import os, sys

try:
    raw = sys.argv[1]
    num = int(sys.argv[2])
except:
    print
    print "Usage: python dngfloat_hdr.py abc.dng 5"
    print "     => abc.dng must be a floating-point DNG with white level set to 65535"
    print "     => 5 is the number of LDR exposures (spaced at 2 EV) to be extracted from our DNG and enfused"
    print
    raise SystemExit

def run(cmd):
    print cmd
    os.system(cmd)

try: os.mkdir("tmp")
except: print "warning: could not create tmp dir"

run("rm tmp/*")
for i in range(num-1,-1,-1):
    cmd = "exiftool -overwrite_original -WhiteLevel=%d %s" % (65536*2 / 2**(i*2), raw)
    run(cmd)
    cmd = "dng_validate.exe -16 -tif tmp/%d.tif %s" % (i, raw)
    run(cmd)
run("enfuse tmp/*.tif")