70 lines
1.8 KiB
Python
Executable File
70 lines
1.8 KiB
Python
Executable File
#!/usr/bin/env 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
|
|
|
|
# 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()
|
|
|
|
# Load a mesh in OFF format
|
|
igl.readOFF(TUTORIAL_SHARED_PATH + "cheburashka.off", V, F)
|
|
|
|
# Read scalar function values from a file, U: #V by 1
|
|
U = igl.eigen.MatrixXd()
|
|
igl.readDMAT(TUTORIAL_SHARED_PATH + "cheburashka-scalar.dmat", U)
|
|
U = U.col(0)
|
|
|
|
# Compute gradient operator: #F*3 by #V
|
|
G = igl.eigen.SparseMatrixd()
|
|
igl.grad(V, F, G)
|
|
|
|
# Compute gradient of U
|
|
GU = (G * U).MapMatrix(F.rows(), 3)
|
|
|
|
# Compute gradient magnitude
|
|
GU_mag = GU.rowwiseNorm()
|
|
|
|
viewer = igl.glfw.Viewer()
|
|
viewer.data().set_mesh(V, F)
|
|
|
|
# Compute pseudocolor for original function
|
|
C = igl.eigen.MatrixXd()
|
|
|
|
igl.jet(U, True, C)
|
|
|
|
# Or for gradient magnitude
|
|
# igl.jet(GU_mag,True,C)
|
|
|
|
viewer.data().set_colors(C)
|
|
|
|
# Average edge length divided by average gradient (for scaling)
|
|
max_size = igl.avg_edge_length(V, F) / GU_mag.mean()
|
|
|
|
# Draw a black segment in direction of gradient at face barycenters
|
|
BC = igl.eigen.MatrixXd()
|
|
igl.barycenter(V, F, BC)
|
|
|
|
black = igl.eigen.MatrixXd([[0.0, 0.0, 0.0]])
|
|
viewer.data().add_edges(BC, BC + max_size * GU, black)
|
|
|
|
# Hide wireframe
|
|
viewer.data().show_lines = False
|
|
|
|
viewer.launch()
|