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igl/python/tutorial/704_SignedDistance.py
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Python

# This file is part of libigl, a simple c++ geometry processing library.
#
# Copyright (C) 2017 Sebastian Koch <s.koch@tu-berlin.de> and Daniele Panozzo <daniele.panozzo@gmail.com>
#
# This Source Code Form is subject to the terms of the Mozilla Public License
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at http://mozilla.org/MPL/2.0/.
import sys, os
import math
# Add the igl library to the modules search path
sys.path.insert(0, os.getcwd() + "/../")
import pyigl as igl
from shared import TUTORIAL_SHARED_PATH, check_dependencies
dependencies = ["glfw"]
check_dependencies(dependencies)
V = igl.eigen.MatrixXd()
F = igl.eigen.MatrixXi()
T = igl.eigen.MatrixXi()
tree = igl.AABB()
FN = igl.eigen.MatrixXd()
VN = igl.eigen.MatrixXd()
EN = igl.eigen.MatrixXd()
E = igl.eigen.MatrixXi()
EMAP = igl.eigen.MatrixXi()
max_distance = 1
slice_z = 0.5
overlay = False
viewer = igl.glfw.Viewer()
def append_mesh(C_vis, F_vis, V_vis, V, F, color):
F_vis.conservativeResize(F_vis.rows() + F.rows(), 3)
F_vis.setBottomRows(F.rows(), F + V_vis.rows())
V_vis.conservativeResize(V_vis.rows() + V.rows(), 3)
V_vis.setBottomRows(V.rows(), V)
C_vis.conservativeResize(C_vis.rows() + V.rows(), 3)
colorM = igl.eigen.MatrixXd(V.rows(), C_vis.cols())
colorM.rowwiseSet(color)
C_vis.setBottomRows(V.rows(), colorM)
def update_visualization(viewer):
global V, F, T, tree, FN, VN, EN, E, EMAP, max_distance, slice_z, overlay
plane = igl.eigen.MatrixXd([0.0, 0.0, 1.0, -((1 - slice_z) * V.col(2).minCoeff() + slice_z * V.col(2).maxCoeff())])
V_vis = igl.eigen.MatrixXd()
F_vis = igl.eigen.MatrixXi()
# Extract triangle mesh slice through volume mesh and subdivide nasty triangles
J = igl.eigen.MatrixXi()
bary = igl.eigen.SparseMatrixd()
igl.slice_tets(V, T, plane, V_vis, F_vis, J, bary)
max_l = 0.03
while True:
l = igl.eigen.MatrixXd()
igl.edge_lengths(V_vis, F_vis, l)
l /= (V_vis.colwiseMaxCoeff() - V_vis.colwiseMinCoeff()).norm()
if l.maxCoeff() < max_l:
break
bad = l.rowwiseMaxCoeff() > max_l
notbad = l.rowwiseMaxCoeff() <= max_l # TODO replace by ~ operator
F_vis_bad = igl.eigen.MatrixXi()
F_vis_good = igl.eigen.MatrixXi()
igl.slice_mask(F_vis, bad, 1, F_vis_bad)
igl.slice_mask(F_vis, notbad, 1, F_vis_good)
igl.upsample(V_vis, F_vis_bad)
F_vis = igl.cat(1, F_vis_bad, F_vis_good)
# Compute signed distance
S_vis = igl.eigen.MatrixXd()
I = igl.eigen.MatrixXi()
N = igl.eigen.MatrixXd()
C = igl.eigen.MatrixXd()
# Bunny is a watertight mesh so use pseudonormal for signing
igl.signed_distance_pseudonormal(V_vis, V, F, tree, FN, VN, EN, EMAP, S_vis, I, C, N)
# push to [0,1] range
S_vis = 0.5 * (S_vis / max_distance) + 0.5
C_vis = igl.eigen.MatrixXd()
# color without normalizing
igl.parula(S_vis, False, C_vis)
if overlay:
append_mesh(C_vis, F_vis, V_vis, V, F, igl.eigen.MatrixXd([[0.8, 0.8, 0.8]]))
viewer.data().clear()
viewer.data().set_mesh(V_vis, F_vis)
viewer.data().set_colors(C_vis)
viewer.core.lighting_factor = overlay
def key_down(viewer, key, modifier):
global slice_z, overlay
if key == ord(' '):
overlay = not overlay
elif key == ord('.'):
slice_z = min(slice_z + 0.01, 0.99)
elif key == ord(','):
slice_z = max(slice_z - 0.01, 0.01)
else:
return False
update_visualization(viewer)
return True
print("Press [space] to toggle showing surface.")
print("Press '.'/',' to push back/pull forward slicing plane.")
# Load mesh: (V,T) tet-mesh of convex hull, F contains original surface triangles
igl.readMESH(TUTORIAL_SHARED_PATH + "bunny.mesh", V, T, F)
# Call to point_mesh_squared_distance to determine bounds
sqrD = igl.eigen.MatrixXd()
I = igl.eigen.MatrixXi()
C = igl.eigen.MatrixXd()
igl.point_mesh_squared_distance(V, V, F, sqrD, I, C)
max_distance = math.sqrt(sqrD.maxCoeff())
# Precompute signed distance AABB tree
tree.init(V, F)
# Precompute vertex, edge and face normals
igl.per_face_normals(V, F, FN)
igl.per_vertex_normals(V, F, igl.PER_VERTEX_NORMALS_WEIGHTING_TYPE_ANGLE, FN, VN)
igl.per_edge_normals(V, F, igl.PER_EDGE_NORMALS_WEIGHTING_TYPE_UNIFORM, FN, EN, E, EMAP)
# Plot the generated mesh
update_visualization(viewer)
viewer.callback_key_down = key_down
viewer.data().show_lines = False
viewer.launch()