From: Wuzzy <Wuzzy2@mail.ru>
Date: Thu, 5 Mar 2020 11:07:52 +0000 (+0100)
Subject: Fix pathfinder bugs: returning nil frequently, broken A*, jump through solid nodes...
X-Git-Tag: 5.2.0~93
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=580e7e8eb902ae2faed36b4982e7e751e35f5201;p=oweals%2Fminetest.git
Fix pathfinder bugs: returning nil frequently, broken A*, jump through solid nodes (#9339)
* 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
---
diff --git a/builtin/game/features.lua b/builtin/game/features.lua
index 0af0dc1da..623f8183b 100644
--- a/builtin/game/features.lua
+++ b/builtin/game/features.lua
@@ -15,6 +15,7 @@ core.features = {
httpfetch_binary_data = true,
formspec_version_element = true,
area_store_persistent_ids = true,
+ pathfinder_works = true,
}
function core.has_feature(arg)
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 4b7132828..af0d35f61 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -4045,6 +4045,8 @@ Utilities
formspec_version_element = true,
-- Whether AreaStore's IDs are kept on save/load (5.1.0)
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`
@@ -4709,16 +4711,25 @@ Environment access
* `objects`: if false, only nodes will be returned. Default is `true`.
* `liquids`: if false, liquid nodes won't be returned. Default is `false`.
* `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
- `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
* `pos2`: end position
- * `searchdistance`: number of blocks to search in each direction using a
- maximum metric.
+ * `searchdistance`: maximum distance from the search positions to search in.
+ 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_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})`
* spawns L-system tree at given `pos` with definition in `treedef` table
* `minetest.transforming_liquid_add(pos)`
diff --git a/src/pathfinder.cpp b/src/pathfinder.cpp
index 48e951477..8195bd643 100644
--- a/src/pathfinder.cpp
+++ b/src/pathfinder.cpp
@@ -58,6 +58,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#define ERROR_TARGET warningstream << "Pathfinder: "
#endif
+#define PATHFINDER_MAX_WAYPOINTS 700
+
/******************************************************************************/
/* Class definitions */
/******************************************************************************/
@@ -78,7 +80,7 @@ public:
bool valid = false; /**< movement is possible */
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 */
};
@@ -117,16 +119,26 @@ public:
bool target = false; /**< node is target position */
bool source = false; /**< node is stating position */
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 pos; /**< real position of node */
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 */
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 PathfinderCompareHeuristic;
/** Abstract class to manage the map data */
class GridNodeContainer {
@@ -224,8 +236,8 @@ private:
PathGridnode &getIdxElem(s16 x, s16 y, s16 z);
/**
- * invert a 3d position
- * @param pos 3d position
+ * invert a 3D position (change sign of coordinates)
+ * @param pos 3D position
* @return pos *-1
*/
v3s16 invert(v3s16 pos);
@@ -237,37 +249,16 @@ private:
*/
bool isValidIndex(v3s16 index);
- /**
- * translate position to float position
- * @param pos integer position
- * @return float position
- */
- v3f tov3f(v3s16 pos);
-
/* algorithm functions */
/**
- * calculate 2d manahttan distance to target on the xz plane
+ * calculate 2D Manhattan distance to target
* @param pos position to calc distance
* @return integer distance
*/
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
* @param pos real world position to start movement
@@ -287,22 +278,32 @@ private:
bool updateAllCosts(v3s16 ipos, v3s16 srcdir, int current_cost, int level);
/**
- * recursive try to find a patrh to destionation
- * @param ipos position to check next
- * @param srcdir positionc checked last time
- * @param total_cost cost of moving to ipos
- * @param level current recursion depth
+ * try to find a path to destination using a heuristic function
+ * to estimate distance to target (A* search algorithm)
+ * @param isource start position (index pos)
+ * @param idestination end position (index pos)
* @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 pos pos to check next
- * @param level recursion depth
+ * @param ipos initial pos to check (index pos)
+ * @return true/false path has been fully built
+ */
+ 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
*/
- void buildPath(std::vector<v3s16> &path, v3s16 pos, int level);
+ v3s16 walkDownwards(v3s16 pos, unsigned int max_down);
/* variables */
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 */
+ friend class PathfinderCompareHeuristic;
+
#ifdef PATHFINDER_DEBUG
/**
@@ -378,6 +381,31 @@ private:
#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 */
/******************************************************************************/
@@ -401,7 +429,7 @@ std::vector<v3s16> get_path(ServerEnvironment* env,
