b[1];\n  return out;\n}\n/**\n * Divides two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction divide(out, a, b) {\n  out[0] = a[0] / b[0];\n  out[1] = a[1] / b[1];\n  return out;\n}\n/**\n * Math.ceil the components of a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to ceil\n * @returns {vec2} out\n */\n\n\nfunction ceil(out, a) {\n  out[0] = Math.ceil(a[0]);\n  out[1] = Math.ceil(a[1]);\n  return out;\n}\n/**\n * Math.floor the components of a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to floor\n * @returns {vec2} out\n */\n\n\nfunction floor(out, a) {\n  out[0] = Math.floor(a[0]);\n  out[1] = Math.floor(a[1]);\n  return out;\n}\n/**\n * Returns the minimum of two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction min(out, a, b) {\n  out[0] = Math.min(a[0], b[0]);\n  out[1] = Math.min(a[1], b[1]);\n  return out;\n}\n/**\n * Returns the maximum of two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec2} out\n */\n\n\nfunction max(out, a, b) {\n  out[0] = Math.max(a[0], b[0]);\n  out[1] = Math.max(a[1], b[1]);\n  return out;\n}\n/**\n * Math.round the components of a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to round\n * @returns {vec2} out\n */\n\n\nfunction round(out, a) {\n  out[0] = Math.round(a[0]);\n  out[1] = Math.round(a[1]);\n  return out;\n}\n/**\n * Scales a vec2 by a scalar number\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the vector to scale\n * @param {Number} b amount to scale the vector by\n * @returns {vec2} out\n */\n\n\nfunction scale(out, a, b) {\n  out[0] = a[0] * b;\n  out[1] = a[1] * b;\n  return out;\n}\n/**\n * Adds two vec2's after scaling the second operand by a scalar value\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @param {Number} scale the amount to scale b by before adding\n * @returns {vec2} out\n */\n\n\nfunction scaleAndAdd(out, a, b, scale) {\n  out[0] = a[0] + b[0] * scale;\n  out[1] = a[1] + b[1] * scale;\n  return out;\n}\n/**\n * Calculates the euclidian distance between two vec2's\n *\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {Number} distance between a and b\n */\n\n\nfunction distance(a, b) {\n  var x = b[0] - a[0],\n      y = b[1] - a[1];\n  return Math.hypot(x, y);\n}\n/**\n * Calculates the squared euclidian distance between two vec2's\n *\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {Number} squared distance between a and b\n */\n\n\nfunction squaredDistance(a, b) {\n  var x = b[0] - a[0],\n      y = b[1] - a[1];\n  return x * x + y * y;\n}\n/**\n * Calculates the length of a vec2\n *\n * @param {ReadonlyVec2} a vector to calculate length of\n * @returns {Number} length of a\n */\n\n\nfunction length(a) {\n  var x = a[0],\n      y = a[1];\n  return Math.hypot(x, y);\n}\n/**\n * Calculates the squared length of a vec2\n *\n * @param {ReadonlyVec2} a vector to calculate squared length of\n * @returns {Number} squared length of a\n */\n\n\nfunction squaredLength(a) {\n  var x = a[0],\n      y = a[1];\n  return x * x + y * y;\n}\n/**\n * Negates the components of a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to negate\n * @returns {vec2} out\n */\n\n\nfunction negate(out, a) {\n  out[0] = -a[0];\n  out[1] = -a[1];\n  return out;\n}\n/**\n * Returns the inverse of the components of a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to invert\n * @returns {vec2} out\n */\n\n\nfunction inverse(out, a) {\n  out[0] = 1.0 / a[0];\n  out[1] = 1.0 / a[1];\n  return out;\n}\n/**\n * Normalize a vec2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a vector to normalize\n * @returns {vec2} out\n */\n\n\nfunction normalize(out, a) {\n  var x = a[0],\n      y = a[1];\n  var len = x * x + y * y;\n\n  if (len > 0) {\n    //TODO: evaluate use of glm_invsqrt here?