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[dragonfireclient.git] / 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 <vector>
27 #include "util/timetaker.h"
28 #include "main.h" // g_profiler
29 #include "profiler.h"
30
31 // Helper function:
32 // Checks for collision of a moving aabbox with a static aabbox
33 // Returns -1 if no collision, 0 if X collision, 1 if Y collision, 2 if Z collision
34 // The time after which the collision occurs is stored in dtime.
35 int axisAlignedCollision(
36                 const aabb3f &staticbox, const aabb3f &movingbox,
37                 const v3f &speed, f32 d, f32 &dtime)
38 {
39         //TimeTaker tt("axisAlignedCollision");
40
41         f32 xsize = (staticbox.MaxEdge.X - staticbox.MinEdge.X);
42         f32 ysize = (staticbox.MaxEdge.Y - staticbox.MinEdge.Y);
43         f32 zsize = (staticbox.MaxEdge.Z - staticbox.MinEdge.Z);
44
45         aabb3f relbox(
46                         movingbox.MinEdge.X - staticbox.MinEdge.X,
47                         movingbox.MinEdge.Y - staticbox.MinEdge.Y,
48                         movingbox.MinEdge.Z - staticbox.MinEdge.Z,
49                         movingbox.MaxEdge.X - staticbox.MinEdge.X,
50                         movingbox.MaxEdge.Y - staticbox.MinEdge.Y,
51                         movingbox.MaxEdge.Z - staticbox.MinEdge.Z
52         );
53
54         if(speed.X > 0) // Check for collision with X- plane
55         {
56                 if(relbox.MaxEdge.X <= d)
57                 {
58                         dtime = - relbox.MaxEdge.X / speed.X;
59                         if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
60                                         (relbox.MaxEdge.Y + speed.Y * dtime > 0) &&
61                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
62                                         (relbox.MaxEdge.Z + speed.Z * dtime > 0))
63                                 return 0;
64                 }
65                 else if(relbox.MinEdge.X > xsize)
66                 {
67                         return -1;
68                 }
69         }
70         else if(speed.X < 0) // Check for collision with X+ plane
71         {
72                 if(relbox.MinEdge.X >= xsize - d)
73                 {
74                         dtime = (xsize - relbox.MinEdge.X) / speed.X;
75                         if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
76                                         (relbox.MaxEdge.Y + speed.Y * dtime > 0) &&
77                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
78                                         (relbox.MaxEdge.Z + speed.Z * dtime > 0))
79                                 return 0;
80                 }
81                 else if(relbox.MaxEdge.X < 0)
82                 {
83                         return -1;
84                 }
85         }
86
87         // NO else if here
88
89         if(speed.Y > 0) // Check for collision with Y- plane
90         {
91                 if(relbox.MaxEdge.Y <= d)
92                 {
93                         dtime = - relbox.MaxEdge.Y / speed.Y;
94                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
95                                         (relbox.MaxEdge.X + speed.X * dtime > 0) &&
96                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
97                                         (relbox.MaxEdge.Z + speed.Z * dtime > 0))
98                                 return 1;
99                 }
100                 else if(relbox.MinEdge.Y > ysize)
101                 {
102                         return -1;
103                 }
104         }
105         else if(speed.Y < 0) // Check for collision with Y+ plane
106         {
107                 if(relbox.MinEdge.Y >= ysize - d)
108                 {
109                         dtime = (ysize - relbox.MinEdge.Y) / speed.Y;
110                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
111                                         (relbox.MaxEdge.X + speed.X * dtime > 0) &&
112                                         (relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
113                                         (relbox.MaxEdge.Z + speed.Z * dtime > 0))
114                                 return 1;
115                 }
116                 else if(relbox.MaxEdge.Y < 0)
117                 {
118                         return -1;
119                 }
120         }
121
122         // NO else if here
123
124         if(speed.Z > 0) // Check for collision with Z- plane
125         {
126                 if(relbox.MaxEdge.Z <= d)
127                 {
128                         dtime = - relbox.MaxEdge.Z / speed.Z;
129                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
130                                         (relbox.MaxEdge.X + speed.X * dtime > 0) &&
131                                         (relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
132                                         (relbox.MaxEdge.Y + speed.Y * dtime > 0))
133                                 return 2;
134                 }
135                 //else if(relbox.MinEdge.Z > zsize)
136                 //{
137                 //      return -1;
138                 //}
139         }
140         else if(speed.Z < 0) // Check for collision with Z+ plane
141         {
142                 if(relbox.MinEdge.Z >= zsize - d)
143                 {
144                         dtime = (zsize - relbox.MinEdge.Z) / speed.Z;
145                         if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
146                                         (relbox.MaxEdge.X + speed.X * dtime > 0) &&
147                                         (relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
148                                         (relbox.MaxEdge.Y + speed.Y * dtime > 0))
149                                 return 2;
150                 }
151                 //else if(relbox.MaxEdge.Z < 0)
152                 //{
153                 //      return -1;
154                 //}
155         }
156
157         return -1;
158 }
159
160 // Helper function:
161 // Checks if moving the movingbox up by the given distance would hit a ceiling.
