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minetest/src/collision.cpp

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/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "collision.h"
#include "mapblock.h"
#include "map.h"
#include "nodedef.h"
#include "gamedef.h"
#include "log.h"
#include "environment.h"
#include "serverobject.h"
#include <vector>
#include <set>
#include "util/timetaker.h"
#include "main.h" // g_profiler
#include "profiler.h"
// float error is 10 - 9.96875 = 0.03125
//#define COLL_ZERO 0.032 // broken unit tests
#define COLL_ZERO 0
// Helper function:
// Checks for collision of a moving aabbox with a static aabbox
// Returns -1 if no collision, 0 if X collision, 1 if Y collision, 2 if Z collision
// The time after which the collision occurs is stored in dtime.
int axisAlignedCollision(
const aabb3f &staticbox, const aabb3f &movingbox,
const v3f &speed, f32 d, f32 &dtime)
{
//TimeTaker tt("axisAlignedCollision");
f32 xsize = (staticbox.MaxEdge.X - staticbox.MinEdge.X) - COLL_ZERO; // reduce box size for solve collision stuck (flying sand)
f32 ysize = (staticbox.MaxEdge.Y - staticbox.MinEdge.Y); // - COLL_ZERO; // Y - no sense for falling, but maybe try later
f32 zsize = (staticbox.MaxEdge.Z - staticbox.MinEdge.Z) - COLL_ZERO;
aabb3f relbox(
movingbox.MinEdge.X - staticbox.MinEdge.X,
movingbox.MinEdge.Y - staticbox.MinEdge.Y,
movingbox.MinEdge.Z - staticbox.MinEdge.Z,
movingbox.MaxEdge.X - staticbox.MinEdge.X,
movingbox.MaxEdge.Y - staticbox.MinEdge.Y,
movingbox.MaxEdge.Z - staticbox.MinEdge.Z
);
if(speed.X > 0) // Check for collision with X- plane
{
if(relbox.MaxEdge.X <= d)
{
dtime = - relbox.MaxEdge.X / speed.X;
if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
(relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO) &&
(relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
(relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
return 0;
}
else if(relbox.MinEdge.X > xsize)
{
return -1;
}
}
else if(speed.X < 0) // Check for collision with X+ plane
{
if(relbox.MinEdge.X >= xsize - d)
{
dtime = (xsize - relbox.MinEdge.X) / speed.X;
if((relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
(relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO) &&
(relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
(relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
return 0;
}
else if(relbox.MaxEdge.X < 0)
{
return -1;
}
}
// NO else if here
if(speed.Y > 0) // Check for collision with Y- plane
{
if(relbox.MaxEdge.Y <= d)
{
dtime = - relbox.MaxEdge.Y / speed.Y;
if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
(relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
(relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
(relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
return 1;
}
else if(relbox.MinEdge.Y > ysize)
{
return -1;
}
}
else if(speed.Y < 0) // Check for collision with Y+ plane
{
if(relbox.MinEdge.Y >= ysize - d)
{
dtime = (ysize - relbox.MinEdge.Y) / speed.Y;
if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
(relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
(relbox.MinEdge.Z + speed.Z * dtime < zsize) &&
(relbox.MaxEdge.Z + speed.Z * dtime > COLL_ZERO))
return 1;
}
else if(relbox.MaxEdge.Y < 0)
{
return -1;
}
}
// NO else if here
if(speed.Z > 0) // Check for collision with Z- plane
{
if(relbox.MaxEdge.Z <= d)
{
dtime = - relbox.MaxEdge.Z / speed.Z;
if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
(relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
(relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
(relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO))
return 2;
}
//else if(relbox.MinEdge.Z > zsize)
//{
// return -1;
//}
}
else if(speed.Z < 0) // Check for collision with Z+ plane
{
if(relbox.MinEdge.Z >= zsize - d)
{
dtime = (zsize - relbox.MinEdge.Z) / speed.Z;
if((relbox.MinEdge.X + speed.X * dtime < xsize) &&
(relbox.MaxEdge.X + speed.X * dtime > COLL_ZERO) &&
(relbox.MinEdge.Y + speed.Y * dtime < ysize) &&
(relbox.MaxEdge.Y + speed.Y * dtime > COLL_ZERO))
return 2;
}
//else if(relbox.MaxEdge.Z < 0)
//{
// return -1;
//}
}
return -1;
}
// Helper function:
// Checks if moving the movingbox up by the given distance would hit a ceiling.