\n    len = 1 / Math.sqrt(len);\n  }\n\n  out[0] = a[0] * len;\n  out[1] = a[1] * len;\n  return out;\n}\n/**\n * Calculates the dot product of two vec2's\n *\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {Number} dot product of a and b\n */\n\n\nfunction dot(a, b) {\n  return a[0] * b[0] + a[1] * b[1];\n}\n/**\n * Computes the cross product of two vec2's\n * Note that the cross product must by definition produce a 3D vector\n *\n * @param {vec3} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @returns {vec3} out\n */\n\n\nfunction cross(out, a, b) {\n  var z = a[0] * b[1] - a[1] * b[0];\n  out[0] = out[1] = 0;\n  out[2] = z;\n  return out;\n}\n/**\n * Performs a linear interpolation between two vec2's\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the first operand\n * @param {ReadonlyVec2} b the second operand\n * @param {Number} t interpolation amount, in the range [0-1], between the two inputs\n * @returns {vec2} out\n */\n\n\nfunction lerp(out, a, b, t) {\n  var ax = a[0],\n      ay = a[1];\n  out[0] = ax + t * (b[0] - ax);\n  out[1] = ay + t * (b[1] - ay);\n  return out;\n}\n/**\n * Generates a random vector with the given scale\n *\n * @param {vec2} out the receiving vector\n * @param {Number} [scale] Length of the resulting vector. If ommitted, a unit vector will be returned\n * @returns {vec2} out\n */\n\n\nfunction random(out, scale) {\n  scale = scale || 1.0;\n  var r = glMatrix.RANDOM() * 2.0 * Math.PI;\n  out[0] = Math.cos(r) * scale;\n  out[1] = Math.sin(r) * scale;\n  return out;\n}\n/**\n * Transforms the vec2 with a mat2\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the vector to transform\n * @param {ReadonlyMat2} m matrix to transform with\n * @returns {vec2} out\n */\n\n\nfunction transformMat2(out, a, m) {\n  var x = a[0],\n      y = a[1];\n  out[0] = m[0] * x + m[2] * y;\n  out[1] = m[1] * x + m[3] * y;\n  return out;\n}\n/**\n * Transforms the vec2 with a mat2d\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the vector to transform\n * @param {ReadonlyMat2d} m matrix to transform with\n * @returns {vec2} out\n */\n\n\nfunction transformMat2d(out, a, m) {\n  var x = a[0],\n      y = a[1];\n  out[0] = m[0] * x + m[2] * y + m[4];\n  out[1] = m[1] * x + m[3] * y + m[5];\n  return out;\n}\n/**\n * Transforms the vec2 with a mat3\n * 3rd vector component is implicitly '1'\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the vector to transform\n * @param {ReadonlyMat3} m matrix to transform with\n * @returns {vec2} out\n */\n\n\nfunction transformMat3(out, a, m) {\n  var x = a[0],\n      y = a[1];\n  out[0] = m[0] * x + m[3] * y + m[6];\n  out[1] = m[1] * x + m[4] * y + m[7];\n  return out;\n}\n/**\n * Transforms the vec2 with a mat4\n * 3rd vector component is implicitly '0'\n * 4th vector component is implicitly '1'\n *\n * @param {vec2} out the receiving vector\n * @param {ReadonlyVec2} a the vector to transform\n * @param {ReadonlyMat4} m matrix to transform with\n * @returns {vec2} out\n */\n\n\nfunction transformMat4(out, a, m) {\n  var x = a[0];\n  var y = a[1];\n  out[0] = m[0] * x + m[4] * y + m[12];\n  out[1] = m[1] * x + m[5] * y + m[13];\n  return out;\n}\n/**\n * Rotate a 2D vector\n * @param {vec2} out The receiving vec2\n * @param {ReadonlyVec2} a The vec2 point to rotate\n * @param {ReadonlyVec2} b The origin of the rotation\n * @param {Number} rad The angle of rotation in radians\n * @returns {vec2} out\n */\n\n\nfunction rotate(out, a, b, rad) {\n  //Translate point to the origin\n  var p0 = a[0] - b[0],\n      p1 = a[1] - b[1],\n      sinC = Math.sin(rad),\n      cosC = Math.cos(rad); //perform rotation and translate to correct position\n\n  out[0] = p0 * cosC - p1 * sinC + b[0];\n  out[1] = p0 * sinC + p1 * cosC + b[1];\n  return out;\n}\n/**\n * Get the angle between two 2D vectors\n * @param {ReadonlyVec2} a The first operand\n * @param {ReadonlyVec2} b The second operand\n * @returns {Number} The angle in radians\n */\n\n\nfunction angle(a, b) {\n  var x1 = a[0],\n      y1 = a[1],\n      x2 = b[0],\n      y2 = b[1],\n      // mag is the product of the magnitudes of a and b\n  mag = Math.sqrt(x1 * x1 + y1 * y1) * Math.sqrt(x2 * x2 + y2 * y2),\n      // mag &&.. short circuits if mag == 0\n  cosine = mag && (x1 * x2 + y1 * y2) / mag; // Math.min(Math.max(cosine, -1), 1) clamps the cosine between -1 and 1\n\n  return Math.acos(Math.min(Math.max(cosine, -1), 1));\n}\n/**\n * Set the components of a vec2 to zero\n