Mirrorlandia_minetest/minetest
1
0
Fork 1
mirror of https://github.com/minetest/minetest.git synced 2024-11-30 03:23:45 +01:00
Code Issues Packages Projects Releases Wiki Activity

Fix pathfinder bugs: returning nil frequently, broken A*, jump through solid nodes (#9339)

Browse Source 
* Fix pathfinder fail when startpos is over air
* Note down pathfinder restrictions
* Implement real A* search
* Pathfinder: Implement buildPath non-recursively
* Update find_path documentation
* Pathfinder: Check if jump path is unobstructed
* Pathfinder: Fix drop check first checking upwards
* Pathfinder: Return nil if source or dest are solid
* Pathfinder: Use priority queue for open list
This commit is contained in:
Wuzzy 2020-03-05 12:07:52 +01:00 committed by sfan5
parent 6d8e2d2483
commit 580e7e8eb9
4 changed files with 353 additions and 250 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
builtin/game/features.lua
View File

@ -15,6 +15,7 @@ core.features = {
httpfetch_binary_data = true, httpfetch_binary_data = true,
formspec_version_element = true, formspec_version_element = true,
area_store_persistent_ids = true, area_store_persistent_ids = true,
pathfinder_works = true,
} }
function core.has_feature(arg) function core.has_feature(arg)

21
doc/lua_api.txt
View File

@ -4045,6 +4045,8 @@ Utilities
formspec_version_element = true, formspec_version_element = true,
-- Whether AreaStore's IDs are kept on save/load (5.1.0) -- Whether AreaStore's IDs are kept on save/load (5.1.0)
area_store_persistent_ids = true, area_store_persistent_ids = true,
-- Whether minetest.find_path is functional (5.2.0)
pathfinder_works = true,
} }
* `minetest.has_feature(arg)`: returns `boolean, missing_features` * `minetest.has_feature(arg)`: returns `boolean, missing_features`
@ -4709,16 +4711,25 @@ Environment access
* `objects`: if false, only nodes will be returned. Default is `true`. * `objects`: if false, only nodes will be returned. Default is `true`.
* `liquids`: if false, liquid nodes won't be returned. Default is `false`. * `liquids`: if false, liquid nodes won't be returned. Default is `false`.
* `minetest.find_path(pos1,pos2,searchdistance,max_jump,max_drop,algorithm)` * `minetest.find_path(pos1,pos2,searchdistance,max_jump,max_drop,algorithm)`
* returns table containing path * returns table containing path that can be walked on
* returns a table of 3D points representing a path from `pos1` to `pos2` or * returns a table of 3D points representing a path from `pos1` to `pos2` or
`nil`. `nil` on failure.
* Reasons for failure:
* No path exists at all
* No path exists within `searchdistance` (see below)
* Start or end pos is buried in land
* `pos1`: start position * `pos1`: start position
* `pos2`: end position * `pos2`: end position
* `searchdistance`: number of blocks to search in each direction using a * `searchdistance`: maximum distance from the search positions to search in.
maximum metric. In detail: Path must be completely inside a cuboid. The minimum
`searchdistance` of 1 will confine search between `pos1` and `pos2`.
Larger values will increase the size of this cuboid in all directions
* `max_jump`: maximum height difference to consider walkable * `max_jump`: maximum height difference to consider walkable
* `max_drop`: maximum height difference to consider droppable * `max_drop`: maximum height difference to consider droppable
* `algorithm`: One of `"A*_noprefetch"` (default), `"A*"`, `"Dijkstra"` * `algorithm`: One of `"A*_noprefetch"` (default), `"A*"`, `"Dijkstra"`.
