decision_control/slotplanner.cc

   1 /*
   2 This file is part of I am car.
   3
   4 I am car is free software: you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation, either version 3 of the License, or
   7 (at your option) any later version.
   8
   9 I am car is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with I am car. If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <algorithm>
  19 #include <cmath>
  20 #include <list>
  21 #include <queue>
  22 #include "slotplanner.h"
  23
  24 ParallelSlot::ParallelSlot()
  25 {}
  26
  27 // getter
  28 std::vector<std::vector<RRTNode *>> &ParallelSlot::cusp()
  29 {
  30         return this->cusp_;
  31 }
  32
  33 float ParallelSlot::DH() const
  34 {
  35         return this->DH_;
  36 }
  37
  38 PolygonObstacle &ParallelSlot::slot()
  39 {
  40         return this->slot_;
  41 }
  42
  43 float ParallelSlot::slotHeading()
  44 {
  45         return this->slotHeading_;
  46 }
  47
  48 SlotSide ParallelSlot::slotSide()
  49 {
  50         return this->slotSide_;
  51 }
  52
  53 SlotType ParallelSlot::slotType()
  54 {
  55         return this->slotType_;
  56 }
  57
  58 // setter
  59 void ParallelSlot::DH(float dh)
  60 {
  61         this->DH_ = dh;
  62 }
  63
  64 void ParallelSlot::setAll()
  65 {
  66         // slot heading
  67         float y0 = this->slot().bnodes()[0]->y();
  68         float x0 = this->slot().bnodes()[0]->x();
  69         float y3 = this->slot().bnodes()[3]->y();
  70         float x3 = this->slot().bnodes()[3]->x();
  71         float dy = y0 - y3;
  72         float dx = x0 - x3;
  73         this->slotHeading_ = atan2(dy, dx);
  74         // slot side
  75         float y1 = this->slot().bnodes()[1]->y();
  76         float x1 = this->slot().bnodes()[1]->x();
  77         if (sgn((x1 - x3) * (y0 - y3) - (y1 - y3) * (x0 - x3)) < 0)
  78                 this->slotSide_ = LEFT;
  79         else
  80                 this->slotSide_ = RIGHT;
  81         // slot type
  82         float d1 = EDIST(
  83                 this->slot().bnodes()[0],
  84                 this->slot().bnodes()[1]
  85         );
  86         float d2 = EDIST(
  87                 this->slot().bnodes()[1],
  88                 this->slot().bnodes()[2]
  89         );
  90         if (d1 > d2)
  91                 this->slotType_ = PERPENDICULAR;
  92         else
  93                 this->slotType_ = PARALLEL;
  94 }
  95
  96 // other
  97 void ParallelSlot::fip(
  98         std::vector<CircleObstacle>& co,
  99         std::vector<SegmentObstacle>& so
 100 )
 101 {
 102         if (this->slotType() == PERPENDICULAR) {
 103                 // TODO different slot headings
 104                 // this is jus for slot heading = pi / 2
 105                 this->DH(0.01 / BCAR_TURNING_RADIUS);
 106                 BicycleCar *perc = nullptr;
 107                 RRTNode *cc = nullptr;
 108                 BicycleCar *p = nullptr;
 109                 int i = 0;
 110                 float x;
 111                 float h;
 112                 float y;
 113                 // parking backward
 114                 x = this->slot().bnodes()[3]->x();
 115                 y = this->slot().bnodes()[3]->y();
 116                 h = 0;
 117                 // -> top
 118                 x -= BCAR_DIST_FRONT;
 119                 y = this->slot().bnodes()[3]->y();
 120                 y += BCAR_OUT_RRADI - BCAR_TURNING_RADIUS;
 121                 if (perc)
 122                         delete perc;
 123                 perc = new BicycleCar(x, y, h);
 124                 if (cc)
 125                         delete cc;
 126                 cc = perc->ccl();
 127                 if (p)
 128                         delete p;
 129                 p = perc->move(cc, i * this->DH());
 130                 while (p->x() < 0) {
 131                         delete p;
 132                         p = perc->move(cc, i * this->DH());
 133                         i++;
 134                 }
 135                 // -> bottom
 136                 // (reset for parking backward)
 137                 x = this->slot().bnodes()[0]->x();
 138                 y = this->slot().bnodes()[0]->y();
 139                 h = 0;
 140                 // -> bottom
 141                 x -= BCAR_DIST_FRONT;
 142                 // get y from quadratic equation
 143                 float tmpD = pow(-2 * this->slot().bnodes()[0]->y(), 2);
