def rotateHue(self, tex, value=0.1):
'''
'''
img = PNMImage()
tex.store(img)
for y in range(img.getReadYSize()):
for x in range(img.getReadXSize()):
r, g, b = img.getXel(x, y)
h, s, v = colorsys.rgb_to_hsv(r, g, b)
h += value
if h < 0:
h += 360
r, g, b = colorsys.hsv_to_rgb(h, s, v)
img.setXel(x, y, r, g, b)
tex.load(img)
