ncode:

depth in [0,1]
depth *= 1 - 1 / (256 * 256 * 256 * 256)
depth in [0,1[

exp = 0
while(depth < 1){
      depth *= 2;
      exp += 1;
}



depth *= 256.0
depth0 = floor(depth)
depth = frac(depth)

depth *= 256.0
depth1 = floor(depth)
depth = frac(depth)

depth *= 256.0
depth2 = floor(depth)
depth = frac(depth)

output : [depth0 / 255.0, depth1 / 255.0, depth2 / 255.0]


###############
decode:
[depth0, depth1, depth2, exp]

depth = depth0 * 255.0 / 256.0 + depth1 * 255.0 / (256.0 * 256.0) + depth2 * 255.0 / (256.0 * 256.0 * 256.0)

while exp != 0 {
  depth = depth / 2;
  exp -= 1;
}



16M [0,1]