Difference between `"A*"` and `"A*_noprefetch"` is that
`"A*"` will pre-calculate the cost-data, the other will calculate it
on-the-fly
* `minetest.spawn_tree (pos, {treedef})` * `minetest.spawn_tree (pos, {treedef})`
* spawns L-system tree at given `pos` with definition in `treedef` table * spawns L-system tree at given `pos` with definition in `treedef` table
* `minetest.transforming_liquid_add(pos)` * `minetest.transforming_liquid_add(pos)`

579
src/pathfinder.cpp
View File

@ -58,6 +58,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#define ERROR_TARGET warningstream << "Pathfinder: " #define ERROR_TARGET warningstream << "Pathfinder: "
#endif #endif
#define PATHFINDER_MAX_WAYPOINTS 700
/******************************************************************************/ /******************************************************************************/
/* Class definitions */ /* Class definitions */
/******************************************************************************/ /******************************************************************************/
@ -78,7 +80,7 @@ public:
bool valid = false; /**< movement is possible */ bool valid = false; /**< movement is possible */
int value = 0; /**< cost of movement */ int value = 0; /**< cost of movement */
int direction = 0; /**< y-direction of movement */ int y_change = 0; /**< change of y position of movement */
bool updated = false; /**< this cost has ben calculated */ bool updated = false; /**< this cost has ben calculated */
}; };
@ -117,16 +119,26 @@ public:
bool target = false; /**< node is target position */ bool target = false; /**< node is target position */
bool source = false; /**< node is stating position */ bool source = false; /**< node is stating position */
int totalcost = -1; /**< cost to move here from starting point */ int totalcost = -1; /**< cost to move here from starting point */
int estimated_cost = -1; /**< totalcost + heuristic cost to end */
v3s16 sourcedir; /**< origin of movement for current cost */ v3s16 sourcedir; /**< origin of movement for current cost */
v3s16 pos; /**< real position of node */ v3s16 pos; /**< real position of node */
PathCost directions[4]; /**< cost in different directions */ PathCost directions[4]; /**< cost in different directions */
bool is_closed = false; /**< for A* search: if true, is in closed list */
bool is_open = false; /**< for A* search: if true, is in open list */
/* debug values */ /* debug values */
bool is_element = false; /**< node is element of path detected */ bool is_element = false; /**< node is element of path detected */
char type = 'u'; /**< type of node */ char type = 'u'; /**< Type of pathfinding node.
* u = unknown
* i = invalid
* s = surface (walkable node)
* - = non-walkable node (e.g. air) above surface
* g = other non-walkable node
*/
}; };
class Pathfinder; class Pathfinder;
class PathfinderCompareHeuristic;
/** Abstract class to manage the map data */ /** Abstract class to manage the map data */
class GridNodeContainer { class GridNodeContainer {
@ -224,8 +236,8 @@ private:
PathGridnode &getIdxElem(s16 x, s16 y, s16 z); PathGridnode &getIdxElem(s16 x, s16 y, s16 z);
/** /**
* invert a 3d position * invert a 3D position (change sign of coordinates)
* @param pos 3d position * @param pos 3D position
* @return pos *-1 * @return pos *-1
*/ */
v3s16 invert(v3s16 pos); v3s16 invert(v3s16 pos);
@ -237,37 +249,16 @@ private:
*/ */
bool isValidIndex(v3s16 index); bool isValidIndex(v3s16 index);
/**
* translate position to float position
* @param pos integer position
* @return float position
*/
v3f tov3f(v3s16 pos);
/* algorithm functions */ /* algorithm functions */
/** /**
* calculate 2d manahttan distance to target on the xz plane * calculate 2D Manhattan distance to target
* @param pos position to calc distance * @param pos position to calc distance
* @return integer distance * @return integer distance
*/ */
int getXZManhattanDist(v3s16 pos); int getXZManhattanDist(v3s16 pos);
/**
* get best direction based uppon heuristics
* @param directions list of unchecked directions
* @param g_pos mapnode to start from
* @return direction to check
*/
v3s16 getDirHeuristic(std::vector<v3s16> &directions, PathGridnode &g_pos);
/**
* build internal data representation of search area
* @return true/false if costmap creation was successfull
*/
bool buildCostmap();
/** /**
* calculate cost of movement * calculate cost of movement
* @param pos real world position to start movement * @param pos real world position to start movement
@ -287,22 +278,32 @@ private:
bool updateAllCosts(v3s16 ipos, v3s16 srcdir, int current_cost, int level); bool updateAllCosts(v3s16 ipos, v3s16 srcdir, int current_cost, int level);
/** /**
* recursive try to find a patrh to destionation * try to find a path to destination using a heuristic function
* @param ipos position to check next * to estimate distance to target (A* search algorithm)
* @param srcdir positionc checked last time * @param isource start position (index pos)
* @param total_cost cost of moving to ipos * @param idestination end position (index pos)
* @param level current recursion depth
* @return true/false path to destination has been found * @return true/false path to destination has been found
*/ */
bool updateCostHeuristic(v3s16 ipos, v3s16 srcdir, int current_cost, int level); bool updateCostHeuristic(v3s16 isource, v3s16 idestination);
/** /**
* recursive build a vector containing all nodes from source to destination * build a vector containing all nodes from destination to source;
* to be called after the node costs have been processed
* @param path vector to add nodes to * @param path vector to add nodes to
* @param pos pos to check next * @param ipos initial pos to check (index pos)
* @param level recursion depth * @return true/false path has been fully built
*/ */
void buildPath(std::vector<v3s16> &path, v3s16 pos, int level); bool buildPath(std::vector<v3s16> &path, v3s16 ipos);
/**
* go downwards from a position until some barrier
* is hit.
