GFTTDetector and calcOpticalFlowPyrLK

Hi, Previously I was using good [featuresToTrack](http://docs.opencv.org/3.0-beta/modules/imgproc/doc/feature_detection.html#goodfeaturestotrack) and [calcOpticalFlowPyrLK](http://docs.opencv.org/3.0-beta/modules/video/doc/motion_analysis_and_object_tracking.html#void%20calcOpticalFlowPyrLK%28InputArray%20prevImg,%20InputArray%20nextImg,%20InputArray%20prevPts,%20InputOutputArray%20nextPts,%20OutputArray%20status,%20OutputArray%20err,%20Size%20winSize,%20int%20maxLevel,%20TermCriteria%20criteria,%20int%20flags,%20double%20minEigThreshold%29) to match features. Now I want to use new interface [GFTT](http://docs.opencv.org/3.0-beta/modules/features2d/doc/common_interfaces_of_feature_detectors.html#gfttdetector). In BFMatcher I cannot find an algorithm like calcOpticalFlowPyrLK. So (I think) I need to use previous function calcOpticalFlowPyrLK. But function argument is InputArray prevPts for Point (and not keyPoints). Must I convert keyPoint in cv::Point2f to use this function? Thanks for your help