162 bool wouldCollideWithCeiling(
163                 const std::vector<aabb3f> &staticboxes,
164                 const aabb3f &movingbox,
165                 f32 y_increase, f32 d)
166 {
167         //TimeTaker tt("wouldCollideWithCeiling");
168
169         assert(y_increase >= 0);
170
171         for(std::vector<aabb3f>::const_iterator
172                         i = staticboxes.begin();
173                         i != staticboxes.end(); i++)
174         {
175                 const aabb3f& staticbox = *i;
176                 if((movingbox.MaxEdge.Y - d <= staticbox.MinEdge.Y) &&
177                                 (movingbox.MaxEdge.Y + y_increase > staticbox.MinEdge.Y) &&
178                                 (movingbox.MinEdge.X < staticbox.MaxEdge.X) &&
179                                 (movingbox.MaxEdge.X > staticbox.MinEdge.X) &&
180                                 (movingbox.MinEdge.Z < staticbox.MaxEdge.Z) &&
181                                 (movingbox.MaxEdge.Z > staticbox.MinEdge.Z))
182                         return true;
183         }
184
185         return false;
186 }
187
188
189 collisionMoveResult collisionMoveSimple(Map *map, IGameDef *gamedef,
190                 f32 pos_max_d, const aabb3f &box_0,
191                 f32 stepheight, f32 dtime,
192                 v3f &pos_f, v3f &speed_f, v3f &accel_f)
193 {
194         //TimeTaker tt("collisionMoveSimple");
195     ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
196
197         collisionMoveResult result;
198
199         /*
200                 Calculate new velocity
201         */
202         if( dtime > 0.5 ) {
203                 infostream<<"collisionMoveSimple: WARNING: maximum step interval exceeded, lost movement details!"<<std::endl;
204                 dtime = 0.5;
205         }
206         speed_f += accel_f * dtime;
207
208     // If there is no speed, there are no collisions
209         if(speed_f.getLength() == 0)
210                 return result;
211
212         /*
213                 Collect node boxes in movement range
214         */
215         std::vector<aabb3f> cboxes;
216         std::vector<bool> is_unloaded;
217         std::vector<bool> is_step_up;
218         std::vector<int> bouncy_values;
219         std::vector<v3s16> node_positions;
220         {
221         //TimeTaker tt2("collisionMoveSimple collect boxes");
222     ScopeProfiler sp(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
223
224         v3s16 oldpos_i = floatToInt(pos_f, BS);
225         v3s16 newpos_i = floatToInt(pos_f + speed_f * dtime, BS);
226         s16 min_x = MYMIN(oldpos_i.X, newpos_i.X) + (box_0.MinEdge.X / BS) - 1;
227         s16 min_y = MYMIN(oldpos_i.Y, newpos_i.Y) + (box_0.MinEdge.Y / BS) - 1;
228         s16 min_z = MYMIN(oldpos_i.Z, newpos_i.Z) + (box_0.MinEdge.Z / BS) - 1;
229         s16 max_x = MYMAX(oldpos_i.X, newpos_i.X) + (box_0.MaxEdge.X / BS) + 1;
230         s16 max_y = MYMAX(oldpos_i.Y, newpos_i.Y) + (box_0.MaxEdge.Y / BS) + 1;
231         s16 max_z = MYMAX(oldpos_i.Z, newpos_i.Z) + (box_0.MaxEdge.Z / BS) + 1;
232
233         for(s16 x = min_x; x <= max_x; x++)
234         for(s16 y = min_y; y <= max_y; y++)
235         for(s16 z = min_z; z <= max_z; z++)
236         {
237                 v3s16 p(x,y,z);
238                 try{
239                         // Object collides into walkable nodes
240                         MapNode n = map->getNode(p);
241                         const ContentFeatures &f = gamedef->getNodeDefManager()->get(n);
