/// <summary>
/// Helper function for creating a Node for an entrace but also checking that it hasn't already been
/// created, and if it has, just using that one instead to avoid multiple Nodes on top of the same
/// tile.
/// </summary>
/// <param name="cluster">The custer which this node lives in.</param>
/// <param name="tile">The tile which this node wraps.</param>
/// <param name="node">
/// If a node already exists over <paramref name="tile"/> this will be that GraphNode. If not it will
/// be a newly created GraphNode.
/// </param>
/// <returns>True if a new GraphNode was created.</returns>
private Boolean CreateEntraceNode(Cluster cluster, Level.Tile tile, out GraphNode node)
{
Boolean created = false;
// First see if this Tile is already managed by this cluster. If it is, it will return us
// the node which contains it.
node = cluster.GetNodeContaining(tile);
// If the node isn't already being managed, we need to create a new one.
if (null == node)
{
node = mNodeFactory.GetNode();
node.pData = tile;
created = true;
// New nodes need to be registers with the Graph.
AddNode(node);
}
return created;
}
/// <summary>
/// Helper function to do the work needed to create a single new extrance/exit based on the current tile being walked,
/// and the Tile at the start of the sequence.
/// </summary>
/// <param name="cluster">The cluster we are evaluating. Hitting a Tile outside this cluster will end that wall.</param>
/// <param name="tile">The current tile to evaluate.</param>
/// <param name="sequeceStart">The tile which started this sequence. Use null to start.</param>
/// <param name="dirWalk">The direction to walk along the wall.</param>
/// <param name="dirCheck">The direction of the neighbouring Cluster to check. It isn't enough to check outselves; the neighbour may be blocking travel.</param>
/// <param name="dirNeighbourCluster">Same as dirCheck but using the enum that Clusters understand.</param>
/// <param name="removeSelf">True if the tile that triggered this call should not be included in the sequence. Useful if this sequence ended because you hit a wall.</param>
private void CreateEntrance(Cluster cluster, Level.Tile tile, ref Level.Tile sequenceStart, Level.Tile.AdjacentTileDir dirWalk, Level.Tile.AdjacentTileDir dirCheck, Cluster.AdjacentClusterDirections dirNeighbourCluster, Boolean removeSelf)
{
// Find the center point between the tile at the start of the sequence of enpty tiles
// and the current tile.
Vector2 sequenceVector = tile.mCollisionRect.pCenterPoint - sequenceStart.mCollisionRect.pCenterPoint;
// If we enter this block by hitting a wall, we need to remove that a Tile length from our
// calculations since that wall is not part of the entrance/exit.
if (removeSelf)
{
sequenceVector -= Vector2.Normalize(sequenceVector) * new Vector2(cluster.pTileDimensions.X, cluster.pTileDimensions.Y);
}
// If the sequence is long enough, instead of putting a GraphNode in the center, create 2 GraphNode objects,
// and place them at opposite ends of the Sequence. This is recommended by the original HPA* white paper.
if (sequenceVector.LengthSquared() >= (mClusterSize * mGetMapInfoMsg.mInfo_Out.mMapWidth * 0.5f))
{
// Add the length of the Sequence to the starting point to get our ending position.
Vector2 end = (sequenceVector) + sequenceStart.mCollisionRect.pCenterPoint;
// We need to find the tile at that position because our GraphNode depends on that data.
mGetTileAtPositionMsg.mPosition_In = end;
WorldManager.pInstance.pCurrentLevel.OnMessage(mGetTileAtPositionMsg);
System.Diagnostics.Debug.Assert(null != mGetTileAtPositionMsg.mTile_Out, "Unable to find tile.");
CreateEntranceNodes(
cluster,
cluster.pNeighbouringClusters[(Int32)dirNeighbourCluster],
mGetTileAtPositionMsg.mTile_Out,
mGetTileAtPositionMsg.mTile_Out.mAdjecentTiles[(Int32)dirCheck]);
CreateEntranceNodes(
cluster,
cluster.pNeighbouringClusters[(Int32)dirNeighbourCluster],
sequenceStart,
sequenceStart.mAdjecentTiles[(Int32)dirCheck]);
}
else
{
// Add half the length in order to put us in the middle of the sequence.
Vector2 middle = (sequenceVector * 0.5f) + sequenceStart.mCollisionRect.pCenterPoint;
// We need to find the tile at that position because our GraphNode depends on that data.
mGetTileAtPositionMsg.mPosition_In = middle;
WorldManager.pInstance.pCurrentLevel.OnMessage(mGetTileAtPositionMsg);
System.Diagnostics.Debug.Assert(null != mGetTileAtPositionMsg.mTile_Out, "Unable to find tile.");
CreateEntranceNodes(
cluster,
cluster.pNeighbouringClusters[(Int32)dirNeighbourCluster],
mGetTileAtPositionMsg.mTile_Out,
mGetTileAtPositionMsg.mTile_Out.mAdjecentTiles[(Int32)dirCheck]);
}
// Start a new sequence.
sequenceStart = null;
}
/// <summary>
/// Helper function for creating 2 linked GraphNodes in neighnbouring clusters.
