Templated draw_sample method and added overloads for vector<float> and vector<double>

This is mainly to accommodate fit-model-ceres, where I've used double for all parameters

include/eos/fitting/ceres_nonlinear.hpp

@@ -27,6 +27,8 @@
 
 #include "glm/gtc/quaternion.hpp"
 
+#include "ceres/cubic_interpolation.h"
+
 #include "opencv2/core/core.hpp" // for Vec2f
 
 #include <array>

include/eos/morphablemodel/PcaModel.hpp

@@ -158,9 +158,14 @@ public:
 	 * The given coefficients should follow a standard normal distribution, i.e.
 	 * not be "normalised" with their eigenvalues/variances.
 	 *
+	 * @tparam T Precision of the given coefficients - can be double or float.
 	 * @param[in] coefficients The PCA coefficients used to generate the sample.
 	 * @return A model instance with given coefficients.
 	 */
+	template<typename T>
+	cv::Mat draw_sample(std::vector<T> coefficients) const;
+	
+	template<>
 	cv::Mat draw_sample(std::vector<float> coefficients) const
 	{
 		// Fill the rest with zeros if not all coefficients are given:
@@ -174,6 +179,14 @@ public:
 		return model_sample;
 	};
 
+	template<>
+	cv::Mat draw_sample(std::vector<double> coefficients) const
+	{
+		// We have to convert the vector of doubles to float:
+		std::vector<float> coeffs_float(std::begin(coefficients), std::end(coefficients));
+		return draw_sample(coeffs_float);
+	};
+
 	/**
 	 * Returns the PCA basis matrix, i.e. the eigenvectors.
 	 * Each column of the matrix is an eigenvector.