import pfpy

def pfNodeName():
	return 'Filter tracks'

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

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

		# copy tracker so that we can read from it without the data being affected by writing to it as well
		t2= t.copy()

		# loop over every frame
		inp= t.getInPoint();
		outp= t.getOutPoint();
		f= inp;
		while (f <= outp):
			
			# is the tracker visible in these 3 adjacent frames?
			if t.getHidden(f-1) == False and \
			   t.getHidden(f)   == False and \
			   t.getHidden(f+1) == False :
				
				# fetch tracker positions in each frame (read from the copy)
				lp= t2.getTrackPosition(f-1)
				cp= t2.getTrackPosition(f)
				np= t2.getTrackPosition(f+1)
				
				# store averaged tracker position
				t.setTrackPosition(f, (lp[0]+cp[0]+np[0])/3.0, (lp[1]+cp[1]+np[1])/3.0)

			f += 1
				
		# free the copied tracker data
		t2.freeCopy()
				
		idx += 1

	print("filtered ", num, " trackers")