src/collision.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "collision.h"
  21 #include "mapblock.h"
  22 #include "map.h"
  23 #include "nodedef.h"
  24 #include "gamedef.h"
  25 #include "log.h"
  26 #include "environment.h"
  27 #include "serverobject.h"
  28 #include <vector>
  29 #include <set>
  30 #include "util/timetaker.h"
  31 #include "profiler.h"
  32
  33 // float error is 10 - 9.96875 = 0.03125
  34 //#define COLL_ZERO 0.032 // broken unit tests
  35 #define COLL_ZERO 0
  36
  37 // Helper function:
  38 // Checks for collision of a moving aabbox with a static aabbox
  39 // Returns -1 if no collision, 0 if X collision, 1 if Y collision, 2 if Z collision
  40 // The time after which the collision occurs is stored in dtime.
  41 int axisAlignedCollision(
  42                 const aabb3f &staticbox, const aabb3f &movingbox,
  43                 const v3f &speed, f32 d, f32 &dtime)
  44 {
  45         //TimeTaker tt("axisAlignedCollision");
  46
  47         f32 xsize = (staticbox.MaxEdge.X - staticbox.MinEdge.X) - COLL_ZERO;     // reduce box size for solve collision stuck (flying sand)
  48         f32 ysize = (staticbox.MaxEdge.Y - staticbox.MinEdge.Y); // - COLL_ZERO; // Y - no sense for falling, but maybe try later
  49         f32 zsize = (staticbox.MaxEdge.Z - staticbox.MinEdge.Z) - COLL_ZERO;
  50
  51         aabb3f relbox(
  52                         movingbox.MinEdge.X - staticbox.MinEdge.X,
  53                         movingbox.MinEdge.Y - staticbox.MinEdge.Y,
  54                         movingbox.MinEdge.Z - staticbox.MinEdge.Z,
  55                         movingbox.MaxEdge.X - staticbox.MinEdge.X,
  56                         movingbox.MaxEdge.Y - staticbox.MinEdge.Y,
  57                         movingbox.MaxEdge.Z - staticbox.MinEdge.Z
  58         );
  59
  60         if(speed.X > 0) // Check for collision with X- plane
  61         {
  62                 if(relbox.MaxEdge.X <= d)
  63                 {
  64                         dtime = - relbox.MaxEdge.X / speed.X;
  65                         if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
  66                                         (relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO) &&
  67                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
  68                                         (relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
  69                                 return 0;
  70                 }
  71                 else if(relbox.MinEdge.X > xsize)
  72                 {
  73                         return -1;
  74                 }
  75         }
  76         else if(speed.X < 0) // Check for collision with X+ plane
  77         {
  78                 if(relbox.MinEdge.X >= xsize - d)
  79                 {
  80                         dtime = (xsize - relbox.MinEdge.X) / speed.X;
  81                         if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
  82                                         (relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO) &&
  83                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
  84                                         (relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
  85                                 return 0;
  86                 }
  87                 else if(relbox.MaxEdge.X < 0)
  88                 {
  89                         return -1;
  90                 }
  91         }
  92
  93         // NO else if here
  94
  95         if(speed.Y > 0) // Check for collision with Y- plane
  96         {
  97                 if(relbox.MaxEdge.Y <= d)
  98                 {
  99                         dtime = - relbox.MaxEdge.Y / speed.Y;
 100                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
 101                                         (relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
 102                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
 103                                         (relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
 104                                 return 1;
 105                 }
 106                 else if(relbox.MinEdge.Y > ysize)
 107                 {
 108                         return -1;
 109                 }
 110         }
 111         else if(speed.Y < 0) // Check for collision with Y+ plane
 112         {
 113                 if(relbox.MinEdge.Y >= ysize - d)
 114                 {
 115                         dtime = (ysize - relbox.MinEdge.Y) / speed.Y;
 116                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
 117                                         (relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
 118                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
 119                                         (relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
 120                                 return 1;
 121                 }
 122                 else if(relbox.MaxEdge.Y < 0)
 123                 {
 124                         return -1;
 125                 }
 126         }
 127
 128         // NO else if here
 129
 130         if(speed.Z > 0) // Check for collision with Z- plane
 131         {
 132                 if(relbox.MaxEdge.Z <= d)
 133                 {
 134                         dtime = - relbox.MaxEdge.Z / speed.Z;
 135                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
 136                                         (relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
 137                                         (relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
 138                                         (relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO))
 139                                 return 2;
 140                 }
 141                 //else if(relbox.MinEdge.Z > zsize)
 142                 //{
 143                 //      return -1;
 144                 //}
 145         }
 146         else if(speed.Z < 0) // Check for collision with Z+ plane
 147         {
 148                 if(relbox.MinEdge.Z >= zsize - d)
 149                 {
 150                         dtime = (zsize - relbox.MinEdge.Z) / speed.Z;
 151                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
 152                                         (relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
 153                                         (relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
 154                                         (relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO))
 155                                 return 2;
 156                 }
 157                 //else if(relbox.MaxEdge.Z < 0)
 158                 //{
 159                 //      return -1;
 160                 //}
 161         }
 162
 163         return -1;
 164 }
 165
 166 // Helper function:
 167 // Checks if moving the movingbox up by the given distance would hit a ceiling.
