pytorch3d/tests/test_sample_points_from_mes...

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Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.
import unittest
import numpy as np
import torch
from PIL import Image
from pytorch3d.io import load_objs_as_meshes
from pytorch3d.ops import sample_points_from_meshes
from pytorch3d.renderer import TexturesVertex
from pytorch3d.renderer.cameras import FoVPerspectiveCameras, look_at_view_transform
from pytorch3d.renderer.mesh.rasterize_meshes import barycentric_coordinates
from pytorch3d.renderer.points import (
NormWeightedCompositor,
PointsRasterizationSettings,
PointsRasterizer,
PointsRenderer,
)
from pytorch3d.structures import Meshes, Pointclouds
from pytorch3d.utils.ico_sphere import ico_sphere
from .common_testing import (
get_pytorch3d_dir,
get_random_cuda_device,
get_tests_dir,
TestCaseMixin,
)
# If DEBUG=True, save out images generated in the tests for debugging.
# All saved images have prefix DEBUG_
DEBUG = False
DATA_DIR = get_tests_dir() / "data"
def init_meshes(
num_meshes: int = 10,
num_verts: int = 1000,
num_faces: int = 3000,
device: str = "cpu",
add_texture: bool = False,
):
device = torch.device(device)
verts_list = []
faces_list = []
texts_list = []
for _ in range(num_meshes):
verts = torch.rand((num_verts, 3), dtype=torch.float32, device=device)
faces = torch.randint(
num_verts, size=(num_faces, 3), dtype=torch.int64, device=device
)
texts = torch.rand((num_verts, 3), dtype=torch.float32, device=device)
verts_list.append(verts)
faces_list.append(faces)
texts_list.append(texts)
# create textures
textures = None
if add_texture:
textures = TexturesVertex(texts_list)
meshes = Meshes(verts=verts_list, faces=faces_list, textures=textures)
return meshes
class TestSamplePoints(TestCaseMixin, unittest.TestCase):
def setUp(self) -> None:
super().setUp()
torch.manual_seed(1)
def test_all_empty_meshes(self):
"""
Check sample_points_from_meshes raises an exception if all meshes are
invalid.
"""
device = get_random_cuda_device()
verts1 = torch.tensor([], dtype=torch.float32, device=device)
faces1 = torch.tensor([], dtype=torch.int64, device=device)
meshes = Meshes(verts=[verts1, verts1, verts1], faces=[faces1, faces1, faces1])
with self.assertRaises(ValueError) as err:
sample_points_from_meshes(meshes, num_samples=100, return_normals=True)
self.assertTrue("Meshes are empty." in str(err.exception))
def test_sampling_output(self):
"""
Check outputs of sampling are correct for different meshes.
For an ico_sphere, the sampled vertices should lie on a unit sphere.
For an empty mesh, the samples and normals should be 0.
"""
device = get_random_cuda_device()
# Unit simplex.
verts_pyramid = torch.tensor(
[[0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]],
dtype=torch.float32,
device=device,
)
faces_pyramid = torch.tensor(
[[0, 1, 2], [0, 2, 3], [0, 1, 3], [1, 2, 3]],
dtype=torch.int64,
device=device,
)
sphere_mesh = ico_sphere(9, device)
verts_sphere, faces_sphere = sphere_mesh.get_mesh_verts_faces(0)
verts_empty = torch.tensor([], dtype=torch.float32, device=device)
faces_empty = torch.tensor([], dtype=torch.int64, device=device)
num_samples = 10
meshes = Meshes(
verts=[verts_empty, verts_sphere, verts_pyramid],
faces=[faces_empty, faces_sphere, faces_pyramid],
)
samples, normals = sample_points_from_meshes(
meshes, num_samples=num_samples, return_normals=True
)
samples = samples.cpu()
normals = normals.cpu()
self.assertEqual(samples.shape, (3, num_samples, 3))
self.assertEqual(normals.shape, (3, num_samples, 3))
# Empty meshes: should have all zeros for samples and normals.
self.assertClose(samples[0, :], torch.zeros((num_samples, 3)))
self.assertClose(normals[0, :], torch.zeros((num_samples, 3)))
# Sphere: points should have radius 1.
x, y, z = samples[1, :].unbind(1)
radius = torch.sqrt(x**2 + y**2 + z**2)
self.assertClose(radius, torch.ones(num_samples))
# Pyramid: points shoudl lie on one of the faces.
pyramid_verts = samples[2, :]
pyramid_normals = normals[2, :]
self.assertClose(pyramid_verts.lt(1).float(), torch.ones_like(pyramid_verts))
self.assertClose((pyramid_verts >= 0).float(), torch.ones_like(pyramid_verts))
# Face 1: z = 0, x + y <= 1, normals = (0, 0, 1).
face_1_idxs = pyramid_verts[:, 2] == 0
face_1_verts, face_1_normals = (
pyramid_verts[face_1_idxs, :],
pyramid_normals[face_1_idxs, :],
)
self.assertTrue(torch.all((face_1_verts[:, 0] + face_1_verts[:, 1]) <= 1))
self.assertClose(
face_1_normals,
torch.tensor([0, 0, 1], dtype=torch.float32).expand(face_1_normals.size()),
)
