message: Change get_mean_at_point() to return an Eigen::Vector3f
  This removes the last usage of OpenCV in PcaModel.
diff: #include "Eigen/Core"
  -#include "opencv2/core/core.hpp"
  -
  #include <string>
  #include <vector>
  #include <array>
  @@ -123,15 +121,14 @@ public:
  /**
  * Return the value of the mean at a given vertex index.
  *
  - * I think we should just return an Eigen::Vector3f - homogenous coords have no place here?
  - *
  * @param[in] vertex_index A vertex index.
  - * @return A homogeneous vector containing the values at the given vertex index.
  + * @return A 3-dimensional vector containing the values at the given vertex index.
  */
  - cv::Vec4f get_mean_at_point(int vertex_index) const
  + Eigen::Vector3f get_mean_at_point(int vertex_index) const
  {
  vertex_index *= 3;
  - return cv::Vec4f(mean(vertex_index), mean(vertex_index + 1), mean(vertex_index + 2), 1.0f);
  + // Note: We could maybe also return a const& to mean.block(...).
  + return Eigen::Vector3f(mean(vertex_index), mean(vertex_index + 1), mean(vertex_index + 2));
  };
  /**
  