* @param pos position from which to go downwards
* @param max_down maximum distance to go downwards
* @return new position after movement; if too far down,
* pos is returned
*/
v3s16 walkDownwards(v3s16 pos, unsigned int max_down);
/* variables */ /* variables */
int m_max_index_x = 0; /**< max index of search area in x direction */ int m_max_index_x = 0; /**< max index of search area in x direction */
@ -329,6 +330,8 @@ private:
ServerEnvironment *m_env = 0; /**< minetest environment pointer */ ServerEnvironment *m_env = 0; /**< minetest environment pointer */
friend class PathfinderCompareHeuristic;
#ifdef PATHFINDER_DEBUG #ifdef PATHFINDER_DEBUG
/** /**
@ -378,6 +381,31 @@ private:
#endif #endif
}; };
/** Helper class for the open list priority queue in the A* pathfinder
* to sort the pathfinder nodes by cost.
*/
class PathfinderCompareHeuristic
{
private:
Pathfinder *myPathfinder;
public:
PathfinderCompareHeuristic(Pathfinder *pf)
{
myPathfinder = pf;
}
bool operator() (v3s16 pos1, v3s16 pos2) {
v3s16 ipos1 = myPathfinder->getIndexPos(pos1);
v3s16 ipos2 = myPathfinder->getIndexPos(pos2);
PathGridnode &g_pos1 = myPathfinder->getIndexElement(ipos1);
PathGridnode &g_pos2 = myPathfinder->getIndexElement(ipos2);
if (!g_pos1.valid)
return false;
if (!g_pos2.valid)
return false;
return g_pos1.estimated_cost > g_pos2.estimated_cost;
}
};
/******************************************************************************/ /******************************************************************************/
/* implementation */ /* implementation */
/******************************************************************************/ /******************************************************************************/
@ -401,7 +429,7 @@ std::vector<v3s16> get_path(ServerEnvironment* env,
PathCost::PathCost(const PathCost &b) PathCost::PathCost(const PathCost &b)
{ {
valid = b.valid; valid = b.valid;
direction = b.direction; y_change = b.y_change;
value = b.value; value = b.value;
updated = b.updated; updated = b.updated;
} }
@ -410,7 +438,7 @@ PathCost::PathCost(const PathCost &b)
PathCost &PathCost::operator= (const PathCost &b) PathCost &PathCost::operator= (const PathCost &b)
{ {
valid = b.valid; valid = b.valid;
direction = b.direction; y_change = b.y_change;
value = b.value; value = b.value;
updated = b.updated; updated = b.updated;
@ -598,10 +626,11 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
//check parameters //check parameters
if (env == 0) { if (env == 0) {
ERROR_TARGET << "missing environment pointer" << std::endl; ERROR_TARGET << "Missing environment pointer" << std::endl;
return retval; return retval;
} }
//initialization
m_searchdistance = searchdistance; m_searchdistance = searchdistance;
m_env = env; m_env = env;
m_maxjump = max_jump; m_maxjump = max_jump;
@ -615,6 +644,7 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
m_prefetch = false; m_prefetch = false;
} }
//calculate boundaries within we're allowed to search
int min_x = MYMIN(source.X, destination.X); int min_x = MYMIN(source.X, destination.X);
int max_x = MYMAX(source.X, destination.X); int max_x = MYMAX(source.X, destination.X);
@ -650,7 +680,37 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
printYdir(); printYdir();
#endif #endif
//fail if source or destination is walkable
const NodeDefManager *ndef = m_env->getGameDef()->ndef();
MapNode node_at_pos = m_env->getMap().getNode(destination);
if (ndef->get(node_at_pos).walkable) {
VERBOSE_TARGET << "Destination is walkable. " <<
"Pos: " << PP(destination) << std::endl;
return retval;
}
node_at_pos = m_env->getMap().getNode(source);
if (ndef->get(node_at_pos).walkable) {
VERBOSE_TARGET << "Source is walkable. " <<
"Pos: " << PP(source) << std::endl;
return retval;
}
//If source pos is hovering above air, drop
//to the first walkable node (up to m_maxdrop).
//All algorithms expect the source pos to be *directly* above
//a walkable node.
v3s16 true_source = v3s16(source);
source = walkDownwards(source, m_maxdrop);
//If destination pos is hovering above air, go downwards
//to the first walkable node (up to m_maxjump).
