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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 <cmath>
#include "mapblock.h"
#include "map.h"
#include "nodedef.h"
#include "gamedef.h"
#ifndef SERVER
#include "client/clientenvironment.h"
#include "client/localplayer.h"
#endif
#include "serverenvironment.h"
#include "server/serveractiveobject.h"
#include "util/timetaker.h"
#include "profiler.h"
#ifdef __FAST_MATH__
#warning "-ffast-math is known to cause bugs in collision code, do not use!"
#endif
struct NearbyCollisionInfo {
// node
NearbyCollisionInfo(bool is_ul, int bouncy, const v3s16 &pos,
const aabb3f &box) :
is_unloaded(is_ul),
obj(nullptr),
bouncy(bouncy),
position(pos),
box(box)
{}
// object
NearbyCollisionInfo(ActiveObject *obj, int bouncy,
const aabb3f &box) :
is_unloaded(false),
obj(obj),
bouncy(bouncy),
box(box)
{}
inline bool isObject() const { return obj != nullptr; }
bool is_unloaded;
bool is_step_up = false;
ActiveObject *obj;
int bouncy;
v3s16 position;
aabb3f box;
};
// Helper functions:
// Truncate floating point numbers to specified number of decimal places
// in order to move all the floating point error to one side of the correct value
static inline f32 truncate(const f32 val, const f32 factor)
{
return truncf(val * factor) / factor;
}
static inline v3f truncate(const v3f& vec, const f32 factor)
{
return v3f(
truncate(vec.X, factor),
truncate(vec.Y, factor),
truncate(vec.Z, factor)
);
}
// 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.
CollisionAxis axisAlignedCollision(
const aabb3f &staticbox, const aabb3f &movingbox,
const v3f &speed, f32 *dtime)
{
//TimeTaker tt("axisAlignedCollision");
aabb3f relbox(
(movingbox.MaxEdge.X - movingbox.MinEdge.X) + (staticbox.MaxEdge.X - staticbox.MinEdge.X), // sum of the widths
(movingbox.MaxEdge.Y - movingbox.MinEdge.Y) + (staticbox.MaxEdge.Y - staticbox.MinEdge.Y),
(movingbox.MaxEdge.Z - movingbox.MinEdge.Z) + (staticbox.MaxEdge.Z - staticbox.MinEdge.Z),
std::max(movingbox.MaxEdge.X, staticbox.MaxEdge.X) - std::min(movingbox.MinEdge.X, staticbox.MinEdge.X), //outer bounding 'box' dimensions
std::max(movingbox.MaxEdge.Y, staticbox.MaxEdge.Y) - std::min(movingbox.MinEdge.Y, staticbox.MinEdge.Y),
std::max(movingbox.MaxEdge.Z, staticbox.MaxEdge.Z) - std::min(movingbox.MinEdge.Z, staticbox.MinEdge.Z)
);
const f32 dtime_max = *dtime;
f32 inner_margin; // the distance of clipping recovery
f32 distance;
f32 time;
if (speed.Y) {
distance = relbox.MaxEdge.Y - relbox.MinEdge.Y;
*dtime = distance / std::abs(speed.Y);
time = std::max(*dtime, 0.0f);
if (*dtime <= dtime_max) {
inner_margin = std::max(-0.5f * (staticbox.MaxEdge.Y - staticbox.MinEdge.Y), -2.0f);
if ((speed.Y > 0 && staticbox.MinEdge.Y - movingbox.MaxEdge.Y > inner_margin) ||
(speed.Y < 0 && movingbox.MinEdge.Y - staticbox.MaxEdge.Y > inner_margin)) {
if (
(std::max(movingbox.MaxEdge.X + speed.X * time, staticbox.MaxEdge.X)
- std::min(movingbox.MinEdge.X + speed.X * time, staticbox.MinEdge.X)
- relbox.MinEdge.X < 0) &&
(std::max(movingbox.MaxEdge.Z + speed.Z * time, staticbox.MaxEdge.Z)
- std::min(movingbox.MinEdge.Z + speed.Z * time, staticbox.MinEdge.Z)
- relbox.MinEdge.Z < 0)
)
return COLLISION_AXIS_Y;
}
}
else {
return COLLISION_AXIS_NONE;
}
}
// NO else if here
if (speed.X) {
distance = relbox.MaxEdge.X - relbox.MinEdge.X;
*dtime = distance / std::abs(speed.X);
time = std::max(*dtime, 0.0f);
if (*dtime <= dtime_max) {
inner_margin = std::max(-0.5f * (staticbox.MaxEdge.X - staticbox.MinEdge.X), -2.0f);
if ((speed.X > 0 && staticbox.MinEdge.X - movingbox.MaxEdge.X > inner_margin) ||