242                         if(f.walkable == false)
243                                 continue;
244                         int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
245
246                         std::vector<aabb3f> nodeboxes = n.getNodeBoxes(gamedef->ndef());
247                         for(std::vector<aabb3f>::iterator
248                                         i = nodeboxes.begin();
249                                         i != nodeboxes.end(); i++)
250                         {
251                                 aabb3f box = *i;
252                                 box.MinEdge += v3f(x, y, z)*BS;
253                                 box.MaxEdge += v3f(x, y, z)*BS;
254                                 cboxes.push_back(box);
255                                 is_unloaded.push_back(false);
256                                 is_step_up.push_back(false);
257                                 bouncy_values.push_back(n_bouncy_value);
258                                 node_positions.push_back(p);
259                         }
260                 }
261                 catch(InvalidPositionException &e)
262                 {
263                         // Collide with unloaded nodes
264                         aabb3f box = getNodeBox(p, BS);
265                         cboxes.push_back(box);
266                         is_unloaded.push_back(true);
267                         is_step_up.push_back(false);
268                         bouncy_values.push_back(0);
269                         node_positions.push_back(p);
270                 }
271         }
272         } // tt2
273
274         assert(cboxes.size() == is_unloaded.size());
275         assert(cboxes.size() == is_step_up.size());
276         assert(cboxes.size() == bouncy_values.size());
277         assert(cboxes.size() == node_positions.size());
278
279         /*
280                 Collision detection
281         */
282
283         /*
284                 Collision uncertainty radius
285                 Make it a bit larger than the maximum distance of movement
286         */
287         f32 d = pos_max_d * 1.1;
288         // A fairly large value in here makes moving smoother
289         //f32 d = 0.15*BS;
290
291         // This should always apply, otherwise there are glitches
292         assert(d > pos_max_d);
293
294         int loopcount = 0;
295
296         while(dtime > BS*1e-10)
297         {
298                 //TimeTaker tt3("collisionMoveSimple dtime loop");
299         ScopeProfiler sp(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
300
301                 // Avoid infinite loop
302                 loopcount++;
303                 if(loopcount >= 100)
304                 {
305                         infostream<<"collisionMoveSimple: WARNING: Loop count exceeded, aborting to avoid infiniite loop"<<std::endl;
306                         dtime = 0;
307                         break;
308                 }
309
310                 aabb3f movingbox = box_0;
311                 movingbox.MinEdge += pos_f;
312                 movingbox.MaxEdge += pos_f;
313
314                 int nearest_collided = -1;
315                 f32 nearest_dtime = dtime;
316                 u32 nearest_boxindex = -1;
317
318                 /*
319                         Go through every nodebox, find nearest collision
320                 */
321                 for(u32 boxindex = 0; boxindex < cboxes.size(); boxindex++)
322                 {
323                         // Ignore if already stepped up this nodebox.
