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;
}
QRectF QTessellator::tessellate(const QPointF *points, int nPoints)
{
Q_ASSERT(points[0] == points[nPoints-1]);
--nPoints;
#ifdef DEBUG
QDEBUG()<< "POINTS:";
for (int i = 0; i < nPoints; ++i) {
QDEBUG() << points[i];
}
#endif
// collect edges and calculate bounds
d->vertices.nPoints = nPoints;
d->vertices.init(nPoints);
int maxActiveEdges = 0;
QRectF br = d->collectAndSortVertices(points, &maxActiveEdges);
d->cancelCoincidingEdges();
#ifdef DEBUG
QDEBUG() << "nPoints = " << nPoints << "using " << d->vertices.nPoints;
QDEBUG()<< "VERTICES:";
for (int i = 0; i < d->vertices.nPoints; ++i) {
QDEBUG() << " " << i << ": "
<< "point=" << d->vertices.position(d->vertices.sorted[i])
<< "flags=" << d->vertices.sorted[i]->flags
<< "pos=(" << Q27Dot5ToDouble(d->vertices.sorted[i]->x) << '/'
<< Q27Dot5ToDouble(d->vertices.sorted[i]->y) << ')';
}
#endif
d->scanline.init(maxActiveEdges);
d->y = INT_MIN/256;
d->currentVertex = 0;
while (d->currentVertex < d->vertices.nPoints) {
d->scanline.clearMarks();
d->y = d->vertices.sorted[d->currentVertex]->y;
if (!d->intersections.isEmpty())
d->y = qMin(d->y, d->intersections.constBegin().key().y);
QDEBUG()<< "===== SCANLINE: y =" << Q27Dot5ToDouble(d->y) << " =====";
d->scanline.prepareLine();
d->processIntersections();
d->removeEdges();
d->addEdges();
d->addIntersections();
d->emitEdges(this);
d->scanline.lineDone();
#ifdef DEBUG
QDEBUG()<< "===== edges:";
for (int i = 0; i < d->scanline.size; ++i) {
QDEBUG() << " " << d->scanline.edges[i]->edge
<< "p0= (" << Q27Dot5ToDouble(d->scanline.edges[i]->v0->x)
<< '/' << Q27Dot5ToDouble(d->scanline.edges[i]->v0->y)
<< ") p1= (" << Q27Dot5ToDouble(d->scanline.edges[i]->v1->x)
<< '/' << Q27Dot5ToDouble(d->scanline.edges[i]->v1->y) << ')'
<< "x=" << Q27Dot5ToDouble(d->scanline.edges[i]->positionAt(d->y))
<< "isLeftOfNext="
<< ((i < d->scanline.size - 1)
? d->scanline.edges[i]->isLeftOf(*d->scanline.edges[i+1], d->y)
: true);
}
#endif
}
d->scanline.done();
d->intersections.clear();
return br;
}
void old_tesselate_polygon(QVector<XTrapezoid> *traps, const QPointF *pg, int pgSize,
bool winding)
{
QVector<QEdge> edges;
edges.reserve(128);
qreal ymin(INT_MAX/256);
qreal ymax(INT_MIN/256);
//painter.begin(pg, pgSize);
if (pg[0] != pg[pgSize-1])
qWarning() << Q_FUNC_INFO << "Malformed polygon (first and last points must be identical)";
// generate edge table
// qDebug() << "POINTS:";
for (int x = 0; x < pgSize-1; ++x) {
QEdge edge;
QPointF p1(Q27Dot5ToDouble(FloatToQ27Dot5(pg[x].x())),
Q27Dot5ToDouble(FloatToQ27Dot5(pg[x].y())));
QPointF p2(Q27Dot5ToDouble(FloatToQ27Dot5(pg[x+1].x())),
Q27Dot5ToDouble(FloatToQ27Dot5(pg[x+1].y())));
// qDebug() << " "
// << p1;
edge.winding = p1.y() > p2.y() ? 1 : -1;
if (edge.winding > 0)
qSwap(p1, p2);
edge.p1.x = XDoubleToFixed(p1.x());
edge.p1.y = XDoubleToFixed(p1.y());
edge.p2.x = XDoubleToFixed(p2.x());
edge.p2.y = XDoubleToFixed(p2.y());
edge.m = (p1.y() - p2.y()) / (p1.x() - p2.x()); // line derivative
edge.b = p1.y() - edge.m * p1.x(); // intersection with y axis
edge.m = edge.m != 0.0 ? 1.0 / edge.m : 0.0; // inverted derivative
edges.append(edge);
ymin = qMin(ymin, qreal(XFixedToDouble(edge.p1.y)));
ymax = qMax(ymax, qreal(XFixedToDouble(edge.p2.y)));
}
QList<const QEdge *> et; // edge list
for (int i = 0; i < edges.size(); ++i)
et.append(&edges.at(i));
// sort edge table by min y value
qSort(et.begin(), et.end(), compareEdges);
// eliminate shared edges
for (int i = 0; i < et.size(); ++i) {
for (int k = i+1; k < et.size(); ++k) {
const QEdge *edgeI = et.at(i);
const QEdge *edgeK = et.at(k);
if (edgeK->p1.y > edgeI->p1.y)
break;
if (edgeI->winding != edgeK->winding &&
isEqual(edgeI->p1, edgeK->p1) && isEqual(edgeI->p2, edgeK->p2)
) {
et.removeAt(k);
et.removeAt(i);
--i;
break;
}
}
}
if (ymax <= ymin)
return;
QList<const QEdge *> aet; // edges that intersects the current scanline
// if (ymin < 0)
// ymin = 0;
// if (paintEventClipRegion) // don't scan more lines than we have to
// ymax = paintEventClipRegion->boundingRect().height();
#ifdef QT_DEBUG_TESSELATOR
qDebug("==> ymin = %f, ymax = %f", ymin, ymax);
#endif // QT_DEBUG_TESSELATOR
currentY = ymin; // used by the less than op
for (qreal y = ymin; y < ymax;) {
// fill active edge table with edges that intersect the current line
for (int i = 0; i < et.size(); ++i) {
const QEdge *edge = et.at(i);
if (edge->p1.y > XDoubleToFixed(y))
break;
aet.append(edge);
et.removeAt(i);
--i;
}
// remove processed edges from active edge table
for (int i = 0; i < aet.size(); ++i) {
if (aet.at(i)->p2.y <= XDoubleToFixed(y)) {
aet.removeAt(i);
--i;
}
}
if (aet.size()%2 != 0) {
#ifndef QT_NO_DEBUG
qWarning("QX11PaintEngine: aet out of sync - this should not happen.");
#endif
return;
}
// done?