(speed.X < 0 && movingbox.MinEdge.X - staticbox.MaxEdge.X > inner_margin)) {
if (
(std::max(movingbox.MaxEdge.Y + speed.Y * time, staticbox.MaxEdge.Y)
- std::min(movingbox.MinEdge.Y + speed.Y * time, staticbox.MinEdge.Y)
- relbox.MinEdge.Y < 0) &&
(std::max(movingbox.MaxEdge.Z + speed.Z * time, staticbox.MaxEdge.Z)
- std::min(movingbox.MinEdge.Z + speed.Z * time, staticbox.MinEdge.Z)
- relbox.MinEdge.Z < 0)
)
return COLLISION_AXIS_X;
}
} else {
return COLLISION_AXIS_NONE;
}
}
// NO else if here
if (speed.Z) {
distance = relbox.MaxEdge.Z - relbox.MinEdge.Z;
*dtime = distance / std::abs(speed.Z);
time = std::max(*dtime, 0.0f);
if (*dtime <= dtime_max) {
inner_margin = std::max(-0.5f * (staticbox.MaxEdge.Z - staticbox.MinEdge.Z), -2.0f);
if ((speed.Z > 0 && staticbox.MinEdge.Z - movingbox.MaxEdge.Z > inner_margin) ||
(speed.Z < 0 && movingbox.MinEdge.Z - staticbox.MaxEdge.Z > inner_margin)) {
if (
(std::max(movingbox.MaxEdge.X + speed.X * time, staticbox.MaxEdge.X)
- std::min(movingbox.MinEdge.X + speed.X * time, staticbox.MinEdge.X)
- relbox.MinEdge.X < 0) &&
(std::max(movingbox.MaxEdge.Y + speed.Y * time, staticbox.MaxEdge.Y)
- std::min(movingbox.MinEdge.Y + speed.Y * time, staticbox.MinEdge.Y)
- relbox.MinEdge.Y < 0)
)
return COLLISION_AXIS_Z;
}
}
}
return COLLISION_AXIS_NONE;
}
// 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->getNode(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();
ScopeProfiler sp(g_profiler, "collisionMoveSimple()", 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);
*speed_f = truncate(*speed_f, 10000.0f);
/*
Collect node boxes in movement range
*/
std::vector<NearbyCollisionInfo> cinfo;
{
//TimeTaker tt2("collisionMoveSimple collect boxes");
ScopeProfiler sp2(g_profiler, "collisionMoveSimple(): collect boxes", 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->getNode(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);
// Calculate float position only once
v3f posf = intToFloat(p, BS);
for (auto box : nodeboxes) {
box.MinEdge += posf;
box.MaxEdge += posf;
cinfo.emplace_back(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, 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)
{
/* add object boxes to cinfo */
std::vector<ActiveObject*> objects;
#ifndef SERVER
ClientEnvironment *c_env = dynamic_cast<ClientEnvironment*>(env);
if (c_env != 0) {
// Calculate distance by speed, add own extent and 1.5m of tolerance
f32 distance = speed_f->getLength() * dtime +
box_0.getExtent().getLength() + 1.5f * BS;
std::vector<DistanceSortedActiveObject> clientobjects;
c_env->getActiveObjects(*pos_f, distance, clientobjects);
for (auto &clientobject : clientobjects) {
// Do collide with everything but itself and the parent CAO
if (!self || (self != clientobject.obj &&
self != clientobject.obj->getParent())) {
objects.push_back((ActiveObject*) clientobject.obj);
}
}
}
else
#endif
{
ServerEnvironment *s_env = dynamic_cast<ServerEnvironment*>(env);
if (s_env != NULL) {
// Calculate distance by speed, add own extent and 1.5m of tolerance
f32 distance = speed_f->getLength() * dtime +
box_0.getExtent().getLength() + 1.5f * BS;
// search for objects which are not us, or we are not its parent
// we directly use the callback to populate the result to prevent
// a useless result loop here
auto include_obj_cb = [self, &objects] (ServerActiveObject *obj) {
if (!obj->isGone() &&
(!self || (self != obj && self != obj->getParent()))) {
objects.push_back((ActiveObject *)obj);
}
return false;
};
std::vector<ServerActiveObject *> s_objects;
s_env->getObjectsInsideRadius(s_objects, *pos_f, distance, include_obj_cb);
}
}
for (std::vector<ActiveObject*>::const_iterator iter = objects.begin();
