3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
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.
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.
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.
20 #include "collision.h"
26 #include "environment.h"
27 #include "serverobject.h"
30 #include "util/timetaker.h"
33 // float error is 10 - 9.96875 = 0.03125
34 //#define COLL_ZERO 0.032 // broken unit tests
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)
45 //TimeTaker tt("axisAlignedCollision");
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;
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
60 if(speed.X > 0) // Check for collision with X- plane
62 if(relbox.MaxEdge.X <= d)
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))
71 else if(relbox.MinEdge.X > xsize)
76 else if(speed.X < 0) // Check for collision with X+ plane
78 if(relbox.MinEdge.X >= xsize - d)
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))
87 else if(relbox.MaxEdge.X < 0)
95 if(speed.Y > 0) // Check for collision with Y- plane
97 if(relbox.MaxEdge.Y <= d)
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))
106 else if(relbox.MinEdge.Y > ysize)
111 else if(speed.Y < 0) // Check for collision with Y+ plane
113 if(relbox.MinEdge.Y >= ysize - d)
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))
122 else if(relbox.MaxEdge.Y < 0)
130 if(speed.Z > 0) // Check for collision with Z- plane
132 if(relbox.MaxEdge.Z <= d)
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))
141 //else if(relbox.MinEdge.Z > zsize)
146 else if(speed.Z < 0) // Check for collision with Z+ plane
148 if(relbox.MinEdge.Z >= zsize - d)
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))
157 //else if(relbox.MaxEdge.Z < 0)
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)
173 //TimeTaker tt("wouldCollideWithCeiling");
175 assert(y_increase >= 0); // pre-condition
177 for(std::vector<aabb3f>::const_iterator
178 i = staticboxes.begin();
179 i != staticboxes.end(); ++i)
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))
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)
202 Map *map = &env->getMap();
203 //TimeTaker tt("collisionMoveSimple");
204 ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
206 collisionMoveResult result;
209 Calculate new velocity
212 warningstream<<"collisionMoveSimple: maximum step interval exceeded, lost movement details!"<<std::endl;
215 speed_f += accel_f * dtime;
217 // If there is no speed, there are no collisions
218 if(speed_f.getLength() == 0)
221 // Limit speed for avoiding hangs
222 speed_f.Y=rangelim(speed_f.Y,-5000,5000);
223 speed_f.X=rangelim(speed_f.X,-5000,5000);
224 speed_f.Z=rangelim(speed_f.Z,-5000,5000);
227 Collect node boxes in movement range
229 std::vector<aabb3f> cboxes;
230 std::vector<bool> is_unloaded;
231 std::vector<bool> is_step_up;
232 std::vector<bool> is_object;
233 std::vector<int> bouncy_values;
234 std::vector<v3s16> node_positions;
236 //TimeTaker tt2("collisionMoveSimple collect boxes");
237 ScopeProfiler sp(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
239 v3s16 oldpos_i = floatToInt(pos_f, BS);
240 v3s16 newpos_i = floatToInt(pos_f + speed_f * dtime, BS);
241 s16 min_x = MYMIN(oldpos_i.X, newpos_i.X) + (box_0.MinEdge.X / BS) - 1;
242 s16 min_y = MYMIN(oldpos_i.Y, newpos_i.Y) + (box_0.MinEdge.Y / BS) - 1;
243 s16 min_z = MYMIN(oldpos_i.Z, newpos_i.Z) + (box_0.MinEdge.Z / BS) - 1;
244 s16 max_x = MYMAX(oldpos_i.X, newpos_i.X) + (box_0.MaxEdge.X / BS) + 1;
245 s16 max_y = MYMAX(oldpos_i.Y, newpos_i.Y) + (box_0.MaxEdge.Y / BS) + 1;
246 s16 max_z = MYMAX(oldpos_i.Z, newpos_i.Z) + (box_0.MaxEdge.Z / BS) + 1;
248 bool any_position_valid = false;
250 for(s16 x = min_x; x <= max_x; x++)
251 for(s16 y = min_y; y <= max_y; y++)
252 for(s16 z = min_z; z <= max_z; z++)
256 bool is_position_valid;
257 MapNode n = map->getNodeNoEx(p, &is_position_valid);
259 if (is_position_valid) {
260 // Object collides into walkable nodes
262 any_position_valid = true;
263 const ContentFeatures &f = gamedef->getNodeDefManager()->get(n);
264 if(f.walkable == false)
266 int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
268 std::vector<aabb3f> nodeboxes = n.getCollisionBoxes(gamedef->ndef());
269 for(std::vector<aabb3f>::iterator
270 i = nodeboxes.begin();
271 i != nodeboxes.end(); ++i)
274 box.MinEdge += v3f(x, y, z)*BS;
275 box.MaxEdge += v3f(x, y, z)*BS;
276 cboxes.push_back(box);
277 is_unloaded.push_back(false);
278 is_step_up.push_back(false);
279 bouncy_values.push_back(n_bouncy_value);
280 node_positions.push_back(p);
281 is_object.push_back(false);
285 // Collide with unloaded nodes
286 aabb3f box = getNodeBox(p, BS);
287 cboxes.push_back(box);
288 is_unloaded.push_back(true);
289 is_step_up.push_back(false);
290 bouncy_values.push_back(0);
291 node_positions.push_back(p);
292 is_object.push_back(false);
296 // Do not move if world has not loaded yet, since custom node boxes
297 // are not available for collision detection.