PathCost::PathCost(const PathCost &b)
{
valid = b.valid;
- direction = b.direction;
+ y_change = b.y_change;
value = b.value;
updated = b.updated;
}
@@ -410,7 +438,7 @@ PathCost::PathCost(const PathCost &b)
PathCost &PathCost::operator= (const PathCost &b)
{
valid = b.valid;
- direction = b.direction;
+ y_change = b.y_change;
value = b.value;
updated = b.updated;
@@ -598,10 +626,11 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
//check parameters
if (env == 0) {
- ERROR_TARGET << "missing environment pointer" << std::endl;
+ ERROR_TARGET << "Missing environment pointer" << std::endl;
return retval;
}
+ //initialization
m_searchdistance = searchdistance;
m_env = env;
m_maxjump = max_jump;
@@ -615,6 +644,7 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
m_prefetch = false;
}
+ //calculate boundaries within we're allowed to search
int min_x = MYMIN(source.X, destination.X);
int max_x = MYMAX(source.X, destination.X);
@@ -650,7 +680,37 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
printYdir();
#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
+
v3s16 StartIndex = getIndexPos(source);
v3s16 EndIndex = getIndexPos(destination);
@@ -658,13 +718,13 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
PathGridnode &endpos = getIndexElement(EndIndex);
if (!startpos.valid) {
- VERBOSE_TARGET << "invalid startpos" <<
+ VERBOSE_TARGET << "Invalid startpos " <<
"Index: " << PP(StartIndex) <<
"Realpos: " << PP(getRealPos(StartIndex)) << std::endl;
return retval;
}
if (!endpos.valid) {
- VERBOSE_TARGET << "invalid stoppos" <<
+ VERBOSE_TARGET << "Invalid stoppos " <<
"Index: " << PP(EndIndex) <<
"Realpos: " << PP(getRealPos(EndIndex)) << std::endl;
return retval;
@@ -676,16 +736,17 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
bool update_cost_retval = false;
+ //calculate node costs
switch (algo) {
case PA_DIJKSTRA:
update_cost_retval = updateAllCosts(StartIndex, v3s16(0, 0, 0), 0, 0);
break;
case PA_PLAIN_NP:
case PA_PLAIN:
- update_cost_retval = updateCostHeuristic(StartIndex, v3s16(0, 0, 0), 0, 0);
+ update_cost_retval = updateCostHeuristic(StartIndex, EndIndex);
break;
default:
- ERROR_TARGET << "missing PathAlgorithm"<< std::endl;
+ ERROR_TARGET << "Missing PathAlgorithm" << std::endl;
break;
}
@@ -697,23 +758,50 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
#endif
//find path
- std::vector<v3s16> path;
- buildPath(path, EndIndex, 0);
+ std::vector<v3s16> index_path;
+ 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
- std::cout << "Full index path:" << std::endl;
- printPath(path);
+ std::cout << "Index path:" << std::endl;
+ printPath(index_path);
#endif
-
- //finalize path
+ //from here we'll make the final changes to the path
std::vector<v3s16> full_path;
- full_path.reserve(path.size());
- for (const v3s16 &i : path) {
- full_path.push_back(getIndexElement(i).pos);
+
+ //calculate required size
+ 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
- std::cout << "full path:" << std::endl;
+ std::cout << "Full path:" << std::endl;
printPath(full_path);
#endif
#ifdef PATHFINDER_CALC_TIME
@@ -734,7 +822,7 @@ std::vector<v3s16> Pathfinder::getPath(ServerEnvironment *env,
#ifdef PATHFINDER_DEBUG
printPathLen();
#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;
}
+ //test if the same-height neighbor is suitable
if (ndef->get(node_below_pos2).walkable) {
+ //SUCCESS!
retval.valid = true;
retval.value = 1;
- retval.direction = 0;
+ retval.y_change = 0;
DEBUG_OUT("Pathfinder: "<< PP(pos)
<< " cost same height found" << std::endl);
}
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);
while ((node_at_pos.param0 != CONTENT_IGNORE) &&
@@ -812,15 +903,16 @@ PathCost Pathfinder::calcCost(v3s16 pos, v3s16 dir)
(node_at_pos.param0 != CONTENT_IGNORE) &&
(ndef->get(node_at_pos).walkable)) {
if ((pos2.Y - testpos.Y - 1) <= m_maxdrop) {
+ //SUCCESS!
retval.valid = true;
retval.value = 2;
//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);
}
else {
INFO_TARGET << "Pathfinder:"
- " distance to surface below to big: "
+ " distance to surface below too big: "
<< (testpos.Y - pos2.Y) << " max: " << m_maxdrop
<< std::endl;
}
@@ -831,29 +923,49 @@ PathCost Pathfinder::calcCost(v3s16 pos, v3s16 dir)
}
}
else {
- v3s16 testpos = pos2;
- MapNode node_at_pos = m_env->getMap().getNode(testpos);
+ //test if we can jump upwards (m_maxjump)
+
+ v3s16 targetpos = pos2; // position for jump target
+ v3s16 jumppos = pos; // position for checking if jumping space is free
+ MapNode node_target = m_env->getMap().getNode(targetpos);
+ MapNode node_jump = m_env->getMap().getNode(jumppos);
+ 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);
- while ((node_at_pos.param0 != CONTENT_IGNORE) &&
- (ndef->get(node_at_pos).walkable) &&
- (testpos.Y < m_limits.MaxEdge.Y)) {
- testpos += v3s16(0, 1, 0);
- node_at_pos = m_env->getMap().getNode(testpos);
+ }
+ //check headbanger one last time
+ if ((node_jump.param0 == CONTENT_IGNORE) ||
+ (ndef->get(node_jump).walkable)) {
+ headbanger = true;
}
- //did we find surface?