iter != objects.end(); ++iter) {
ActiveObject *object = *iter;
if (object && object->collideWithObjects()) {
aabb3f object_collisionbox;
if (object->getCollisionBox(&object_collisionbox))
cinfo.emplace_back(object, 0, object_collisionbox);
}
}
#ifndef SERVER
if (self && c_env) {
LocalPlayer *lplayer = c_env->getLocalPlayer();
if (lplayer->getParent() == nullptr) {
aabb3f lplayer_collisionbox = lplayer->getCollisionbox();
v3f lplayer_pos = lplayer->getPosition();
lplayer_collisionbox.MinEdge += lplayer_pos;
lplayer_collisionbox.MaxEdge += lplayer_pos;
ActiveObject *obj = (ActiveObject*) lplayer->getCAO();
cinfo.emplace_back(obj, 0, lplayer_collisionbox);
}
}
#endif
} //tt3
/*
Collision detection
*/
f32 d = 0.0f;
int loopcount = 0;
while(dtime > BS * 1e-10f) {
// 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;
CollisionAxis nearest_collided = COLLISION_AXIS_NONE;
f32 nearest_dtime = dtime;
int nearest_boxindex = -1;
/*
Go through every nodebox, find nearest collision
*/
for (u32 boxindex = 0; boxindex < cinfo.size(); boxindex++) {
const 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 = nearest_dtime;
CollisionAxis collided = axisAlignedCollision(box_info.box,
movingbox, *speed_f, &dtime_tmp);
if (collided == -1 || dtime_tmp >= nearest_dtime)
continue;
nearest_dtime = dtime_tmp;
nearest_collided = collided;
nearest_boxindex = boxindex;
}
if (nearest_collided == COLLISION_AXIS_NONE) {
// No collision with any collision box.
*pos_f += truncate(*speed_f * dtime, 100.0f);
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;
//movingbox except moved to the horizontal position it would be after step up
aabb3f stepbox = movingbox;
stepbox.MinEdge.X += speed_f->X * dtime;
stepbox.MinEdge.Z += speed_f->Z * dtime;
stepbox.MaxEdge.X += speed_f->X * dtime;
stepbox.MaxEdge.Z += speed_f->Z * dtime;
// Check for stairs.
bool step_up = (nearest_collided != COLLISION_AXIS_Y) && // must not be Y direction
(movingbox.MinEdge.Y < cbox.MaxEdge.Y) &&
(movingbox.MinEdge.Y + stepheight > cbox.MaxEdge.Y) &&
(!wouldCollideWithCeiling(cinfo, stepbox,
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
if (!step_up) {
if (nearest_collided == COLLISION_AXIS_X)
pos_f->X += speed_f->X * nearest_dtime;
if (nearest_collided == COLLISION_AXIS_Y)
pos_f->Y += speed_f->Y * nearest_dtime;
if (nearest_collided == COLLISION_AXIS_Z)
pos_f->Z += speed_f->Z * nearest_dtime;
}
} else {
*pos_f += truncate(*speed_f * nearest_dtime, 100.0f);
dtime -= nearest_dtime;
}
bool is_collision = true;
if (nearest_info.is_unloaded)
is_collision = false;
CollisionInfo info;
if (nearest_info.isObject())
info.type = COLLISION_OBJECT;
else
info.type = COLLISION_NODE;
info.node_p = nearest_info.position;
info.object = nearest_info.obj;
info.old_speed = *speed_f;
info.plane = nearest_collided;
// 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 == COLLISION_AXIS_X) {
if (fabs(speed_f->X) > BS * 3)
speed_f->X *= bounce;
else
speed_f->X = 0;
result.collides = true;
} else if (nearest_collided == COLLISION_AXIS_Y) {
if(fabs(speed_f->Y) > BS * 3)
speed_f->Y *= bounce;
else
speed_f->Y = 0;
result.collides = true;
} else if (nearest_collided == COLLISION_AXIS_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) {
info.axis = nearest_collided;
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.
*/
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 (std::fabs(cbox.MaxEdge.Y - box.MinEdge.Y) < 0.05f) {
result.touching_ground = true;
if (box_info.isObject())
result.standing_on_object = true;
}
}
}
return result;
}
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