 144                 tmpD -= 4 * (
 145                         pow(x - this->slot().bnodes()[0]->x(), 2) +
 146                         pow(this->slot().bnodes()[0]->y(), 2) -
 147                         pow(BCAR_IN_RADI, 2)
 148                 );
 149                 y = 2 * this->slot().bnodes()[0]->y();
 150                 y += sqrt(tmpD);
 151                 y /= 2;
 152                 y -= BCAR_TURNING_RADIUS;
 153                 // -- end of quadratic equation
 154                 if (perc)
 155                         delete perc;
 156                 perc = new BicycleCar(x, y, h);
 157                 if (cc)
 158                         delete cc;
 159                 cc = perc->ccl();
 160                 if (p)
 161                         delete p;
 162                 p = perc->move(cc, i * this->DH());
 163                 while (p->x() < 0) {
 164                         delete p;
 165                         p = perc->move(cc, i * this->DH());
 166                         i++;
 167                 }
 168                 // store nodes
 169                 std::vector<RRTNode *> cusp;
 170                 cusp.push_back(new RRTNode(p->x(), p->y(), p->h()));
 171                 cusp.push_back(new RRTNode(x, y, h));
 172                 this->cusp().push_back(cusp);
 173                 return;
 174         }
 175         // see https://courses.cs.washington.edu/courses/cse326/03su/homework/hw3/bfs.html
 176         // RRTNode.s() works as iteration level
 177         std::queue<BicycleCar *, std::list<BicycleCar *>> q;
 178         std::queue<BicycleCar *, std::list<BicycleCar *>> empty;
 179         int di = -1;
 180         if (this->slotSide() == LEFT)
 181                 di = 1;
 182         BicycleCar *CC = this->getEPC();
 183         BicycleCar *B = this->getEP();
 184         this->DH(di * 0.01 / CC->out_radi());
 185         BicycleCar *c;
 186         int i = 0;
 187         c = B->move(CC, -i * di * 0.01 / CC->diag_radi());
 188         while (!this->slot().collide(c->frame())) {
 189                 bool end = false;
 190                 std::vector<RRTEdge *> eds = c->frame();
 191                 for (auto o: co)
 192                         if (o.collide(eds))
 193                                 end = true;
 194                 for (auto o: so)
 195                         if (o.collide(eds))
 196                                 end = true;
 197                 for (auto e: eds)
 198                         delete e;
 199                 if (!end)
 200                         q.push(c);
 201                 c = B->move(CC, -i * di * 0.01 / CC->diag_radi());
 202                 i += 1;
 203         }
 204         delete c; // not in q and collide
 205         while (!q.empty()) {
 206                 c = q.front();
 207                 q.pop();
 208                 if (this->isInside(c)) {
 209                         goto createcuspandfinish;
 210                 } else if (c->s() < 9) {
 211                         BicycleCar *cc = this->flnc(c, co, so);
 212                         cc->s(c->s() + 1);
 213                         cc->bcparent(c);
 214                         q.push(cc);
 215                 } else {
 216                         delete c; // not in q and collide
 217                 }
 218         }
 219         std::swap(q, empty);
 220         return;
 221 createcuspandfinish:
 222         std::vector<RRTNode *> cusp;
 223         while (c) {
 224                 cusp.push_back(new RRTNode(c->x(), c->y(), c->h()));
 225                 c = c->bcparent();
 226         }
 227         std::reverse(cusp.begin(), cusp.end());
 228         this->cusp().push_back(cusp);
 229         std::swap(q, empty);
 230 }
 231
 232 void ParallelSlot::fipr(RRTNode *n)
 233 {
 234         return this->fipr(new BicycleCar(n->x(), n->y(), n->h()));
 235 }
 236
 237 void ParallelSlot::fipr(BicycleCar *B)
 238 {
 239         std::vector<RRTNode *> cusp;
 240         cusp.push_back(new RRTNode(B->x(), B->y(), B->h()));
 241         int di = 1;
 242         if (this->slotSide() == LEFT)
 243                 di = -1;
 244         if (this->slotType() == PERPENDICULAR) {
 245                 this->DH(di * 0.01 / B->out_radi()); // TODO car in slot h()
 246                 RRTNode *cc;
 247                 if (this->slotSide() == LEFT)
