C++ GeoDataCoordinates::quaternion方法代码示例

GeoDataCoordinates GeoDataLineStringPrivate::findDateLine( const GeoDataCoordinates & previousCoords,
                                             const GeoDataCoordinates & currentCoords,
                                             int recursionCounter )
{
    int currentSign = ( currentCoords.longitude() < 0.0 ) ? -1 : +1 ;
    int previousSign = ( previousCoords.longitude() < 0.0 ) ? -1 : +1 ;

    qreal longitudeDiff =   fabs( previousSign * M_PI  - previousCoords.longitude() )
                          + fabs( currentSign * M_PI - currentCoords.longitude() );

    if ( longitudeDiff < 0.001 || recursionCounter == 100 ) {
//        mDebug() << "stopped at recursion" << recursionCounter << " and longitude difference " << longitudeDiff;
        return currentCoords;
    }
    ++recursionCounter;

    qreal  lon = 0.0;
    qreal  lat = 0.0;

    qreal altDiff = currentCoords.altitude() - previousCoords.altitude();

    const Quaternion itpos = Quaternion::nlerp( previousCoords.quaternion(), currentCoords.quaternion(), 0.5 );
    itpos.getSpherical( lon, lat );

    qreal altitude = previousCoords.altitude() + 0.5 * altDiff;

    GeoDataCoordinates interpolatedCoords( lon, lat, altitude );

    int interpolatedSign = ( interpolatedCoords.longitude() < 0.0 ) ? -1 : +1 ;

/*
    mDebug() << "SRC" << previousCoords.toString();
    mDebug() << "TAR" << currentCoords.toString();
    mDebug() << "IPC" << interpolatedCoords.toString();
*/

    if ( interpolatedSign != currentSign ) {
        return findDateLine( interpolatedCoords, currentCoords, recursionCounter );
    }

    return findDateLine( previousCoords, interpolatedCoords, recursionCounter );
}

bool SphericalProjection::screenCoordinates( const GeoDataCoordinates &coordinates, 
                                             const ViewportParams *viewport,
                                             qreal &x, qreal &y, bool &globeHidesPoint ) const
{
    qreal       absoluteAltitude = coordinates.altitude() + EARTH_RADIUS;
    Quaternion  qpos             = coordinates.quaternion();

    qpos.rotateAroundAxis( viewport->planetAxisMatrix() );

    qreal      pixelAltitude = ( ( viewport->radius() ) 
                                  / EARTH_RADIUS * absoluteAltitude );
    if ( coordinates.altitude() < 10000 ) {
        // Skip placemarks at the other side of the earth.
        if ( qpos.v[Q_Z] < 0 ) {
            globeHidesPoint = true;
            return false;
        }
    }
    else {
        qreal  earthCenteredX = pixelAltitude * qpos.v[Q_X];
        qreal  earthCenteredY = pixelAltitude * qpos.v[Q_Y];
        qreal  radius         = viewport->radius();

        // Don't draw high placemarks (e.g. satellites) that aren't visible.
        if ( qpos.v[Q_Z] < 0
             && ( ( earthCenteredX * earthCenteredX
                    + earthCenteredY * earthCenteredY )
                  < radius * radius ) ) {
            globeHidesPoint = true;
            return false;
        }
    }

    // Let (x, y) be the position on the screen of the placemark..
    x = ((qreal)(viewport->width())  / 2 + pixelAltitude * qpos.v[Q_X]);
    y = ((qreal)(viewport->height()) / 2 - pixelAltitude * qpos.v[Q_Y]);

    // Skip placemarks that are outside the screen area
    if ( x < 0 || x >= viewport->width() || y < 0 || y >= viewport->height() ) {
        globeHidesPoint = false;
        return false;
    }

    globeHidesPoint = false;
    return true;
}

int CylindricalProjectionPrivate::processTessellation( const GeoDataCoordinates &previousCoords,
                                                    const GeoDataCoordinates &currentCoords,
                                                    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;
}