aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/libraries/ode-0.9/ode/src/util.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'libraries/ode-0.9/ode/src/util.cpp')
-rw-r--r--libraries/ode-0.9/ode/src/util.cpp374
1 files changed, 374 insertions, 0 deletions
diff --git a/libraries/ode-0.9/ode/src/util.cpp b/libraries/ode-0.9/ode/src/util.cpp
new file mode 100644
index 0000000..c8d6230
--- /dev/null
+++ b/libraries/ode-0.9/ode/src/util.cpp
@@ -0,0 +1,374 @@
1/*************************************************************************
2 * *
3 * Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. *
4 * All rights reserved. Email: russ@q12.org Web: www.q12.org *
5 * *
6 * This library is free software; you can redistribute it and/or *
7 * modify it under the terms of EITHER: *
8 * (1) The GNU Lesser General Public License as published by the Free *
9 * Software Foundation; either version 2.1 of the License, or (at *
10 * your option) any later version. The text of the GNU Lesser *
11 * General Public License is included with this library in the *
12 * file LICENSE.TXT. *
13 * (2) The BSD-style license that is included with this library in *
14 * the file LICENSE-BSD.TXT. *
15 * *
16 * This library is distributed in the hope that it will be useful, *
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files *
19 * LICENSE.TXT and LICENSE-BSD.TXT for more details. *
20 * *
21 *************************************************************************/
22
23#include "ode/ode.h"
24#include "objects.h"
25#include "joint.h"
26#include "util.h"
27
28#define ALLOCA dALLOCA16
29
30//****************************************************************************
31// Auto disabling
32
33void dInternalHandleAutoDisabling (dxWorld *world, dReal stepsize)
34{
35 dxBody *bb;
36 for ( bb=world->firstbody; bb; bb=(dxBody*)bb->next )
37 {
38 // don't freeze objects mid-air (patch 1586738)
39 if ( bb->firstjoint == NULL ) continue;
40
41 // nothing to do unless this body is currently enabled and has
42 // the auto-disable flag set
43 if ( (bb->flags & (dxBodyAutoDisable|dxBodyDisabled)) != dxBodyAutoDisable ) continue;
44
45 // if sampling / threshold testing is disabled, we can never sleep.
46 if ( bb->adis.average_samples == 0 ) continue;
47
48 //
49 // see if the body is idle
50 //
51
52#ifndef dNODEBUG
53 // sanity check
54 if ( bb->average_counter >= bb->adis.average_samples )
55 {
56 dUASSERT( bb->average_counter < bb->adis.average_samples, "buffer overflow" );
57
58 // something is going wrong, reset the average-calculations
59 bb->average_ready = 0; // not ready for average calculation
60 bb->average_counter = 0; // reset the buffer index
61 }
62#endif // dNODEBUG
63
64 // sample the linear and angular velocity
65 bb->average_lvel_buffer[bb->average_counter][0] = bb->lvel[0];
66 bb->average_lvel_buffer[bb->average_counter][1] = bb->lvel[1];
67 bb->average_lvel_buffer[bb->average_counter][2] = bb->lvel[2];
68 bb->average_avel_buffer[bb->average_counter][0] = bb->avel[0];
69 bb->average_avel_buffer[bb->average_counter][1] = bb->avel[1];
70 bb->average_avel_buffer[bb->average_counter][2] = bb->avel[2];
71 bb->average_counter++;
72
73 // buffer ready test
74 if ( bb->average_counter >= bb->adis.average_samples )
75 {
76 bb->average_counter = 0; // fill the buffer from the beginning
77 bb->average_ready = 1; // this body is ready now for average calculation
78 }
79
80 int idle = 0; // Assume it's in motion unless we have samples to disprove it.
81
82 // enough samples?
83 if ( bb->average_ready )
84 {
85 idle = 1; // Initial assumption: IDLE
86
87 // the sample buffers are filled and ready for calculation
88 dVector3 average_lvel, average_avel;
89
90 // Store first velocity samples
91 average_lvel[0] = bb->average_lvel_buffer[0][0];
92 average_avel[0] = bb->average_avel_buffer[0][0];
93 average_lvel[1] = bb->average_lvel_buffer[0][1];
94 average_avel[1] = bb->average_avel_buffer[0][1];
95 average_lvel[2] = bb->average_lvel_buffer[0][2];
96 average_avel[2] = bb->average_avel_buffer[0][2];
97
98 // If we're not in "instantaneous mode"
99 if ( bb->adis.average_samples > 1 )
100 {
101 // add remaining velocities together
102 for ( unsigned int i = 1; i < bb->adis.average_samples; ++i )
103 {
104 average_lvel[0] += bb->average_lvel_buffer[i][0];
105 average_avel[0] += bb->average_avel_buffer[i][0];
106 average_lvel[1] += bb->average_lvel_buffer[i][1];
107 average_avel[1] += bb->average_avel_buffer[i][1];
108 average_lvel[2] += bb->average_lvel_buffer[i][2];
109 average_avel[2] += bb->average_avel_buffer[i][2];
110 }
111
112 // make average
113 dReal r1 = dReal( 1.0 ) / dReal( bb->adis.average_samples );
114
115 average_lvel[0] *= r1;
116 average_avel[0] *= r1;
117 average_lvel[1] *= r1;
118 average_avel[1] *= r1;
119 average_lvel[2] *= r1;
120 average_avel[2] *= r1;
121 }
122
123 // threshold test
124 dReal av_lspeed, av_aspeed;
125 av_lspeed = dDOT( average_lvel, average_lvel );
126 if ( av_lspeed > bb->adis.linear_average_threshold )
127 {
128 idle = 0; // average linear velocity is too high for idle
129 }
130 else
131 {
132 av_aspeed = dDOT( average_avel, average_avel );
133 if ( av_aspeed > bb->adis.angular_average_threshold )
134 {
135 idle = 0; // average angular velocity is too high for idle
136 }
137 }
138 }
139
140 // if it's idle, accumulate steps and time.
