110 lines
2.7 KiB
Python
110 lines
2.7 KiB
Python
# This file is part of libigl, a simple c++ geometry processing library.
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#
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# Copyright (C) 2017 Sebastian Koch <s.koch@tu-berlin.de> and Daniele Panozzo <daniele.panozzo@gmail.com>
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#
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# This Source Code Form is subject to the terms of the Mozilla Public License
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# v. 2.0. If a copy of the MPL was not distributed with this file, You can
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# obtain one at http://mozilla.org/MPL/2.0/.
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import sys, os
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# Add the igl library to the modules search path
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sys.path.insert(0, os.getcwd() + "/../")
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import pyigl as igl
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from shared import TUTORIAL_SHARED_PATH, check_dependencies
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dependencies = ["glfw"]
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check_dependencies(dependencies)
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V = igl.eigen.MatrixXd()
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F = igl.eigen.MatrixXi()
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igl.readOFF(TUTORIAL_SHARED_PATH + "cheburashka.off", V, F)
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# Two fixed points
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# Left hand, left foot
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b = igl.eigen.MatrixXd([[4331], [5957]]).castint()
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bc = igl.eigen.MatrixXd([[1], [-1]])
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# Construct Laplacian and mass matrix
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L = igl.eigen.SparseMatrixd()
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M = igl.eigen.SparseMatrixd()
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Minv = igl.eigen.SparseMatrixd()
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Q = igl.eigen.SparseMatrixd()
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igl.cotmatrix(V, F, L)
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igl.massmatrix(V, F, igl.MASSMATRIX_TYPE_VORONOI, M)
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igl.invert_diag(M, Minv)
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# Bi-Laplacian
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Q = L * (Minv * L)
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# Zero linear term
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B = igl.eigen.MatrixXd.Zero(V.rows(), 1)
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Z = igl.eigen.MatrixXd()
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Z_const = igl.eigen.MatrixXd()
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# Alternative, short hand
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mqwf = igl.min_quad_with_fixed_data()
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# Empty constraints
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Beq = igl.eigen.MatrixXd()
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Aeq = igl.eigen.SparseMatrixd()
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igl.min_quad_with_fixed_precompute(Q, b, Aeq, True, mqwf)
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igl.min_quad_with_fixed_solve(mqwf, B, bc, Beq, Z)
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# Constraint forcing difference of two points to be 0
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Aeq = igl.eigen.SparseMatrixd(1, V.rows())
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# Right hand, right foot
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Aeq.insert(0, 6074, 1)
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Aeq.insert(0, 6523, -1)
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Aeq.makeCompressed()
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Beq = igl.eigen.MatrixXd([[0]])
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igl.min_quad_with_fixed_precompute(Q, b, Aeq, True, mqwf)
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igl.min_quad_with_fixed_solve(mqwf, B, bc, Beq, Z_const)
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# Global definitions for viewer
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# Pseudo-color based on solution
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C = igl.eigen.MatrixXd()
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C_const = igl.eigen.MatrixXd()
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toggle = True
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# Use same color axes
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min_z = min(Z.minCoeff(), Z_const.minCoeff())
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max_z = max(Z.maxCoeff(), Z_const.maxCoeff())
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igl.jet(Z, min_z, max_z, C)
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igl.jet(Z_const, min_z, max_z, C_const)
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# Plot the mesh with pseudocolors
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viewer = igl.glfw.Viewer()
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viewer.data().set_mesh(V, F)
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viewer.data().show_lines = False
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viewer.data().set_colors(C)
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def key_down(viewer, key, mode):
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if key == ord(' '):
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global toggle, C, C_const
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if toggle:
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viewer.data().set_colors(C)
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else:
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viewer.data().set_colors(C_const)
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toggle = not toggle
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return True
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return False
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viewer.callback_key_down = key_down
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print("Press [space] to toggle between unconstrained and constrained.")
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viewer.launch()
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