/*
* Preview path, marks tiles.
*/
bool Pathfinding::previewPath(bool bRemove)
{
if (_path.empty())
return false;
if (!bRemove && _pathPreviewed)
return false;
_pathPreviewed = !bRemove;
Position pos = _unit->getPosition();
Position destination;
int tus = _unit->getTimeUnits();
int size = _unit->getArmor()->getSize() - 1;
for (std::vector<int>::reverse_iterator i = _path.rbegin(); i != _path.rend(); ++i)
{
int dir = *i;
int tu = getTUCost(pos, dir, &destination, _unit); // gets tu cost, but also gets the destination position.
tus -= tu;
pos = destination;
for (int x = size; x >= 0; x--)
{
for (int y = size; y >= 0; y--)
{
_save->getTile(pos + Position(x,y,0))->setMarkerColor(bRemove?0:(tus>0?4:3));
}
}
}
return true;
}
/**
* Calculate the shortest path using a simple A-Star algorithm.
* The unit information and movement type must have already been set.
* The path information is set only if a valid path is found.
* @param startPosition The position to start from.
* @param endPosition The position we want to reach.
* @return True if a path exists, false otherwise.
*/
bool Pathfinding::aStarPath(const Position &startPosition, const Position &endPosition)
{
// reset every node, so we have to check them all
for (std::vector<PathfindingNode>::iterator it = _nodes.begin(); it != _nodes.end(); ++it)
it->reset();
// start position is the first one in our "open" list
PathfindingNode *start = getNode(startPosition);
start->connect(0, 0, 0, endPosition);
PathfindingOpenSet openList;
openList.push(start);
// if the open list is empty, we've reached the end
while(!openList.empty())
{
PathfindingNode *currentNode = openList.pop();
Position const ¤tPos = currentNode->getPosition();
currentNode->setChecked();
if (currentPos == endPosition) // We found our target.
{
_path.clear();
PathfindingNode *pf = currentNode;
while (pf->getPrevNode())
{
_path.push_back(pf->getPrevDir());
pf = pf->getPrevNode();
}
return true;
}
// Try all reachable neighbours.
for (int direction = 0; direction < 10; direction++)
{
Position nextPos;
int tuCost = getTUCost(currentPos, direction, &nextPos, _unit);
if (tuCost == 255) // Skip unreachable / blocked
continue;
PathfindingNode *nextNode = getNode(nextPos);
if (nextNode->isChecked()) // Our algorithm means this node is already at minimum cost.
continue;
int totalTuCost = currentNode->getTUCost() + tuCost;
// If this node is unvisited or visited from a better path.
if (!nextNode->inOpenSet() || nextNode->getTUCost() > totalTuCost)
{
nextNode->connect(totalTuCost, currentNode, direction, endPosition);
openList.push(nextNode);
}
}
}
// Unble to reach the target
return false;
}
/**
* Use Dijkstra's algorithm to locate all tiles reachable to @a *unit with a TU cost no more than @a tuMax.
* @param unit Pointer to the unit.
* @param tuMax The maximum cost of the path to each tile.
* @return An array of reachable tiles, sorted in ascending order of cost. The first tile is the start location.
*/
std::vector<int> Pathfinding::findReachable(BattleUnit *unit, int tuMax)
{
const Position &start = unit->getPosition();
for (std::vector<PathfindingNode>::iterator it = _nodes.begin(); it != _nodes.end(); ++it)
{
it->reset();
}
PathfindingNode *startNode = getNode(start);
startNode->connect(0, 0, 0);
PathfindingOpenSet unvisited;
unvisited.push(startNode);
std::vector<PathfindingNode*> reachable;
while (!unvisited.empty())
{
PathfindingNode *currentNode = unvisited.pop();
Position const ¤tPos = currentNode->getPosition();
// Try all reachable neighbours.
for (int direction = 0; direction < 10; direction++)
{
Position nextPos;
int tuCost = getTUCost(currentPos, direction, &nextPos, unit);
if (tuCost == 255) // Skip unreachable / blocked
continue;
if (tuCost > tuMax) // Run out of TUs
continue;
PathfindingNode *nextNode = getNode(nextPos);
if (nextNode->isChecked()) // Our algorithm means this node is already at minimum cost.
continue;
int totalTuCost = currentNode->getTUCost() + tuCost;
// If this node is unvisited or visited from a better path.