//This means a hovering destination pos could be reached
//by a final upwards jump.
v3s16 true_destination = v3s16(destination);
destination = walkDownwards(destination, m_maxjump);
//validate and mark start and end pos //validate and mark start and end pos
v3s16 StartIndex = getIndexPos(source); v3s16 StartIndex = getIndexPos(source);
v3s16 EndIndex = getIndexPos(destination); v3s16 EndIndex = getIndexPos(destination);
@ -658,13 +718,13 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
PathGridnode &endpos = getIndexElement(EndIndex); PathGridnode &endpos = getIndexElement(EndIndex);
if (!startpos.valid) { if (!startpos.valid) {
VERBOSE_TARGET << "invalid startpos" << VERBOSE_TARGET << "Invalid startpos " <<
"Index: " << PP(StartIndex) << "Index: " << PP(StartIndex) <<
"Realpos: " << PP(getRealPos(StartIndex)) << std::endl; "Realpos: " << PP(getRealPos(StartIndex)) << std::endl;
return retval; return retval;
} }
if (!endpos.valid) { if (!endpos.valid) {
VERBOSE_TARGET << "invalid stoppos" << VERBOSE_TARGET << "Invalid stoppos " <<
"Index: " << PP(EndIndex) << "Index: " << PP(EndIndex) <<
"Realpos: " << PP(getRealPos(EndIndex)) << std::endl; "Realpos: " << PP(getRealPos(EndIndex)) << std::endl;
return retval; return retval;
@ -676,16 +736,17 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
bool update_cost_retval = false; bool update_cost_retval = false;
//calculate node costs
switch (algo) { switch (algo) {
case PA_DIJKSTRA: case PA_DIJKSTRA:
update_cost_retval = updateAllCosts(StartIndex, v3s16(0, 0, 0), 0, 0); update_cost_retval = updateAllCosts(StartIndex, v3s16(0, 0, 0), 0, 0);
break; break;
case PA_PLAIN_NP: case PA_PLAIN_NP:
case PA_PLAIN: case PA_PLAIN:
update_cost_retval = updateCostHeuristic(StartIndex, v3s16(0, 0, 0), 0, 0); update_cost_retval = updateCostHeuristic(StartIndex, EndIndex);
break; break;
default: default:
ERROR_TARGET << "missing PathAlgorithm"<< std::endl; ERROR_TARGET << "Missing PathAlgorithm" << std::endl;
break; break;
} }
@ -697,23 +758,50 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
#endif #endif
//find path //find path
std::vector<v3s16> path; std::vector<v3s16> index_path;
buildPath(path, EndIndex, 0); buildPath(index_path, EndIndex);
//Now we have a path of index positions,
//and it's in reverse.
//The "true" start or end position might be missing
//since those have been given special treatment.
#ifdef PATHFINDER_DEBUG #ifdef PATHFINDER_DEBUG
std::cout << "Full index path:" << std::endl; std::cout << "Index path:" << std::endl;
printPath(path); printPath(index_path);
#endif #endif
//from here we'll make the final changes to the path
//finalize path
std::vector<v3s16> full_path; std::vector<v3s16> full_path;
full_path.reserve(path.size());
for (const v3s16 &i : path) { //calculate required size
full_path.push_back(getIndexElement(i).pos); int full_path_size = index_path.size();
if (source != true_source) {
full_path_size++;
}
if (destination != true_destination) {
full_path_size++;
}
full_path.reserve(full_path_size);
//manually add true_source to start of path, if needed
if (source != true_source) {
full_path.push_back(true_source);
}
//convert all index positions to "normal" positions and insert
//them into full_path in reverse
std::vector<v3s16>::reverse_iterator rit = index_path.rbegin();
for (; rit != index_path.rend(); ++rit) {
full_path.push_back(getIndexElement(*rit).pos);
}
//manually add true_destination to end of path, if needed
if (destination != true_destination) {
full_path.push_back(true_destination);
} }
//Done! We now have a complete path of normal positions.
#ifdef PATHFINDER_DEBUG #ifdef PATHFINDER_DEBUG
std::cout << "full path:" << std::endl; std::cout << "Full path:" << std::endl;
printPath(full_path); printPath(full_path);
#endif #endif
#ifdef PATHFINDER_CALC_TIME #ifdef PATHFINDER_CALC_TIME
@ -734,7 +822,7 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
#ifdef PATHFINDER_DEBUG #ifdef PATHFINDER_DEBUG
printPathLen(); printPathLen();
#endif #endif
ERROR_TARGET << "failed to update cost map"<< std::endl; INFO_TARGET << "No path found" << std::endl;
} }
@ -789,15 +877,18 @@ PathCost Pathfinder::calcCost(v3s16 pos, v3s16 dir)
return retval; return retval;
} }
//test if the same-height neighbor is suitable
if (ndef->get(node_below_pos2).walkable) { if (ndef->get(node_below_pos2).walkable) {
//SUCCESS!
