import numpy as np
import zarr

cos = zarr.open("PHerc0306B_cos.ome.zarr/1", mode="r")  # every 2nd scan voxel
nx = zarr.open("PHerc0306B_nx.ome.zarr/2", mode="r")    # every 4th scan voxel
ny = zarr.open("PHerc0306B_ny.ome.zarr/2", mode="r")
print("cos", cos.shape, "normals", nx.shape)

z, y, x = 1536, 4424, 4424                             # a point in full-resolution scan voxels
patch = cos[z // 2, y // 2 - 256:y // 2 + 256, x // 2 - 256:x // 2 + 256]
a = (float(nx[z // 4, y // 4, x // 4]) - 128) / 127
b = (float(ny[z // 4, y // 4, x // 4]) - 128) / 127
print("cos patch", patch.shape, "mean", round(float(patch.mean()), 1))
print("normal", round(a, 3), round(b, 3), round(float(np.sqrt(max(0.0, 1 - a * a - b * b))), 3))