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Use common coordinate transform code

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This commit is contained in:
Jon Beniston 2022-03-01 17:26:35 +00:00
parent 652ecc91e4
commit a4d6564854
2 changed files with 3 additions and 158 deletions
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149
plugins/feature/map/czml.cpp
View File

@ -21,7 +21,7 @@
#include "mapsettings.h"
#include "mapmodel.h"
#include "util/units.h"
#include "util/coordinates.h"
CZML::CZML(const MapSettings *settings) :
m_settings(settings)
@ -48,149 +48,6 @@ QJsonObject CZML::init()
return doc;
}
// Convert a position specified in longitude, latitude in degrees and height in metres above WGS84 ellipsoid in to
// Earth Centered Earth Fixed frame cartesian coordinates
// See Cesium.Cartesian3.fromDegrees
QVector3D CZML::cartesian3FromDegrees(double longitude, double latitude, double height) const
{
return cartesianFromRadians(Units::degreesToRadians(longitude), Units::degreesToRadians(latitude), height);
}
// FIXME: QVector3D is only float!
// See Cesium.Cartesian3.fromRadians
QVector3D CZML::cartesianFromRadians(double longitude, double latitude, double height) const
{
QVector3D wgs84RadiiSquared(6378137.0 * 6378137.0, 6378137.0 * 6378137.0, 6356752.3142451793 * 6356752.3142451793);
double cosLatitude = cos(latitude);
QVector3D n;
n.setX(cosLatitude * cos(longitude));
n.setY(cosLatitude * sin(longitude));
n.setZ(sin(latitude));
n.normalize();
QVector3D k;
k = wgs84RadiiSquared * n;
double gamma = sqrt(QVector3D::dotProduct(n, k));
k = k / gamma;
n = n * height;
return k + n;
}
// Convert heading, pitch and roll in degrees to a quaternoin
// See: Cesium.Quaternion.fromHeadingPitchRoll
QQuaternion CZML::fromHeadingPitchRoll(double heading, double pitch, double roll) const
{
QVector3D xAxis(1, 0, 0);
QVector3D yAxis(0, 1, 0);
QVector3D zAxis(0, 0, 1);
QQuaternion rollQ = QQuaternion::fromAxisAndAngle(xAxis, roll);
QQuaternion pitchQ = QQuaternion::fromAxisAndAngle(yAxis, -pitch);
QQuaternion headingQ = QQuaternion::fromAxisAndAngle(zAxis, -heading);
QQuaternion temp = rollQ * pitchQ;
return headingQ * temp;
}
// Calculate a transformation matrix from a East, North, Up frame at the given position to Earth Centered Earth Fixed frame
// See: Cesium.Transforms.eastNorthUpToFixedFrame
QMatrix4x4 CZML::eastNorthUpToFixedFrame(QVector3D origin) const
{
// TODO: Handle special case at centre of earth and poles
QVector3D up = origin.normalized();
QVector3D east(-origin.y(), origin.x(), 0.0);
east.normalize();
QVector3D north = QVector3D::crossProduct(up, east);
QMatrix4x4 result(
east.x(), north.x(), up.x(), origin.x(),
east.y(), north.y(), up.y(), origin.y(),
east.z(), north.z(), up.z(), origin.z(),
0.0, 0.0, 0.0, 1.0
);
return result;
}
// Convert 3x3 rotation matrix to a quaternoin
// Although there is a method for this in Qt: QQuaternion::fromRotationMatrix, it seems to
// result in different signs, so the following is based on Cesium code
QQuaternion CZML::fromRotation(QMatrix3x3 mat) const
{
QQuaternion q;
double trace = mat(0, 0) + mat(1, 1) + mat(2, 2);
if (trace > 0.0)
{
double root = sqrt(trace + 1.0);
q.setScalar(0.5 * root);
root = 0.5 / root;
q.setX((mat(2,1) - mat(1,2)) * root);
q.setY((mat(0,2) - mat(2,0)) * root);
q.setZ((mat(1,0) - mat(0,1)) * root);
}
else
{
double next[] = {1, 2, 0};
int i = 0;
if (mat(1,1) > mat(0,0)) {
i = 1;
}
if (mat(2,2) > mat(0,0) && mat(2,2) > mat(1,1)) {
i = 2;
}
int j = next[i];
int k = next[j];
double root = sqrt(mat(i,i) - mat(j,j) - mat(k,k) + 1);
double quat[] = {0.0, 0.0, 0.0};