retval.valid = true; retval.valid = true;
retval.value = 1; retval.value = 1;
retval.direction = 0; retval.y_change = 0;
DEBUG_OUT("Pathfinder: "<< PP(pos) DEBUG_OUT("Pathfinder: "<< PP(pos)
<< " cost same height found" << std::endl); << " cost same height found" << std::endl);
} }
else { else {
v3s16 testpos = pos2 - v3s16(0, -1, 0); //test if we can fall a couple of nodes (m_maxdrop)
v3s16 testpos = pos2 + v3s16(0, -1, 0);
MapNode node_at_pos = m_env->getMap().getNode(testpos); MapNode node_at_pos = m_env->getMap().getNode(testpos);
while ((node_at_pos.param0 != CONTENT_IGNORE) && while ((node_at_pos.param0 != CONTENT_IGNORE) &&
@ -812,15 +903,16 @@ PathCost Pathfinder::calcCost(v3s16 pos, v3s16 dir)
(node_at_pos.param0 != CONTENT_IGNORE) && (node_at_pos.param0 != CONTENT_IGNORE) &&
(ndef->get(node_at_pos).walkable)) { (ndef->get(node_at_pos).walkable)) {
if ((pos2.Y - testpos.Y - 1) <= m_maxdrop) { if ((pos2.Y - testpos.Y - 1) <= m_maxdrop) {
//SUCCESS!
retval.valid = true; retval.valid = true;
retval.value = 2; retval.value = 2;
//difference of y-pos +1 (target node is ABOVE solid node) //difference of y-pos +1 (target node is ABOVE solid node)
retval.direction = ((testpos.Y - pos2.Y) +1); retval.y_change = ((testpos.Y - pos2.Y) +1);
DEBUG_OUT("Pathfinder cost below height found" << std::endl); DEBUG_OUT("Pathfinder cost below height found" << std::endl);
} }
else { else {
INFO_TARGET << "Pathfinder:" INFO_TARGET << "Pathfinder:"
" distance to surface below to big: " " distance to surface below too big: "
<< (testpos.Y - pos2.Y) << " max: " << m_maxdrop << (testpos.Y - pos2.Y) << " max: " << m_maxdrop
<< std::endl; << std::endl;
} }
@ -831,29 +923,49 @@ PathCost Pathfinder::calcCost(v3s16 pos, v3s16 dir)
} }
} }
else { else {
v3s16 testpos = pos2; //test if we can jump upwards (m_maxjump)
MapNode node_at_pos = m_env->getMap().getNode(testpos);
while ((node_at_pos.param0 != CONTENT_IGNORE) && v3s16 targetpos = pos2; // position for jump target
(ndef->get(node_at_pos).walkable) && v3s16 jumppos = pos; // position for checking if jumping space is free
(testpos.Y < m_limits.MaxEdge.Y)) { MapNode node_target = m_env->getMap().getNode(targetpos);
testpos += v3s16(0, 1, 0); MapNode node_jump = m_env->getMap().getNode(jumppos);
node_at_pos = m_env->getMap().getNode(testpos); bool headbanger = false; // true if anything blocks jumppath
while ((node_target.param0 != CONTENT_IGNORE) &&
(ndef->get(node_target).walkable) &&
(targetpos.Y < m_limits.MaxEdge.Y)) {
//if the jump would hit any solid node, discard
if ((node_jump.param0 == CONTENT_IGNORE) ||
(ndef->get(node_jump).walkable)) {
headbanger = true;
break;
}
targetpos += v3s16(0, 1, 0);
jumppos += v3s16(0, 1, 0);
node_target = m_env->getMap().getNode(targetpos);
node_jump = m_env->getMap().getNode(jumppos);
}
//check headbanger one last time
if ((node_jump.param0 == CONTENT_IGNORE) ||
(ndef->get(node_jump).walkable)) {
headbanger = true;
} }
//did we find surface? //did we find surface without banging our head?
if ((testpos.Y <= m_limits.MaxEdge.Y) && if ((!headbanger) && (targetpos.Y <= m_limits.MaxEdge.Y) &&
(!ndef->get(node_at_pos).walkable)) { (!ndef->get(node_target).walkable)) {
if (testpos.Y - pos2.Y <= m_maxjump) { if (targetpos.Y - pos2.Y <= m_maxjump) {
//SUCCESS!
