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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"
#ifndef SERVER
#include "clientenvironment.h"
#endif
#include "serverenvironment.h"
#include "serverobject.h"
#include "util/timetaker.h"
#include "profiler.h"
// float error is 10 - 9.96875 = 0.03125
//#define COLL_ZERO 0.032 // broken unit tests
#define COLL_ZERO 0
struct NearbyCollisionInfo {
NearbyCollisionInfo(bool is_ul, bool is_obj, int bouncy,
const v3s16 &pos, const aabb3f &box) :
is_unloaded(is_ul),
is_object(is_obj),
bouncy(bouncy),
position(pos),
box(box)
{}
bool is_unloaded;
bool is_step_up = false;
bool is_object;
int bouncy;
v3s16 position;
aabb3f box;
};
// 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<NearbyCollisionInfo> &cinfo,
const aabb3f &movingbox,
f32 y_increase, f32 d)
{
//TimeTaker tt("wouldCollideWithCeiling");
assert(y_increase >= 0); // pre-condition
for (const auto &it : cinfo) {
const aabb3f &staticbox = it.box;
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;
}
static inline void getNeighborConnectingFace(const v3s16 &p,
const NodeDefManager *nodedef, Map *map, MapNode n, int v, int *neighbors)
{
MapNode n2 = map->getNodeNoEx(p);
if (nodedef->nodeboxConnects(n, n2, v))
*neighbors |= v;
}
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)
{
static bool time_notification_done = false;
Map *map = &env->getMap();
//TimeTaker tt("collisionMoveSimple");
ScopeProfiler sp(g_profiler, "collisionMoveSimple avg", SPT_AVG);
collisionMoveResult result;
/*
Calculate new velocity
*/
if (dtime > 0.5f) {
if (!time_notification_done) {
time_notification_done = true;
infostream << "collisionMoveSimple: maximum step interval exceeded,"
" lost movement details!"<<std::endl;
}
dtime = 0.5f;
} else {
time_notification_done = false;
}
*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<NearbyCollisionInfo> cinfo;
{
//TimeTaker tt2("collisionMoveSimple collect boxes");
ScopeProfiler sp2(g_profiler, "collisionMoveSimple collect boxes avg", SPT_AVG);
v3f newpos_f = *pos_f + *speed_f * dtime;
v3f minpos_f(
MYMIN(pos_f->X, newpos_f.X),
MYMIN(pos_f->Y, newpos_f.Y) + 0.01f * BS, // bias rounding, player often at +/-n.5
MYMIN(pos_f->Z, newpos_f.Z)
);
v3f maxpos_f(
MYMAX(pos_f->X, newpos_f.X),
MYMAX(pos_f->Y, newpos_f.Y),
MYMAX(pos_f->Z, newpos_f.Z)
);
v3s16 min = floatToInt(minpos_f + box_0.MinEdge, BS) - v3s16(1, 1, 1);
v3s16 max = floatToInt(maxpos_f + box_0.MaxEdge, BS) + v3s16(1, 1, 1);
bool any_position_valid = false;
v3s16 p;
for (p.X = min.X; p.X <= max.X; p.X++)
for (p.Y = min.Y; p.Y <= max.Y; p.Y++)
for (p.Z = min.Z; p.Z <= max.Z; p.Z++) {
bool is_position_valid;
MapNode n = map->getNodeNoEx(p, &is_position_valid);
if (is_position_valid && n.getContent() != CONTENT_IGNORE) {
// Object collides into walkable nodes
any_position_valid = true;
const NodeDefManager *nodedef = gamedef->getNodeDefManager();
const ContentFeatures &f = nodedef->get(n);
if (!f.walkable)
continue;
int n_bouncy_value = itemgroup_get(f.groups, "bouncy");
int neighbors = 0;
if (f.drawtype == NDT_NODEBOX &&
f.node_box.type == NODEBOX_CONNECTED) {
v3s16 p2 = p;
p2.Y++;
getNeighborConnectingFace(p2, nodedef, map, n, 1, &neighbors);
p2 = p;
p2.Y--;
getNeighborConnectingFace(p2, nodedef, map, n, 2, &neighbors);
p2 = p;
p2.Z--;
getNeighborConnectingFace(p2, nodedef, map, n, 4, &neighbors);
p2 = p;
p2.X--;
getNeighborConnectingFace(p2, nodedef, map, n, 8, &neighbors);
p2 = p;
p2.Z++;
getNeighborConnectingFace(p2, nodedef, map, n, 16, &neighbors);
p2 = p;
p2.X++;
getNeighborConnectingFace(p2, nodedef, map, n, 32, &neighbors);
}
std::vector<aabb3f> nodeboxes;
n.getCollisionBoxes(gamedef->ndef(), &nodeboxes, neighbors);
for (auto box : nodeboxes) {
box.MinEdge += intToFloat(p, BS);
box.MaxEdge += intToFloat(p, BS);
cinfo.emplace_back(false, false, n_bouncy_value, p, box);
}
} else {
// Collide with unloaded nodes (position invalid) and loaded
// CONTENT_IGNORE nodes (position valid)
aabb3f box = getNodeBox(p, BS);
cinfo.emplace_back(true, false, 0, p, box);
}
}
// Do not move if world has not loaded yet, since custom node boxes
// are not available for collision detection.
