/**
* Generate the rotation matrix to rotate to this point.
* @param a :: The x mouse coordinate
* @param b :: The y mouse coordinate
*/
void Viewport::generateRotationTo(int a,int b)
{
Mantid::Kernel::V3D newpoint;
projectOnSphere( a, b, newpoint );
Mantid::Kernel::V3D diff( m_lastpoint );
// Difference between old point and new point
diff -= newpoint;
// Angle is given in degrees as the dot product of the two vectors
double angle = m_rotationspeed * newpoint.angle( m_lastpoint );
diff = m_lastpoint.cross_prod( newpoint );
// Create a quaternion from the angle and vector direction
Mantid::Kernel::Quat temp( angle, diff );
// Left multiply
temp *= m_quaternion;
// Assignment of _quaternion
m_quaternion( temp );
// Get the corresponding OpenGL rotation matrix
m_quaternion.GLMatrix( &m_rotationmatrix[0] );
}
/**
* Start a trackball rotation from here.
* @param a :: The x mouse coordinate
* @param b :: The y mouse coordinate
*/
void Viewport::initRotationFrom(int a,int b)
{
projectOnSphere(a,b,m_lastpoint);
}
void GLTrackball::initRotationFrom(int a,int b)
{
projectOnSphere(a,b,_lastpoint);
}