retval.valid = true; retval.valid = true;
retval.value = 2; retval.value = 2;
retval.direction = (testpos.Y - pos2.Y); retval.y_change = (targetpos.Y - pos2.Y);
DEBUG_OUT("Pathfinder cost above found" << std::endl); DEBUG_OUT("Pathfinder cost above found" << std::endl);
} }
else { else {
DEBUG_OUT("Pathfinder: distance to surface above to big: " DEBUG_OUT("Pathfinder: distance to surface above too big: "
<< (testpos.Y - pos2.Y) << " max: " << m_maxjump << (targetpos.Y - pos2.Y) << " max: " << m_maxjump
<< std::endl); << std::endl);
} }
} }
@ -929,19 +1041,20 @@ bool Pathfinder::updateAllCosts(v3s16 ipos,
bool retval = false; bool retval = false;
std::vector<v3s16> directions; // the 4 cardinal directions
const static v3s16 directions[4] = {
v3s16(1,0, 0),
v3s16(-1,0, 0),
v3s16(0,0, 1),
v3s16(0,0,-1)
};
directions.emplace_back(1,0, 0); for (v3s16 direction : directions) {
directions.emplace_back(-1,0, 0);
directions.emplace_back(0,0, 1);
directions.emplace_back(0,0,-1);
for (v3s16 &direction : directions) {
if (direction != srcdir) { if (direction != srcdir) {
PathCost cost = g_pos.getCost(direction); PathCost cost = g_pos.getCost(direction);
if (cost.valid) { if (cost.valid) {
direction.Y = cost.direction; direction.Y = cost.y_change;
v3s16 ipos2 = ipos + direction; v3s16 ipos2 = ipos + direction;
@ -1006,194 +1119,172 @@ int Pathfinder::getXZManhattanDist(v3s16 pos)
return (max_x - min_x) + (max_z - min_z); return (max_x - min_x) + (max_z - min_z);
} }
/******************************************************************************/ /******************************************************************************/
v3s16 Pathfinder::getDirHeuristic(std::vector<v3s16> &directions, PathGridnode &g_pos) bool Pathfinder::updateCostHeuristic(v3s16 isource, v3s16 idestination)
{ {
int minscore = -1; // A* search algorithm.
v3s16 retdir = v3s16(0, 0, 0);
v3s16 srcpos = g_pos.pos;
DEBUG_OUT("Pathfinder: remaining dirs at beginning:"
<< directions.size() << std::endl);
for (v3s16 &direction : directions) { // The open list contains the pathfinder nodes that still need to be
// checked. The priority queue sorts the pathfinder nodes by
// estimated cost, with lowest cost on the top.
std::priority_queue<v3s16, std::vector<v3s16>, PathfinderCompareHeuristic>
openList(PathfinderCompareHeuristic(this));
v3s16 pos1 = v3s16(srcpos.X + direction.X, 0, srcpos.Z+ direction.Z); v3s16 source = getRealPos(isource);
v3s16 destination = getRealPos(idestination);
int cur_manhattan = getXZManhattanDist(pos1); // initial position
PathCost cost = g_pos.getCost(direction); openList.push(source);
if (!cost.updated) { // the 4 cardinal directions
cost = calcCost(g_pos.pos, direction); const static v3s16 directions[4] = {
g_pos.setCost(direction, cost); v3s16(1,0, 0),
v3s16(-1,0, 0),
v3s16(0,0, 1),
v3s16(0,0,-1)
};
v3s16 current_pos;
PathGridnode& s_pos = getIndexElement(isource);
s_pos.source = true;
s_pos.totalcost = 0;
// estimated cost from start to finish
int cur_manhattan = getXZManhattanDist(destination);
s_pos.estimated_cost = cur_manhattan;
while (!openList.empty()) {
// Pick node with lowest total cost estimate.
// The "cheapest" node is always on top.