 168 bool wouldCollideWithCeiling(
 169                 const std::vector<aabb3f> &staticboxes,
 170                 const aabb3f &movingbox,
 171                 f32 y_increase, f32 d)
 172 {
 173         //TimeTaker tt("wouldCollideWithCeiling");
 174
 175         assert(y_increase >= 0);        // pre-condition
 176
 177         for(std::vector<aabb3f>::const_iterator
 178                         i = staticboxes.begin();
 179                         i != staticboxes.end(); ++i)
 180         {
 181                 const aabb3f& staticbox = *i;
 182                 if((movingbox.MaxEdge.Y - d <= staticbox.MinEdge.Y) &&
 183                                 (movingbox.MaxEdge.Y + y_increase > staticbox.MinEdge.Y) &&
 184                                 (movingbox.MinEdge.X < staticbox.MaxEdge.X) &&
 185                                 (movingbox.MaxEdge.X > staticbox.MinEdge.X) &&
 186                                 (movingbox.MinEdge.Z < staticbox.MaxEdge.Z) &&
 187                                 (movingbox.MaxEdge.Z > staticbox.MinEdge.Z))
 188                         return true;
 189         }
 190
 191         return false;
 192 }
 193
 194
 195 collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
 196                 f32 pos_max_d, const aabb3f &box_0,
 197                 f32 stepheight, f32 dtime,
 198                 v3f &pos_f, v3f &speed_f,
 199                 v3f &accel_f,ActiveObject* self,
 200                 bool collideWithObjects)
 201 {
 202         static bool time_notification_done = false;
 203         Map *map = &env->getMap();
 204         //TimeTaker tt("collisionMoveSimple");
 205         ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
 206
 207         collisionMoveResult result;
 208
 209         /*
 210                 Calculate new velocity
 211         */
 212         if (dtime > 0.5) {
 213                 if (!time_notification_done) {
 214                         time_notification_done = true;
 215                         infostream << "collisionMoveSimple: maximum step interval exceeded,"
 216                                         " lost movement details!"<<std::endl;
 217                 }
 218                 dtime = 0.5;
 219         } else {
 220                 time_notification_done = false;
 221         }
 222         speed_f += accel_f * dtime;
 223
 224         // If there is no speed, there are no collisions
 225         if(speed_f.getLength() == 0)
 226                 return result;
 227
 228         // Limit speed for avoiding hangs
 229         speed_f.Y=rangelim(speed_f.Y,-5000,5000);
 230         speed_f.X=rangelim(speed_f.X,-5000,5000);
 231         speed_f.Z=rangelim(speed_f.Z,-5000,5000);
 232
 233         /*
 234                 Collect node boxes in movement range
 235         */
 236         std::vector<aabb3f> cboxes;
 237         std::vector<bool> is_unloaded;
 238         std::vector<bool> is_step_up;
 239         std::vector<bool> is_object;
 240         std::vector<int> bouncy_values;
 241         std::vector<v3s16> node_positions;
 242         {
 243         //TimeTaker tt2("collisionMoveSimple collect boxes");
 244     ScopeProfiler sp(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
 245
 246         v3s16 oldpos_i = floatToInt(pos_f, BS);
 247         v3s16 newpos_i = floatToInt(pos_f + speed_f * dtime, BS);
 248         s16 min_x = MYMIN(oldpos_i.X, newpos_i.X) + (box_0.MinEdge.X / BS) - 1;
 249         s16 min_y = MYMIN(oldpos_i.Y, newpos_i.Y) + (box_0.MinEdge.Y / BS) - 1;
 250         s16 min_z = MYMIN(oldpos_i.Z, newpos_i.Z) + (box_0.MinEdge.Z / BS) - 1;
 251         s16 max_x = MYMAX(oldpos_i.X, newpos_i.X) + (box_0.MaxEdge.X / BS) + 1;
 252         s16 max_y = MYMAX(oldpos_i.Y, newpos_i.Y) + (box_0.MaxEdge.Y / BS) + 1;
 253         s16 max_z = MYMAX(oldpos_i.Z, newpos_i.Z) + (box_0.MaxEdge.Z / BS) + 1;
 254
 255         bool any_position_valid = false;
 256
 257         for(s16 x = min_x; x <= max_x; x++)
 258         for(s16 y = min_y; y <= max_y; y++)
 259         for(s16 z = min_z; z <= max_z; z++)
 260         {
 261                 v3s16 p(x,y,z);
 262
 263                 bool is_position_valid;
 264                 MapNode n = map->getNodeNoEx(p, &is_position_valid);
 265
 266                 if (is_position_valid) {
 267                         // Object collides into walkable nodes
