/*************************************************************************
* *
* Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. *
* All rights reserved. Email: russ@q12.org Web: www.q12.org *
* *
* 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. *
* *
*************************************************************************/
#include <ode/ode.h>
#include "object.h"
#include "joint.h"
#include "util.h"
#include <ode/lookup_tables.h>
//#define ALLOCA dALLOCA16
//****************************************************************************
// Auto disabling
void dInternalHandleAutoDisabling (dxWorld *world, dReal stepsize)
{
dxBody *bb;
for ( bb=world->firstbody; bb; bb=(dxBody*)bb->next )
{
// don't freeze objects mid-air (patch 1586738)
if ( bb->firstjoint == NULL ) continue;
// nothing to do unless this body is currently enabled and has
// the auto-disable flag set
if ( (bb->flags & (dxBodyAutoDisable|dxBodyDisabled)) != dxBodyAutoDisable ) continue;
// if sampling / threshold testing is disabled, we can never sleep.
if ( bb->adis.average_samples == 0 ) continue;
//
// see if the body is idle
//
#ifndef dNODEBUG
// sanity check
if ( bb->average_counter >= bb->adis.average_samples )
{
// something is going wrong, reset the average-calculations
bb->average_ready = 0; // not ready for average calculation
bb->average_counter = 0; // reset the buffer index
}
#endif // dNODEBUG
// sample the linear and angular velocity
bb->average_lvel_buffer[bb->average_counter][0] = bb->lvel[0];
bb->average_lvel_buffer[bb->average_counter][1] = bb->lvel[1];
bb->average_lvel_buffer[bb->average_counter][2] = bb->lvel[2];
bb->average_avel_buffer[bb->average_counter][0] = bb->avel[0];
bb->average_avel_buffer[bb->average_counter][1] = bb->avel[1];
bb->average_avel_buffer[bb->average_counter][2] = bb->avel[2];
bb->average_counter++;
// buffer ready test
if ( bb->average_counter >= bb->adis.average_samples )
{
bb->average_counter = 0; // fill the buffer from the beginning
bb->average_ready = 1; // this body is ready now for average calculation
}
int idle = 0; // Assume it's in motion unless we have samples to disprove it.
// enough samples?
if ( bb->average_ready )
{
idle = 1; // Initial assumption: IDLE
// the sample buffers are filled and ready for calculation
dVector3 average_lvel, average_avel;
// Store first velocity samples
average_lvel[0] = bb->average_lvel_buffer[0][0];
average_avel[0] = bb->average_avel_buffer[0][0];
average_lvel[1] = bb->average_lvel_buffer[0][1];
average_avel[1] = bb->average_avel_buffer[0][1];
average_lvel[2] = bb->average_lvel_buffer[0][2];
average_avel[2] = bb->average_avel_buffer[0][2];
// If we're not in "instantaneous mode"
if ( bb->adis.average_samples > 1 )
{
// add remaining velocities together
for ( unsigned int i = 1; i < bb->adis.average_samples; ++i )
{
average_lvel[0] += bb->average_lvel_buffer[i][0];
average_avel[0] += bb->average_avel_buffer[i][0];
average_lvel[1] += bb->average_lvel_buffer[i][1];
average_avel[1] += bb->average_avel_buffer[i][1];
average_lvel[2] += bb->average_lvel_buffer[i][2];
average_avel[2] += bb->average_avel_buffer[i][2];
}
// make average
dReal r1 = dDIV(REAL( 1.0 ),REAL( bb->adis.average_samples ));
average_lvel[0] = dMUL(average_lvel[0],r1);
average_avel[0] = dMUL(average_avel[0],r1);
average_lvel[1] = dMUL(average_lvel[1],r1);
average_avel[1] = dMUL(average_avel[1],r1);
average_lvel[2] = dMUL(average_lvel[2],r1);
average_avel[2] = dMUL(average_avel[2],r1);
}
// threshold test
dReal av_lspeed, av_aspeed;
av_lspeed = dDOT( average_lvel, average_lvel );
if ( av_lspeed > bb->adis.linear_average_threshold )
{
idle = 0; // average linear velocity is too high for idle
}
else
{
av_aspeed = dDOT( average_avel, average_avel );
if ( av_aspeed > bb->adis.angular_average_threshold )
{
idle = 0; // average angular velocity is too high for idle
}
}
}
// if it's idle, accumulate steps and time.
