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bluecore/ode/src/stepfast.cpp

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/*************************************************************************
* *
* Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. *
* All rights reserved. Email: russ@q12.org Web: www.q12.org *
* *
* Fast iterative solver, David Whittaker. Email: david@csworkbench.com *
* *
* This library is free software; you can redistribute it and/or *
* modify it under the terms of EITHER: *
* (1) The GNU Lesser General Public License as published by the Free *
* Software Foundation; either version 2.1 of the License, or (at *
* your option) any later version. The text of the GNU Lesser *
* General Public License is included with this library in the *
* file LICENSE.TXT. *
* (2) The BSD-style license that is included with this library in *
* the file LICENSE-BSD.TXT. *
* *
* This library 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 files *
* LICENSE.TXT and LICENSE-BSD.TXT for more details. *
* *
*************************************************************************/
// This is the StepFast code by David Whittaker. This code is faster, but
// sometimes less stable than, the original "big matrix" code.
// Refer to the user's manual for more information.
// Note that this source file duplicates a lot of stuff from step.cpp,
// eventually we should move the common code to a third file.
#include "objects.h"
#include "joint.h"
#include <ode/config.h>
#include <ode/objects.h>
#include <ode/odemath.h>
#include <ode/rotation.h>
#include <ode/timer.h>
#include <ode/error.h>
#include <ode/matrix.h>
#include <ode/misc.h>
#include "lcp.h"
#include "step.h"
#include "util.h"
// misc defines
#define ALLOCA dALLOCA16
#define RANDOM_JOINT_ORDER
//#define FAST_FACTOR //use a factorization approximation to the LCP solver (fast, theoretically less accurate)
#define SLOW_LCP //use the old LCP solver
//#define NO_ISLANDS //does not perform island creation code (3~4% of simulation time), body disabling doesn't work
//#define TIMING
static int autoEnableDepth = 2;
void dWorldSetAutoEnableDepthSF1 (dxWorld *world, int autodepth)
{
if (autodepth > 0)
autoEnableDepth = autodepth;
else
autoEnableDepth = 0;
}
int dWorldGetAutoEnableDepthSF1 (dxWorld *world)
{
return autoEnableDepth;
}
//little bit of math.... the _sym_ functions assume the return matrix will be symmetric
static void
Multiply2_sym_p8p (dReal * A, dReal * B, dReal * C, int p, int Askip)
{
int i, j;
dReal sum, *aa, *ad, *bb, *cc;
dIASSERT (p > 0 && A && B && C);
bb = B;
for (i = 0; i < p; i++)
{
//aa is going accross the matrix, ad down
aa = ad = A;
cc = C;
for (j = i; j < p; j++)
{
sum = bb[0] * cc[0];
sum += bb[1] * cc[1];
sum += bb[2] * cc[2];
sum += bb[4] * cc[4];
sum += bb[5] * cc[5];
sum += bb[6] * cc[6];
*(aa++) = *ad = sum;
ad += Askip;
cc += 8;
}
bb += 8;
A += Askip + 1;
C += 8;
}
}
static void
MultiplyAdd2_sym_p8p (dReal * A, dReal * B, dReal * C, int p, int Askip)
{
int i, j;
dReal sum, *aa, *ad, *bb, *cc;
dIASSERT (p > 0 && A && B && C);
bb = B;
for (i = 0; i < p; i++)
{
//aa is going accross the matrix, ad down
aa = ad = A;
cc = C;
for (j = i; j < p; j++)
{
sum = bb[0] * cc[0];
sum += bb[1] * cc[1];
sum += bb[2] * cc[2];
sum += bb[4] * cc[4];
sum += bb[5] * cc[5];
sum += bb[6] * cc[6];
*(aa++) += sum;
*ad += sum;
ad += Askip;
cc += 8;
}
bb += 8;
A += Askip + 1;
C += 8;
}
}
// this assumes the 4th and 8th rows of B are zero.
static void
Multiply0_p81 (dReal * A, dReal * B, dReal * C, int p)
{
int i;
dIASSERT (p > 0 && A && B && C);
dReal sum;
for (i = p; i; i--)
{
sum = B[0] * C[0];
sum += B[1] * C[1];
sum += B[2] * C[2];
sum += B[4] * C[4];
sum += B[5] * C[5];
sum += B[6] * C[6];
*(A++) = sum;
B += 8;
}
}
// this assumes the 4th and 8th rows of B are zero.
