import math
import cv2
import numpy

xlist=[]
ylist=[]

xres=1600/2
yres=900/2

#constant = 1./math.sqrt((xres/2)**2 + (yres/2)**2)
constant = 30./41.5*3
# found out experimentally
constant2= 1./(1280/2.)*math.atan(30./40)
print constant2

# calculated from official spec: maximum angle (i.e., over the diagonals)
# is 92 deg. -> angle over half a diagonal's length is 92/2 deg
constant2= 1./(math.sqrt((1280/2)**2+(720/2)**2))*(92/2)/180*math.pi
print constant2

for y in xrange(0,yres):
    xtmp=[]
    ytmp=[]

    yy=(y-yres/2.)/xres # yes, xres.
    for x in xrange(0,xres):
        xx=(x-xres/2.)/xres

        dist = math.sqrt(xx**2 + yy**2)
        
        if (dist != 0):
            xtmp=xtmp+[ 1280/2+  xx/dist/constant2*math.atan(constant*dist)  ]
            ytmp=ytmp+[ 720/2 +  yy/dist/constant2*math.atan(constant*dist)  ]
        else:
            xtmp=xtmp+[0+1280/2]
            ytmp=ytmp+[0+720/2]
        
    xlist=xlist+[xtmp]
    ylist=ylist+[ytmp]
    
    if y % 10 == 0:
        print y

xmap=numpy.array(xlist).astype('float32')
ymap=numpy.array(ylist).astype('float32')

img=cv2.imread("cam42.png")
img2=cv2.remap(img, xmap, ymap, cv2.INTER_CUBIC)

cv2.imshow("orig", img)
cv2.imshow("remap", img2)

print img2.shape

while cv2.waitKey(50) & 256 != ord("q"):
    pass