 268
 269                         any_position_valid = true;
 270                         const ContentFeatures &f = gamedef->getNodeDefManager()->get(n);
 271                         if(f.walkable == false)
 272                                 continue;
 273                         int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
 274
 275                         std::vector<aabb3f> nodeboxes = n.getCollisionBoxes(gamedef->ndef());
 276                         for(std::vector<aabb3f>::iterator
 277                                         i = nodeboxes.begin();
 278                                         i != nodeboxes.end(); ++i)
 279                         {
 280                                 aabb3f box = *i;
 281                                 box.MinEdge += v3f(x, y, z)*BS;
 282                                 box.MaxEdge += v3f(x, y, z)*BS;
 283                                 cboxes.push_back(box);
 284                                 is_unloaded.push_back(false);
 285                                 is_step_up.push_back(false);
 286                                 bouncy_values.push_back(n_bouncy_value);
 287                                 node_positions.push_back(p);
 288                                 is_object.push_back(false);
 289                         }
 290                 }
 291                 else {
 292                         // Collide with unloaded nodes
 293                         aabb3f box = getNodeBox(p, BS);
 294                         cboxes.push_back(box);
 295                         is_unloaded.push_back(true);
 296                         is_step_up.push_back(false);
 297                         bouncy_values.push_back(0);
 298                         node_positions.push_back(p);
 299                         is_object.push_back(false);
 300                 }
 301         }
 302
 303         // Do not move if world has not loaded yet, since custom node boxes
 304         // are not available for collision detection.
 305         if (!any_position_valid)
 306                 return result;
 307
 308         } // tt2
 309
 310         if(collideWithObjects)
 311         {
 312                 ScopeProfiler sp(g_profiler, "collisionMoveSimple objects avg", SPT_AVG);
 313                 //TimeTaker tt3("collisionMoveSimple collect object boxes");
 314
 315                 /* add object boxes to cboxes */
 316
 317                 std::vector<ActiveObject*> objects;
 318 #ifndef SERVER
 319                 ClientEnvironment *c_env = dynamic_cast<ClientEnvironment*>(env);
 320                 if (c_env != 0) {
 321                         f32 distance = speed_f.getLength();
 322                         std::vector<DistanceSortedActiveObject> clientobjects;
 323                         c_env->getActiveObjects(pos_f,distance * 1.5,clientobjects);
 324                         for (size_t i=0; i < clientobjects.size(); i++) {
 325                                 if ((self == 0) || (self != clientobjects[i].obj)) {
 326                                         objects.push_back((ActiveObject*)clientobjects[i].obj);
 327                                 }
 328                         }
 329                 }
 330                 else
 331 #endif
 332                 {
 333                         ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
 334                         if (s_env != 0) {
 335                                 f32 distance = speed_f.getLength();
 336                                 std::vector<u16> s_objects;
 337                                 s_env->getObjectsInsideRadius(s_objects, pos_f, distance * 1.5);
 338                                 for (std::vector<u16>::iterator iter = s_objects.begin(); iter != s_objects.end(); ++iter) {
 339                                         ServerActiveObject *current = s_env->getActiveObject(*iter);
 340                                         if ((self == 0) || (self != current)) {
 341                                                 objects.push_back((ActiveObject*)current);
 342                                         }
 343                                 }
 344                         }
 345                 }
 346
 347                 for (std::vector<ActiveObject*>::const_iterator iter = objects.begin();