static void
MultiplyAdd0_p81 (dReal * A, dReal * B, dReal * C, int p)
{
int i;
dIASSERT (p > 0 && A && B && C);
dReal sum;
for (i = p; i; i--)
{
sum = B[0] * C[0];
sum += B[1] * C[1];
sum += B[2] * C[2];
sum += B[4] * C[4];
sum += B[5] * C[5];
sum += B[6] * C[6];
*(A++) += sum;
B += 8;
}
}
// this assumes the 4th and 8th rows of B are zero.
static void
Multiply1_8q1 (dReal * A, dReal * B, dReal * C, int q)
{
int k;
dReal sum;
dIASSERT (q > 0 && A && B && C);
sum = 0;
for (k = 0; k < q; k++)
sum += B[k * 8] * C[k];
A[0] = sum;
sum = 0;
for (k = 0; k < q; k++)
sum += B[1 + k * 8] * C[k];
A[1] = sum;
sum = 0;
for (k = 0; k < q; k++)
sum += B[2 + k * 8] * C[k];
A[2] = sum;
sum = 0;
for (k = 0; k < q; k++)
sum += B[4 + k * 8] * C[k];
A[4] = sum;
sum = 0;
for (k = 0; k < q; k++)
sum += B[5 + k * 8] * C[k];
A[5] = sum;
sum = 0;
for (k = 0; k < q; k++)
sum += B[6 + k * 8] * C[k];
A[6] = sum;
}
//****************************************************************************
// body rotation
// return sin(x)/x. this has a singularity at 0 so special handling is needed
// for small arguments.
static inline dReal
sinc (dReal x)
{
// if |x| < 1e-4 then use a taylor series expansion. this two term expansion
// is actually accurate to one LS bit within this range if double precision
// is being used - so don't worry!
if (dFabs (x) < 1.0e-4)
return REAL (1.0) - x * x * REAL (0.166666666666666666667);
else
return dSin (x) / x;
}
// given a body b, apply its linear and angular rotation over the time
// interval h, thereby adjusting its position and orientation.
static inline void
moveAndRotateBody (dxBody * b, dReal h)
{
int j;
// handle linear velocity
for (j = 0; j < 3; j++)
b->posr.pos[j] += h * b->lvel[j];
if (b->flags & dxBodyFlagFiniteRotation)
{
dVector3 irv; // infitesimal rotation vector
dQuaternion q; // quaternion for finite rotation
if (b->flags & dxBodyFlagFiniteRotationAxis)
{
// split the angular velocity vector into a component along the finite
// rotation axis, and a component orthogonal to it.
dVector3 frv, irv; // finite rotation vector
dReal k = dDOT (b->finite_rot_axis, b->avel);
frv[0] = b->finite_rot_axis[0] * k;
frv[1] = b->finite_rot_axis[1] * k;
frv[2] = b->finite_rot_axis[2] * k;
irv[0] = b->avel[0] - frv[0];
irv[1] = b->avel[1] - frv[1];
irv[2] = b->avel[2] - frv[2];
// make a rotation quaternion q that corresponds to frv * h.
// compare this with the full-finite-rotation case below.
h *= REAL (0.5);
dReal theta = k * h;
q[0] = dCos (theta);
dReal s = sinc (theta) * h;
q[1] = frv[0] * s;
q[2] = frv[1] * s;
q[3] = frv[2] * s;
}
else
{
// make a rotation quaternion q that corresponds to w * h
dReal wlen = dSqrt (b->avel[0] * b->avel[0] + b->avel[1] * b->avel[1] + b->avel[2] * b->avel[2]);
h *= REAL (0.5);
dReal theta = wlen * h;
q[0] = dCos (theta);
dReal s = sinc (theta) * h;
q[1] = b->avel[0] * s;
q[2] = b->avel[1] * s;
q[3] = b->avel[2] * s;
}
// do the finite rotation
dQuaternion q2;
dQMultiply0 (q2, q, b->q);
for (j = 0; j < 4; j++)
b->q[j] = q2[j];
// do the infitesimal rotation if required
if (b->flags & dxBodyFlagFiniteRotationAxis)
{
dReal dq[4];
dWtoDQ (irv, b->q, dq);
for (j = 0; j < 4; j++)
b->q[j] += h * dq[j];
}
}
else
{
// the normal way - do an infitesimal rotation
dReal dq[4];
dWtoDQ (b->avel, b->q, dq);
for (j = 0; j < 4; j++)
b->q[j] += h * dq[j];
}
// normalize the quaternion and convert it to a rotation matrix
dNormalize4 (b->q);
dQtoR (b->q, b->posr.R);
// notify all attached geoms that this body has moved
for (dxGeom * geom = b->geom; geom; geom = dGeomGetBodyNext (geom))
dGeomMoved (geom);
}
//****************************************************************************
//This is an implementation of the iterated/relaxation algorithm.