 248                         cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 249                 else
 250                         cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 251                 BicycleCar *p;
 252                 int i = 1;
 253                 p = B->move(cc, i * this->DH());
 254                 while (
 255                         !this->slot().collide(p->frame())
 256                         && this->slot().collide(p)
 257                 ) {
 258                         delete p;
 259                         i += 10;
 260                         p = B->move(cc, i * this->DH());
 261                 }
 262                 i -= 10;
 263                 p = B->move(cc, i * this->DH());
 264                 while (
 265                         !this->slot().collide(p->frame())
 266                         && this->slot().collide(p)
 267                 ) {
 268                         delete p;
 269                         i += 1;
 270                         p = B->move(cc, i * this->DH());
 271                 }
 272                 i -= 1;
 273                 p = B->move(cc, i * this->DH());
 274                 cusp.push_back(new RRTNode(p->x(), p->y(), p->h()));
 275                 std::reverse(cusp.begin(), cusp.end());
 276                 this->cusp().push_back(cusp);
 277                 return;
 278         }
 279         this->DH(di * 0.01 / B->out_radi());
 280         BicycleCar *c;
 281         c = this->flncr(B);
 282         c->s(B->s() + 1);
 283         while ((
 284                 this->slotSide() == LEFT
 285                 && this->slot().collide(new RRTNode(c->lfx(), c->lfy(), 0))
 286         ) || (
 287                 this->slotSide() == RIGHT
 288                 && this->slot().collide(new RRTNode(c->rfx(), c->rfy(), 0))
 289         )) {
 290                 cusp.push_back(new RRTNode(c->x(), c->y(), c->h()));
 291                 BicycleCar *cc = this->flncr(c);
 292                 cc->s(c->s() + 1);
 293                 delete c;
 294                 c = cc;
 295         }
 296         cusp.push_back(new RRTNode(c->x(), c->y(), c->h()));
 297         std::reverse(cusp.begin(), cusp.end());
 298         this->cusp().push_back(cusp);
 299 }
 300
 301 BicycleCar *ParallelSlot::flnc(
 302         BicycleCar *B,
 303         std::vector<CircleObstacle>& co,
 304         std::vector<SegmentObstacle>& so
 305 )
 306 {
 307         RRTNode *cc;
 308         if (this->slotSide() == LEFT) {
 309                 if (int(B->s()) % 2 == 0)
 310                         cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 311                 else
 312                         cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 313         } else {
 314                 if (int(B->s()) % 2 == 0)
 315                         cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 316                 else
 317                         cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 318         }
 319         BicycleCar *p;
 320         int i = 1;
 321         p = B->move(cc, i * this->DH());
 322         while (
 323                 !this->slot().collide(p->frame())
 324                 && std::abs(this->slotHeading() - p->h()) < M_PI / 2
 325         ) {
 326                 delete p;
 327                 i += 10;
 328                 p = B->move(cc, i * this->DH());
 329                 bool end = false;
 330                 std::vector<RRTEdge *> eds = p->frame();
 331                 for (auto o: co)
 332                         if (o.collide(eds))
 333                                 end = true;
 334                 for (auto o: so)
 335                         if (o.collide(eds))
 336                                 end = true;
 337                 for (auto e: eds)
 338                         delete e;
 339                 if (end)
 340                         break;
 341         }
 342         i -= 10;
 343         p = B->move(cc, i * this->DH());
 344         while (
 345                 !this->slot().collide(p->frame())
 346                 && std::abs(this->slotHeading() - p->h()) < M_PI / 2
 347         ) {
 348                 if (this->isInside(p)) {
 349                         i += 1;
 350                         break;
 351                 }
 352                 delete p;
 353                 i += 1;
 354                 p = B->move(cc, i * this->DH());
 355                 bool end = false;
