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igl/python/tutorial/404_DualQuaternionSkinning.py
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#!/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
from math import sin, cos, pi
# Add the igl library to the modules search path
import math
sys.path.insert(0, os.getcwd() + "/../")
import pyigl as igl
from shared import TUTORIAL_SHARED_PATH, check_dependencies, print_usage
dependencies = ["glfw"]
check_dependencies(dependencies)
def pre_draw(viewer):
global recompute, anim_t, poses, C, BE, P, U, M, anim_t_dir
if recompute:
# Find pose interval
begin = int(math.floor(anim_t)) % len(poses)
end = int(math.floor(anim_t) + 1) % len(poses)
t = anim_t - math.floor(anim_t)
# Interpolate pose and identity
anim_pose = igl.RotationList()
for e in range(len(poses[begin])):
anim_pose.append(poses[begin][e].slerp(t, poses[end][e]))
# Propagate relative rotations via FK to retrieve absolute transformations
vQ = igl.RotationList()
vT = []
igl.forward_kinematics(C, BE, P, anim_pose, vQ, vT)
dim = C.cols()
T = igl.eigen.MatrixXd(BE.rows() * (dim + 1), dim)
for e in range(BE.rows()):
a = igl.eigen.Affine3d.Identity()
a.translate(vT[e])
a.rotate(vQ[e])
T.setBlock(e * (dim + 1), 0, dim + 1, dim, a.matrix().transpose().block(0, 0, dim + 1, dim))
# Compute deformation via LBS as matrix multiplication
if use_dqs:
igl.dqs(V, W, vQ, vT, U)
else:
U = M * T
# Also deform skeleton edges
CT = igl.eigen.MatrixXd()
BET = igl.eigen.MatrixXi()
igl.deform_skeleton(C, BE, T, CT, BET)
viewer.data().set_vertices(U)
viewer.data().set_edges(CT, BET, sea_green)
viewer.data().compute_normals()
if viewer.core().is_animating:
anim_t += anim_t_dir
else:
recompute = False
return False
def key_down(viewer, key, mods):
global recompute, use_dqs, animation
recompute = True
if key == ord('D') or key == ord('d'):
use_dqs = not use_dqs
viewer.core().is_animating = False
animation = False
if use_dqs:
print("Switched to Dual Quaternion Skinning")
else:
print("Switched to Linear Blend Skinning")
elif key == ord(' '):
if animation:
viewer.core().is_animating = False
animation = False
else:
viewer.core().is_animating = True
animation = True
return False
if __name__ == "__main__":
keys = {"d": "toggle between LBS and DQS",
"space": "toggle animation"}
print_usage(keys)
V = igl.eigen.MatrixXd()
F = igl.eigen.MatrixXi()
C = igl.eigen.MatrixXd()
BE = igl.eigen.MatrixXi()
P = igl.eigen.MatrixXi()
W = igl.eigen.MatrixXd()
M = igl.eigen.MatrixXd()
sea_green = igl.eigen.MatrixXd([[70. / 255., 252. / 255., 167. / 255.]])
anim_t = 0.0
anim_t_dir = 0.015
use_dqs = False
recompute = True
animation = False # Flag needed as there is some synchronization problem with viewer.core().is_animating
poses = [[]]
igl.readOBJ(TUTORIAL_SHARED_PATH + "arm.obj", V, F)
U = igl.eigen.MatrixXd(V)
igl.readTGF(TUTORIAL_SHARED_PATH + "arm.tgf", C, BE)
# retrieve parents for forward kinematics
igl.directed_edge_parents(BE, P)
rest_pose = igl.RotationList()
igl.directed_edge_orientations(C, BE, rest_pose)
poses = [[igl.eigen.Quaterniond.Identity() for i in range(4)] for j in range(4)]
twist = igl.eigen.Quaterniond(pi, igl.eigen.MatrixXd([1, 0, 0]))
poses[1][2] = rest_pose[2] * twist * rest_pose[2].conjugate()
bend = igl.eigen.Quaterniond(-pi * 0.7, igl.eigen.MatrixXd([0, 0, 1]))
poses[3][2] = rest_pose[2] * bend * rest_pose[2].conjugate()
igl.readDMAT(TUTORIAL_SHARED_PATH + "arm-weights.dmat", W)
igl.lbs_matrix(V, W, M)
# Plot the mesh with pseudocolors
viewer = igl.glfw.Viewer()
viewer.data().set_mesh(U, F)
viewer.data().set_edges(C, BE, sea_green)
viewer.data().show_lines = False
viewer.data().show_overlay_depth = False
viewer.data().line_width = 1
viewer.core().trackball_angle.normalize()
viewer.callback_pre_draw = pre_draw
viewer.callback_key_down = key_down
viewer.core().is_animating = False
viewer.core().camera_zoom = 2.5
viewer.core().animation_max_fps = 30.0
viewer.launch()