//Here is a quick overview of the algorithm per Sergi Valverde's posts to the
//mailing list:
//
// for i=0..N-1 do
// for c = 0..C-1 do
// Solve constraint c-th
// Apply forces to constraint bodies
// next
// next
// Integrate bodies
void
dInternalStepFast (dxWorld * world, dxBody * body[2], dReal * GI[2], dReal * GinvI[2], dxJoint * joint, dxJoint::Info1 info, dxJoint::Info2 Jinfo, dReal stepsize)
{
int i, j, k;
# ifdef TIMING
dTimerNow ("constraint preprocessing");
# endif
dReal stepsize1 = dRecip (stepsize);
int m = info.m;
// nothing to do if no constraints.
if (m <= 0)
return;
int nub = 0;
if (info.nub == info.m)
nub = m;
// compute A = J*invM*J'. first compute JinvM = J*invM. this has the same
// format as J so we just go through the constraints in J multiplying by
// the appropriate scalars and matrices.
# ifdef TIMING
dTimerNow ("compute A");
# endif
dReal JinvM[2 * 6 * 8];
//dSetZero (JinvM, 2 * m * 8);
dReal *Jsrc = Jinfo.J1l;
dReal *Jdst = JinvM;
if (body[0])
{
for (j = m - 1; j >= 0; j--)
{
for (k = 0; k < 3; k++)
Jdst[k] = Jsrc[k] * body[0]->invMass;
dMULTIPLY0_133 (Jdst + 4, Jsrc + 4, GinvI[0]);
Jsrc += 8;
Jdst += 8;
}
}
if (body[1])
{
Jsrc = Jinfo.J2l;
Jdst = JinvM + 8 * m;
for (j = m - 1; j >= 0; j--)
{
for (k = 0; k < 3; k++)
Jdst[k] = Jsrc[k] * body[1]->invMass;
dMULTIPLY0_133 (Jdst + 4, Jsrc + 4, GinvI[1]);
Jsrc += 8;
Jdst += 8;
}
}
// now compute A = JinvM * J'.
int mskip = dPAD (m);
dReal A[6 * 8];
//dSetZero (A, 6 * 8);
if (body[0]) {
Multiply2_sym_p8p (A, JinvM, Jinfo.J1l, m, mskip);
if (body[1])
MultiplyAdd2_sym_p8p (A, JinvM + 8 * m, Jinfo.J2l,
m, mskip);
} else {
if (body[1])
Multiply2_sym_p8p (A, JinvM + 8 * m, Jinfo.J2l,
m, mskip);
}
// add cfm to the diagonal of A
for (i = 0; i < m; i++)
A[i * mskip + i] += Jinfo.cfm[i] * stepsize1;
// compute the right hand side `rhs'
# ifdef TIMING
dTimerNow ("compute rhs");
# endif
dReal tmp1[16];
//dSetZero (tmp1, 16);
// put v/h + invM*fe into tmp1
for (i = 0; i < 2; i++)
{
if (!body[i])
continue;
for (j = 0; j < 3; j++)
tmp1[i * 8 + j] = body[i]->facc[j] * body[i]->invMass + body[i]->lvel[j] * stepsize1;
dMULTIPLY0_331 (tmp1 + i * 8 + 4, GinvI[i], body[i]->tacc);
for (j = 0; j < 3; j++)
tmp1[i * 8 + 4 + j] += body[i]->avel[j] * stepsize1;
}
// put J*tmp1 into rhs
dReal rhs[6];
//dSetZero (rhs, 6);
if (body[0]) {
Multiply0_p81 (rhs, Jinfo.J1l, tmp1, m);
if (body[1])
MultiplyAdd0_p81 (rhs, Jinfo.J2l, tmp1 + 8, m);
} else {
if (body[1])
Multiply0_p81 (rhs, Jinfo.J2l, tmp1 + 8, m);
}
// complete rhs
for (i = 0; i < m; i++)
rhs[i] = Jinfo.c[i] * stepsize1 - rhs[i];
#ifdef SLOW_LCP
// solve the LCP problem and get lambda.
// this will destroy A but that's okay
# ifdef TIMING
dTimerNow ("solving LCP problem");
# endif
dReal *lambda = (dReal *) ALLOCA (m * sizeof (dReal));
dReal *residual = (dReal *) ALLOCA (m * sizeof (dReal));
dReal lo[6], hi[6];
memcpy (lo, Jinfo.lo, m * sizeof (dReal));
memcpy (hi, Jinfo.hi, m * sizeof (dReal));
dSolveLCP (m, A, lambda, rhs, residual, nub, lo, hi, Jinfo.findex);
#endif
// LCP Solver replacement:
// This algorithm goes like this:
// Do a straightforward LDLT factorization of the matrix A, solving for
// A*x = rhs
// For each x[i] that is outside of the bounds of lo[i] and hi[i],
// clamp x[i] into that range.