# Face 2: x = 0, z + y <= 1, normals = (1, 0, 0).
face_2_idxs = pyramid_verts[:, 0] == 0
face_2_verts, face_2_normals = (
pyramid_verts[face_2_idxs, :],
pyramid_normals[face_2_idxs, :],
)
self.assertTrue(torch.all((face_2_verts[:, 1] + face_2_verts[:, 2]) <= 1))
self.assertClose(
face_2_normals,
torch.tensor([1, 0, 0], dtype=torch.float32).expand(face_2_normals.size()),
)
# Face 3: y = 0, x + z <= 1, normals = (0, -1, 0).
face_3_idxs = pyramid_verts[:, 1] == 0
face_3_verts, face_3_normals = (
pyramid_verts[face_3_idxs, :],
pyramid_normals[face_3_idxs, :],
)
self.assertTrue(torch.all((face_3_verts[:, 0] + face_3_verts[:, 2]) <= 1))
self.assertClose(
face_3_normals,
torch.tensor([0, -1, 0], dtype=torch.float32).expand(face_3_normals.size()),
)
# Face 4: x + y + z = 1, normals = (1, 1, 1)/sqrt(3).
face_4_idxs = pyramid_verts.gt(0).all(1)
face_4_verts, face_4_normals = (
pyramid_verts[face_4_idxs, :],
pyramid_normals[face_4_idxs, :],
)
self.assertClose(face_4_verts.sum(1), torch.ones(face_4_verts.size(0)))
self.assertClose(
face_4_normals,
(
torch.tensor([1, 1, 1], dtype=torch.float32)
/ torch.sqrt(torch.tensor(3, dtype=torch.float32))
).expand(face_4_normals.size()),
)
def test_multinomial(self):
"""
Confirm that torch.multinomial does not sample elements which have
zero probability.
"""
freqs = torch.cuda.FloatTensor(
[
0.0,
0.0,
0.0,
0.0,
0.0,
0.0,
0.0,
0.0,
0.0,
0.03178183361887932,
0.027680952101945877,
0.033176131546497345,
0.046052902936935425,
0.07742464542388916,
0.11543981730937958,
0.14148041605949402,
0.15784293413162231,
0.13180233538150787,
0.08271478116512299,
0.049702685326337814,
0.027557924389839172,
0.018125897273421288,
0.011851548217236996,
0.010252203792333603,
0.007422595750540495,
0.005372154992073774,
0.0045109698548913,
0.0036087757907807827,
0.0035267581697553396,
0.0018864056328311563,
0.0024605290964245796,
0.0022964938543736935,
0.0018453967059031129,
0.0010662291897460818,
0.0009842115687206388,
0.00045109697384759784,
0.0007791675161570311,
0.00020504408166743815,
0.00020504408166743815,
0.00020504408166743815,
0.00012302644609007984,
0.0,
0.00012302644609007984,
4.100881778867915e-05,
0.0,
0.0,
0.0,
0.0,
0.0,
0.0,
]
)
sample = []
for _ in range(1000):
torch.cuda.get_rng_state()
sample = torch.multinomial(freqs, 1000, True)
if freqs[sample].min() == 0:
sample_idx = (freqs[sample] == 0).nonzero()[0][0]
sampled = sample[sample_idx]
print(
"%s th element of last sample was %s, which has probability %s"
% (sample_idx, sampled, freqs[sampled])
)
return False
return True
def test_multinomial_weights(self):
"""
Confirm that torch.multinomial does not sample elements which have
zero probability using a real example of input from a training run.
"""
weights = torch.load(get_tests_dir() / "weights.pt")
S = 4096
num_trials = 100
for _ in range(0, num_trials):
weights[weights < 0] = 0.0
samples = weights.multinomial(S, replacement=True)
sampled_weights = weights[samples]
assert sampled_weights.min() > 0
if sampled_weights.min() <= 0:
return False
return True
def test_verts_nan(self):
num_verts = 30
num_faces = 50
for device in ["cpu", "cuda:0"]:
for invalid in ["nan", "inf"]:
verts = torch.rand((num_verts, 3), dtype=torch.float32, device=device)
# randomly assign an invalid type
verts[torch.randperm(num_verts)[:10]] = float(invalid)
faces = torch.randint(
num_verts, size=(num_faces, 3), dtype=torch.int64, device=device
)
meshes = Meshes(verts=[verts], faces=[faces])
with self.assertRaisesRegex(ValueError, "Meshes contain nan or inf."):
sample_points_from_meshes(
meshes, num_samples=100, return_normals=True
)
def test_outputs(self):
for add_texture in (True, False):
meshes = init_meshes(device=torch.device("cuda:0"), add_texture=add_texture)
out1 = sample_points_from_meshes(meshes, num_samples=100)
self.assertTrue(torch.is_tensor(out1))
out2 = sample_points_from_meshes(
meshes, num_samples=100, return_normals=True
)
self.assertTrue(isinstance(out2, tuple) and len(out2) == 2)
if add_texture:
out3 = sample_points_from_meshes(
meshes, num_samples=100, return_textures=True
)
self.assertTrue(isinstance(out3, tuple) and len(out3) == 2)
out4 = sample_points_from_meshes(
meshes, num_samples=100, return_normals=True, return_textures=True
)
self.assertTrue(isinstance(out4, tuple) and len(out4) == 3)
else:
with self.assertRaisesRegex(
ValueError, "Meshes do not contain textures."
