Multiply cv::Mat and std::vector<cv::Point2f>

edit

Without testing, but this should do it:

std::vector< cv::Point2f > Vec = ... ;
std::vector< cv::Point2f > P;
cv::Mat V = M * cv::Mat(Vec, false) /* Vec is just wrapped, no copying is performed */;
V.copyTo( cv::Mat(P, false) );
// P now contains the result