RTVector3 RTMath::poseFromAccelMag(const RTVector3& accel, const RTVector3& mag)
{
RTVector3 result;
RTQuaternion m;
RTQuaternion q;
accel.accelToEuler(result);
// q.fromEuler(result);
// since result.z() is always 0, this can be optimized a little
RTFLOAT cosX2 = cos(result.x() / 2.0f);
RTFLOAT sinX2 = sin(result.x() / 2.0f);
RTFLOAT cosY2 = cos(result.y() / 2.0f);
RTFLOAT sinY2 = sin(result.y() / 2.0f);
q.setScalar(cosX2 * cosY2);
q.setX(sinX2 * cosY2);
q.setY(cosX2 * sinY2);
q.setZ(-sinX2 * sinY2);
// q.normalize();
m.setScalar(0);
m.setX(mag.x());
m.setY(mag.y());
m.setZ(mag.z());
m = q * m * q.conjugate();
result.setZ(-atan2(m.y(), m.x()));
return result;
}
void RTFusion::calculatePose(const RTVector3& accel, const RTVector3& mag)
{
RTQuaternion m;
RTQuaternion q;
if (m_enableAccel) {
accel.accelToEuler(m_measuredPose);
} else {
m_measuredPose = m_fusionPose;
m_measuredPose.setZ(0);
}
if (m_enableCompass) {
q.fromEuler(m_measuredPose);
m.setScalar(0);
m.setX(mag.x());
m.setY(mag.y());
m.setZ(mag.z());
m = q * m * q.conjugate();
m_measuredPose.setZ(-atan2(m.y(), m.x()));
} else {
m_measuredPose.setZ(m_fusionPose.z());
}
m_measuredQPose.fromEuler(m_measuredPose);
// check for quaternion aliasing. If the quaternion has the wrong sign
// the kalman filter will be very unhappy.
int maxIndex = -1;
RTFLOAT maxVal = -1000;
for (int i = 0; i < 4; i++) {
if (fabs(m_measuredQPose.data(i)) > maxVal) {
maxVal = fabs(m_measuredQPose.data(i));
maxIndex = i;
}
}
// if the biggest component has a different sign in the measured and kalman poses,
// change the sign of the measured pose to match.
if (((m_measuredQPose.data(maxIndex) < 0) && (m_fusionQPose.data(maxIndex) > 0)) ||
((m_measuredQPose.data(maxIndex) > 0) && (m_fusionQPose.data(maxIndex) < 0))) {
m_measuredQPose.setScalar(-m_measuredQPose.scalar());
m_measuredQPose.setX(-m_measuredQPose.x());
m_measuredQPose.setY(-m_measuredQPose.y());
m_measuredQPose.setZ(-m_measuredQPose.z());
m_measuredQPose.toEuler(m_measuredPose);
}
}