// Check that we are still close to the start of the A* path,
// and the end of the path is close to our goal
static int AStarCloseToPath(
AIGotoContext *c, Vec2i currentTile, Vec2i goalTile)
{
Vec2i *pathTile;
Vec2i *pathEnd;
if (!c ||
c->PathIndex >= (int)ASPathGetCount(c->Path) - 1) // at end of path
{
return 0;
}
// Check if we're too far from the current start of the path
pathTile = ASPathGetNode(c->Path, c->PathIndex);
if (CHEBYSHEV_DISTANCE(
currentTile.x, currentTile.y, pathTile->x, pathTile->y) > 2)
{
return 0;
}
// Check if we're too far from the end of the path
pathEnd = ASPathGetNode(c->Path, ASPathGetCount(c->Path) - 1);
if (CHEBYSHEV_DISTANCE(
goalTile.x, goalTile.y, pathEnd->x, pathEnd->y) > 0)
{
return 0;
}
return 1;
}
int AIGoto(TActor *actor, Vec2i p, bool ignoreObjects)
{
Vec2i a = Vec2iFull2Real(actor->Pos);
Vec2i currentTile = Vec2iToTile(a);
Vec2i goalTile = Vec2iToTile(p);
AIGotoContext *c = &actor->aiContext->Goto;
// If we are already there, bail
// This can happen if AI is trying to track the player,
// but the player has died, for example.
if (Vec2iEqual(currentTile, goalTile))
{
return 0;
}
// If we are currently following an A* path,
// and it is still valid, keep following it until
// we have reached a new tile
if (c && c->IsFollowing && AStarCloseToPath(c, currentTile, goalTile))
{
return AStarFollow(c, currentTile, &actor->tileItem, a);
}
else if (AIHasClearPath(a, p, ignoreObjects))
{
// Simple case: if there's a clear line between AI and target,
// walk straight towards it
return AIGotoDirect(a, p);
}
else
{
// We need to recalculate A*
AStarContext ac;
ac.Map = &gMap;
ac.IsTileOk =
ignoreObjects ? IsTileWalkable : IsTileWalkableAroundObjects;
// First, if the goal tile is blocked itself,
// find a nearby tile that can be walked to
c->Goal = MapSearchTileAround(ac.Map, goalTile, ac.IsTileOk);
c->PathIndex = 1; // start navigating to the next path node
ASPathDestroy(c->Path);
c->Path = ASPathCreate(
&cPathNodeSource, &ac, ¤tTile, &c->Goal);
// In case we can't calculate A* for some reason,
// try simple navigation again
if (ASPathGetCount(c->Path) <= 1)
{
debug(
D_MAX,
"Error: can't calculate path from {%d, %d} to {%d, %d}",
currentTile.x, currentTile.y,
goalTile.x, goalTile.y);
return AIGotoDirect(a, p);
}
return AStarFollow(c, currentTile, &actor->tileItem, a);
}
}
// Use pathfinding to check that there is a path between
// source and destination tiles
bool AIHasPath(const Vec2i from, const Vec2i to, const bool ignoreObjects)
{
// Quick first test: check there is a clear path
if (AIHasClearPath(from, to, ignoreObjects))
{
return true;
}
// Pathfind
AStarContext ac;
ac.Map = &gMap;
ac.IsTileOk = ignoreObjects ? IsTileWalkable : IsTileWalkableAroundObjects;
Vec2i fromTile = Vec2iToTile(from);
Vec2i toTile = MapSearchTileAround(ac.Map, Vec2iToTile(to), ac.IsTileOk);
ASPath path = ASPathCreate(&cPathNodeSource, &ac, &fromTile, &toTile);
size_t pathCount = ASPathGetCount(path);
ASPathDestroy(path);
return pathCount > 1;
}
int getEdgeCount(ASPath path) {
return ASPathGetCount(path) - 1;
}
