Function computeWindingNumber

Engine/CoonsRegularization.cpp:1347–1377

Return the winding number of the region bounded by the (cyclic) path relative to the point z, or the largest odd integer if the point lies on the path.

// relative to the point z, or the largest odd integer if the point lies on
// the path.
static int
computeWindingNumber(const BezierCPs& patch,
                     double time,
                     const Point& z)
{
    assert(patch.size() >= 3);

    static const int undefined = std::numeric_limits<int>::max() % 2 ? std::numeric_limits<int>::max() : std::numeric_limits<int>::max() - 1;
    const unsigned maxdepth = DBL_MANT_DIG;
    int count = 0;
    BezierCPs::const_iterator it = patch.begin();
    BezierCPs::const_iterator next = it;
    ++next;
    for (; it != patch.end(); ++it, ++next) {
        if ( next == patch.end() ) {
            next = patch.begin();
        }

        Point p0, p1, p2, p3;
        (*it)->getPositionAtTime(false, time, ViewIdx(0), &p0.x, &p0.y);
        (*it)->getRightBezierPointAtTime(false, time, ViewIdx(0), &p1.x, &p1.y);
        (*next)->getLeftBezierPointAtTime(false, time, ViewIdx(0), &p2.x, &p2.y);
        (*next)->getPositionAtTime(false, time, ViewIdx(0), &p3.x, &p3.y);

        if ( checkCurve(p0, p1, p2, p3, z, &count, maxdepth) ) {
            return undefined;
        }
    }

    return count;
}

void
CoonsRegularization::regularize(const BezierCPs &patch,