 356                 std::vector<RRTEdge *> eds = p->frame();
 357                 for (auto o: co)
 358                         if (o.collide(eds))
 359                                 end = true;
 360                 for (auto o: so)
 361                         if (o.collide(eds))
 362                                 end = true;
 363                 for (auto e: eds)
 364                         delete e;
 365                 if (end)
 366                         break;
 367         }
 368         delete p;
 369         return B->move(cc, (i - 1) * this->DH());
 370 }
 371
 372 BicycleCar *ParallelSlot::flncr(BicycleCar *B)
 373 {
 374         RRTNode *cc;
 375         if (this->slotSide() == LEFT) {
 376                 if (int(B->s()) % 2 == 0)
 377                         cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 378                 else
 379                         cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 380         } else {
 381                 if (int(B->s()) % 2 == 0)
 382                         cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 383                 else
 384                         cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 385         }
 386         BicycleCar *p;
 387         int i = 1;
 388         p = B->move(cc, i * this->DH());
 389         while (
 390                 !this->slot().collide(p->frame())
 391                 && ((
 392                         this->slotSide() == LEFT
 393                         && this->slot().collide(new RRTNode(
 394                                 p->lfx(),
 395                                 p->lfy(),
 396                                 0
 397                         ))
 398                 ) || (
 399                         this->slotSide() == RIGHT
 400                         && this->slot().collide(new RRTNode(
 401                                 p->rfx(),
 402                                 p->rfy(),
 403                                 0
 404                         ))
 405                 ))
 406         ) {
 407                 delete p;
 408                 i += 10;
 409                 p = B->move(cc, i * this->DH());
 410         }
 411         i -= 10;
 412         p = B->move(cc, i * this->DH());
 413         while (!this->slot().collide(p->frame())) {
 414                 if(
 415                         this->slotSide() == LEFT
 416                         && !this->slot().collide(new RRTNode(
 417                                 p->lfx(),
 418                                 p->lfy(),
 419                                 0
 420                         ))
 421                 ) {
 422                         i += 1;
 423                         break;
 424                 }
 425                 if(
 426                         this->slotSide() == RIGHT
 427                         && !this->slot().collide(new RRTNode(
 428                                 p->rfx(),
 429                                 p->rfy(),
 430                                 0
 431                         ))
 432                 ) {
 433                         i += 1;
 434                         break;
 435                 }
 436                 i += 1;
 437                 p = B->move(cc, i * this->DH());
 438         }
 439         delete p;
 440         return B->move(cc, (i - 1) * this->DH());
 441 }
 442
 443 RRTNode *ParallelSlot::fposecenter()
 444 {
 445         return this->slot().bnodes().front();
 446 }
 447
 448 bool ParallelSlot::flast(
 449         RRTNode *P,
 450         bool right,
 451         int il,
 452         std::vector<RRTNode *> &cusp
 453 )
 454 {
 455         BicycleCar *B = new BicycleCar(P->x(), P->y(), P->h());
 456         RRTNode *cc;
 457         if (right)
 458                 cc = BicycleCar(B->x(), B->y(), B->h()).ccr();
 459         else
 460                 cc = BicycleCar(B->x(), B->y(), B->h()).ccl();
 461         BicycleCar *p;
 462         int i = 1;
 463         p = B->move(cc, i * this->DH());
 464         while (!this->slot().collide(p->frame())
 465                         && (
 466                                 (this->DH() > 0 && p->x() <= 0)
 467                                 || (this->DH() < 0 && p->x() >= 0)
 468                         )) {
 469                 delete p;
 470                 i += 10;
 471                 p = B->move(cc, i * this->DH());
 472         }
 473         i -= 10;
