public int isReachable(FE fromField, FieldElement target, FieldElement.Neighbor[] neighborTypes) {
if (fromField.equals(target)) {
return 0;
}
if (neighborTypes == null || neighborTypes.length == 0) {
return -1;
}
// clear pathfinding data
for (FE e : this) {
e.mPathfindingValue = 0;
}
mPathfindingNodes.clear();
// ant algorithm, start with fromField
mPathfindingNodes.add(fromField);
fromField.mPathfindingValue = 1;
do {
FieldElement currField = mPathfindingNodes.poll();
for (FieldElement.Neighbor n : neighborTypes) {
if (hasNeighbor(currField, n)) {
FE nextField = getNeighbor(currField, n);
if (nextField.equals(target)) {
return currField.mPathfindingValue;
}
if (nextField.mPathfindingValue == 0 && !nextField.isBlocked()) {
// field not yet reached and
// the next field is not blocked, go on
mPathfindingNodes.add(nextField);
nextField.mPathfindingValue = currField.mPathfindingValue + 1;
}
}
}
} while (!mPathfindingNodes.isEmpty());
return -1;
}