if (!nextNode->inOpenSet() || nextNode->getTUCost() > totalTuCost)
{
nextNode->connect(totalTuCost, currentNode, direction);
unvisited.push(nextNode);
}
}
currentNode->setChecked();
reachable.push_back(currentNode);
}
std::sort(reachable.begin(), reachable.end(), MinNodeCosts());
std::vector<int> tiles;
tiles.reserve(reachable.size());
for (std::vector<PathfindingNode*>::const_iterator it = reachable.begin(); it != reachable.end(); ++it)
{
tiles.push_back(_save->getTileIndex((*it)->getPosition()));
}
return tiles;
}
// this works in only x/y plane
bool Pathfinding::bresenhamPath(const Position& origin, const Position& target)
{
int xd[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int yd[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int x, x0, x1, delta_x, step_x;
int y, y0, y1, delta_y, step_y;
int z, z0, z1, delta_z, step_z;
int swap_xy, swap_xz;
int drift_xy, drift_xz;
int cx, cy, cz;
Position lastPoint(origin);
int dir;
int lastTUCost = -1;
Position nextPoint;
//start and end points
x0 = origin.x; x1 = target.x;
y0 = origin.y; y1 = target.y;
z0 = origin.z; z1 = target.z;
//'steep' xy Line, make longest delta x plane
swap_xy = abs(y1 - y0) > abs(x1 - x0);
if (swap_xy)
{
std::swap(x0, y0);
std::swap(x1, y1);
}
//do same for xz
swap_xz = abs(z1 - z0) > abs(x1 - x0);
if (swap_xz)
{
std::swap(x0, z0);
std::swap(x1, z1);
}
//delta is Length in each plane
delta_x = abs(x1 - x0);
delta_y = abs(y1 - y0);
delta_z = abs(z1 - z0);
//drift controls when to step in 'shallow' planes
//starting value keeps Line centred
drift_xy = (delta_x / 2);
drift_xz = (delta_x / 2);
//direction of line
step_x = 1; if (x0 > x1) { step_x = -1; }
step_y = 1; if (y0 > y1) { step_y = -1; }
step_z = 1; if (z0 > z1) { step_z = -1; }
//starting point
y = y0;
z = z0;
//step through longest delta (which we have swapped to x)
for (x = x0; x != (x1+step_x); x += step_x)
{
//copy position
cx = x; cy = y; cz = z;
//unswap (in reverse)
if (swap_xz) std::swap(cx, cz);
if (swap_xy) std::swap(cx, cy);
if (x != x0 || y != y0 || z != z0)
{
Position realNextPoint = Position(cx, cy, cz);
nextPoint = realNextPoint;
// get direction
for (dir = 0; dir < 8; ++dir)
{
if (xd[dir] == cx-lastPoint.x && yd[dir] == cy-lastPoint.y) break;
}
int tuCost = getTUCost(lastPoint, dir, &nextPoint, _unit);
if (nextPoint == realNextPoint && tuCost < 255 && (tuCost == lastTUCost || (dir&1 && tuCost == lastTUCost*1.5) || (!(dir&1) && tuCost*1.5 == lastTUCost) || lastTUCost == -1)
&& !isBlocked(_save->getTile(lastPoint), _save->getTile(nextPoint), dir))
{
_path.push_back(dir);
}
else
{
return false;
}
lastTUCost = tuCost;
lastPoint = Position(cx, cy, cz);
}
//update progress in other planes
drift_xy = drift_xy - delta_y;
drift_xz = drift_xz - delta_z;
//step in y plane
if (drift_xy < 0)
{
y = y + step_y;
drift_xy = drift_xy + delta_x;
}
//same in z
if (drift_xz < 0)
{
z = z + step_z;
drift_xz = drift_xz + delta_x;
}
}
return true;
}
void Pathfinding::calculate(BattleUnit *unit, Position &endPosition)
{
std::list<PathfindingNode*> openList;
Position currentPos, nextPos, startPosition = unit->getPosition();
int tuCost;
_movementType = MT_WALK; // should be parameter
_unit = unit;
Tile *destinationTile = _save->getTile(endPosition);
// check if destination is not blocked
if (isBlocked(destinationTile, MapData::O_FLOOR) || isBlocked(destinationTile, MapData::O_OBJECT)) return;
// the following check avoids that the unit walks behind the stairs if we click behind the stairs to make it go up the stairs.