298 if (!any_position_valid)
303 if(collideWithObjects)
305 ScopeProfiler sp(g_profiler, "collisionMoveSimple objects avg", SPT_AVG);
306 //TimeTaker tt3("collisionMoveSimple collect object boxes");
308 /* add object boxes to cboxes */
310 std::vector<ActiveObject*> objects;
312 ClientEnvironment *c_env = dynamic_cast<ClientEnvironment*>(env);
314 f32 distance = speed_f.getLength();
315 std::vector<DistanceSortedActiveObject> clientobjects;
316 c_env->getActiveObjects(pos_f,distance * 1.5,clientobjects);
317 for (size_t i=0; i < clientobjects.size(); i++) {
318 if ((self == 0) || (self != clientobjects[i].obj)) {
319 objects.push_back((ActiveObject*)clientobjects[i].obj);
326 ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
328 f32 distance = speed_f.getLength();
329 std::vector<u16> s_objects;
330 s_env->getObjectsInsideRadius(s_objects, pos_f, distance * 1.5);
331 for (std::vector<u16>::iterator iter = s_objects.begin(); iter != s_objects.end(); ++iter) {
332 ServerActiveObject *current = s_env->getActiveObject(*iter);
333 if ((self == 0) || (self != current)) {
334 objects.push_back((ActiveObject*)current);
340 for (std::vector<ActiveObject*>::const_iterator iter = objects.begin();
341 iter != objects.end(); ++iter) {
342 ActiveObject *object = *iter;
344 if (object != NULL) {
345 aabb3f object_collisionbox;
346 if (object->getCollisionBox(&object_collisionbox) &&
347 object->collideWithObjects()) {
348 cboxes.push_back(object_collisionbox);
349 is_unloaded.push_back(false);
350 is_step_up.push_back(false);
351 bouncy_values.push_back(0);
352 node_positions.push_back(v3s16(0,0,0));
353 is_object.push_back(true);
359 assert(cboxes.size() == is_unloaded.size()); // post-condition
360 assert(cboxes.size() == is_step_up.size()); // post-condition
361 assert(cboxes.size() == bouncy_values.size()); // post-condition
362 assert(cboxes.size() == node_positions.size()); // post-condition
363 assert(cboxes.size() == is_object.size()); // post-condition
370 Collision uncertainty radius
371 Make it a bit larger than the maximum distance of movement
373 f32 d = pos_max_d * 1.1;
374 // A fairly large value in here makes moving smoother
377 // This should always apply, otherwise there are glitches
378 assert(d > pos_max_d); // invariant
382 while(dtime > BS * 1e-10) {
383 //TimeTaker tt3("collisionMoveSimple dtime loop");
384 ScopeProfiler sp(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
386 // Avoid infinite loop
388 if (loopcount >= 100) {
389 warningstream << "collisionMoveSimple: Loop count exceeded, aborting to avoid infiniite loop" << std::endl;
394 aabb3f movingbox = box_0;
395 movingbox.MinEdge += pos_f;
396 movingbox.MaxEdge += pos_f;
398 int nearest_collided = -1;
399 f32 nearest_dtime = dtime;
400 u32 nearest_boxindex = -1;
403 Go through every nodebox, find nearest collision
405 for (u32 boxindex = 0; boxindex < cboxes.size(); boxindex++) {
406 // Ignore if already stepped up this nodebox.