quat[i] = 0.5 * root;
root = 0.5 / root;
q.setScalar((mat(j,k) - mat(k,j)) * root);
quat[j] = (mat(i,j) + mat(j,i)) * root;
quat[k] = (mat(i,k) + mat(k,i)) * root;
q.setX(-quat[0]);
q.setY(-quat[1]);
q.setZ(-quat[2]);
}
return q;
}
// Calculate orientation quaternion for a model (such as an aircraft) based on position and (HPR) heading, pitch and roll (in degrees)
// While Cesium supports specifying orientation as HPR, CZML doesn't currently. See https://github.com/CesiumGS/cesium/issues/5184
// CZML requires the orientation to be in the Earth Centered Earth Fixed (geocentric) reference frame (https://en.wikipedia.org/wiki/Local_tangent_plane_coordinates)
// The orientation therefore depends not only on HPR but also on position
//
// glTF uses a right-handed axis convention; that is, the cross product of right and forward yields up. glTF defines +Y as up, +Z as forward, and -X as right.
// Cesium.Quaternion.fromHeadingPitchRoll Heading is the rotation about the negative z axis. Pitch is the rotation about the negative y axis. Roll is the rotation about the positive x axis.
QQuaternion CZML::orientation(double longitude, double latitude, double altitude, double heading, double pitch, double roll) const
{
// Forward direction for gltf models in Cesium seems to be Eastward, rather than Northward, so we adjust heading by -90 degrees
heading = -90 + heading;
// Convert position to Earth Centered Earth Fixed (ECEF) frame
QVector3D positionECEF = cartesian3FromDegrees(longitude, latitude, altitude);
// Calculate matrix to transform from East, North, Up (ENU) frame to ECEF frame
QMatrix4x4 enuToECEFTransform = eastNorthUpToFixedFrame(positionECEF);
// Calculate rotation based on HPR in ENU frame
QQuaternion hprENU = fromHeadingPitchRoll(heading, pitch, roll);
// Transform rotation from ENU to ECEF
QMatrix3x3 hprENU3 = hprENU.toRotationMatrix();
QMatrix4x4 hprENU4(hprENU3);
QMatrix4x4 transform = enuToECEFTransform * hprENU4;
// Convert from 4x4 matrix to 3x3 matrix then to a quaternion
QQuaternion oq = fromRotation(transform.toGenericMatrix<3,3>());
return oq;
}
QJsonObject CZML::update(MapItem *mapItem, bool isTarget, bool isSelected)
{
@ -316,8 +173,8 @@ QJsonObject CZML::update(MapItem *mapItem, bool isTarget, bool isSelected)
}
}
QQuaternion q = orientation(mapItem->m_longitude, mapItem->m_latitude, mapItem->m_altitude,
mapItem->m_heading, mapItem->m_pitch, mapItem->m_roll);
QQuaternion q = Coordinates::orientation(mapItem->m_longitude, mapItem->m_latitude, mapItem->m_altitude,
mapItem->m_heading, mapItem->m_pitch, mapItem->m_roll);
QJsonArray quaternion;
if (!fixedPosition && mapItem->m_orientationDateTime.isValid()) {
quaternion.push_back(mapItem->m_orientationDateTime.toString(Qt::ISODateWithMs));

12
plugins/feature/map/czml.h
View File

@ -20,10 +20,6 @@
#include <QHash>
#include <QJsonArray>
#include <QMatrix3x3>
#include <QMatrix4x4>
#include <QQuaternion>
#include <QVector3D>
#include <QJsonObject>
struct MapSettings;
@ -42,14 +38,6 @@ public:
QJsonObject init();
QJsonObject update(MapItem *mapItem, bool isTarget, bool isSelected);
protected:
QVector3D cartesian3FromDegrees(double longitude, double latitude, double height=0.0) const;
QVector3D cartesianFromRadians(double longitude, double latitude, double height=0.0) const;
QQuaternion fromHeadingPitchRoll(double heading, double pitch, double roll) const;
QMatrix4x4 eastNorthUpToFixedFrame(QVector3D origin) const;
QQuaternion fromRotation(QMatrix3x3 mat) const;
QQuaternion orientation(double longitude, double latitude, double altitude, double heading, double pitch, double roll) const;
signals:
void connected();
};