// Substitute into A the now known x's
// subtract the residual away from the rhs.
// Remove row and column i from L, updating the factorization
// place the known x's at the end of the array, keeping up with location in p
// Repeat until all constraints have been clamped or all are within bounds
//
// This is probably only faster in the single joint case where only one repeat is
// the norm.
#ifdef FAST_FACTOR
// factorize A (L*D*L'=A)
# ifdef TIMING
dTimerNow ("factorize A");
# endif
dReal d[6];
dReal L[6 * 8];
memcpy (L, A, m * mskip * sizeof (dReal));
dFactorLDLT (L, d, m, mskip);
// compute lambda
# ifdef TIMING
dTimerNow ("compute lambda");
# endif
int left = m; //constraints left to solve.
int remove[6];
dReal lambda[6];
dReal x[6];
int p[6];
for (i = 0; i < 6; i++)
p[i] = i;
while (true)
{
memcpy (x, rhs, left * sizeof (dReal));
dSolveLDLT (L, d, x, left, mskip);
int fixed = 0;
for (i = 0; i < left; i++)
{
j = p[i];
remove[i] = false;
// This isn't the exact same use of findex as dSolveLCP.... since x[findex]
// may change after I've already clamped x[i], but it should be close
if (Jinfo.findex[j] > -1)
{
dReal f = fabs (Jinfo.hi[j] * x[p[Jinfo.findex[j]]]);
if (x[i] > f)
x[i] = f;
else if (x[i] < -f)
x[i] = -f;
else
continue;
}
else
{
if (x[i] > Jinfo.hi[j])
x[i] = Jinfo.hi[j];
else if (x[i] < Jinfo.lo[j])
x[i] = Jinfo.lo[j];
else
continue;
}
remove[i] = true;
fixed++;
}
if (fixed == 0 || fixed == left) //no change or all constraints solved
break;
for (i = 0; i < left; i++) //sub in to right hand side.
if (remove[i])
for (j = 0; j < left; j++)
if (!remove[j])
rhs[j] -= A[j * mskip + i] * x[i];
for (int r = left - 1; r >= 0; r--) //eliminate row/col for fixed variables
{
if (remove[r])
{
//dRemoveLDLT adapted for use without row pointers.
if (r == left - 1)
{
left--;
continue; // deleting last row/col is easy
}
else if (r == 0)
{
dReal a[6];
for (i = 0; i < left; i++)
a[i] = -A[i * mskip];
a[0] += REAL (1.0);
dLDLTAddTL (L, d, a, left, mskip);
}
else
{
dReal t[6];
dReal a[6];
for (i = 0; i < r; i++)
t[i] = L[r * mskip + i] / d[i];
for (i = 0; i < left - r; i++)
a[i] = dDot (L + (r + i) * mskip, t, r) - A[(r + i) * mskip + r];
a[0] += REAL (1.0);
dLDLTAddTL (L + r * mskip + r, d + r, a, left - r, mskip);
}
dRemoveRowCol (L, left, mskip, r);
//end dRemoveLDLT
left--;
if (r < (left - 1))
{
dReal tx = x[r];
memmove (d + r, d + r + 1, (left - r) * sizeof (dReal));
memmove (rhs + r, rhs + r + 1, (left - r) * sizeof (dReal));
//x will get written over by rhs anyway, no need to move it around
//just store the fixed value we just discovered in it.
x[left] = tx;
for (i = 0; i < m; i++)
if (p[i] > r && p[i] <= left)
p[i]--;
p[r] = left;
}
}
}
}
for (i = 0; i < m; i++)
lambda[i] = x[p[i]];
# endif
// compute the constraint force `cforce'
# ifdef TIMING
dTimerNow ("compute constraint force");
#endif
// compute cforce = J'*lambda
dJointFeedback *fb = joint->feedback;
dReal cforce[16];
//dSetZero (cforce, 16);
if (fb)
{
// the user has requested feedback on the amount of force that this
// joint is applying to the bodies. we use a slightly slower
// computation that splits out the force components and puts them
// in the feedback structure.
