import cv2
import numpy as np

cap = cv2.VideoCapture(0)

def mayorContorno(contornos):
        mayor=0;puntosmax=0;i=0
        for cont in contornos:
        #       print puntosmax, len(cont)
                if puntosmax < len(cont):
                        mayor = i
                        puntosmax=len(cont)
                i = i + 1
        return mayor


while(1):
    	ret ,frame = cap.read()
	img_gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
	ret, thresh = cv2.threshold(img_gray, 127, 255,0)
	contours,hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
	cnt = contours[mayorContorno(contours)]

	#print len(cnt),cnt
	if len(cnt) > 5:
		hull = cv2.convexHull(cnt,returnPoints = False)

		defects = cv2.convexityDefects(cnt,hull)
		#print type(defects)
		if defects is None:
			print "nada"
		else:
		  for i in range(defects.shape[0]):
		    s,e,f,d = defects[i,0]
		    start = tuple(cnt[s][0])
		    end = tuple(cnt[e][0])
		    far = tuple(cnt[f][0])
		    cv2.line(frame,start,end,[0,255,0],2)
		    cv2.circle(frame,far,5,[0,0,255],-1)

	cv2.imshow('img',frame)
 	k = cv2.waitKey(60) & 0xff
        if k == 27:
            break

cv2.destroyAllWindows()
cap.release()