void Trackball::UpdateBall(double x, double y)
{
Vec3d toPos = MouseOnSphere(x,y);
Vec4d newQuat = Qt_FromBallPoints(mStartPos, toPos);
mStartPos = toPos;
mCurrQuat = Qt_Mul(newQuat, mCurrQuat);
}
void
ArcBall_Update (void)
{
int setSize = setSizes[axisSet];
HVect *set = (HVect *)(sets[axisSet]);
vFrom = MouseOnSphere(vDown, center, radius);
vTo = MouseOnSphere(vNow, center, radius);
if (dragging)
{
if (axisSet!=NoAxes)
{
vFrom = ConstrainToAxis(vFrom, set[axisIndex]);
vTo = ConstrainToAxis(vTo, set[axisIndex]);
}
qDrag = Qt_FromBallPoints(vFrom, vTo);
qNow = Qt_Mul(qDrag, qDown);
}
else
{
if (axisSet!=NoAxes) axisIndex = NearestConstraintAxis(vTo, set, setSize);
}
Qt_ToBallPoints(qDown, &vrFrom, &vrTo);
Qt_ToMatrix(Qt_Conj(qNow), mNow); /* Gives transpose for GL. */
}