 474         p = B->move(cc, i * this->DH());
 475         while (!this->slot().collide(p->frame())
 476                         && (
 477                                 (this->DH() > 0 && p->x() <= 0)
 478                                 || (this->DH() < 0 && p->x() >= 0)
 479                         )) {
 480                 if (this->DH() > 0 && p->rfx() <= 0 && p->rrx() <= 0) {
 481                         i += 1;
 482                         break;
 483                 }
 484                 if (this->DH() < 0 && p->lfx() >= 0 && p->lrx() >= 0) {
 485                         i += 1;
 486                         break;
 487                 }
 488                 delete p;
 489                 i += 1;
 490                 p = B->move(cc, i * this->DH());
 491         }
 492         delete p;
 493         p = B->move(cc, (i - 1) * this->DH());
 494         if (this->DH() > 0 && p->rfx() <= 0 && p->rrx() <= 0) {
 495                 cusp.push_back(p);
 496                 return true;
 497         } else if (this->DH() < 0 && p->lfx() >= 0 && p->lrx() >= 0) {
 498                 cusp.push_back(p);
 499                 return true;
 500         } else if (il < 8) {
 501                 cusp.push_back(p);
 502                 return this->flast(p, !right, il + 1, cusp);
 503         }
 504         return false;
 505 }
 506
 507 void ParallelSlot::fpose()
 508 {
 509         bool left = false; // right parking slot
 510         float di = -1;
 511         BicycleCar *CC = new BicycleCar(
 512                 this->fposecenter()->x(),
 513                 this->fposecenter()->y() - 0.01,
 514                 this->slotHeading()
 515         );
 516         BicycleCar *B = new BicycleCar(
 517                 CC->x() - CC->width() / 2,
 518                 CC->y() - (CC->length() + CC->wheelbase()) / 2,
 519                 this->slotHeading()
 520         );
 521         if (this->slot().bnodes()[0]->x() > this->slot().bnodes()[1]->x()) {
 522                 left = true;
 523                 di = 1;
 524                 delete B;
 525                 B = new BicycleCar(
 526                         CC->x() + CC->width() / 2,
 527                         CC->y() - (CC->length() + CC->wheelbase()) / 2,
 528                         this->slotHeading()
 529                 );
 530         }
 531         this->DH(di * 0.01 / CC->out_radi());
 532         BicycleCar *p;
 533         int i = 0;
 534         p = B->move(CC, -i * di * 0.01 / CC->diag_radi());
 535         while (!this->slot().collide(p->frame())) {
 536                 std::vector<RRTNode *> tmpcusp;
 537                 tmpcusp.push_back(new BicycleCar(p->x(), p->y(), p->h()));
 538                 if (this->flast(p, left, 0, tmpcusp)) {
 539                         this->cusp().push_back(tmpcusp);
 540                         return;
 541                 }
 542                 i += 1;
 543                 delete p;
 544                 p = B->move(CC, -i * di * 0.01 / CC->diag_radi());
 545         }
 546 }
 547
 548 BicycleCar *ParallelSlot::getEP()
 549 {
 550         // new pose for parallel parking to right slot
 551         float tnx;
 552         float tny;
 553         float nx;
 554         float ny;
 555         BicycleCar *CC = this->getEPC();
 556         // move left by car width / 2
 557         tnx = CC->x() + CC->width() / 2 * cos(CC->h() + M_PI / 2);
 558         tny = CC->y() + CC->width() / 2 * sin(CC->h() + M_PI / 2);
 559         if (this->slotSide() == LEFT) {
 560                 // move right by car width / 2
 561                 tnx = CC->x() + CC->width() / 2 * cos(CC->h() - M_PI / 2);
 562                 tny = CC->y() + CC->width() / 2 * sin(CC->h() - M_PI / 2);
 563         }
 564         if (this->slotType() == PARALLEL) {
 565                 // move down
 566                 nx = tnx - (CC->length() + CC->wheelbase()) / 2 * cos(CC->h());
 567                 ny = tny - (CC->length() + CC->wheelbase()) / 2 * sin(CC->h());
 568         } else {
 569                 // move down
 570                 nx = tnx + (CC->length() - CC->wheelbase()) / 2 * cos(CC->h());
 571                 ny = tny + (CC->length() - CC->wheelbase()) / 2 * sin(CC->h());
 572         }
 573         return new BicycleCar(nx, ny, CC->h());
 574 }
 575
 576 BicycleCar *ParallelSlot::getEPC()
 577 {
 578         // new pose for parallel parking to right slot
 579         float ta;