// these counters won't overflow because this code doesn't run for disabled bodies.
if (idle) {
bb->adis_stepsleft--;
bb->adis_timeleft -= stepsize;
}
else {
// Reset countdowns
bb->adis_stepsleft = bb->adis.idle_steps;
bb->adis_timeleft = bb->adis.idle_time;
}
// disable the body if it's idle for a long enough time
if ( bb->adis_stepsleft <= 0 && bb->adis_timeleft <= 0 )
{
bb->flags |= dxBodyDisabled; // set the disable flag
// disabling bodies should also include resetting the velocity
// should prevent jittering in big "islands"
bb->lvel[0] = 0;
bb->lvel[1] = 0;
bb->lvel[2] = 0;
bb->avel[0] = 0;
bb->avel[1] = 0;
bb->avel[2] = 0;
}
}
}
//****************************************************************************
// 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) < REAL(1.0e-4)) return REAL(1.0) - dMUL(dMUL(x,x),REAL(0.166666666666666666667));
else return dDIV(dSin(x),x);
}
// given a body b, apply its linear and angular rotation over the time
// interval h, thereby adjusting its position and orientation.
void dxStepBody (dxBody *b, dReal h)
{
int j;
// handle linear velocity
for (j=0; j<3; j++) b->posr.pos[j] += dMUL(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; // finite rotation vector
dReal k = dDOT (b->finite_rot_axis,b->avel);
frv[0] = dMUL(b->finite_rot_axis[0],k);
frv[1] = dMUL(b->finite_rot_axis[1],k);
frv[2] = dMUL(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 = dMUL(h,REAL(0.5));
dReal theta = dMUL(k,h);
q[0] = dCos(theta);
dReal s = dMUL(sinc(theta),h);
q[1] = dMUL(frv[0],s);
q[2] = dMUL(frv[1],s);
q[3] = dMUL(frv[2],s);
}
else {
// make a rotation quaternion q that corresponds to w * h
dReal wlen = dSqrt (dMUL(b->avel[0],b->avel[0]) + dMUL(b->avel[1],b->avel[1]) +
dMUL(b->avel[2],b->avel[2]));
h = dMUL(h,REAL(0.5));
dReal theta = dMUL(wlen,h);
q[0] = dCos(theta);
dReal s = dMUL(sinc(theta),h);
q[1] = dMUL(b->avel[0],s);
q[2] = dMUL(b->avel[1],s);
q[3] = dMUL(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] += dMUL(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] += dMUL(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);
}
//****************************************************************************
// 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.
void dxProcessIslands (dxWorld *world, dReal stepsize, dstepper_fn_t stepper)
{
dxBody *b,*bb,**body;
dxJoint *j,**joint;
// nothing to do if no bodies
if (world->nb <= 0) return;
// handle auto-disabling of bodies
dInternalHandleAutoDisabling (world,stepsize);
// make arrays for body and joint lists (for a single island) to go into
body = (dxBody**) malloc (world->nb * sizeof(dxBody*));
if(body == NULL){
return;
}
joint = (dxJoint**) malloc (world->nj * sizeof(dxJoint*));
if(joint == NULL){
free(body);
return;
}
int bcount = 0; // number of bodies in `body'
int jcount = 0; // number of joints in `joint'
// 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**) malloc (stackalloc * sizeof(dxBody*));
if(stack == NULL){
free(body);
free(joint);
return;
}
for (bb=world->firstbody; bb; bb=(dxBody*)bb->next) {
// 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 firsttime = 1;
b = bb;
body[0] = bb;
bcount = 1;
jcount = 0;
while (stacksize > 0 || firsttime)
{
if (!firsttime)
{
b = stack[--stacksize]; // pop body off stack
body[bcount++] = b; // put body on body list
}
else
{
firsttime = 0;
}
// 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) {
n->joint->tag = 1;
joint[jcount++] = n->joint;
if (n->body && !n->body->tag) {
n->body->tag = 1;
stack[stacksize++] = n->body;
}
}
}
}
// now do something with body and joint lists
stepper (world,body,bcount,joint,jcount,stepsize);
// 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;
}
free(body);
free(joint);
free(stack);
}