// it only works if the unit is on one of the 2 tiles on the stairs, or on the tile right in front of the stairs.
if (isOnStairs(startPosition, endPosition))
{
endPosition.z++;
destinationTile = _save->getTile(endPosition);
}
// check if we have floor, else lower destination (for non flying units only, because otherwise they never reached this place)
while (canFallDown(destinationTile))
{
endPosition.z--;
destinationTile = _save->getTile(endPosition);
}
_path.clear();
// reset every node, so we have to check them all
for (int i = 0; i < _size; ++i)
_nodes[i]->reset();
// start position is the first one in our "open" list
openList.push_back(getNode(startPosition));
openList.front()->check(0, 0, 0, 0);
// if the open list is empty, we've reached the end
while(!openList.empty())
{
// this algorithm expands in all directions
for (int direction = 0; direction < 8; direction++)
{
currentPos = openList.front()->getPosition();
tuCost = getTUCost(currentPos, direction, &nextPos, unit);
if(tuCost < 255)
{
if( (!getNode(nextPos)->isChecked() ||
getNode(nextPos)->getTUCost() > getNode(currentPos)->getTUCost() + tuCost) &&
(!getNode(endPosition)->isChecked() ||
getNode(endPosition)->getTUCost() > getNode(currentPos)->getTUCost() + tuCost)
)
{
getNode(nextPos)->check(getNode(currentPos)->getTUCost() + tuCost,
getNode(currentPos)->getStepsNum() + 1,
getNode(currentPos),
direction);
openList.push_back(getNode(nextPos));
}
}
}
openList.pop_front();
}
if(!getNode(endPosition)->isChecked()) return;
//Backward tracking of the path
PathfindingNode* pf = getNode(endPosition);
for (int i = getNode(endPosition)->getStepsNum(); i > 0; i--)
{
_path.push_back(pf->getPrevDir());
pf=pf->getPrevNode();
}
}
void Pathfinding::calculate(BattleUnit *unit, Position endPosition)
{
std::list<PathfindingNode*> openList;
PathfindingNode *currentNode, *nextNode;
Position currentPos, nextPos, startPosition = unit->getPosition();
int tuCost, totalTuCost = 0;
_movementType = unit->getUnit()->getArmor()->getMovementType();
_unit = unit;
Tile *destinationTile = _save->getTile(endPosition);
// check if destination is not blocked
if (isBlocked(destinationTile, MapData::O_FLOOR) || isBlocked(destinationTile, MapData::O_OBJECT)) return;
// the following check avoids that the unit walks behind the stairs if we click behind the stairs to make it go up the stairs.
// it only works if the unit is on one of the 2 tiles on the stairs, or on the tile right in front of the stairs.
if (isOnStairs(startPosition, endPosition))
{
endPosition.z++;
destinationTile = _save->getTile(endPosition);
}
// check if we have floor, else lower destination (for non flying units only, because otherwise they never reached this place)
while (canFallDown(destinationTile) && _movementType != MT_FLY)
{
endPosition.z--;
destinationTile = _save->getTile(endPosition);
}
_path.clear();
if (startPosition.z == endPosition.z && bresenhamPath(startPosition, endPosition))
return;
_path.clear();
// reset every node, so we have to check them all
for (int i = 0; i < _size; ++i)
_nodes[i]->reset();
// start position is the first one in our "open" list
openList.push_back(getNode(startPosition));
openList.front()->check(0, 0, 0, 0);
// if the open list is empty, we've reached the end
while(!openList.empty())
{
currentPos = openList.front()->getPosition();
currentNode = getNode(currentPos);
// this algorithm expands in all directions
for (int direction = 0; direction < 10; direction++)
{
tuCost = getTUCost(currentPos, direction, &nextPos, unit);
if(tuCost < 255) // check if we can go to this node (ie is not blocked)
{
nextNode = getNode(nextPos);
totalTuCost = currentNode->getTUCost() + tuCost;
// if we haven't checked this node, or the current cost tu cost is lower than our previous path, push this node in the open list to visit later.
if( (!nextNode->isChecked() || nextNode->getTUCost() > totalTuCost)
&& // this will keep pushing back nodes, as long as we did not reach the end position or there are still possible shorter paths
(!getNode(endPosition)->isChecked() || getNode(endPosition)->getTUCost() > totalTuCost)
)
{
nextNode->check(totalTuCost,
currentNode->getStepsNum() + 1,
currentNode,
direction);
openList.push_back(nextNode);
}
}
}
openList.pop_front();
}
if(!getNode(endPosition)->isChecked()) return;
//Backward tracking of the path
PathfindingNode* pf = getNode(endPosition);
for (int i = getNode(endPosition)->getStepsNum(); i > 0; i--)
{
_path.push_back(pf->getPrevDir());
pf=pf->getPrevNode();
}
}