dReal data1[8], data2[8];
if (body[0])
{
Multiply1_8q1 (data1, Jinfo.J1l, lambda, m);
dReal *cf1 = cforce;
cf1[0] = (fb->f1[0] = data1[0]);
cf1[1] = (fb->f1[1] = data1[1]);
cf1[2] = (fb->f1[2] = data1[2]);
cf1[4] = (fb->t1[0] = data1[4]);
cf1[5] = (fb->t1[1] = data1[5]);
cf1[6] = (fb->t1[2] = data1[6]);
}
if (body[1])
{
Multiply1_8q1 (data2, Jinfo.J2l, lambda, m);
dReal *cf2 = cforce + 8;
cf2[0] = (fb->f2[0] = data2[0]);
cf2[1] = (fb->f2[1] = data2[1]);
cf2[2] = (fb->f2[2] = data2[2]);
cf2[4] = (fb->t2[0] = data2[4]);
cf2[5] = (fb->t2[1] = data2[5]);
cf2[6] = (fb->t2[2] = data2[6]);
}
}
else
{
// no feedback is required, let's compute cforce the faster way
if (body[0])
Multiply1_8q1 (cforce, Jinfo.J1l, lambda, m);
if (body[1])
Multiply1_8q1 (cforce + 8, Jinfo.J2l, lambda, m);
}
for (i = 0; i < 2; i++)
{
if (!body[i])
continue;
for (j = 0; j < 3; j++)
{
body[i]->facc[j] += cforce[i * 8 + j];
body[i]->tacc[j] += cforce[i * 8 + 4 + j];
}
}
}
void
dInternalStepIslandFast (dxWorld * world, dxBody * const *bodies, int nb, dxJoint * const *_joints, int nj, dReal stepsize, int maxiterations)
{
# ifdef TIMING
dTimerNow ("preprocessing");
# endif
dxBody *bodyPair[2], *body;
dReal *GIPair[2], *GinvIPair[2];
dxJoint *joint;
int iter, b, j, i;
dReal ministep = stepsize / maxiterations;
// make a local copy of the joint array, because we might want to modify it.
// (the "dxJoint *const*" declaration says we're allowed to modify the joints
// but not the joint array, because the caller might need it unchanged).
dxJoint **joints = (dxJoint **) ALLOCA (nj * sizeof (dxJoint *));
memcpy (joints, _joints, nj * sizeof (dxJoint *));
// get m = total constraint dimension, nub = number of unbounded variables.
// create constraint offset array and number-of-rows array for all joints.
// the constraints are re-ordered as follows: the purely unbounded
// constraints, the mixed unbounded + LCP constraints, and last the purely
// LCP constraints. this assists the LCP solver to put all unbounded
// variables at the start for a quick factorization.
//
// joints with m=0 are inactive and are removed from the joints array
// entirely, so that the code that follows does not consider them.
// also number all active joints in the joint list (set their tag values).
// inactive joints receive a tag value of -1.
int m = 0;
dxJoint::Info1 * info = (dxJoint::Info1 *) ALLOCA (nj * sizeof (dxJoint::Info1));
int *ofs = (int *) ALLOCA (nj * sizeof (int));
for (i = 0, j = 0; j < nj; j++)
{ // i=dest, j=src
joints[j]->vtable->getInfo1 (joints[j], info + i);
dIASSERT (info[i].m >= 0 && info[i].m <= 6 && info[i].nub >= 0 && info[i].nub <= info[i].m);
if (info[i].m > 0)
{
joints[i] = joints[j];
joints[i]->tag = i;
i++;
}
else
{
joints[j]->tag = -1;
}
}
nj = i;
// the purely unbounded constraints
for (i = 0; i < nj; i++)
{
ofs[i] = m;
m += info[i].m;
}
dReal *c = NULL;
dReal *cfm = NULL;
dReal *lo = NULL;
dReal *hi = NULL;
int *findex = NULL;
dReal *J = NULL;
dxJoint::Info2 * Jinfo = NULL;
if (m)
{
// create a constraint equation right hand side vector `c', a constraint
// force mixing vector `cfm', and LCP low and high bound vectors, and an
// 'findex' vector.
c = (dReal *) ALLOCA (m * sizeof (dReal));
cfm = (dReal *) ALLOCA (m * sizeof (dReal));
lo = (dReal *) ALLOCA (m * sizeof (dReal));
hi = (dReal *) ALLOCA (m * sizeof (dReal));
findex = (int *) ALLOCA (m * sizeof (int));
dSetZero (c, m);
dSetValue (cfm, m, world->global_cfm);
dSetValue (lo, m, -dInfinity);
dSetValue (hi, m, dInfinity);
for (i = 0; i < m; i++)
findex[i] = -1;
// get jacobian data from constraints. a (2*m)x8 matrix will be created
// to store the two jacobian blocks from each constraint. it has this
// format:
//
// l l l 0 a a a 0 \ .