if (!aet.size()) {
if (!et.size()) {
break;
} else {
y = currentY = XFixedToDouble(et.at(0)->p1.y);
continue;
}
}
// calculate the next y where we have to start a new set of trapezoids
qreal next_y(INT_MAX/256);
for (int i = 0; i < aet.size(); ++i) {
const QEdge *edge = aet.at(i);
if (XFixedToDouble(edge->p2.y) < next_y)
next_y = XFixedToDouble(edge->p2.y);
}
if (et.size() && next_y > XFixedToDouble(et.at(0)->p1.y))
next_y = XFixedToDouble(et.at(0)->p1.y);
int aetSize = aet.size();
for (int i = 0; i < aetSize; ++i) {
for (int k = i+1; k < aetSize; ++k) {
const QEdge *edgeI = aet.at(i);
const QEdge *edgeK = aet.at(k);
qreal m1 = edgeI->m;
qreal b1 = edgeI->b;
qreal m2 = edgeK->m;
qreal b2 = edgeK->b;
if (qAbs(m1 - m2) < 0.001)
continue;
// ### intersect is not calculated correctly when optimized with -O2 (gcc)
volatile qreal intersect = 0;
if (!qIsFinite(b1))
intersect = (1.f / m2) * XFixedToDouble(edgeI->p1.x) + b2;
else if (!qIsFinite(b2))
intersect = (1.f / m1) * XFixedToDouble(edgeK->p1.x) + b1;
else
intersect = (b1*m1 - b2*m2) / (m1 - m2);
if (intersect > y && intersect < next_y)
next_y = intersect;
}
}
XFixed yf, next_yf;
yf = qrealToXFixed(y);
next_yf = qrealToXFixed(next_y);
if (yf == next_yf) {
y = currentY = next_y;
continue;
}
#ifdef QT_DEBUG_TESSELATOR
qDebug("###> y = %f, next_y = %f, %d active edges", y, next_y, aet.size());
qDebug("===> edges");
dump_edges(et);
qDebug("===> active edges");
dump_edges(aet);
#endif
// calc intersection points
QVarLengthArray<QIntersectionPoint> isects(aet.size()+1);
for (int i = 0; i < isects.size()-1; ++i) {
const QEdge *edge = aet.at(i);
isects[i].x = (edge->p1.x != edge->p2.x) ?
((y - edge->b)*edge->m) : XFixedToDouble(edge->p1.x);
isects[i].edge = edge;
}
if (isects.size()%2 != 1)
qFatal("%s: number of intersection points must be odd", Q_FUNC_INFO);
// sort intersection points
qSort(&isects[0], &isects[isects.size()-1], compareIntersections);
// qDebug() << "INTERSECTION_POINTS:";
// for (int i = 0; i < isects.size(); ++i)
// qDebug() << isects[i].edge << isects[i].x;
if (winding) {
// winding fill rule
for (int i = 0; i < isects.size()-1;) {
int winding = 0;
const QEdge *left = isects[i].edge;
const QEdge *right = 0;
winding += isects[i].edge->winding;
for (++i; i < isects.size()-1 && winding != 0; ++i) {
winding += isects[i].edge->winding;
right = isects[i].edge;
}
if (!left || !right)
break;
//painter.addTrapezoid(&toXTrapezoid(yf, next_yf, *left, *right));
traps->append(toXTrapezoid(yf, next_yf, *left, *right));
}
} else {
// odd-even fill rule
for (int i = 0; i < isects.size()-2; i += 2) {
//painter.addTrapezoid(&toXTrapezoid(yf, next_yf, *isects[i].edge, *isects[i+1].edge));
traps->append(toXTrapezoid(yf, next_yf, *isects[i].edge, *isects[i+1].edge));
}
}
y = currentY = next_y;
}
#ifdef QT_DEBUG_TESSELATOR
qDebug("==> number of trapezoids: %d - edge table size: %d\n", traps->size(), et.size());
for (int i = 0; i < traps->size(); ++i)
dump_trap(traps->at(i));
#endif
// optimize by unifying trapezoids that share left/right lines
// and have a common top/bottom edge
// for (int i = 0; i < tps.size(); ++i) {
// for (int k = i+1; k < tps.size(); ++k) {
// if (i != k && tps.at(i).right == tps.at(k).right
// && tps.at(i).left == tps.at(k).left
// && (tps.at(i).top == tps.at(k).bottom
// || tps.at(i).bottom == tps.at(k).top))
// {
// tps[i].bottom = tps.at(k).bottom;
// tps.removeAt(k);
// i = 0;
// break;
// }
// }
// }
//static int i = 0;
//QImage img = painter.end();
//img.save(QString("res%1.png").arg(i++), "PNG");
}