- if ((testpos.Y <= m_limits.MaxEdge.Y) &&
- (!ndef->get(node_at_pos).walkable)) {
+ //did we find surface without banging our head?
+ if ((!headbanger) && (targetpos.Y <= m_limits.MaxEdge.Y) &&
+ (!ndef->get(node_target).walkable)) {
- if (testpos.Y - pos2.Y <= m_maxjump) {
+ if (targetpos.Y - pos2.Y <= m_maxjump) {
+ //SUCCESS!
retval.valid = true;
retval.value = 2;
- retval.direction = (testpos.Y - pos2.Y);
+ retval.y_change = (targetpos.Y - pos2.Y);
DEBUG_OUT("Pathfinder cost above found" << std::endl);
}
else {
- DEBUG_OUT("Pathfinder: distance to surface above to big: "
- << (testpos.Y - pos2.Y) << " max: " << m_maxjump
+ DEBUG_OUT("Pathfinder: distance to surface above too big: "
+ << (targetpos.Y - pos2.Y) << " max: " << m_maxjump
<< std::endl);
}
}
@@ -929,19 +1041,20 @@ bool Pathfinder::updateAllCosts(v3s16 ipos,
bool retval = false;
- std::vector<v3s16> directions;
-
- directions.emplace_back(1,0, 0);
- directions.emplace_back(-1,0, 0);
- directions.emplace_back(0,0, 1);
- directions.emplace_back(0,0,-1);
+ // 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)
+ };
- for (v3s16 &direction : directions) {
+ for (v3s16 direction : directions) {
if (direction != srcdir) {
PathCost cost = g_pos.getCost(direction);
if (cost.valid) {
- direction.Y = cost.direction;
+ direction.Y = cost.y_change;
v3s16 ipos2 = ipos + direction;
@@ -1006,194 +1119,172 @@ int Pathfinder::getXZManhattanDist(v3s16 pos)
return (max_x - min_x) + (max_z - min_z);
}
-/******************************************************************************/
-v3s16 Pathfinder::getDirHeuristic(std::vector<v3s16> &directions, PathGridnode &g_pos)
-{
- int minscore = -1;
- 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) {
- v3s16 pos1 = v3s16(srcpos.X + direction.X, 0, srcpos.Z+ direction.Z);
- int cur_manhattan = getXZManhattanDist(pos1);
- PathCost cost = g_pos.getCost(direction);
-
- if (!cost.updated) {
- cost = calcCost(g_pos.pos, direction);
- g_pos.setCost(direction, cost);
+/******************************************************************************/
+bool Pathfinder::updateCostHeuristic(v3s16 isource, v3s16 idestination)
+{
+ // A* search algorithm.
+
+ // 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 source = getRealPos(isource);
+ v3s16 destination = getRealPos(idestination);
+
+ // initial position
+ openList.push(source);
+
+ // 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)
+ };
+
+ 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) {
- int score = cost.value + cur_manhattan;
-
- if ((minscore < 0)|| (score < minscore)) {
- minscore = score;
- retdir = direction;
- }
+ PathGridnode& g_pos = getIndexElement(ipos);
+ g_pos.is_closed = true;
+ g_pos.is_open = false;
+ if (!g_pos.valid) {
+ continue;
}
- }
- if (retdir != v3s16(0, 0, 0)) {
- 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;
- }
+ if (current_pos == destination) {
+ // destination found, terminate
+ g_pos.target = true;
+ return true;
}
- }
- 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,
- v3s16 srcdir,
- int current_cost,
- int level)
-{
-
- PathGridnode &g_pos = getIndexElement(ipos);
- g_pos.totalcost = current_cost;
- g_pos.sourcedir = srcdir;
-
- level ++;
-
- //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;
-
- std::vector<v3s16> directions;
-
- directions.emplace_back(1, 0, 0);
- directions.emplace_back(-1, 0, 0);
- directions.emplace_back(0, 0, 1);
- directions.emplace_back(0, 0, -1);
-
- v3s16 direction = getDirHeuristic(directions, g_pos);
-
- while (direction != v3s16(0, 0, 0) && (!retval)) {
-
- if (direction != srcdir) {
- PathCost cost = g_pos.getCost(direction);
-
- if (cost.valid) {
- direction.Y = cost.direction;
-
- v3s16 ipos2 = ipos + direction;
-
- if (!isValidIndex(ipos2)) {
- DEBUG_OUT(LVL " Pathfinder: " << PP(ipos2) <<