// l l l 0 a a a 0 }-- jacobian body 1 block for joint 0 (3 rows)
// l l l 0 a a a 0 /
// l l l 0 a a a 0 \ .
// l l l 0 a a a 0 }-- jacobian body 2 block for joint 0 (3 rows)
// l l l 0 a a a 0 /
// l l l 0 a a a 0 }--- jacobian body 1 block for joint 1 (1 row)
// l l l 0 a a a 0 }--- jacobian body 2 block for joint 1 (1 row)
// etc...
//
// (lll) = linear jacobian data
// (aaa) = angular jacobian data
//
# ifdef TIMING
dTimerNow ("create J");
# endif
J = (dReal *) ALLOCA (2 * m * 8 * sizeof (dReal));
dSetZero (J, 2 * m * 8);
Jinfo = (dxJoint::Info2 *) ALLOCA (nj * sizeof (dxJoint::Info2));
for (i = 0; i < nj; i++)
{
Jinfo[i].rowskip = 8;
Jinfo[i].fps = dRecip (stepsize);
Jinfo[i].erp = world->global_erp;
Jinfo[i].J1l = J + 2 * 8 * ofs[i];
Jinfo[i].J1a = Jinfo[i].J1l + 4;
Jinfo[i].J2l = Jinfo[i].J1l + 8 * info[i].m;
Jinfo[i].J2a = Jinfo[i].J2l + 4;
Jinfo[i].c = c + ofs[i];
Jinfo[i].cfm = cfm + ofs[i];
Jinfo[i].lo = lo + ofs[i];
Jinfo[i].hi = hi + ofs[i];
Jinfo[i].findex = findex + ofs[i];
//joints[i]->vtable->getInfo2 (joints[i], Jinfo+i);
}
}
dReal *saveFacc = (dReal *) ALLOCA (nb * 4 * sizeof (dReal));
dReal *saveTacc = (dReal *) ALLOCA (nb * 4 * sizeof (dReal));
dReal *globalI = (dReal *) ALLOCA (nb * 12 * sizeof (dReal));
dReal *globalInvI = (dReal *) ALLOCA (nb * 12 * sizeof (dReal));
for (b = 0; b < nb; b++)
{
for (i = 0; i < 4; i++)
{
saveFacc[b * 4 + i] = bodies[b]->facc[i];
saveTacc[b * 4 + i] = bodies[b]->tacc[i];
}
bodies[b]->tag = b;
}
for (iter = 0; iter < maxiterations; iter++)
{
# ifdef TIMING
dTimerNow ("applying inertia and gravity");
# endif
dReal tmp[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
for (b = 0; b < nb; b++)
{
body = bodies[b];
// for all bodies, compute the inertia tensor and its inverse in the global
// frame, and compute the rotational force and add it to the torque
// accumulator. I and invI are vertically stacked 3x4 matrices, one per body.
// @@@ check computation of rotational force.
// compute inertia tensor in global frame
dMULTIPLY2_333 (tmp, body->mass.I, body->posr.R);
dMULTIPLY0_333 (globalI + b * 12, body->posr.R, tmp);
// compute inverse inertia tensor in global frame
dMULTIPLY2_333 (tmp, body->invI, body->posr.R);
dMULTIPLY0_333 (globalInvI + b * 12, body->posr.R, tmp);
for (i = 0; i < 4; i++)
body->tacc[i] = saveTacc[b * 4 + i];
#ifdef dGYROSCOPIC
// compute rotational force
dMULTIPLY0_331 (tmp, globalI + b * 12, body->avel);
dCROSS (body->tacc, -=, body->avel, tmp);
#endif
// add the gravity force to all bodies
if ((body->flags & dxBodyNoGravity) == 0)
{
body->facc[0] = saveFacc[b * 4 + 0] + body->mass.mass * world->gravity[0];
body->facc[1] = saveFacc[b * 4 + 1] + body->mass.mass * world->gravity[1];
body->facc[2] = saveFacc[b * 4 + 2] + body->mass.mass * world->gravity[2];
body->facc[3] = 0;
} else {
body->facc[0] = saveFacc[b * 4 + 0];
body->facc[1] = saveFacc[b * 4 + 1];
body->facc[2] = saveFacc[b * 4 + 2];
body->facc[3] = 0;
}
}
#ifdef RANDOM_JOINT_ORDER
#ifdef TIMING
dTimerNow ("randomizing joint order");
#endif
//randomize the order of the joints by looping through the array
//and swapping the current joint pointer with a random one before it.
