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bidi pathing

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This commit is contained in:
Chris Forbes
2009-11-07 15:13:47 +13:00
parent 2c545466ee
commit bb64327568
2 changed files with 109 additions and 36 deletions
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144
OpenRa.Game/PathFinder.cs
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@@ -97,7 +97,14 @@ namespace OpenRa.Game
prev = sl;
}
if (queue.Empty) return new List<int2>();
var ret = FindPath(cellInfo, queue, estimator, umt, true);
var h2 = DefaultEstimator(path[0]);
var otherQueue = new PriorityQueue<PathDistance>();
otherQueue.Add(new PathDistance(h2(from), from));
var ret = FindBidiPath(cellInfo, InitCellInfo(), queue, otherQueue, estimator, h2, umt, true);
//var ret = FindPath(cellInfo, queue, estimator, umt, true);
ret.Reverse();
return ret;
}
@@ -124,53 +131,26 @@ namespace OpenRa.Game
List<int2> FindPath( CellInfo[ , ] cellInfo, PriorityQueue<PathDistance> queue, Func<int2, float> estimator, UnitMovementType umt, bool checkForBlock )
{
int samples = 0;
int nodesExpanded = 0;
using (new PerfSample("find_path_inner"))
{
while (!queue.Empty)
{
PathDistance p = queue.Pop();
int2 here = p.Location;
cellInfo[here.X, here.Y].Seen = true;
cellInfo[p.Location.X, p.Location.Y].Seen = true;
if (estimator(here) == 0.0)
if (estimator(p.Location) == 0)
{
PerfHistory.Increment("nodes_expanded", samples * .01);
return MakePath(cellInfo, here);
PerfHistory.Increment("nodes_expanded", nodesExpanded * .01);
return MakePath(cellInfo, p.Location);
}
samples++;
nodesExpanded++;
foreach (int2 d in Util.directions)
{
int2 newHere = here + d;
if (cellInfo[newHere.X, newHere.Y].Seen)
continue;
if (passableCost[(int)umt][newHere.X, newHere.Y] == float.PositiveInfinity)
continue;
if (!Game.BuildingInfluence.CanMoveHere(newHere))
continue;
if (checkForBlock && Game.UnitInfluence.GetUnitAt(newHere) != null)
continue;
var est = estimator(newHere);
if (est == float.PositiveInfinity)
continue;
float cellCost = ((d.X * d.Y != 0) ? 1.414213563f : 1.0f) * passableCost[(int)umt][newHere.X, newHere.Y];
float newCost = cellInfo[here.X, here.Y].MinCost + cellCost;
if (newCost >= cellInfo[newHere.X, newHere.Y].MinCost)
continue;
cellInfo[newHere.X, newHere.Y].Path = here;
cellInfo[newHere.X, newHere.Y].MinCost = newCost;
queue.Add(new PathDistance(newCost + est, newHere));
}
ExpandNode(cellInfo, queue, p, umt, checkForBlock, estimator);
}
PerfHistory.Increment("nodes_expanded", samples * .01);
PerfHistory.Increment("nodes_expanded", nodesExpanded * .01);
// no path exists
return new List<int2>();
}
@@ -211,6 +191,98 @@ namespace OpenRa.Game
return 1.5f * diag + straight;
};
}
void ExpandNode(CellInfo[,] ci, PriorityQueue<PathDistance> q, PathDistance p, UnitMovementType umt, bool checkForBlock, Func<int2, float> h)
{
foreach (int2 d in Util.directions)
{
int2 newHere = p.Location + d;
if (ci[newHere.X, newHere.Y].Seen)
continue;
if (passableCost[(int)umt][newHere.X, newHere.Y] == float.PositiveInfinity)
continue;
if (!Game.BuildingInfluence.CanMoveHere(newHere))
continue;
if (checkForBlock && Game.UnitInfluence.GetUnitAt(newHere) != null)
continue;
var est = h(newHere);
if (est == float.PositiveInfinity)
continue;
float cellCost = ((d.X * d.Y != 0) ? 1.414213563f : 1.0f) * passableCost[(int)umt][newHere.X, newHere.Y];
float newCost = ci[p.Location.X, p.Location.Y].MinCost + cellCost;
if (newCost >= ci[newHere.X, newHere.Y].MinCost)
continue;
ci[newHere.X, newHere.Y].Path = p.Location;
ci[newHere.X, newHere.Y].MinCost = newCost;
q.Add(new PathDistance(newCost + est, newHere));
}
}
List<int2> FindBidiPath( /* searches from both ends toward each other */
CellInfo[,] ca,
CellInfo[,] cb,
PriorityQueue<PathDistance> qa,
PriorityQueue<PathDistance> qb,
Func<int2, float> ha,
Func<int2, float> hb,
UnitMovementType umt,
bool checkForBlocked)
{
while (!qa.Empty && !qb.Empty)
{
{ /* make some progress on the first search */
var p = qa.Pop();
ca[p.Location.X, p.Location.Y].Seen = true;
if (cb[p.Location.X, p.Location.Y].MinCost < float.PositiveInfinity)
return MakeBidiPath(ca, cb, p.Location);
else
ExpandNode(ca, qa, p, umt, checkForBlocked, ha);
}
{ /* make some progress on the second search */
var p = qb.Pop();
cb[p.Location.X, p.Location.Y].Seen = true;
//if (ca[p.Location.X, p.Location.Y].MinCost < float.PositiveInfinity)
// return MakeBidiPath(ca, cb, p.Location);
//else
ExpandNode(cb, qb, p, umt, checkForBlocked, hb);
}
}
return new List<int2>();
}
static List<int2> MakeBidiPath(CellInfo[,] ca, CellInfo[,] cb, int2 p)
{
var a = new List<int2>();
var b = new List<int2>();
var q = p;
while (ca[q.X, q.Y].Path != q)
{
q = ca[q.X, q.Y].Path;
a.Add(q);
}
q = p;
while (cb[q.X, q.Y].Path != q)
{
q = cb[q.X, q.Y].Path;
b.Add(q);
}
a.Add(p);
for (var v = b.Count - 1; v >= 0; v--) a.Add(b[v]);
return a;
}
}
struct CellInfo