void GeoDataLineStringPrivate::interpolateDateLine( const GeoDataCoordinates & previousCoords,
const GeoDataCoordinates & currentCoords,
GeoDataCoordinates & previousAtDateLine,
GeoDataCoordinates & currentAtDateLine,
TessellationFlags f )
{
GeoDataCoordinates dateLineCoords;
int recursionCounter = 0;
// mDebug() << Q_FUNC_INFO;
if ( f.testFlag( RespectLatitudeCircle ) && previousCoords.latitude() == currentCoords.latitude() ) {
dateLineCoords = currentCoords;
}
else {
dateLineCoords = findDateLine( previousCoords, currentCoords, recursionCounter );
}
previousAtDateLine = dateLineCoords;
currentAtDateLine = dateLineCoords;
if ( previousCoords.longitude() < 0 ) {
previousAtDateLine.setLongitude( -M_PI );
currentAtDateLine.setLongitude( +M_PI );
}
else {
previousAtDateLine.setLongitude( +M_PI );
currentAtDateLine.setLongitude( -M_PI );
}
}
int CylindricalProjectionPrivate::processTessellation( const GeoDataCoordinates &previousCoords,
const GeoDataCoordinates ¤tCoords,
int tessellatedNodes,
QVector<QPolygonF*> &polygons,
const ViewportParams *viewport,
TessellationFlags f,
int mirrorCount,
qreal repeatDistance) const
{
const bool clampToGround = f.testFlag( FollowGround );
const bool followLatitudeCircle = f.testFlag( RespectLatitudeCircle )
&& previousCoords.latitude() == currentCoords.latitude();
// Calculate steps for tessellation: lonDiff and altDiff
qreal lonDiff = 0.0;
if ( followLatitudeCircle ) {
const int previousSign = previousCoords.longitude() > 0 ? 1 : -1;
const int currentSign = currentCoords.longitude() > 0 ? 1 : -1;
lonDiff = currentCoords.longitude() - previousCoords.longitude();
if ( previousSign != currentSign
&& fabs(previousCoords.longitude()) + fabs(currentCoords.longitude()) > M_PI ) {
if ( previousSign > currentSign ) {
// going eastwards ->
lonDiff += 2 * M_PI ;
} else {
// going westwards ->
lonDiff -= 2 * M_PI;
}
}
if ( fabs( lonDiff ) == 2 * M_PI ) {
return mirrorCount;
}
}
const qreal altDiff = currentCoords.altitude() - previousCoords.altitude();
// Create the tessellation nodes.
GeoDataCoordinates previousTessellatedCoords = previousCoords;
for ( int i = 1; i <= tessellatedNodes; ++i ) {
const qreal t = (qreal)(i) / (qreal)( tessellatedNodes + 1 );
// interpolate the altitude, too
const qreal altitude = clampToGround ? 0 : altDiff * t + previousCoords.altitude();
qreal lon = 0.0;
qreal lat = 0.0;
if ( followLatitudeCircle ) {
// To tessellate along latitude circles use the
// linear interpolation of the longitude.
lon = lonDiff * t + previousCoords.longitude();
lat = previousTessellatedCoords.latitude();
}
else {
// To tessellate along great circles use the
// normalized linear interpolation ("NLERP") for latitude and longitude.
const Quaternion itpos = Quaternion::nlerp( previousCoords.quaternion(), currentCoords.quaternion(), t );
itpos. getSpherical( lon, lat );
}
const GeoDataCoordinates currentTessellatedCoords( lon, lat, altitude );
Q_Q(const CylindricalProjection);
qreal bx, by;
q->screenCoordinates( currentTessellatedCoords, viewport, bx, by );
mirrorCount = crossDateLine( previousTessellatedCoords, currentTessellatedCoords, bx, by, polygons,
mirrorCount, repeatDistance );
previousTessellatedCoords = currentTessellatedCoords;
}
// For the clampToGround case add the "current" coordinate after adding all other nodes.
GeoDataCoordinates currentModifiedCoords( currentCoords );
if ( clampToGround ) {
currentModifiedCoords.setAltitude( 0.0 );
}
Q_Q(const CylindricalProjection);
qreal bx, by;
q->screenCoordinates( currentModifiedCoords, viewport, bx, by );
mirrorCount = crossDateLine( previousTessellatedCoords, currentModifiedCoords, bx, by, polygons,
mirrorCount, repeatDistance );
return mirrorCount;
}