407 if(is_step_up[boxindex])
410 // Find nearest collision of the two boxes (raytracing-like)
412 int collided = axisAlignedCollision(
413 cboxes[boxindex], movingbox, speed_f, d, dtime_tmp);
415 if (collided == -1 || dtime_tmp >= nearest_dtime)
418 nearest_dtime = dtime_tmp;
419 nearest_collided = collided;
420 nearest_boxindex = boxindex;
423 if (nearest_collided == -1) {
424 // No collision with any collision box.
425 pos_f += speed_f * dtime;
426 dtime = 0; // Set to 0 to avoid "infinite" loop due to small FP numbers
428 // Otherwise, a collision occurred.
430 const aabb3f& cbox = cboxes[nearest_boxindex];
432 bool step_up = (nearest_collided != 1) && // must not be Y direction
433 (movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
434 (movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
435 (!wouldCollideWithCeiling(cboxes, movingbox,
436 cbox.MaxEdge.Y - movingbox.MinEdge.Y,
439 // Get bounce multiplier
440 bool bouncy = (bouncy_values[nearest_boxindex] >= 1);
441 float bounce = -(float)bouncy_values[nearest_boxindex] / 100.0;
443 // Move to the point of collision and reduce dtime by nearest_dtime
444 if (nearest_dtime < 0) {
445 // Handle negative nearest_dtime (can be caused by the d allowance)
447 if (nearest_collided == 0)
448 pos_f.X += speed_f.X * nearest_dtime;
449 if (nearest_collided == 1)
450 pos_f.Y += speed_f.Y * nearest_dtime;
451 if (nearest_collided == 2)
452 pos_f.Z += speed_f.Z * nearest_dtime;
455 pos_f += speed_f * nearest_dtime;
456 dtime -= nearest_dtime;
459 bool is_collision = true;
460 if (is_unloaded[nearest_boxindex])
461 is_collision = false;
464 if (is_object[nearest_boxindex])
465 info.type = COLLISION_OBJECT;
467 info.type = COLLISION_NODE;
469 info.node_p = node_positions[nearest_boxindex];
470 info.bouncy = bouncy;
471 info.old_speed = speed_f;
473 // Set the speed component that caused the collision to zero
475 // Special case: Handle stairs
476 is_step_up[nearest_boxindex] = true;
477 is_collision = false;
478 } else if(nearest_collided == 0) { // X
479 if (fabs(speed_f.X) > BS * 3)
483 result.collides = true;
484 result.collides_xz = true;
486 else if(nearest_collided == 1) { // Y
487 if(fabs(speed_f.Y) > BS * 3)
491 result.collides = true;
492 } else if(nearest_collided == 2) { // Z
493 if (fabs(speed_f.Z) > BS * 3)
497 result.collides = true;
498 result.collides_xz = true;
501 info.new_speed = speed_f;
502 if (info.new_speed.getDistanceFrom(info.old_speed) < 0.1 * BS)
503 is_collision = false;
506 result.collisions.push_back(info);
512 Final touches: Check if standing on ground, step up stairs.
515 box.MinEdge += pos_f;
516 box.MaxEdge += pos_f;
517 for (u32 boxindex = 0; boxindex < cboxes.size(); boxindex++) {
518 const aabb3f& cbox = cboxes[boxindex];
521 See if the object is touching ground.
523 Object touches ground if object's minimum Y is near node's
524 maximum Y and object's X-Z-area overlaps with the node's
527 Use 0.15*BS so that it is easier to get on a node.
529 if (cbox.MaxEdge.X - d > box.MinEdge.X && cbox.MinEdge.X + d < box.MaxEdge.X &&
530 cbox.MaxEdge.Z - d > box.MinEdge.Z &&
531 cbox.MinEdge.Z + d < box.MaxEdge.Z) {
532 if (is_step_up[boxindex]) {
533 pos_f.Y += (cbox.MaxEdge.Y - box.MinEdge.Y);
535 box.MinEdge += pos_f;
536 box.MaxEdge += pos_f;
538 if (fabs(cbox.MaxEdge.Y - box.MinEdge.Y) < 0.15 * BS) {
539 result.touching_ground = true;
541 if (is_object[boxindex])
542 result.standing_on_object = true;
543 if (is_unloaded[boxindex])
544 result.standing_on_unloaded = true;