Exemplo n.º 1
0
bool QTessellatorPrivate::edgeInChain(Intersection i, int edge)
{
    int end = i.edge;
    while (1) {
        if (i.edge == edge)
            return true;
        IntersectionLink l = intersections.value(i);
        if (l.next == end)
            break;
        Q_ASSERT(l.next != -1);
        Q_ASSERT(l.prev != -1);

        Intersection i2 = i;
        i2.edge = l.next;

#ifndef QT_NO_DEBUG
        IntersectionLink l2 = intersections.value(i2);
        Q_ASSERT(l2.next != -1);
        Q_ASSERT(l2.prev != -1);
        Q_ASSERT(l.next == i2.edge);
        Q_ASSERT(l2.prev == i.edge);
#endif
        i = i2;
    }
    return false;
}
Exemplo n.º 2
0
void QTessellatorPrivate::addIntersection(const Edge *e1, const Edge *e2)
{
    const IntersectionLink emptyLink = {-1, -1};

    int next = vertices.nextPos(vertices[e1->edge]);
    if (e2->edge == next)
        return;
    int prev = vertices.prevPos(vertices[e1->edge]);
    if (e2->edge == prev)
        return;

    Q27Dot5 yi;
    bool det_positive;
    bool isect = e1->intersect(*e2, &yi, &det_positive);
    QDEBUG("checking edges %d and %d", e1->edge, e2->edge);
    if (!isect) {
        QDEBUG() << "    no intersection";
        return;
    }

    // don't emit an intersection if it's at the start of a line segment or above us
    if (yi <= y) {
        if (!det_positive)
            return;
        QDEBUG() << "        ----->>>>>> WRONG ORDER!";
        yi = y;
    }
    QDEBUG() << "   between edges " << e1->edge << "and" << e2->edge << "at point ("
             << Q27Dot5ToDouble(yi) << ')';

    Intersection i1;
    i1.y = yi;
    i1.edge = e1->edge;
    IntersectionLink link1 = intersections.value(i1, emptyLink);
    Intersection i2;
    i2.y = yi;
    i2.edge = e2->edge;
    IntersectionLink link2 = intersections.value(i2, emptyLink);

    // new pair of edges
    if (link1.next == -1 && link2.next == -1) {
        link1.next = link1.prev = i2.edge;
        link2.next = link2.prev = i1.edge;
    } else if (link1.next == i2.edge || link1.prev == i2.edge
               || link2.next == i1.edge || link2.prev == i1.edge) {
#ifdef DEBUG
        checkLinkChain(intersections, i1);
        checkLinkChain(intersections, i2);
        Q_ASSERT(edgeInChain(i1, i2.edge));
#endif
        return;
    } else if (link1.next == -1 || link2.next == -1) {
        if (link2.next == -1) {
            qSwap(i1, i2);
            qSwap(link1, link2);
        }
        Q_ASSERT(link1.next == -1);
#ifdef DEBUG
        checkLinkChain(intersections, i2);
#endif
        // only i2 in list
        link1.next = i2.edge;
        link1.prev = link2.prev;
        link2.prev = i1.edge;
        Intersection other;
        other.y = yi;
        other.edge = link1.prev;
        IntersectionLink link = intersections.value(other, emptyLink);
        Q_ASSERT(link.next == i2.edge);
        Q_ASSERT(link.prev != -1);
        link.next = i1.edge;
        intersections.insert(other, link);
    } else {
        bool connected = edgeInChain(i1, i2.edge);
        if (connected)
            return;
#ifdef DEBUG
        checkLinkChain(intersections, i1);
        checkLinkChain(intersections, i2);
#endif
        // both already in some list. Have to make sure they are connected
        // this can be done by cutting open the ring(s) after the two eges and
        // connecting them again
        Intersection other1;
        other1.y = yi;
        other1.edge = link1.next;
        IntersectionLink linko1 = intersections.value(other1, emptyLink);
        Intersection other2;
        other2.y = yi;
        other2.edge = link2.next;
        IntersectionLink linko2 = intersections.value(other2, emptyLink);

        linko1.prev = i2.edge;
        link2.next = other1.edge;

        linko2.prev = i1.edge;
        link1.next = other2.edge;
        intersections.insert(other1, linko1);
        intersections.insert(other2, linko2);
    }
    intersections.insert(i1, link1);
    intersections.insert(i2, link2);
#ifdef DEBUG
    checkLinkChain(intersections, i1);
    checkLinkChain(intersections, i2);
    Q_ASSERT(edgeInChain(i1, i2.edge));
#endif
    return;

}