/// </summary>
/// <param name="localCluster">The cluster currently being evaluated.</param>
/// <param name="otherCluster">The neighbouring cluster of <paramref name="localCluster"/>.</param>
/// <param name="localTile">The Tile on which the new entrance sits on top of.</param>
/// <param name="otherTile">The Tile on wihich the other new entrace sits on top of.</param>
private void CreateEntranceNodes(Cluster localCluster, Cluster otherCluster, Level.Tile localTile, Level.Tile otherTile)
{
GraphNode localNode;
GraphNode otherNode;
// Create the new nodes with the appropriate Tile data.
Boolean localCreated = CreateEntraceNode(localCluster, localTile, out localNode);
Boolean otherCreated = CreateEntraceNode(otherCluster, otherTile, out otherNode);
// Link the two nodes together creating an Intra-Connection.
localNode.AddNeighbour(otherNode);
otherNode.AddNeighbour(localNode);
// Add the nodes the appropriate Cluster objects.
if (localCreated)
{
localCluster.AddNode(localNode);
}
if (otherCreated)
{
otherCluster.AddNode(otherNode);
}
}
/// <summary>
/// Constrctor.
/// </summary>
/// <param name="solid">The direction of the solid tile relative to the tile that would be a doorway.</param>
/// <param name="empty">The direction of the emoty tile relative to teh tile that would be a doorway.</param>
public DoorwayConfiguration(Level.Tile.AdjacentTileDir solid, Level.Tile.AdjacentTileDir empty)
{
mSolid = solid;
mEmpty = empty;
}
/// <summary>
/// Recursive algorithm for finding all entraces/exits in a cluster, and creating GraphNodes at those points
/// in neighbouring Clusters and linking them together. Has logic to only create on entrance/exit per concurent
/// set of empty tiles.
/// </summary>
/// <param name="cluster">The cluster we are evaluating. Hitting a Tile outside this cluster will end that wall.</param>
/// <param name="tile">The current tile to evaluate.</param>
/// <param name="sequeceStart">The tile which started this sequence. Use null to start.</param>
/// <param name="dirWalk">The direction to walk along the wall.</param>
/// <param name="dirCheck">The direction of the neighbouring Cluster to check. It isn't enough to check outselves; the neighbour may be blocking travel.</param>
/// <param name="dirNeighbourCluster">Same as dirCheck but using the enum that Clusters understand.</param>
/// <returns>The last tile visited on this wall. Useful for walking an entire perimeter.</returns>
private Level.Tile WalkWall(Cluster cluster, Level.Tile tile, Level.Tile sequeceStart, Level.Tile.AdjacentTileDir dirWalk, Level.Tile.AdjacentTileDir dirCheck, Cluster.AdjacentClusterDirections dirNeighbourCluster)
{
// Get the Tile in the neighbouring Cluster. It being solid creates a wall just the same as
// if the tile in this Cluster is solid.
Level.Tile adj = tile.mAdjecentTiles[(Int32)dirCheck];
Boolean entraceMade = false;
if (null != adj)
{
// If we don't yet have a sequence start point, and this tile is an entrace,
// it becomes the new sequence start.
if (null == sequeceStart && tile.mType == Level.Tile.TileTypes.Empty && adj.mType == Level.Tile.TileTypes.Empty)
{
sequeceStart = tile;
}
// The sequence has started already and we just hit a wall. Time to create an entrance in the
// center of this sequence.
else if (null != sequeceStart && (tile.mType != Level.Tile.TileTypes.Empty || adj.mType != Level.Tile.TileTypes.Empty))
{
CreateEntrance(cluster, tile, ref sequeceStart, dirWalk, dirCheck, dirNeighbourCluster, true);
entraceMade = true;
}
}
// Walk to the next Tile.
adj = tile.mAdjecentTiles[(Int32)dirWalk];
// Are we still in the Cluster/Level?
if (null != adj && cluster.IsInBounds(adj))
{
// Recursivly visit the next Tile.
return WalkWall(cluster, adj, sequeceStart, dirWalk, dirCheck, dirNeighbourCluster);
}
else
{
// We have left either the map or the Cluster. Either way that is considered an end to
// the current sequence, should one be in progress.
if (null != sequeceStart)
{
System.Diagnostics.Debug.Assert(!entraceMade, "Entrance made twice.");
CreateEntrance(cluster, tile, ref sequeceStart, dirWalk, dirCheck, dirNeighbourCluster, false);
}
return tile;
}
}
/// <summary>
/// Does a kind of flood fill of game objects inside a structure in a way that the user
/// would expect, meaning 1 tile opening are treating like doors, which can connect rooms
/// or be an exit to the outside world.
