118 lines
3.4 KiB
C++
118 lines
3.4 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
|
|
//
|
|
// Copyright (C) 2013 Alec Jacobson <alecjacobson@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/.
|
|
#include "snap_to_canonical_view_quat.h"
|
|
|
|
#include "canonical_quaternions.h"
|
|
#include "normalize_quat.h"
|
|
|
|
#include <cstdio>
|
|
#include <cassert>
|
|
|
|
// Note: For the canonical view quaternions it should be completely possible to
|
|
// determine this anaylitcally. That is the max_distance should be a
|
|
// theoretical known value
|
|
// Also: I'm not sure it matters in this case, but. We are dealing with
|
|
// quaternions on the 4d unit sphere, but measuring distance in general 4d
|
|
// space (i.e. not geodesics on the sphere). Probably something with angles
|
|
// would be better.
|
|
template <typename Q_type>
|
|
IGL_INLINE bool igl::snap_to_canonical_view_quat(
|
|
const Q_type* q,
|
|
const Q_type threshold,
|
|
Q_type* s)
|
|
{
|
|
// Copy input into output
|
|
// CANNOT use std::copy here according to:
|
|
// http://www.cplusplus.com/reference/algorithm/copy/
|
|
s[0] = q[0];
|
|
s[1] = q[1];
|
|
s[2] = q[2];
|
|
s[3] = q[3];
|
|
|
|
// Normalize input quaternion
|
|
Q_type qn[4];
|
|
bool valid_len =
|
|
igl::normalize_quat(q,qn);
|
|
// If normalizing valid then don't bother
|
|
if(!valid_len)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// 0.290019
|
|
const Q_type MAX_DISTANCE = 0.4;
|
|
Q_type min_distance = 2*MAX_DISTANCE;
|
|
int min_index = -1;
|
|
double min_sign = 0;
|
|
// loop over canonical view quaternions
|
|
for(double sign = -1;sign<=1;sign+=2)
|
|
{
|
|
for(int i = 0; i<NUM_CANONICAL_VIEW_QUAT; i++)
|
|
{
|
|
Q_type distance = 0.0;
|
|
// loop over coordinates
|
|
for(int j = 0;j<4;j++)
|
|
{
|
|
// Double cast because of bug in llvm version 4.2 with -O3
|
|
distance +=
|
|
(qn[j]-sign*igl::CANONICAL_VIEW_QUAT<Q_type>(i,j))*
|
|
(qn[j]-sign*igl::CANONICAL_VIEW_QUAT<Q_type>(i,j));
|
|
}
|
|
if(min_distance > distance)
|
|
{
|
|
min_distance = distance;
|
|
min_index = i;
|
|
min_sign = sign;
|
|
}
|
|
}
|
|
}
|
|
|
|
if(MAX_DISTANCE < min_distance)
|
|
{
|
|
fprintf(
|
|
stderr,
|
|
"ERROR: found new max MIN_DISTANCE: %g\n"
|
|
"PLEASE update snap_to_canonical_quat()",
|
|
min_distance);
|
|
}
|
|
|
|
assert(min_distance < MAX_DISTANCE);
|
|
assert(min_index >= 0);
|
|
|
|
if( min_distance/MAX_DISTANCE <= threshold)
|
|
{
|
|
// loop over coordinates
|
|
for(int j = 0;j<4;j++)
|
|
{
|
|
s[j] = min_sign*igl::CANONICAL_VIEW_QUAT<Q_type>(min_index,j);
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
template <typename Scalarq, typename Scalars>
|
|
IGL_INLINE bool igl::snap_to_canonical_view_quat(
|
|
const Eigen::Quaternion<Scalarq> & q,
|
|
const double threshold,
|
|
Eigen::Quaternion<Scalars> & s)
|
|
{
|
|
return snap_to_canonical_view_quat<Scalars>(
|
|
q.coeffs().data(),threshold,s.coeffs().data());
|
|
}
|
|
|
|
#ifdef IGL_STATIC_LIBRARY
|
|
// Explicit template instantiation
|
|
// generated by autoexplicit.sh
|
|
template bool igl::snap_to_canonical_view_quat<double>(const double*, double, double*);
|
|
// generated by autoexplicit.sh
|
|
template bool igl::snap_to_canonical_view_quat<float>(const float*, float, float*);
|
|
template bool igl::snap_to_canonical_view_quat<float, float>(Eigen::Quaternion<float, 0> const&, double, Eigen::Quaternion<float, 0>&);
|
|
template bool igl::snap_to_canonical_view_quat<double, double>(Eigen::Quaternion<double, 0> const&, double, Eigen::Quaternion<double, 0>&);
|
|
#endif
|