 348                                 iter != objects.end(); ++iter) {
 349                         ActiveObject *object = *iter;
 350
 351                         if (object != NULL) {
 352                                 aabb3f object_collisionbox;
 353                                 if (object->getCollisionBox(&object_collisionbox) &&
 354                                                 object->collideWithObjects()) {
 355                                         cboxes.push_back(object_collisionbox);
 356                                         is_unloaded.push_back(false);
 357                                         is_step_up.push_back(false);
 358                                         bouncy_values.push_back(0);
 359                                         node_positions.push_back(v3s16(0,0,0));
 360                                         is_object.push_back(true);
 361                                 }
 362                         }
 363                 }
 364         } //tt3
 365
 366         assert(cboxes.size() == is_unloaded.size());    // post-condition
 367         assert(cboxes.size() == is_step_up.size());     // post-condition
 368         assert(cboxes.size() == bouncy_values.size());  // post-condition
 369         assert(cboxes.size() == node_positions.size()); // post-condition
 370         assert(cboxes.size() == is_object.size());      // post-condition
 371
 372         /*
 373                 Collision detection
 374         */
 375
 376         /*
 377                 Collision uncertainty radius
 378                 Make it a bit larger than the maximum distance of movement
 379         */
 380         f32 d = pos_max_d * 1.1;
 381         // A fairly large value in here makes moving smoother
 382         //f32 d = 0.15*BS;
 383
 384         // This should always apply, otherwise there are glitches
 385         assert(d > pos_max_d);  // invariant
 386
 387         int loopcount = 0;
 388
 389         while(dtime > BS * 1e-10) {
 390                 //TimeTaker tt3("collisionMoveSimple dtime loop");
 391         ScopeProfiler sp(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
 392
 393                 // Avoid infinite loop
 394                 loopcount++;
 395                 if (loopcount >= 100) {
 396                         warningstream << "collisionMoveSimple: Loop count exceeded, aborting to avoid infiniite loop" << std::endl;
 397                         dtime = 0;
 398                         break;
 399                 }
 400
 401                 aabb3f movingbox = box_0;
 402                 movingbox.MinEdge += pos_f;
 403                 movingbox.MaxEdge += pos_f;
 404
 405                 int nearest_collided = -1;
 406                 f32 nearest_dtime = dtime;
 407                 u32 nearest_boxindex = -1;
 408
 409                 /*
 410                         Go through every nodebox, find nearest collision
 411                 */
 412                 for (u32 boxindex = 0; boxindex < cboxes.size(); boxindex++) {
 413                         // Ignore if already stepped up this nodebox.
 414                         if(is_step_up[boxindex])
 415                                 continue;
 416
 417                         // Find nearest collision of the two boxes (raytracing-like)
 418                         f32 dtime_tmp;
 419                         int collided = axisAlignedCollision(
 420                                         cboxes[boxindex], movingbox, speed_f, d, dtime_tmp);
 421
 422                         if (collided == -1 || dtime_tmp >= nearest_dtime)
 423                                 continue;
 424
 425                         nearest_dtime = dtime_tmp;
 426                         nearest_collided = collided;
 427                         nearest_boxindex = boxindex;
 428                 }
 429
 430                 if (nearest_collided == -1) {
 431                         // No collision with any collision box.
 432                         pos_f += speed_f * dtime;
 433                         dtime = 0;  // Set to 0 to avoid "infinite" loop due to small FP numbers
 434                 } else {
 435                         // Otherwise, a collision occurred.
 436
 437                         const aabb3f& cbox = cboxes[nearest_boxindex];
 438                         // Check for stairs.
