import math, pfpy

def pfNodeName():
	return 'Hide bad points'

def calcResidual(a, b):
        return math.sqrt((a[0]-b[0])*(a[0]-b[0])+(a[1]-b[1])*(a[1]-b[1]))

def main():
	# how many trackers?
	num= pfpy.getNumTrackers()

        # fetch the camera
	cam= pfpy.getCameraRef(0)

	# loop over every tracker
	idx= 0
	while (idx < num):
		
                # fetch a reference to this tracker
                t= pfpy.getTrackerRef(idx)

                # is the tracker solved?
                if t.getSolved() :

                        # fetch the tracker's 3D point position
                        X= t.getSolvedPos()

                        # loop over every frame
                        inp= t.getInPoint();
                        outp= t.getOutPoint();
                        f= inp;
                        while (f <= outp):
			
                                # is the tracker visible in this frame?
                                if t.getHidden(f) == False :

                                        # is the tracker infront of the camera?
                                        if cam.inFront(f, X) :

                                                # project the tracker into the camera
                                                proj= cam.project(f, X)

                                                # fetch the tracker position in the image
                                                pos= t.getTrackPosition(f)

                                                # calculate the distance between the points
                                                err= calcResidual(proj, pos)

                                                # more than two pixels difference?
                                                if err > 2.0 :

                                                        # hide the tracker in this frame
                                                        t.setHidden(f, True)

                                                        print("Removed", t.getName(), "from frame", f, "error:", err)

                                f += 1
				
                idx += 1

	print("Done")