141 // these counters won't overflow because this code doesn't run for disabled bodies.
142 if (idle) {
143 bb->adis_stepsleft--;
144 bb->adis_timeleft -= stepsize;
145 }
146 else {
147 // Reset countdowns
148 bb->adis_stepsleft = bb->adis.idle_steps;
149 bb->adis_timeleft = bb->adis.idle_time;
150 }
151
152 // disable the body if it's idle for a long enough time
153 if ( bb->adis_stepsleft <= 0 && bb->adis_timeleft <= 0 )
154 {
155 bb->flags |= dxBodyDisabled; // set the disable flag
156
157 // disabling bodies should also include resetting the velocity
158 // should prevent jittering in big "islands"
159 bb->lvel[0] = 0;
160 bb->lvel[1] = 0;
161 bb->lvel[2] = 0;
162 bb->avel[0] = 0;
163 bb->avel[1] = 0;
164 bb->avel[2] = 0;
165 }
166 }
167}
168
169
170//****************************************************************************
171// body rotation
172
173// return sin(x)/x. this has a singularity at 0 so special handling is needed
174// for small arguments.
175
176static inline dReal sinc (dReal x)
177{
178 // if |x| < 1e-4 then use a taylor series expansion. this two term expansion
179 // is actually accurate to one LS bit within this range if double precision
180 // is being used - so don't worry!
181 if (dFabs(x) < 1.0e-4) return REAL(1.0) - x*x*REAL(0.166666666666666666667);
182 else return dSin(x)/x;
183}
184
185
186// given a body b, apply its linear and angular rotation over the time
187// interval h, thereby adjusting its position and orientation.
188
189void dxStepBody (dxBody *b, dReal h)
190{
191 int j;
192
193 // handle linear velocity
194 for (j=0; j<3; j++) b->posr.pos[j] += h * b->lvel[j];
195
196 if (b->flags & dxBodyFlagFiniteRotation) {
197 dVector3 irv; // infitesimal rotation vector
198 dQuaternion q; // quaternion for finite rotation
199
200 if (b->flags & dxBodyFlagFiniteRotationAxis) {
201 // split the angular velocity vector into a component along the finite
202 // rotation axis, and a component orthogonal to it.
203 dVector3 frv; // finite rotation vector
204 dReal k = dDOT (b->finite_rot_axis,b->avel);
205 frv[0] = b->finite_rot_axis[0] * k;
206 frv[1] = b->finite_rot_axis[1] * k;
207 frv[2] = b->finite_rot_axis[2] * k;
208 irv[0] = b->avel[0] - frv[0];
209 irv[1] = b->avel[1] - frv[1];
210 irv[2] = b->avel[2] - frv[2];
211
212 // make a rotation quaternion q that corresponds to frv * h.
213 // compare this with the full-finite-rotation case below.
214 h *= REAL(0.5);
215 dReal theta = k * h;
216 q[0] = dCos(theta);
217 dReal s = sinc(theta) * h;
218 q[1] = frv[0] * s;
219 q[2] = frv[1] * s;
220 q[3] = frv[2] * s;
221 }
222 else {
223 // make a rotation quaternion q that corresponds to w * h
224 dReal wlen = dSqrt (b->avel[0]*b->avel[0] + b->avel[1]*b->avel[1] +
225 b->avel[2]*b->avel[2]);
226 h *= REAL(0.5);
227 dReal theta = wlen * h;
228 q[0] = dCos(theta);
229 dReal s = sinc(theta) * h;
230 q[1] = b->avel[0] * s;
231 q[2] = b->avel[1] * s;
232 q[3] = b->avel[2] * s;
233 }
234
235 // do the finite rotation
236 dQuaternion q2;
237 dQMultiply0 (q2,q,b->q);
238 for (j=0; j<4; j++) b->q[j] = q2[j];
239
240 // do the infitesimal rotation if required
241 if (b->flags & dxBodyFlagFiniteRotationAxis) {
242 dReal dq[4];
243 dWtoDQ (irv,b->q,dq);
244 for (j=0; j<4; j++) b->q[j] += h * dq[j];
245 }
246 }
247 else {
248 // the normal way - do an infitesimal rotation
249 dReal dq[4];
250 dWtoDQ (b->avel,b->q,dq);
251 for (j=0; j<4; j++) b->q[j] += h * dq[j];
252 }
253
254 // normalize the quaternion and convert it to a rotation matrix
255 dNormalize4 (b->q);
256 dQtoR (b->q,b->posr.R);
257
258 // notify all attached geoms that this body has moved
259 for (dxGeom *geom = b->geom; geom; geom = dGeomGetBodyNext (geom))
260 dGeomMoved (geom);
261}
262
263//****************************************************************************
264// island processing
265
266// this groups all joints and bodies in a world into islands. all objects
267// in an island are reachable by going through connected bodies and joints.
