Method getRotationMatrix

apps/point_cloud_editor/src/trackball.cpp:162–200

}

void
TrackBall::getRotationMatrix(float (&rot)[MATRIX_SIZE])
{
  // This function is based on quaternion_to_R3_rotation from
  // http://www.boost.org/doc/libs/1_41_0/libs/math/quaternion/HSO3.hpp
    
  float a = quat_.R_component_1();
  float b = quat_.R_component_2();
  float c = quat_.R_component_3();
  float d = quat_.R_component_4();
    
  float aa = a*a;
  float ab = a*b;
  float ac = a*c;
  float ad = a*d;
  float bb = b*b;
  float bc = b*c;
  float bd = b*d;
  float cc = c*c;
  float cd = c*d;
  float dd = d*d;
    
  setIdentity(rot);
  float n = aa + bb + cc + dd;
    
  if (n <= std::numeric_limits<float>::epsilon())
    return;

  // fill the upper 3x3
  rot[0] = (aa + bb - cc - dd);
  rot[1] = 2 * (-ad + bc);
  rot[2] = 2 * (ac + bd);
  rot[MATRIX_SIZE_DIM+0] = 2 * (ad + bc);
  rot[MATRIX_SIZE_DIM+1] = (aa - bb + cc - dd);
  rot[MATRIX_SIZE_DIM+2] = 2 * (-ab + cd);
  rot[2*MATRIX_SIZE_DIM+0] = 2 * (-ac + bd);
  rot[2*MATRIX_SIZE_DIM+1] = 2 * (ab + cd);
  rot[2*MATRIX_SIZE_DIM+2] = (aa - bb - cc + dd);
}

void
TrackBall::reset()