// This also intentionally occurs in the case of the object being positioned
// solely on loaded CONTENT_IGNORE nodes, no matter where they come from.
if (!any_position_valid) {
*speed_f = v3f(0, 0, 0);
return result;
}
} // tt2
if(collideWithObjects)
{
ScopeProfiler sp2(g_profiler, "collisionMoveSimple objects avg", SPT_AVG);
//TimeTaker tt3("collisionMoveSimple collect object boxes");
/* add object boxes to cinfo */
std::vector<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 * 1.5f, clientobjects);
for (auto &clientobject : clientobjects) {
if (!self || (self != clientobject.obj)) {
objects.push_back((ActiveObject*) clientobject.obj);
}
}
}
else
#endif
{
ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
if (s_env != NULL) {
f32 distance = speed_f->getLength();
std::vector<u16> s_objects;
s_env->getObjectsInsideRadius(s_objects, *pos_f, distance * 1.5f);
for (u16 obj_id : s_objects) {
ServerActiveObject *current = s_env->getActiveObject(obj_id);
if (!self || (self != current)) {
objects.push_back((ActiveObject*)current);
}
}
}
}
for (std::vector<ActiveObject*>::const_iterator iter = objects.begin();
iter != objects.end(); ++iter) {
ActiveObject *object = *iter;
if (object) {
aabb3f object_collisionbox;
if (object->getCollisionBox(&object_collisionbox) &&
object->collideWithObjects()) {
cinfo.emplace_back(false, true, 0, v3s16(), object_collisionbox);
}
}
}
} //tt3
/*
Collision detection
*/
/*
Collision uncertainty radius
Make it a bit larger than the maximum distance of movement
*/
f32 d = pos_max_d * 1.1f;
// 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); // invariant
int loopcount = 0;
while(dtime > BS * 1e-10f) {
//TimeTaker tt3("collisionMoveSimple dtime loop");
ScopeProfiler sp2(g_profiler, "collisionMoveSimple dtime loop avg", SPT_AVG);
// Avoid infinite loop
loopcount++;
if (loopcount >= 100) {
warningstream << "collisionMoveSimple: Loop count exceeded, aborting to avoid infiniite loop" << std::endl;
break;
}
aabb3f movingbox = box_0;
movingbox.MinEdge += *pos_f;
movingbox.MaxEdge += *pos_f;
int nearest_collided = -1;
f32 nearest_dtime = dtime;
int nearest_boxindex = -1;
/*
Go through every nodebox, find nearest collision
*/
for (u32 boxindex = 0; boxindex < cinfo.size(); boxindex++) {
NearbyCollisionInfo box_info = cinfo[boxindex];
// Ignore if already stepped up this nodebox.
if (box_info.is_step_up)
continue;
// Find nearest collision of the two boxes (raytracing-like)
f32 dtime_tmp;
int collided = axisAlignedCollision(box_info.box,
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.
NearbyCollisionInfo &nearest_info = cinfo[nearest_boxindex];
const aabb3f& cbox = nearest_info.box;
// 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(cinfo, movingbox,
cbox.MaxEdge.Y - movingbox.MinEdge.Y,
d));
// Get bounce multiplier
float bounce = -(float)nearest_info.bouncy / 100.0f;
// 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 (nearest_info.is_unloaded)
is_collision = false;
CollisionInfo info;
if (nearest_info.is_object)
info.type = COLLISION_OBJECT;
else
info.type = COLLISION_NODE;
info.node_p = nearest_info.position;
info.old_speed = *speed_f;
// Set the speed component that caused the collision to zero
if (step_up) {
// Special case: Handle stairs
nearest_info.is_step_up = 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;
} 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;
}
info.new_speed = *speed_f;
if (info.new_speed.getDistanceFrom(info.old_speed) < 0.1f * 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 (const auto &box_info : cinfo) {
const aabb3f &cbox = box_info.box;
/*
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 (box_info.is_step_up) {
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) < 0.15f * BS) {
result.touching_ground = true;
if (box_info.is_object)
result.standing_on_object = true;
}
}
}
return result;
}
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