268// each island can be simulated separately.
269// note that joints that are not attached to anything will not be included
270// in any island, an so they do not affect the simulation.
271//
272// this function starts new island from unvisited bodies. however, it will
273// never start a new islands from a disabled body. thus islands of disabled
274// bodies will not be included in the simulation. disabled bodies are
275// re-enabled if they are found to be part of an active island.
276
277void dxProcessIslands (dxWorld *world, dReal stepsize, dstepper_fn_t stepper)
278{
279 dxBody *b,*bb,**body;
280 dxJoint *j,**joint;
281
282 // nothing to do if no bodies
283 if (world->nb <= 0) return;
284
285 // handle auto-disabling of bodies
286 dInternalHandleAutoDisabling (world,stepsize);
287
288 // make arrays for body and joint lists (for a single island) to go into
289 body = (dxBody**) ALLOCA (world->nb * sizeof(dxBody*));
290 joint = (dxJoint**) ALLOCA (world->nj * sizeof(dxJoint*));
291 int bcount = 0; // number of bodies in `body'
292 int jcount = 0; // number of joints in `joint'
293
294 // set all body/joint tags to 0
295 for (b=world->firstbody; b; b=(dxBody*)b->next) b->tag = 0;
296 for (j=world->firstjoint; j; j=(dxJoint*)j->next) j->tag = 0;
297
298 // allocate a stack of unvisited bodies in the island. the maximum size of
299 // the stack can be the lesser of the number of bodies or joints, because
300 // new bodies are only ever added to the stack by going through untagged
301 // joints. all the bodies in the stack must be tagged!
302 int stackalloc = (world->nj < world->nb) ? world->nj : world->nb;
303 dxBody **stack = (dxBody**) ALLOCA (stackalloc * sizeof(dxBody*));
304
305 for (bb=world->firstbody; bb; bb=(dxBody*)bb->next) {
306 // get bb = the next enabled, untagged body, and tag it
307 if (bb->tag || (bb->flags & dxBodyDisabled)) continue;
308 bb->tag = 1;
309
310 // tag all bodies and joints starting from bb.
311 int stacksize = 0;
312 b = bb;
313 body[0] = bb;
314 bcount = 1;
315 jcount = 0;
316 goto quickstart;
317 while (stacksize > 0) {
318 b = stack[--stacksize]; // pop body off stack
319 body[bcount++] = b; // put body on body list
320 quickstart:
321
322 // traverse and tag all body's joints, add untagged connected bodies
323 // to stack
324 for (dxJointNode *n=b->firstjoint; n; n=n->next) {
325 if (!n->joint->tag) {
326 n->joint->tag = 1;
327 joint[jcount++] = n->joint;
328 if (n->body && !n->body->tag) {
329 n->body->tag = 1;
330 stack[stacksize++] = n->body;
331 }
332 }
333 }
334 dIASSERT(stacksize <= world->nb);
335 dIASSERT(stacksize <= world->nj);
336 }
337
338 // now do something with body and joint lists
339 stepper (world,body,bcount,joint,jcount,stepsize);
340
341 // what we've just done may have altered the body/joint tag values.
342 // we must make sure that these tags are nonzero.
343 // also make sure all bodies are in the enabled state.
344 int i;
345 for (i=0; i<bcount; i++) {
346 body[i]->tag = 1;
347 body[i]->flags &= ~dxBodyDisabled;
348 }
349 for (i=0; i<jcount; i++) joint[i]->tag = 1;
350 }
351
352 // if debugging, check that all objects (except for disabled bodies,
353 // unconnected joints, and joints that are connected to disabled bodies)
354 // were tagged.
355# ifndef dNODEBUG
356 for (b=world->firstbody; b; b=(dxBody*)b->next) {
357 if (b->flags & dxBodyDisabled) {
358 if (b->tag) dDebug (0,"disabled body tagged");
359 }
360 else {
361 if (!b->tag) dDebug (0,"enabled body not tagged");
362 }
363 }
364 for (j=world->firstjoint; j; j=(dxJoint*)j->next) {
365 if ((j->node[0].body && (j->node[0].body->flags & dxBodyDisabled)==0) ||
366 (j->node[1].body && (j->node[1].body->flags & dxBodyDisabled)==0)) {
367 if (!j->tag) dDebug (0,"attached enabled joint not tagged");
368 }
369 else {
370 if (j->tag) dDebug (0,"unattached or disabled joint tagged");
371 }
372 }
373# endif
374}