QDebug operator<<(QDebug dbg, const QDoubleVector3D &vector)
{
QDebugStateSaver saver(dbg);
dbg.nospace() << "QDoubleVector3D("
<< vector.x() << ", " << vector.y() << ", " << vector.z() << ')';
return dbg;
}
void QGeoCameraTilesPrivate::appendZIntersects(const QDoubleVector3D &start,
const QDoubleVector3D &end,
double z,
QVector<QDoubleVector3D> &results) const
{
if (start.z() == end.z()) {
if (start.z() == z) {
results.append(start);
results.append(end);
}
} else {
double f = (start.z() - z) / (start.z() - end.z());
if ((0 <= f) && (f <= 1.0)) {
results.append((1 - f) * start + f * end);
}
}
}
// Returns the intersection of the plane of the map and the camera frustum as a right handed polygon
Polygon QGeoCameraTilesPrivate::frustumFootprint(const Frustum &frustum) const
{
Polygon points;
points.reserve(24);
appendZIntersects(frustum.topLeftNear, frustum.topLeftFar, 0.0, points);
appendZIntersects(frustum.topRightNear, frustum.topRightFar, 0.0, points);
appendZIntersects(frustum.bottomLeftNear, frustum.bottomLeftFar, 0.0, points);
appendZIntersects(frustum.bottomRightNear, frustum.bottomRightFar, 0.0, points);
appendZIntersects(frustum.topLeftNear, frustum.bottomLeftNear, 0.0, points);
appendZIntersects(frustum.bottomLeftNear, frustum.bottomRightNear, 0.0, points);
appendZIntersects(frustum.bottomRightNear, frustum.topRightNear, 0.0, points);
appendZIntersects(frustum.topRightNear, frustum.topLeftNear, 0.0, points);
appendZIntersects(frustum.topLeftFar, frustum.bottomLeftFar, 0.0, points);
appendZIntersects(frustum.bottomLeftFar, frustum.bottomRightFar, 0.0, points);
appendZIntersects(frustum.bottomRightFar, frustum.topRightFar, 0.0, points);
appendZIntersects(frustum.topRightFar, frustum.topLeftFar, 0.0, points);
if (points.isEmpty())
return points;
// sort points into a right handed polygon
LengthSorter sorter;
// - initial sort to remove duplicates
sorter.base = points.first();
qSort(points.begin(), points.end(), sorter);
for (int i = points.size() - 1; i > 0; --i) {
if (points.at(i) == points.at(i - 1))
points.remove(i);
}
// - proper sort
// - start with the first point, put it in the sorted part of the list
// - add the nearest unsorted point to the last sorted point to the end
// of the sorted points
Polygon::iterator i;
for (i = points.begin(); i != points.end(); ++i) {
sorter.base = *i;
if (i + 1 != points.end())
qSort(i + 1, points.end(), sorter);
}
// - determine if what we have is right handed
int size = points.size();
if (size >= 3) {
QDoubleVector3D normal = QDoubleVector3D::normal(points.at(1) - points.at(0),
points.at(2) - points.at(1));
// - if not, reverse the list
if (normal.z() < 0.0) {
int halfSize = size / 2;
for (int i = 0; i < halfSize; ++i) {
QDoubleVector3D spare = points.at(i);
points[i] = points[size - 1 - i];
points[size - 1 - i] = spare;
}
}
}
return points;
}