Function isEarHashed

docs/tests/v2/es6/js/sanddance.js:69471–69521

(ear, minX, minY, invSize)

}

function isEarHashed(ear, minX, minY, invSize) {
    var a = ear.prev,
        b = ear,
        c = ear.next;

    if (area(a, b, c) >= 0) return false; // reflex, can't be an ear

    // triangle bbox; min & max are calculated like this for speed
    var minTX = a.x < b.x ? (a.x < c.x ? a.x : c.x) : (b.x < c.x ? b.x : c.x),
        minTY = a.y < b.y ? (a.y < c.y ? a.y : c.y) : (b.y < c.y ? b.y : c.y),
        maxTX = a.x > b.x ? (a.x > c.x ? a.x : c.x) : (b.x > c.x ? b.x : c.x),
        maxTY = a.y > b.y ? (a.y > c.y ? a.y : c.y) : (b.y > c.y ? b.y : c.y);

    // z-order range for the current triangle bbox;
    var minZ = zOrder(minTX, minTY, minX, minY, invSize),
        maxZ = zOrder(maxTX, maxTY, minX, minY, invSize);

    var p = ear.prevZ,
        n = ear.nextZ;

    // look for points inside the triangle in both directions
    while (p && p.z >= minZ && n && n.z <= maxZ) {
        if (p !== ear.prev && p !== ear.next &&
            pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) &&
            area(p.prev, p, p.next) >= 0) return false;
        p = p.prevZ;

        if (n !== ear.prev && n !== ear.next &&
            pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, n.x, n.y) &&
            area(n.prev, n, n.next) >= 0) return false;
        n = n.nextZ;
    }

    // look for remaining points in decreasing z-order
    while (p && p.z >= minZ) {
        if (p !== ear.prev && p !== ear.next &&
            pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, p.x, p.y) &&
            area(p.prev, p, p.next) >= 0) return false;
        p = p.prevZ;
    }

    // look for remaining points in increasing z-order
    while (n && n.z <= maxZ) {
        if (n !== ear.prev && n !== ear.next &&
            pointInTriangle(a.x, a.y, b.x, b.y, c.x, c.y, n.x, n.y) &&
            area(n.prev, n, n.next) >= 0) return false;
        n = n.nextZ;
    }

    return true;
}

// go through all polygon nodes and cure small local self-intersections
function cureLocalIntersections(start, triangles, dim) {