- " out of range, max=" << PP(m_limits.MaxEdge) << std::endl);
- direction = getDirHeuristic(directions, g_pos);
- continue;
- }
-
- PathGridnode &g_pos2 = getIndexElement(ipos2);
+ // for this node, check the 4 cardinal directions
+ for (v3s16 direction_flat : directions) {
+ int current_totalcost = g_pos.totalcost;
- 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);
- }
+ // 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);
}
- else {
- DEBUG_OUT(LVL "Pathfinder:"
- " not moving to invalid direction: "
- << PP(direction) << std::endl);
+ // 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);
}
}
- else {
- DEBUG_OUT(LVL "Pathfinder:"
- " skipping srcdir: "
- << PP(direction) << std::endl);
- }
- direction = getDirHeuristic(directions, g_pos);
}
- return retval;
+ // no path found; all possible nodes within searchdistance have been exhausted
+ return false;
}
/******************************************************************************/
-void Pathfinder::buildPath(std::vector<v3s16> &path, v3s16 pos, int level)
+bool Pathfinder::buildPath(std::vector<v3s16> &path, v3s16 ipos)
{
- 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;
- }
+ // 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;
+ }
- g_pos.is_element = true;
+ g_pos.is_element = true;
+ path.push_back(ipos);
+ if (g_pos.source)
+ // start node found, terminate
+ return true;
- //check if source reached
- if (g_pos.source) {
- path.push_back(pos);
- return;
+ // go to the node from which the pathfinder came
+ ipos += g_pos.sourcedir;
}
- buildPath(path, pos + g_pos.sourcedir, level);
- path.push_back(pos);
+ ERROR_TARGET << "Pathfinder: buildPath: no source node found" << std::endl;
+ return false;
}
/******************************************************************************/
-v3f Pathfinder::tov3f(v3s16 pos)
-{
- return v3f(BS * pos.X, BS * pos.Y, BS * pos.Z);
+v3s16 Pathfinder::walkDownwards(v3s16 pos, unsigned int max_down) {
+ if (max_down == 0)
+ return pos;
+ v3s16 testpos = v3s16(pos);
+ MapNode node_at_pos = m_env->getMap().getNode(testpos);
+ const NodeDefManager *ndef = m_env->getGameDef()->ndef();
+ unsigned int down = 0;
+ while ((node_at_pos.param0 != CONTENT_IGNORE) &&
+ (!ndef->get(node_at_pos).walkable) &&
+ (testpos.Y > m_limits.MinEdge.Y) &&
+ (down <= max_down)) {
+ testpos += v3s16(0, -1, 0);
+ down++;
+ node_at_pos = m_env->getMap().getNode(testpos);
+ }
+ //did we find surface?
+ if ((testpos.Y >= m_limits.MinEdge.Y) &&
+ (node_at_pos.param0 != CONTENT_IGNORE) &&
+ (ndef->get(node_at_pos).walkable)) {
+ if (down == 0) {
+ pos = testpos;
+ } else if ((down - 1) <= max_down) {
+ //difference of y-pos +1 (target node is ABOVE solid node)
+ testpos += v3s16(0, 1, 0);
+ pos = testpos;
+ }
+ else {
+ VERBOSE_TARGET << "Pos too far above ground: " <<
+ "Index: " << PP(getIndexPos(pos)) <<
+ "Realpos: " << PP(getRealPos(getIndexPos(pos))) << std::endl;
+ }
+ } else {
+ DEBUG_OUT("Pathfinder: no surface found below pos" << std::endl);
+ }
+ return pos;
}
#ifdef PATHFINDER_DEBUG
@@ -1268,7 +1359,7 @@ void Pathfinder::printYdir(PathDirections dir)
for (int x = 0; x < m_max_index_x; x++) {
if (getIdxElem(x, y, z).directions[dir].valid)
std::cout << std::setw(4)
- << getIdxElem(x, y, z).directions[dir].direction;
+ << getIdxElem(x, y, z).directions[dir].y_change;
else
std::cout << std::setw(4) << "-";
}
diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index a175569d8..352c75fb2 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -1194,7 +1194,7 @@ int ModApiEnvMod::l_find_path(lua_State *L)
unsigned int max_jump = luaL_checkint(L, 4);
unsigned int max_drop = luaL_checkint(L, 5);
PathAlgorithm algo = PA_PLAIN_NP;
- if (!lua_isnil(L, 6)) {
+ if (!lua_isnoneornil(L, 6)) {
std::string algorithm = luaL_checkstring(L,6);
if (algorithm == "A*")