current_pos = openList.top();
openList.pop();
v3s16 ipos = getIndexPos(current_pos);
// check if node is inside searchdistance and valid
if (!isValidIndex(ipos)) {
DEBUG_OUT(LVL " Pathfinder: " << PP(current_pos) <<
" out of search distance, max=" << PP(m_limits.MaxEdge) << std::endl);
continue;
} }
if (cost.valid) { PathGridnode& g_pos = getIndexElement(ipos);
int score = cost.value + cur_manhattan; g_pos.is_closed = true;
g_pos.is_open = false;
if (!g_pos.valid) {
continue;
}
if ((minscore < 0)|| (score < minscore)) { if (current_pos == destination) {
minscore = score; // destination found, terminate
retdir = direction; g_pos.target = true;
return true;
}
// for this node, check the 4 cardinal directions
for (v3s16 direction_flat : directions) {
int current_totalcost = g_pos.totalcost;
// get cost from current node to currently checked direction
PathCost cost = g_pos.getCost(direction_flat);
if (!cost.updated) {
cost = calcCost(current_pos, direction_flat);
g_pos.setCost(direction_flat, cost);
}
// update Y component of direction if neighbor requires jump or fall
v3s16 direction_3d = v3s16(direction_flat);
direction_3d.Y = cost.y_change;
// get position of true neighbor
v3s16 neighbor = current_pos + direction_3d;
v3s16 ineighbor = getIndexPos(neighbor);
PathGridnode &n_pos = getIndexElement(ineighbor);
if (cost.valid && !n_pos.is_closed && !n_pos.is_open) {
// heuristic function; estimate cost from neighbor to destination
cur_manhattan = getXZManhattanDist(neighbor);
// add neighbor to open list
n_pos.sourcedir = invert(direction_3d);
n_pos.totalcost = current_totalcost + cost.value;
n_pos.estimated_cost = current_totalcost + cost.value + cur_manhattan;
n_pos.is_open = true;
openList.push(neighbor);
} }
} }
} }
// no path found; all possible nodes within searchdistance have been exhausted
if (retdir != v3s16(0, 0, 0)) { return false;
for (std::vector<v3s16>::iterator iter = directions.begin();
iter != directions.end();
++iter) {
if(*iter == retdir) {
DEBUG_OUT("Pathfinder: removing return direction" << std::endl);
directions.erase(iter);
break;
}
}
}
else {
DEBUG_OUT("Pathfinder: didn't find any valid direction clearing"
<< std::endl);
directions.clear();
}
DEBUG_OUT("Pathfinder: remaining dirs at end:" << directions.size()
<< std::endl);
return retdir;
} }
/******************************************************************************/ /******************************************************************************/
bool Pathfinder::updateCostHeuristic( v3s16 ipos, bool Pathfinder::buildPath(std::vector<v3s16> &path, v3s16 ipos)
v3s16 srcdir,
int current_cost,
int level)
{ {
// The cost calculation should have set a source direction for all relevant nodes.
// To build the path, we go backwards from the destination until we reach the start.
for(u32 waypoints = 1; waypoints++; ) {
if (waypoints > PATHFINDER_MAX_WAYPOINTS) {
ERROR_TARGET << "Pathfinder: buildPath: path is too long (too many waypoints), aborting" << std::endl;
return false;
}
// Insert node into path
PathGridnode &g_pos = getIndexElement(ipos);
if (!g_pos.valid) {
ERROR_TARGET << "Pathfinder: buildPath: invalid next pos detected, aborting" << std::endl;
return false;
}
PathGridnode &g_pos = getIndexElement(ipos); g_pos.is_element = true;
g_pos.totalcost = current_cost; path.push_back(ipos);
g_pos.sourcedir = srcdir; if (g_pos.source)
// start node found, terminate
return true;
level ++; // go to the node from which the pathfinder came
ipos += g_pos.sourcedir;
//check if target has been found
if (g_pos.target) {
m_min_target_distance = current_cost;
DEBUG_OUT(LVL " Pathfinder: target found!" << std::endl);
return true;
} }
bool retval = false; ERROR_TARGET << "Pathfinder: buildPath: no source node found" << std::endl;
return false;
}
std::vector<v3s16> directions; /******************************************************************************/
v3s16 Pathfinder::walkDownwards(v3s16 pos, unsigned int max_down) {
directions.emplace_back(1, 0, 0); if (max_down == 0)
directions.emplace_back(-1, 0, 0); return pos;
directions.emplace_back(0, 0, 1); v3s16 testpos = v3s16(pos);
directions.emplace_back(0, 0, -1); MapNode node_at_pos = m_env->getMap().getNode(testpos);
const NodeDefManager *ndef = m_env->getGameDef()->ndef();
v3s16 direction = getDirHeuristic(directions, g_pos); unsigned int down = 0;
while ((node_at_pos.param0 != CONTENT_IGNORE) &&
while (direction != v3s16(0, 0, 0) && (!retval)) { (!ndef->get(node_at_pos).walkable) &&
(testpos.Y > m_limits.MinEdge.Y) &&
if (direction != srcdir) { (down <= max_down)) {
PathCost cost = g_pos.getCost(direction); testpos += v3s16(0, -1, 0);
down++;
if (cost.valid) { node_at_pos = m_env->getMap().getNode(testpos);
direction.Y = cost.direction; }
//did we find surface?