for (j = 0; j < nj; j++)
{
joint = joints[j];
dxJoint::Info1 i1 = info[j];
dxJoint::Info2 i2 = Jinfo[j];
const int r = dRandInt(j+1);
dIASSERT (r < nj);
joints[j] = joints[r];
info[j] = info[r];
Jinfo[j] = Jinfo[r];
joints[r] = joint;
info[r] = i1;
Jinfo[r] = i2;
}
#endif
//now iterate through the random ordered joint array we created.
for (j = 0; j < nj; j++)
{
#ifdef TIMING
dTimerNow ("setting up joint");
#endif
joint = joints[j];
bodyPair[0] = joint->node[0].body;
bodyPair[1] = joint->node[1].body;
if (bodyPair[0] && (bodyPair[0]->flags & dxBodyDisabled))
bodyPair[0] = 0;
if (bodyPair[1] && (bodyPair[1]->flags & dxBodyDisabled))
bodyPair[1] = 0;
//if this joint is not connected to any enabled bodies, skip it.
if (!bodyPair[0] && !bodyPair[1])
continue;
if (bodyPair[0])
{
GIPair[0] = globalI + bodyPair[0]->tag * 12;
GinvIPair[0] = globalInvI + bodyPair[0]->tag * 12;
}
if (bodyPair[1])
{
GIPair[1] = globalI + bodyPair[1]->tag * 12;
GinvIPair[1] = globalInvI + bodyPair[1]->tag * 12;
}
joints[j]->vtable->getInfo2 (joints[j], Jinfo + j);
//dInternalStepIslandFast is an exact copy of the old routine with one
//modification: the calculated forces are added back to the facc and tacc
//vectors instead of applying them to the bodies and moving them.
if (info[j].m > 0)
{
dInternalStepFast (world, bodyPair, GIPair, GinvIPair, joint, info[j], Jinfo[j], ministep);
}
}
// }
# ifdef TIMING
dTimerNow ("moving bodies");
# endif
//Now we can simulate all the free floating bodies, and move them.
for (b = 0; b < nb; b++)
{
body = bodies[b];
for (i = 0; i < 4; i++)
{
body->facc[i] *= ministep;
body->tacc[i] *= ministep;
}
//apply torque
dMULTIPLYADD0_331 (body->avel, globalInvI + b * 12, body->tacc);
//apply force
for (i = 0; i < 3; i++)
body->lvel[i] += body->invMass * body->facc[i];
//move It!
moveAndRotateBody (body, ministep);
}
}
for (b = 0; b < nb; b++)
for (j = 0; j < 4; j++)
bodies[b]->facc[j] = bodies[b]->tacc[j] = 0;
}
#ifdef NO_ISLANDS
// Since the iterative algorithm doesn't care about islands of bodies, this is a
// faster algorithm that just sends it all the joints and bodies in one array.
// It's downfall is it's inability to handle disabled bodies as well as the old one.
static void
processIslandsFast (dxWorld * world, dReal stepsize, int maxiterations)
{
// nothing to do if no bodies
if (world->nb <= 0)
return;
dInternalHandleAutoDisabling (world,stepsize);
# ifdef TIMING
dTimerStart ("creating joint and body arrays");
# endif
dxBody **bodies, *body;
dxJoint **joints, *joint;
joints = (dxJoint **) ALLOCA (world->nj * sizeof (dxJoint *));
bodies = (dxBody **) ALLOCA (world->nb * sizeof (dxBody *));
int nj = 0;
for (joint = world->firstjoint; joint; joint = (dxJoint *) joint->next)
joints[nj++] = joint;
int nb = 0;
for (body = world->firstbody; body; body = (dxBody *) body->next)
bodies[nb++] = body;
dInternalStepIslandFast (world, bodies, nb, joints, nj, stepsize, maxiterations);
# ifdef TIMING
dTimerEnd ();
dTimerReport (stdout, 1);
# endif
}
#else
//****************************************************************************
// island processing
// this groups all joints and bodies in a world into islands. all objects
// in an island are reachable by going through connected bodies and joints.
// each island can be simulated separately.
// note that joints that are not attached to anything will not be included
// in any island, an so they do not affect the simulation.