 580         float nx;
 581         float ny;
 582         ta = this->slotHeading() + M_PI;
 583         if (this->slotSide() == RIGHT)
 584                 ta -= M_PI / 4;
 585         else
 586                 ta += M_PI / 4;
 587         nx = this->fposecenter()->x() + 0.01 * cos(ta);
 588         ny = this->fposecenter()->y() + 0.01 * sin(ta);
 589         return new BicycleCar(nx, ny, this->slotHeading());
 590 }
 591
 592 BicycleCar *ParallelSlot::getFP()
 593 {
 594         float x = this->slot().bnodes()[3]->x();
 595         float y = this->slot().bnodes()[3]->y();
 596         float h = this->slotHeading();
 597         float nx;
 598         float ny;
 599         if (this->slotType() == PARALLEL) {
 600                 if (this->slotSide() == LEFT) {
 601                         nx = x + BCAR_WIDTH / 2 * cos(h + M_PI / 2);
 602                         ny = y + BCAR_WIDTH / 2 * sin(h + M_PI / 2);
 603                 } else {
 604                         nx = x + BCAR_WIDTH / 2 * cos(h - M_PI / 2);
 605                         ny = y + BCAR_WIDTH / 2 * sin(h - M_PI / 2);
 606                 }
 607                 x = nx + ((BCAR_LENGTH - BCAR_WHEEL_BASE) / 2 + 0.01) * cos(h);
 608                 y = ny + ((BCAR_LENGTH - BCAR_WHEEL_BASE) / 2 + 0.01) * sin(h);
 609         } else {
 610                 if (this->slotSide() == LEFT) {
 611                         h -= M_PI / 2;
 612                         nx = x + (BCAR_LENGTH + BCAR_WHEEL_BASE) / 2
 613                                 * cos(h + M_PI);
 614                         ny = y + (BCAR_LENGTH + BCAR_WHEEL_BASE) / 2
 615                                 * sin(h + M_PI);
 616                         x = nx + (BCAR_DIAG_RRADI) * cos(h + M_PI / 2);
 617                         y = ny + (BCAR_DIAG_RRADI) * sin(h + M_PI / 2);
 618                 } else {
 619                         h += M_PI / 2;
 620                         nx = x + (BCAR_LENGTH + BCAR_WHEEL_BASE) / 2
 621                                 * cos(h - M_PI);
 622                         ny = y + (BCAR_LENGTH + BCAR_WHEEL_BASE) / 2
 623                                 * sin(h - M_PI);
 624                         x = nx + (BCAR_DIAG_RRADI) * cos(h - M_PI / 2);
 625                         y = ny + (BCAR_DIAG_RRADI) * sin(h - M_PI / 2);
 626                 }
 627         }
 628         return new BicycleCar(x, y, h);
 629 }
 630
 631 bool ParallelSlot::isInside(BicycleCar *c)
 632 {
 633         bool inside = true;
 634         RRTNode *tmpn;
 635         tmpn = new RRTNode(c->lfx(), c->lfy(), 0);
 636         if (!this->slot().collide(tmpn))
 637                 inside = false;
 638         delete tmpn;
 639         tmpn = new RRTNode(c->lrx(), c->lry(), 0);
 640         if (!this->slot().collide(tmpn))
 641                 inside = false;
 642         delete tmpn;
 643         tmpn = new RRTNode(c->rrx(), c->rry(), 0);
 644         if (!this->slot().collide(tmpn))
 645                 inside = false;
 646         delete tmpn;
 647         tmpn = new RRTNode(c->rfx(), c->rfy(), 0);
 648         if (!this->slot().collide(tmpn))
 649                 inside = false;
 650         delete tmpn;
 651         return inside;
 652 }
 653
 654 struct SamplingInfo ParallelSlot::getSamplingInfo()
 655 {
 656         struct SamplingInfo si;
 657         if (this->slotType() == PARALLEL) {
 658                 si.x = this->slot().bnodes().front()->x();
 659                 si.y = this->slot().bnodes().front()->y();
 660                 si.mr = BCAR_WIDTH / 2;
 661                 si.mmh = 0;
 662         } else {
 663                 si.x = this->slot().bnodes().back()->x();
 664                 si.x -= this->slot().bnodes().front()->x();
 665                 si.x /= 2;
 666                 si.x += this->slot().bnodes().front()->x();
 667                 si.y = this->slot().bnodes().back()->y();
 668                 si.y -= this->slot().bnodes().front()->y();
 669                 si.y /= 2;
 670                 si.y += this->slot().bnodes().front()->y();
 671                 si.mr = 0;
 672                 si.mmh = (M_PI - M_PI / 6) / 2;
 673         }
 674         si.r = BCAR_LENGTH;
 675         si.h = M_PI;
 676         si.mh = M_PI / 2;
 677         si.sh = this->slotHeading();
 678         if (this->slotSide() == RIGHT)
 679                 si.dh = 1;
 680         else
 681                 si.dh = -1;
 682         return si;
 683 }