324                         if(is_step_up[boxindex])
325                                 continue;
326
327                         // Find nearest collision of the two boxes (raytracing-like)
328                         f32 dtime_tmp;
329                         int collided = axisAlignedCollision(
330                                         cboxes[boxindex], movingbox, speed_f, d, dtime_tmp);
331
332                         if(collided == -1 || dtime_tmp >= nearest_dtime)
333                                 continue;
334
335                         nearest_dtime = dtime_tmp;
336                         nearest_collided = collided;
337                         nearest_boxindex = boxindex;
338                 }
339
340                 if(nearest_collided == -1)
341                 {
342                         // No collision with any collision box.
343                         pos_f += speed_f * dtime;
344                         dtime = 0;  // Set to 0 to avoid "infinite" loop due to small FP numbers
345                 }
346                 else
347                 {
348                         // Otherwise, a collision occurred.
349
350                         const aabb3f& cbox = cboxes[nearest_boxindex];
351
352                         // Check for stairs.
353                         bool step_up = (nearest_collided != 1) && // must not be Y direction
354                                         (movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
355                                         (movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
356                                         (!wouldCollideWithCeiling(cboxes, movingbox,
357                                                         cbox.MaxEdge.Y - movingbox.MinEdge.Y,
358                                                         d));
359
360                         // Get bounce multiplier
361                         bool bouncy = (bouncy_values[nearest_boxindex] >= 1);
362                         float bounce = -(float)bouncy_values[nearest_boxindex] / 100.0;
363
364                         // Move to the point of collision and reduce dtime by nearest_dtime
365                         if(nearest_dtime < 0)
366                         {
367                                 // Handle negative nearest_dtime (can be caused by the d allowance)
368                                 if(!step_up)
369                                 {
370                                         if(nearest_collided == 0)
371                                                 pos_f.X += speed_f.X * nearest_dtime;
372                                         if(nearest_collided == 1)
373                                                 pos_f.Y += speed_f.Y * nearest_dtime;
374                                         if(nearest_collided == 2)
375                                                 pos_f.Z += speed_f.Z * nearest_dtime;
376                                 }
377                         }
378                         else
379                         {
380                                 pos_f += speed_f * nearest_dtime;
381                                 dtime -= nearest_dtime;
382                         }
383                         
384                         bool is_collision = true;
385                         if(is_unloaded[nearest_boxindex])
386                                 is_collision = false;
387
388                         CollisionInfo info;
389                         info.type = COLLISION_NODE;
390                         info.node_p = node_positions[nearest_boxindex];
391                         info.bouncy = bouncy;
392                         info.old_speed = speed_f;
393
394                         // Set the speed component that caused the collision to zero
395                         if(step_up)
396                         {
397                                 // Special case: Handle stairs
398                                 is_step_up[nearest_boxindex] = true;
399                                 is_collision = false;
400                         }
401                         else if(nearest_collided == 0) // X
402                         {
403                                 if(fabs(speed_f.X) > BS*3)
404                                         speed_f.X *= bounce;
405                                 else
406                                         speed_f.X = 0;
407                                 result.collides = true;
408                                 result.collides_xz = true;
409                         }
410                         else if(nearest_collided == 1) // Y
411                         {
412                                 if(fabs(speed_f.Y) > BS*3)
413                                         speed_f.Y *= bounce;
414                                 else
415                                         speed_f.Y = 0;
416                                 result.collides = true;
417                         }
418                         else if(nearest_collided == 2) // Z
419                         {
420                                 if(fabs(speed_f.Z) > BS*3)
421                                         speed_f.Z *= bounce;
422                                 else
423                                         speed_f.Z = 0;
424                                 result.collides = true;
425                                 result.collides_xz = true;
426                         }
427
428                         info.new_speed = speed_f;
429                         if(info.new_speed.getDistanceFrom(info.old_speed) < 0.1*BS)
430                                 is_collision = false;
431
432                         if(is_collision){
433                                 result.collisions.push_back(info);