//
// this function starts new island from unvisited bodies. however, it will
// never start a new islands from a disabled body. thus islands of disabled
// bodies will not be included in the simulation. disabled bodies are
// re-enabled if they are found to be part of an active island.
static void
processIslandsFast (dxWorld * world, dReal stepsize, int maxiterations)
{
#ifdef TIMING
dTimerStart ("Island Setup");
#endif
dxBody *b, *bb, **body;
dxJoint *j, **joint;
// nothing to do if no bodies
if (world->nb <= 0)
return;
dInternalHandleAutoDisabling (world,stepsize);
// make arrays for body and joint lists (for a single island) to go into
body = (dxBody **) ALLOCA (world->nb * sizeof (dxBody *));
joint = (dxJoint **) ALLOCA (world->nj * sizeof (dxJoint *));
int bcount = 0; // number of bodies in `body'
int jcount = 0; // number of joints in `joint'
int tbcount = 0;
int tjcount = 0;
// set all body/joint tags to 0
for (b = world->firstbody; b; b = (dxBody *) b->next)
b->tag = 0;
for (j = world->firstjoint; j; j = (dxJoint *) j->next)
j->tag = 0;
// allocate a stack of unvisited bodies in the island. the maximum size of
// the stack can be the lesser of the number of bodies or joints, because
// new bodies are only ever added to the stack by going through untagged
// joints. all the bodies in the stack must be tagged!
int stackalloc = (world->nj < world->nb) ? world->nj : world->nb;
dxBody **stack = (dxBody **) ALLOCA (stackalloc * sizeof (dxBody *));
int *autostack = (int *) ALLOCA (stackalloc * sizeof (int));
for (bb = world->firstbody; bb; bb = (dxBody *) bb->next)
{
#ifdef TIMING
dTimerNow ("Island Processing");
#endif
// get bb = the next enabled, untagged body, and tag it
if (bb->tag || (bb->flags & dxBodyDisabled))
continue;
bb->tag = 1;
// tag all bodies and joints starting from bb.
int stacksize = 0;
int autoDepth = autoEnableDepth;
b = bb;
body[0] = bb;
bcount = 1;
jcount = 0;
goto quickstart;
while (stacksize > 0)
{
b = stack[--stacksize]; // pop body off stack
autoDepth = autostack[stacksize];
body[bcount++] = b; // put body on body list
quickstart:
// traverse and tag all body's joints, add untagged connected bodies
// to stack
for (dxJointNode * n = b->firstjoint; n; n = n->next)
{
if (!n->joint->tag)
{
int thisDepth = autoEnableDepth;
n->joint->tag = 1;
joint[jcount++] = n->joint;
if (n->body && !n->body->tag)
{
if (n->body->flags & dxBodyDisabled)
thisDepth = autoDepth - 1;
if (thisDepth < 0)
continue;
n->body->flags &= ~dxBodyDisabled;
n->body->tag = 1;
autostack[stacksize] = thisDepth;
stack[stacksize++] = n->body;
}
}
}
dIASSERT (stacksize <= world->nb);
dIASSERT (stacksize <= world->nj);
}
// now do something with body and joint lists
dInternalStepIslandFast (world, body, bcount, joint, jcount, stepsize, maxiterations);
// what we've just done may have altered the body/joint tag values.
// we must make sure that these tags are nonzero.
// also make sure all bodies are in the enabled state.
int i;
for (i = 0; i < bcount; i++)
{
body[i]->tag = 1;
body[i]->flags &= ~dxBodyDisabled;
}
for (i = 0; i < jcount; i++)
joint[i]->tag = 1;
tbcount += bcount;
tjcount += jcount;
}
#ifdef TIMING
dMessage(0, "Total joints processed: %i, bodies: %i", tjcount, tbcount);
#endif
// if debugging, check that all objects (except for disabled bodies,
// unconnected joints, and joints that are connected to disabled bodies)
// were tagged.
# ifndef dNODEBUG
for (b = world->firstbody; b; b = (dxBody *) b->next)
{
if (b->flags & dxBodyDisabled)
{
if (b->tag)
dDebug (0, "disabled body tagged");
}
else
{
if (!b->tag)
dDebug (0, "enabled body not tagged");
}
}
for (j = world->firstjoint; j; j = (dxJoint *) j->next)
{
if ((j->node[0].body && (j->node[0].body->flags & dxBodyDisabled) == 0) || (j->node[1].body && (j->node[1].body->flags & dxBodyDisabled) == 0))
{
if (!j->tag)
dDebug (0, "attached enabled joint not tagged");
}
else
{
if (j->tag)
dDebug (0, "unattached or disabled joint tagged");
}
}
# endif
# ifdef TIMING
dTimerEnd ();
dTimerReport (stdout, 1);
# endif
}
#endif
void dWorldStepFast1 (dWorldID w, dReal stepsize, int maxiterations)
{
dUASSERT (w, "bad world argument");
dUASSERT (stepsize > 0, "stepsize must be > 0");
processIslandsFast (w, stepsize, maxiterations);
}
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