import open3d as o3d
import numpy as np

# --------------------------- 加载点云 ---------------------------
print("->正在加载点云... ")
# ply = o3d.io.read_point_cloud("../laser1.ply")
pcd = o3d.io.read_point_cloud("./data/PointClound_01.ply")

# 展示点云、打印点云
print('pcd data: ~~~~~~~~~~~~~~~~~~~')
print(pcd)
# print(np.asarray(pcd.points))
# print(np.asarray(pcd.normals))
# print(np.asarray(pcd.covariances))
# print(np.asarray(pcd.colors))
print('end of pcd data ~~~~~~~~~~~~~~~~~~~')
axes = o3d.geometry.TriangleMesh.create_coordinate_frame()
o3d.visualization.draw([pcd, axes])

# 降采样
pcd = pcd.voxel_down_sample(voxel_size=0.1)
o3d.visualization.draw([pcd])

# ------------------------- Alpha shapes -----------------------
alpha = 20
print(f"alpha={alpha:.3f}")
mesh = o3d.geometry.TriangleMesh.create_from_point_cloud_alpha_shape(pcd, alpha)
mesh.compute_vertex_normals()
o3d.visualization.draw_geometries([mesh], mesh_show_back_face=True)
volume = mesh.get_volume()      # 计算体积
print("体积为：", volume)
# ==============================================================