a.cpp

// Get the 2D shape (in image space) from global and local parameters
void PDM::CalcShape2D(cv::Mat_<double>& out_shape, const cv::Mat_<double>& params_local, const cv::Vec6d& params_global) const
{

	int n = this->NumberOfPoints();

	double s = params_global[0]; // scaling factor
	double tx = params_global[4]; // x offset
	double ty = params_global[5]; // y offset

	// get the rotation matrix from the euler angles
	cv::Vec3d euler(params_global[1], params_global[2], params_global[3]);
	cv::Matx33d currRot = Euler2RotationMatrix(euler);
	
	// get the 3D shape of the object
	cv::Mat_<double> Shape_3D = mean_shape + princ_comp * params_local;

	// create the 2D shape matrix (if it has not been defined yet)
	if((out_shape.rows != mean_shape.rows) || (out_shape.cols != 1))
	{
		out_shape.create(2*n,1);
	}
	// for every vertex
	for(int i = 0; i < n; i++)
	{
		// Transform this using the weak-perspective mapping to 2D from 3D
		out_shape.at<double>(i  ,0) = s * ( currRot(0,0) * Shape_3D.at<double>(i, 0) + currRot(0,1) * Shape_3D.at<double>(i+n  ,0) + currRot(0,2) * Shape_3D.at<double>(i+n*2,0) ) + tx;
		out_shape.at<double>(i+n,0) = s * ( currRot(1,0) * Shape_3D.at<double>(i, 0) + currRot(1,1) * Shape_3D.at<double>(i+n  ,0) + currRot(1,2) * Shape_3D.at<double>(i+n*2,0) ) + ty;
	}
}