# -*- coding: utf-8 -*-

import numpy as np

# produce dense points
def generate_dense_grid_points(bbox_min: np.ndarray,
                               bbox_max: np.ndarray,
                               octree_depth: int,
                               indexing: str = "ij"):
    length = bbox_max - bbox_min
    num_cells = np.exp2(octree_depth)
    x = np.linspace(bbox_min[0], bbox_max[0], int(num_cells) + 1, dtype=np.float32)
    y = np.linspace(bbox_min[1], bbox_max[1], int(num_cells) + 1, dtype=np.float32)
    z = np.linspace(bbox_min[2], bbox_max[2], int(num_cells) + 1, dtype=np.float32)
    [xs, ys, zs] = np.meshgrid(x, y, z, indexing=indexing)
    xyz = np.stack((xs, ys, zs), axis=-1)
    xyz = xyz.reshape(-1, 3)
    grid_size = [int(num_cells) + 1, int(num_cells) + 1, int(num_cells) + 1]

    return xyz, grid_size, length

