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/**
* $Id$
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Original Author: Laurence
* Contributor(s): Brecht
*
* ***** END GPL LICENSE BLOCK *****
*/
#include <stdio.h>
#include "IK_QJacobianSolver.h"
#include "MT_Quaternion.h"
//#include "analyze.h"
IK_QJacobianSolver::IK_QJacobianSolver()
{
m_poleconstraint = false;
m_getpoleangle = false;
m_rootmatrix.setIdentity();
}
MT_Scalar IK_QJacobianSolver::ComputeScale()
{
std::vector<IK_QSegment*>::iterator seg;
float length = 0.0f;
for (seg = m_segments.begin(); seg != m_segments.end(); seg++)
length += (*seg)->MaxExtension();
if(length == 0.0f)
return 1.0f;
else
return 1.0f/length;
}
void IK_QJacobianSolver::Scale(float scale, std::list<IK_QTask*>& tasks)
{
std::list<IK_QTask*>::iterator task;
std::vector<IK_QSegment*>::iterator seg;
for (task = tasks.begin(); task != tasks.end(); task++)
(*task)->Scale(scale);
for (seg = m_segments.begin(); seg != m_segments.end(); seg++)
(*seg)->Scale(scale);
m_rootmatrix.getOrigin() *= scale;
m_goal *= scale;
m_polegoal *= scale;
}
void IK_QJacobianSolver::AddSegmentList(IK_QSegment *seg)
{
m_segments.push_back(seg);
IK_QSegment *child;
for (child = seg->Child(); child; child = child->Sibling())
AddSegmentList(child);
}
bool IK_QJacobianSolver::Setup(IK_QSegment *root, std::list<IK_QTask*>& tasks)
{
m_segments.clear();
AddSegmentList(root);
// assign each segment a unique id for the jacobian
std::vector<IK_QSegment*>::iterator seg;
int num_dof = 0;
for (seg = m_segments.begin(); seg != m_segments.end(); seg++) {
(*seg)->SetDoFId(num_dof);
num_dof += (*seg)->NumberOfDoF();
}
if (num_dof == 0)
return false;
// compute task id's and assing weights to task
int primary_size = 0, primary = 0;
int secondary_size = 0, secondary = 0;
MT_Scalar primary_weight = 0.0, secondary_weight = 0.0;
std::list<IK_QTask*>::iterator task;
for (task = tasks.begin(); task != tasks.end(); task++) {
IK_QTask *qtask = *task;
if (qtask->Primary()) {
qtask->SetId(primary_size);
primary_size += qtask->Size();
primary_weight += qtask->Weight();
primary++;
}
else {
qtask->SetId(secondary_size);
secondary_size += qtask->Size();
secondary_weight += qtask->Weight();
secondary++;
}
}
if (primary_size == 0 || MT_fuzzyZero(primary_weight))
return false;
m_secondary_enabled = (secondary > 0);
// rescale weights of tasks to sum up to 1
MT_Scalar primary_rescale = 1.0/primary_weight;
MT_Scalar secondary_rescale;
if (MT_fuzzyZero(secondary_weight))
secondary_rescale = 0.0;
else
secondary_rescale = 1.0/secondary_weight;
for (task = tasks.begin(); task != tasks.end(); task++) {
IK_QTask *qtask = *task;
if (qtask->Primary())
qtask->SetWeight(qtask->Weight()*primary_rescale);
else
qtask->SetWeight(qtask->Weight()*secondary_rescale);
}
// set matrix sizes
m_jacobian.ArmMatrices(num_dof, primary_size);
if (secondary > 0)
m_jacobian_sub.ArmMatrices(num_dof, secondary_size);
// set dof weights
int i;
for (seg = m_segments.begin(); seg != m_segments.end(); seg++)
for (i = 0; i < (*seg)->NumberOfDoF(); i++)
m_jacobian.SetDoFWeight((*seg)->DoFId()+i, (*seg)->Weight(i));
return true;
}
void IK_QJacobianSolver::SetPoleVectorConstraint(IK_QSegment *tip, MT_Vector3& goal, MT_Vector3& polegoal, float poleangle, bool getangle)
{
m_poleconstraint = true;
m_poletip = tip;
m_goal = goal;
m_polegoal = polegoal;
m_poleangle = (getangle)? 0.0f: poleangle;
m_getpoleangle = getangle;
}
static MT_Scalar safe_acos(MT_Scalar f)
{
// acos that does not return NaN with rounding errors
if (f <= -1.0f) return MT_PI;
else if (f >= 1.0f) return 0.0;
else return acos(f);
}
static MT_Vector3 normalize(const MT_Vector3& v)
{
// a sane normalize function that doesn't give (1, 0, 0) in case
// of a zero length vector, like MT_Vector3.normalize
MT_Scalar len = v.length();
return MT_fuzzyZero(len)? MT_Vector3(0, 0, 0): v/len;
}
static float angle(const MT_Vector3& v1, const MT_Vector3& v2)
{
return safe_acos(v1.dot(v2));
}
void IK_QJacobianSolver::ConstrainPoleVector(IK_QSegment *root, std::list<IK_QTask*>& tasks)
{
// this function will be called before and after solving. calling it before
// solving gives predictable solutions by rotating towards the solution,
// and calling it afterwards ensures the solution is exact.
if(!m_poleconstraint)
return;
// disable pole vector constraint in case of multiple position tasks
std::list<IK_QTask*>::iterator task;
int positiontasks = 0;
for (task = tasks.begin(); task != tasks.end(); task++)
if((*task)->PositionTask())
positiontasks++;
if (positiontasks >= 2) {
m_poleconstraint = false;
return;
}
// get positions and rotations
root->UpdateTransform(m_rootmatrix);
const MT_Vector3 rootpos = root->GlobalStart();
const MT_Vector3 endpos = m_poletip->GlobalEnd();
const MT_Matrix3x3& rootbasis = root->GlobalTransform().getBasis();
// construct "lookat" matrices (like gluLookAt), based on a direction and
// an up vector, with the direction going from the root to the end effector
// and the up vector going from the root to the pole constraint position.