v3s16 ipos2 = ipos + direction; if ((testpos.Y >= m_limits.MinEdge.Y) &&
(node_at_pos.param0 != CONTENT_IGNORE) &&
if (!isValidIndex(ipos2)) { (ndef->get(node_at_pos).walkable)) {
DEBUG_OUT(LVL " Pathfinder: " << PP(ipos2) << if (down == 0) {
" out of range, max=" << PP(m_limits.MaxEdge) << std::endl); pos = testpos;
direction = getDirHeuristic(directions, g_pos); } else if ((down - 1) <= max_down) {
continue; //difference of y-pos +1 (target node is ABOVE solid node)
} testpos += v3s16(0, 1, 0);
pos = testpos;
PathGridnode &g_pos2 = getIndexElement(ipos2);
if (!g_pos2.valid) {
VERBOSE_TARGET << LVL "Pathfinder: no data for new position: "
<< PP(ipos2) << std::endl;
direction = getDirHeuristic(directions, g_pos);
continue;
}
assert(cost.value > 0);
int new_cost = current_cost + cost.value;
// check if there already is a smaller path
if ((m_min_target_distance > 0) &&
(m_min_target_distance < new_cost)) {
DEBUG_OUT(LVL "Pathfinder:"
" already longer than best already found path "
<< PP(ipos2) << std::endl);
return false;
}
if ((g_pos2.totalcost < 0) ||
(g_pos2.totalcost > new_cost)) {
DEBUG_OUT(LVL "Pathfinder: updating path at: "<<
PP(ipos2) << " from: " << g_pos2.totalcost << " to "<<
new_cost << " srcdir=" <<
PP(invert(direction))<< std::endl);
if (updateCostHeuristic(ipos2, invert(direction),
new_cost, level)) {
retval = true;
}
}
else {
DEBUG_OUT(LVL "Pathfinder:"
" already found shorter path to: "
<< PP(ipos2) << std::endl);
}
}
else {
DEBUG_OUT(LVL "Pathfinder:"
" not moving to invalid direction: "
<< PP(direction) << std::endl);
}
} }
else { else {
DEBUG_OUT(LVL "Pathfinder:" VERBOSE_TARGET << "Pos too far above ground: " <<
" skipping srcdir: " "Index: " << PP(getIndexPos(pos)) <<
<< PP(direction) << std::endl); "Realpos: " << PP(getRealPos(getIndexPos(pos))) << std::endl;
} }
direction = getDirHeuristic(directions, g_pos); } else {
DEBUG_OUT("Pathfinder: no surface found below pos" << std::endl);
} }
return retval; return pos;
}
/******************************************************************************/
void Pathfinder::buildPath(std::vector<v3s16> &path, v3s16 pos, int level)
{
level ++;
if (level > 700) {
ERROR_TARGET
<< LVL "Pathfinder: path is too long aborting" << std::endl;
return;
}
PathGridnode &g_pos = getIndexElement(pos);
if (!g_pos.valid) {
ERROR_TARGET
<< LVL "Pathfinder: invalid next pos detected aborting" << std::endl;
return;
}
g_pos.is_element = true;
//check if source reached
if (g_pos.source) {
path.push_back(pos);
return;
}
buildPath(path, pos + g_pos.sourcedir, level);
path.push_back(pos);
}
/******************************************************************************/
v3f Pathfinder::tov3f(v3s16 pos)
{
return v3f(BS * pos.X, BS * pos.Y, BS * pos.Z);
} }
#ifdef PATHFINDER_DEBUG #ifdef PATHFINDER_DEBUG
@ -1268,7 +1359,7 @@ void Pathfinder::printYdir(PathDirections dir)
for (int x = 0; x < m_max_index_x; x++) { for (int x = 0; x < m_max_index_x; x++) {
if (getIdxElem(x, y, z).directions[dir].valid) if (getIdxElem(x, y, z).directions[dir].valid)
std::cout << std::setw(4) std::cout << std::setw(4)
<< getIdxElem(x, y, z).directions[dir].direction; << getIdxElem(x, y, z).directions[dir].y_change;
else else
std::cout << std::setw(4) << "-"; std::cout << std::setw(4) << "-";
} }

2
src/script/lua_api/l_env.cpp
View File

@ -1194,7 +1194,7 @@ int ModApiEnvMod::l_find_path(lua_State *L)
unsigned int max_jump = luaL_checkint(L, 4); unsigned int max_jump = luaL_checkint(L, 4);
unsigned int max_drop = luaL_checkint(L, 5); unsigned int max_drop = luaL_checkint(L, 5);
PathAlgorithm algo = PA_PLAIN_NP; PathAlgorithm algo = PA_PLAIN_NP;
if (!lua_isnil(L, 6)) { if (!lua_isnoneornil(L, 6)) {
std::string algorithm = luaL_checkstring(L,6); std::string algorithm = luaL_checkstring(L,6);
if (algorithm == "A*") if (algorithm == "A*")