434                         }
435                 }
436         }
437
438         /*
439                 Final touches: Check if standing on ground, step up stairs.
440         */
441         aabb3f box = box_0;
442         box.MinEdge += pos_f;
443         box.MaxEdge += pos_f;
444         for(u32 boxindex = 0; boxindex < cboxes.size(); boxindex++)
445         {
446                 const aabb3f& cbox = cboxes[boxindex];
447
448                 /*
449                         See if the object is touching ground.
450
451                         Object touches ground if object's minimum Y is near node's
452                         maximum Y and object's X-Z-area overlaps with the node's
453                         X-Z-area.
454
455                         Use 0.15*BS so that it is easier to get on a node.
456                 */
457                 if(
458                                 cbox.MaxEdge.X-d > box.MinEdge.X &&
459                                 cbox.MinEdge.X+d < box.MaxEdge.X &&
460                                 cbox.MaxEdge.Z-d > box.MinEdge.Z &&
461                                 cbox.MinEdge.Z+d < box.MaxEdge.Z
462                 ){
463                         if(is_step_up[boxindex])
464                         {
465                                 pos_f.Y += (cbox.MaxEdge.Y - box.MinEdge.Y);
466                                 box = box_0;
467                                 box.MinEdge += pos_f;
468                                 box.MaxEdge += pos_f;
469                         }
470                         if(fabs(cbox.MaxEdge.Y-box.MinEdge.Y) < 0.15*BS)
471                         {
472                                 result.touching_ground = true;
473                                 if(is_unloaded[boxindex])
474                                         result.standing_on_unloaded = true;
475                         }
476                 }
477         }
478
479         return result;
480 }
481
482 #if 0
483 // This doesn't seem to work and isn't used
484 collisionMoveResult collisionMovePrecise(Map *map, IGameDef *gamedef,
485                 f32 pos_max_d, const aabb3f &box_0,
486                 f32 stepheight, f32 dtime,
487                 v3f &pos_f, v3f &speed_f, v3f &accel_f)
488 {
489         //TimeTaker tt("collisionMovePrecise");
490     ScopeProfiler sp(g_profiler, "collisionMovePrecise avg", SPT_AVG);
491         
492         collisionMoveResult final_result;
493
494         // If there is no speed, there are no collisions
495         if(speed_f.getLength() == 0)
496                 return final_result;
497
498         // Don't allow overly huge dtime
499         if(dtime > 2.0)
500                 dtime = 2.0;
501
502         f32 dtime_downcount = dtime;
503
504         u32 loopcount = 0;
505         do
506         {
507                 loopcount++;
508
509                 // Maximum time increment (for collision detection etc)
510                 // time = distance / speed
511                 f32 dtime_max_increment = 1.0;
512                 if(speed_f.getLength() != 0)
513                         dtime_max_increment = pos_max_d / speed_f.getLength();
514
515                 // Maximum time increment is 10ms or lower
516                 if(dtime_max_increment > 0.01)
517                         dtime_max_increment = 0.01;
518
519                 f32 dtime_part;
520                 if(dtime_downcount > dtime_max_increment)
521                 {
522                         dtime_part = dtime_max_increment;
523                         dtime_downcount -= dtime_part;
524                 }
525                 else
526                 {
527                         dtime_part = dtime_downcount;
528                         /*
529                                 Setting this to 0 (no -=dtime_part) disables an infinite loop
530                                 when dtime_part is so small that dtime_downcount -= dtime_part
531                                 does nothing
532                         */
533                         dtime_downcount = 0;
534                 }
535
536                 collisionMoveResult result = collisionMoveSimple(map, gamedef,
537                                 pos_max_d, box_0, stepheight, dtime_part,
538                                 pos_f, speed_f, accel_f);
539
540                 if(result.touching_ground)
541                         final_result.touching_ground = true;
542                 if(result.collides)
543                         final_result.collides = true;
544                 if(result.collides_xz)
545                         final_result.collides_xz = true;
546                 if(result.standing_on_unloaded)
547                         final_result.standing_on_unloaded = true;
548         }
549         while(dtime_downcount > 0.001);
550
551         return final_result;
552 }
553 #endif