MT_Vector3 dir = normalize(endpos - rootpos);
MT_Vector3 rootx= rootbasis.getColumn(0);
MT_Vector3 rootz= rootbasis.getColumn(2);
MT_Vector3 up = rootx*cos(m_poleangle) + rootz*sin(m_poleangle);
// in post, don't rotate towards the goal but only correct the pole up
MT_Vector3 poledir = (m_getpoleangle)? dir: normalize(m_goal - rootpos);
MT_Vector3 poleup = normalize(m_polegoal - rootpos);
MT_Matrix3x3 mat, polemat;
mat[0] = normalize(MT_cross(dir, up));
mat[1] = MT_cross(mat[0], dir);
mat[2] = -dir;
polemat[0] = normalize(MT_cross(poledir, poleup));
polemat[1] = MT_cross(polemat[0], poledir);
polemat[2] = -poledir;
if(m_getpoleangle) {
// we compute the pole angle that to rotate towards the target
m_poleangle = angle(mat[1], polemat[1]);
if(rootz.dot(mat[1]*cos(m_poleangle) + mat[0]*sin(m_poleangle)) > 0.0f)
m_poleangle = -m_poleangle;
// solve again, with the pole angle we just computed
m_getpoleangle = false;
ConstrainPoleVector(root, tasks);
}
else {
// now we set as root matrix the difference between the current and
// desired rotation based on the pole vector constraint. we use
// transpose instead of inverse because we have orthogonal matrices
// anyway, and in case of a singular matrix we don't get NaN's.
MT_Transform trans(MT_Point3(0, 0, 0), polemat.transposed()*mat);
m_rootmatrix = trans*m_rootmatrix;
}
}
bool IK_QJacobianSolver::UpdateAngles(MT_Scalar& norm)
{
// assing each segment a unique id for the jacobian
std::vector<IK_QSegment*>::iterator seg;
IK_QSegment *qseg, *minseg = NULL;
MT_Scalar minabsdelta = 1e10, absdelta;
MT_Vector3 delta, mindelta;
bool locked = false, clamp[3];
int i, mindof = 0;
// here we check if any angle limits were violated. angles whose clamped
// position is the same as it was before, are locked immediate. of the
// other violation angles the most violating angle is rememberd
for (seg = m_segments.begin(); seg != m_segments.end(); seg++) {
qseg = *seg;
if (qseg->UpdateAngle(m_jacobian, delta, clamp)) {
for (i = 0; i < qseg->NumberOfDoF(); i++) {
if (clamp[i] && !qseg->Locked(i)) {
absdelta = MT_abs(delta[i]);
if (absdelta < MT_EPSILON) {
qseg->Lock(i, m_jacobian, delta);
locked = true;
}
else if (absdelta < minabsdelta) {
minabsdelta = absdelta;
mindelta = delta;
minseg = qseg;
mindof = i;
}
}
}
}
}
// lock most violating angle
if (minseg) {
minseg->Lock(mindof, m_jacobian, mindelta);
locked = true;
if (minabsdelta > norm)
norm = minabsdelta;
}
if (locked == false)
// no locking done, last inner iteration, apply the angles
for (seg = m_segments.begin(); seg != m_segments.end(); seg++) {
(*seg)->UnLock();
(*seg)->UpdateAngleApply();
}
// signal if another inner iteration is needed
return locked;
}
bool IK_QJacobianSolver::Solve(
IK_QSegment *root,
std::list<IK_QTask*> tasks,
const MT_Scalar,
const int max_iterations
)
{
float scale = ComputeScale();
bool solved = false;
//double dt = analyze_time();
Scale(scale, tasks);
ConstrainPoleVector(root, tasks);
root->UpdateTransform(m_rootmatrix);
// iterate
for (int iterations = 0; iterations < max_iterations; iterations++) {
// update transform
root->UpdateTransform(m_rootmatrix);
std::list<IK_QTask*>::iterator task;
// compute jacobian
for (task = tasks.begin(); task != tasks.end(); task++) {
if ((*task)->Primary())
(*task)->ComputeJacobian(m_jacobian);
else
(*task)->ComputeJacobian(m_jacobian_sub);
}
MT_Scalar norm = 0.0;
do {
// invert jacobian
try {
m_jacobian.Invert();
if (m_secondary_enabled)
m_jacobian.SubTask(m_jacobian_sub);
}
catch (...) {
fprintf(stderr, "IK Exception\n");
return false;
}
// update angles and check limits
} while (UpdateAngles(norm));
// unlock segments again after locking in clamping loop
std::vector<IK_QSegment*>::iterator seg;
for (seg = m_segments.begin(); seg != m_segments.end(); seg++)
(*seg)->UnLock();
// compute angle update norm
MT_Scalar maxnorm = m_jacobian.AngleUpdateNorm();
if (maxnorm > norm)
norm = maxnorm;
// check for convergence
if (norm < 1e-3) {
solved = true;
break;
}
}
if(m_poleconstraint)
root->PrependBasis(m_rootmatrix.getBasis());
Scale(1.0f/scale, tasks);
//analyze_add_run(max_iterations, analyze_time()-dt);
return solved;
}
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