bool wouldCollideWithCeiling(
const std::vector<aabb3f> &staticboxes,
const aabb3f &movingbox,
f32 y_increase, f32 d)
{
//TimeTaker tt("wouldCollideWithCeiling");
assert(y_increase >= 0);
for(std::vector<aabb3f>::const_iterator
i = staticboxes.begin();
i != staticboxes.end(); i++)
{
const aabb3f& staticbox = *i;
if((movingbox.MaxEdge.Y - d <= staticbox.MinEdge.Y) &&
(movingbox.MaxEdge.Y + y_increase > staticbox.MinEdge.Y) &&
(movingbox.MinEdge.X < staticbox.MaxEdge.X) &&
(movingbox.MaxEdge.X > staticbox.MinEdge.X) &&
(movingbox.MinEdge.Z < staticbox.MaxEdge.Z) &&
(movingbox.MaxEdge.Z > staticbox.MinEdge.Z))
return true;
}
return false;
}
collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
f32 pos_max_d, const aabb3f &box_0,
f32 stepheight, f32 dtime,
v3f &pos_f, v3f &speed_f,
v3f &accel_f,ActiveObject* self,
bool collideWithObjects)
{
Map *map = &env->getMap();
//TimeTaker tt("collisionMoveSimple");
ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
collisionMoveResult result;
/*
Calculate new velocity
*/
if( dtime > 0.5 ) {
infostream<<"collisionMoveSimple: WARNING: maximum step interval exceeded, lost movement details!"<<std::endl;
dtime = 0.5;
}
speed_f += accel_f * dtime;
// If there is no speed, there are no collisions
if(speed_f.getLength() == 0)
return result;
// Limit speed for avoiding hangs
speed_f.Y=rangelim(speed_f.Y,-5000,5000);
speed_f.X=rangelim(speed_f.X,-5000,5000);
speed_f.Z=rangelim(speed_f.Z,-5000,5000);
/*
Collect node boxes in movement range
*/
std::vector<aabb3f> cboxes;
std::vector<bool> is_unloaded;
std::vector<bool> is_step_up;
std::vector<bool> is_object;
std::vector<int> bouncy_values;
std::vector<v3s16> node_positions;
{
//TimeTaker tt2("collisionMoveSimple collect boxes");
ScopeProfiler sp(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
v3s16 oldpos_i = floatToInt(pos_f, BS);
v3s16 newpos_i = floatToInt(pos_f + speed_f * dtime, BS);
s16 min_x = MYMIN(oldpos_i.X, newpos_i.X) + (box_0.MinEdge.X / BS) - 1;
s16 min_y = MYMIN(oldpos_i.Y, newpos_i.Y) + (box_0.MinEdge.Y / BS) - 1;
s16 min_z = MYMIN(oldpos_i.Z, newpos_i.Z) + (box_0.MinEdge.Z / BS) - 1;
s16 max_x = MYMAX(oldpos_i.X, newpos_i.X) + (box_0.MaxEdge.X / BS) + 1;
s16 max_y = MYMAX(oldpos_i.Y, newpos_i.Y) + (box_0.MaxEdge.Y / BS) + 1;
s16 max_z = MYMAX(oldpos_i.Z, newpos_i.Z) + (box_0.MaxEdge.Z / BS) + 1;
for(s16 x = min_x; x <= max_x; x++)
for(s16 y = min_y; y <= max_y; y++)
for(s16 z = min_z; z <= max_z; z++)
{
v3s16 p(x,y,z);
bool is_position_valid;
MapNode n = map->getNodeNoEx(p, &is_position_valid);
if (is_position_valid) {
// Object collides into walkable nodes
const ContentFeatures &f = gamedef->getNodeDefManager()->get(n);
if(f.walkable == false)
continue;
int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
std::vector<aabb3f> nodeboxes = n.getCollisionBoxes(gamedef->ndef());
for(std::vector<aabb3f>::iterator
i = nodeboxes.begin();
i != nodeboxes.end(); i++)
{
aabb3f box = *i;
box.MinEdge += v3f(x, y, z)*BS;
box.MaxEdge += v3f(x, y, z)*BS;
cboxes.push_back(box);
is_unloaded.push_back(false);
is_step_up.push_back(false);
bouncy_values.push_back(n_bouncy_value);
node_positions.push_back(p);
is_object.push_back(false);
}
}
else {
// Collide with unloaded nodes
aabb3f box = getNodeBox(p, BS);
cboxes.push_back(box);
is_unloaded.push_back(true);
is_step_up.push_back(false);
bouncy_values.push_back(0);
node_positions.push_back(p);
is_object.push_back(false);