 439                         bool step_up = (nearest_collided != 1) && // must not be Y direction
 440                                         (movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
 441                                         (movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
 442                                         (!wouldCollideWithCeiling(cboxes, movingbox,
 443                                                         cbox.MaxEdge.Y - movingbox.MinEdge.Y,
 444                                                         d));
 445
 446                         // Get bounce multiplier
 447                         bool bouncy = (bouncy_values[nearest_boxindex] >= 1);
 448                         float bounce = -(float)bouncy_values[nearest_boxindex] / 100.0;
 449
 450                         // Move to the point of collision and reduce dtime by nearest_dtime
 451                         if (nearest_dtime < 0) {
 452                                 // Handle negative nearest_dtime (can be caused by the d allowance)
 453                                 if (!step_up) {
 454                                         if (nearest_collided == 0)
 455                                                 pos_f.X += speed_f.X * nearest_dtime;
 456                                         if (nearest_collided == 1)
 457                                                 pos_f.Y += speed_f.Y * nearest_dtime;
 458                                         if (nearest_collided == 2)
 459                                                 pos_f.Z += speed_f.Z * nearest_dtime;
 460                                 }
 461                         } else {
 462                                 pos_f += speed_f * nearest_dtime;
 463                                 dtime -= nearest_dtime;
 464                         }
 465
 466                         bool is_collision = true;
 467                         if (is_unloaded[nearest_boxindex])
 468                                 is_collision = false;
 469
 470                         CollisionInfo info;
 471                         if (is_object[nearest_boxindex])
 472                                 info.type = COLLISION_OBJECT;
 473                         else
 474                                 info.type = COLLISION_NODE;
 475
 476                         info.node_p = node_positions[nearest_boxindex];
 477                         info.bouncy = bouncy;
 478                         info.old_speed = speed_f;
 479
 480                         // Set the speed component that caused the collision to zero
 481                         if (step_up) {
 482                                 // Special case: Handle stairs
 483                                 is_step_up[nearest_boxindex] = true;
 484                                 is_collision = false;
 485                         } else if(nearest_collided == 0) { // X
 486                                 if (fabs(speed_f.X) > BS * 3)
 487                                         speed_f.X *= bounce;
 488                                 else
 489                                         speed_f.X = 0;
 490                                 result.collides = true;
 491                                 result.collides_xz = true;
 492                         }
 493                         else if(nearest_collided == 1) { // Y
 494                                 if(fabs(speed_f.Y) > BS * 3)
 495                                         speed_f.Y *= bounce;
 496                                 else
 497                                         speed_f.Y = 0;
 498                                 result.collides = true;
 499                         } else if(nearest_collided == 2) { // Z
 500                                 if (fabs(speed_f.Z) > BS * 3)
 501                                         speed_f.Z *= bounce;
 502                                 else
 503                                         speed_f.Z = 0;
 504                                 result.collides = true;
 505                                 result.collides_xz = true;
 506                         }
 507
 508                         info.new_speed = speed_f;
 509                         if (info.new_speed.getDistanceFrom(info.old_speed) < 0.1 * BS)
 510                                 is_collision = false;
 511
 512                         if (is_collision) {
 513                                 result.collisions.push_back(info);
 514                         }
 515                 }
 516         }
 517
 518         /*
 519                 Final touches: Check if standing on ground, step up stairs.
 520         */
 521         aabb3f box = box_0;
 522         box.MinEdge += pos_f;
 523         box.MaxEdge += pos_f;
 524         for (u32 boxindex = 0; boxindex < cboxes.size(); boxindex++) {
 525                 const aabb3f& cbox = cboxes[boxindex];
 526
 527                 /*
 528                         See if the object is touching ground.
 529
 530                         Object touches ground if object's minimum Y is near node's
 531                         maximum Y and object's X-Z-area overlaps with the node's
 532                         X-Z-area.
 533
 534                         Use 0.15*BS so that it is easier to get on a node.
 535                 */
 536                 if (cbox.MaxEdge.X - d > box.MinEdge.X && cbox.MinEdge.X + d < box.MaxEdge.X &&
 537                                 cbox.MaxEdge.Z - d > box.MinEdge.Z &&
 538                                 cbox.MinEdge.Z + d < box.MaxEdge.Z) {
 539                         if (is_step_up[boxindex]) {
 540                                 pos_f.Y += (cbox.MaxEdge.Y - box.MinEdge.Y);
 541                                 box = box_0;
 542                                 box.MinEdge += pos_f;
 543                                 box.MaxEdge += pos_f;
 544                         }
 545                         if (fabs(cbox.MaxEdge.Y - box.MinEdge.Y) < 0.15 * BS) {
 546                                 result.touching_ground = true;
 547
 548                                 if (is_object[boxindex])
 549                                         result.standing_on_object = true;
 550                                 if (is_unloaded[boxindex])
 551                                         result.standing_on_unloaded = true;
 552                         }
 553                 }
 554         }
 555
 556         return result;
 557 }