):
sample_points_from_meshes(
meshes, num_samples=100, return_textures=True
)
with self.assertRaisesRegex(
ValueError, "Meshes do not contain textures."
):
sample_points_from_meshes(
meshes,
num_samples=100,
return_normals=True,
return_textures=True,
)
def test_texture_sampling(self):
device = torch.device("cuda:0")
batch_size = 6
# verts
verts = torch.rand((batch_size, 6, 3), device=device, dtype=torch.float32)
verts[:, :3, 2] = 1.0
verts[:, 3:, 2] = -1.0
# textures
texts = torch.rand((batch_size, 6, 3), device=device, dtype=torch.float32)
# faces
faces = torch.tensor([[0, 1, 2], [3, 4, 5]], device=device, dtype=torch.int64)
faces = faces.view(1, 2, 3).expand(batch_size, -1, -1)
meshes = Meshes(verts=verts, faces=faces, textures=TexturesVertex(texts))
num_samples = 24
samples, normals, textures = sample_points_from_meshes(
meshes, num_samples=num_samples, return_normals=True, return_textures=True
)
textures_naive = torch.zeros(
(batch_size, num_samples, 3), dtype=torch.float32, device=device
)
for n in range(batch_size):
for i in range(num_samples):
p = samples[n, i]
if p[2] > 0.0: # sampled from 1st face
v0, v1, v2 = verts[n, 0, :2], verts[n, 1, :2], verts[n, 2, :2]
w0, w1, w2 = barycentric_coordinates(p[:2], v0, v1, v2)
t0, t1, t2 = texts[n, 0], texts[n, 1], texts[n, 2]
else: # sampled from 2nd face
v0, v1, v2 = verts[n, 3, :2], verts[n, 4, :2], verts[n, 5, :2]
w0, w1, w2 = barycentric_coordinates(p[:2], v0, v1, v2)
t0, t1, t2 = texts[n, 3], texts[n, 4], texts[n, 5]
tt = w0 * t0 + w1 * t1 + w2 * t2
textures_naive[n, i] = tt
self.assertClose(textures, textures_naive)
def test_texture_sampling_cow(self):
# test texture sampling for the cow example by converting
# the cow mesh and its texture uv to a pointcloud with texture
device = torch.device("cuda:0")
obj_dir = get_pytorch3d_dir() / "docs/tutorials/data"
obj_filename = obj_dir / "cow_mesh/cow.obj"
for text_type in ("uv", "atlas"):
# Load mesh + texture
if text_type == "uv":
mesh = load_objs_as_meshes(
[obj_filename], device=device, load_textures=True, texture_wrap=None
)
elif text_type == "atlas":
mesh = load_objs_as_meshes(
[obj_filename],
device=device,
load_textures=True,
create_texture_atlas=True,
texture_atlas_size=8,
texture_wrap=None,
)
points, normals, textures = sample_points_from_meshes(
mesh, num_samples=50000, return_normals=True, return_textures=True
)
pointclouds = Pointclouds(points, normals=normals, features=textures)
for pos in ("front", "back"):
# Init rasterizer settings
if pos == "back":
azim = 0.0
elif pos == "front":
azim = 180
R, T = look_at_view_transform(2.7, 0, azim)
cameras = FoVPerspectiveCameras(device=device, R=R, T=T)
raster_settings = PointsRasterizationSettings(
image_size=512, radius=1e-2, points_per_pixel=1
)
rasterizer = PointsRasterizer(
cameras=cameras, raster_settings=raster_settings
)
compositor = NormWeightedCompositor()
renderer = PointsRenderer(rasterizer=rasterizer, compositor=compositor)
images = renderer(pointclouds)
rgb = images[0, ..., :3].squeeze().cpu()
if DEBUG:
filename = "DEBUG_cow_mesh_to_pointcloud_%s_%s.png" % (
text_type,
pos,
)
Image.fromarray((rgb.numpy() * 255).astype(np.uint8)).save(
DATA_DIR / filename
)
@staticmethod
def sample_points_with_init(
num_meshes: int,
num_verts: int,
num_faces: int,
num_samples: int,
device: str = "cpu",
):
verts_list = []
faces_list = []
for _ in range(num_meshes):
verts = torch.rand((num_verts, 3), dtype=torch.float32, device=device)
faces = torch.randint(
num_verts, size=(num_faces, 3), dtype=torch.int64, device=device
)
verts_list.append(verts)
faces_list.append(faces)
meshes = Meshes(verts_list, faces_list)
torch.cuda.synchronize()
def sample_points():
sample_points_from_meshes(
meshes, num_samples=num_samples, return_normals=True
)
torch.cuda.synchronize()
return sample_points