}
}
} // tt2
if(collideWithObjects)
{
ScopeProfiler sp(g_profiler, "collisionMoveSimple objects avg", SPT_AVG);
//TimeTaker tt3("collisionMoveSimple collect object boxes");
/* add object boxes to cboxes */
std::list<ActiveObject*> objects;
#ifndef SERVER
ClientEnvironment *c_env = dynamic_cast<ClientEnvironment*>(env);
if (c_env != 0)
{
f32 distance = speed_f.getLength();
std::vector<DistanceSortedActiveObject> clientobjects;
c_env->getActiveObjects(pos_f,distance * 1.5,clientobjects);
for (size_t i=0; i < clientobjects.size(); i++)
{
if ((self == 0) || (self != clientobjects[i].obj)) {
objects.push_back((ActiveObject*)clientobjects[i].obj);
}
}
}
else
#endif
{
ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
if (s_env != 0)
{
f32 distance = speed_f.getLength();
std::set<u16> s_objects = s_env->getObjectsInsideRadius(pos_f,distance * 1.5);
for (std::set<u16>::iterator iter = s_objects.begin(); iter != s_objects.end(); iter++)
{
ServerActiveObject *current = s_env->getActiveObject(*iter);
if ((self == 0) || (self != current)) {
objects.push_back((ActiveObject*)current);
}
}
}
}
for (std::list<ActiveObject*>::const_iterator iter = objects.begin();iter != objects.end(); ++iter)
{
ActiveObject *object = *iter;
if (object != NULL)
{
aabb3f object_collisionbox;
if (object->getCollisionBox(&object_collisionbox) &&
object->collideWithObjects())
{
cboxes.push_back(object_collisionbox);
is_unloaded.push_back(false);
is_step_up.push_back(false);
bouncy_values.push_back(0);
node_positions.push_back(v3s16(0,0,0));
is_object.push_back(true);
}
}
}
} //tt3
assert(cboxes.size() == is_unloaded.size());
assert(cboxes.size() == is_step_up.size());
assert(cboxes.size() == bouncy_values.size());
assert(cboxes.size() == node_positions.size());
assert(cboxes.size() == is_object.size());
/*
Collision detection
*/
/*
Collision uncertainty radius
Make it a bit larger than the maximum distance of movement
*/
f32 d = pos_max_d * 1.1;
// A fairly large value in here makes moving smoother
//f32 d = 0.15*BS;
// This should always apply, otherwise there are glitches
assert(d > pos_max_d);
int loopcount = 0;
while(dtime > BS*1e-10)
{
//TimeTaker tt3("collisionMoveSimple dtime loop");
ScopeProfiler sp(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
// Avoid infinite loop
loopcount++;
if(loopcount >= 100)
{
infostream<<"collisionMoveSimple: WARNING: Loop count exceeded, aborting to avoid infiniite loop"<<std::endl;
dtime = 0;
break;
}
aabb3f movingbox = box_0;
movingbox.MinEdge += pos_f;
movingbox.MaxEdge += pos_f;
int nearest_collided = -1;
f32 nearest_dtime = dtime;
u32 nearest_boxindex = -1;
/*
Go through every nodebox, find nearest collision
*/
for(u32 boxindex = 0; boxindex < cboxes.size(); boxindex++)
{
// Ignore if already stepped up this nodebox.
if(is_step_up[boxindex])
continue;
// Find nearest collision of the two boxes (raytracing-like)
f32 dtime_tmp;
int collided = axisAlignedCollision(
cboxes[boxindex], movingbox, speed_f, d, dtime_tmp);
if(collided == -1 || dtime_tmp >= nearest_dtime)
continue;
nearest_dtime = dtime_tmp;
nearest_collided = collided;
nearest_boxindex = boxindex;
}
if(nearest_collided == -1)
{
// No collision with any collision box.
pos_f += speed_f * dtime;
dtime = 0; // Set to 0 to avoid "infinite" loop due to small FP numbers
}
else
{
// Otherwise, a collision occurred.
const aabb3f& cbox = cboxes[nearest_boxindex];
// Check for stairs.
bool step_up = (nearest_collided != 1) && // must not be Y direction
(movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
(movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
(!wouldCollideWithCeiling(cboxes, movingbox,
cbox.MaxEdge.Y - movingbox.MinEdge.Y,
d));
// Get bounce multiplier
bool bouncy = (bouncy_values[nearest_boxindex] >= 1);
float bounce = -(float)bouncy_values[nearest_boxindex] / 100.0;
// Move to the point of collision and reduce dtime by nearest_dtime
if(nearest_dtime < 0)
{
// Handle negative nearest_dtime (can be caused by the d allowance)
if(!step_up)
{
if(nearest_collided == 0)
pos_f.X += speed_f.X * nearest_dtime;
if(nearest_collided == 1)
pos_f.Y += speed_f.Y * nearest_dtime;
if(nearest_collided == 2)
pos_f.Z += speed_f.Z * nearest_dtime;
}
}
else
{
pos_f += speed_f * nearest_dtime;
dtime -= nearest_dtime;
}
bool is_collision = true;
if(is_unloaded[nearest_boxindex])
is_collision = false;
CollisionInfo info;
if (is_object[nearest_boxindex]) {
info.type = COLLISION_OBJECT;
}
else {
info.type = COLLISION_NODE;
}
info.node_p = node_positions[nearest_boxindex];
info.bouncy = bouncy;
info.old_speed = speed_f;
// Set the speed component that caused the collision to zero
if(step_up)
{
// Special case: Handle stairs
is_step_up[nearest_boxindex] = true;
is_collision = false;
}
else if(nearest_collided == 0) // X
{
if(fabs(speed_f.X) > BS*3)
speed_f.X *= bounce;
else
speed_f.X = 0;
result.collides = true;
result.collides_xz = true;
}
else if(nearest_collided == 1) // Y
{
if(fabs(speed_f.Y) > BS*3)
speed_f.Y *= bounce;
else
speed_f.Y = 0;
result.collides = true;
}
else if(nearest_collided == 2) // Z
{
if(fabs(speed_f.Z) > BS*3)
speed_f.Z *= bounce;
else
speed_f.Z = 0;
result.collides = true;
result.collides_xz = true;
}
info.new_speed = speed_f;
if(info.new_speed.getDistanceFrom(info.old_speed) < 0.1*BS)
is_collision = false;
if(is_collision){
result.collisions.push_back(info);
}
}
}
/*
Final touches: Check if standing on ground, step up stairs.
*/
aabb3f box = box_0;
box.MinEdge += pos_f;
box.MaxEdge += pos_f;
for(u32 boxindex = 0; boxindex < cboxes.size(); boxindex++)
{
const aabb3f& cbox = cboxes[boxindex];
/*
See if the object is touching ground.
Object touches ground if object's minimum Y is near node's
maximum Y and object's X-Z-area overlaps with the node's
X-Z-area.
Use 0.15*BS so that it is easier to get on a node.
*/
if(
cbox.MaxEdge.X-d > box.MinEdge.X &&
cbox.MinEdge.X+d < box.MaxEdge.X &&
cbox.MaxEdge.Z-d > box.MinEdge.Z &&
cbox.MinEdge.Z+d < box.MaxEdge.Z
){
if(is_step_up[boxindex])
{
pos_f.Y += (cbox.MaxEdge.Y - box.MinEdge.Y);
box = box_0;
box.MinEdge += pos_f;
box.MaxEdge += pos_f;
}
if(fabs(cbox.MaxEdge.Y-box.MinEdge.Y) < 0.15*BS)
{
result.touching_ground = true;
if(is_unloaded[boxindex])
result.standing_on_unloaded = true;
}
}
}
return result;
}
#if 0
// This doesn't seem to work and isn't used
collisionMoveResult collisionMovePrecise(Map *map, IGameDef *gamedef,
f32 pos_max_d, const aabb3f &box_0,
f32 stepheight, f32 dtime,
v3f &pos_f, v3f &speed_f, v3f &accel_f)
{
//TimeTaker tt("collisionMovePrecise");
ScopeProfiler sp(g_profiler, "collisionMovePrecise avg", SPT_AVG);
collisionMoveResult final_result;
// If there is no speed, there are no collisions
if(speed_f.getLength() == 0)
return final_result;
// Don't allow overly huge dtime
if(dtime > 2.0)
dtime = 2.0;
f32 dtime_downcount = dtime;
u32 loopcount = 0;
do
{
loopcount++;
// Maximum time increment (for collision detection etc)
// time = distance / speed
f32 dtime_max_increment = 1.0;
if(speed_f.getLength() != 0)
dtime_max_increment = pos_max_d / speed_f.getLength();
// Maximum time increment is 10ms or lower
if(dtime_max_increment > 0.01)
dtime_max_increment = 0.01;
f32 dtime_part;
if(dtime_downcount > dtime_max_increment)
{
dtime_part = dtime_max_increment;
dtime_downcount -= dtime_part;
}
else
{
dtime_part = dtime_downcount;
/*
Setting this to 0 (no -=dtime_part) disables an infinite loop
when dtime_part is so small that dtime_downcount -= dtime_part
does nothing
*/
dtime_downcount = 0;
}
collisionMoveResult result = collisionMoveSimple(map, gamedef,
pos_max_d, box_0, stepheight, dtime_part,
pos_f, speed_f, accel_f);
if(result.touching_ground)
final_result.touching_ground = true;
if(result.collides)
final_result.collides = true;
if(result.collides_xz)
final_result.collides_xz = true;
if(result.standing_on_unloaded)
final_result.standing_on_unloaded = true;
}
while(dtime_downcount > 0.001);
return final_result;
}
#endif
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