/// </summary>
/// <param name="firstTile">The Tile to start the fill at.</param>
/// <param name="maxFillCount">
/// The maximum number of tiles to search before considering
/// the SafeHouse filled. Any rooms to completely changed when this cap is hit will not
/// be filled.
/// </param>
/// <param name="gameObjectTemplateName">The name of the GameObject which will be flood filled.</param>
/// <returns>True if at least one room was filled.</returns>
public Boolean FloodFill(Level.Tile firstTile, UInt32 maxFillCount, String gameObjectTemplateName)
{
// Tracks whether or not any rooms were filled.
Boolean success = false;
// Store for use later.
mGameObjectTemplateName = gameObjectTemplateName;
// A new fill means any currently running should stop.
mTilesToChangeFinal.Clear();
// This algorithm works by breaking the world into rooms. A room is an area surrounded
// by wall, with the one cavet that spaces 1 pixel wide are allowed when moving from
// one room to another, but are considered a wall when exiting the entire structure.
// Filling is done on a per room basis. If we reach maxFillCount before a room is filled,
// none of the room gets filled in. However, any rooms previously filled in stay, and
// rooms still in the queue can potentially be filled if they are smaller than the one
// that failed.
mRoomStarters.Enqueue(firstTile);
// Keep track of how many tiles have been changed overall in order to make sure
// we don't go over maxFillCount over all.
Int32 curFillCount = 0;
// Go room by room trying to cover it in the desired object.
while (mRoomStarters.Count > 0 && (curFillCount <= maxFillCount))
{
// The starting tile is the tile in the roomStarters Queue.
Level.Tile startTile = mRoomStarters.Dequeue();
// Clear out any data that might be sitting around from the previous room.
mTilesToCheck.Clear();
mTilesToChange.Clear();
mRoomStartersToAdd.Clear();
// There is a chance we were given a Tile that is null or not empty. In those cases
// we just want to skip over them. It was Dequeued from roomStarters so it will be
// forgotten.
if (null != startTile && startTile.mType == Level.Tile.TileTypes.Empty)
{
// Start the tile travesal with the roomStarter.
mTilesToCheck.Enqueue(startTile);
mProcessedTiles.Add(startTile);
}
// Breath first search through the tile map stopping at walls and doors, or at a point
// where we have visiting more tiles than allowed by maxFillCount.
while ((mTilesToCheck.Count) > 0 && (mTilesToChange.Count + curFillCount <= maxFillCount))
{
// Grab the next Tile, or in the case of the first interation it will be a roomStarter.
Level.Tile currentTile = mTilesToCheck.Dequeue();
// Safety check in case we got sent a bad starting tile.
if (null == currentTile || currentTile.mType != Level.Tile.TileTypes.Empty)
{
continue;
}
// Should this room be completed, this tile should be changed.
mTilesToChange.Add(currentTile);
// Loop through all the surrounding tiles adding the appropriate ones to the
// tiles Queue.
for (UInt32 tileIndex = (UInt32)Level.Tile.AdjacentTileDir.START_HORZ; (tileIndex < (UInt32)Level.Tile.AdjacentTileDir.NUM_DIRECTIONS); tileIndex += 1)
{
Level.Tile nextTile = currentTile.mAdjecentTiles[tileIndex];
if (null != nextTile && nextTile.mType == Level.Tile.TileTypes.Empty && // Safety check
false == mProcessedTiles.Contains(nextTile) && // Don't check the same tile more than once.
!Level.IsAttemptingInvalidDiagonalMove((Level.Tile.AdjacentTileDir)tileIndex, currentTile)) // Don't clip through diagonal walls.
{
if (IsDoorway(nextTile))
{
// If this tile is actually a doorway, it becomes the start of a new room.
mRoomStartersToAdd.Add(nextTile);
}
else
{
// This is just a regular tile, so it should be changed, should this room be completed.
mTilesToCheck.Enqueue(nextTile);
}
// This tile has been processed so it should not be checked again.
mProcessedTiles.Add(nextTile);
}
}
}
// The breath first search has completed. If it exusted all tiles, then the room is considered
// completed, and we can start actually changing tiles and adding the connected rooms.
if (mTilesToCheck.Count <= 0)
{
// Once any room gets filled it is considered a success.
success = true;
// This is a legit change now, so count it towards to total fill count.
curFillCount += mTilesToChange.Count;
mTilesToChangeFinal.AddRange(mTilesToChange);
// Any new rooms that were queued up can now be safely added as the room that
// linked to them was completed.
for (Int32 i = 0; i < mRoomStartersToAdd.Count; i++)
{
mRoomStarters.Enqueue(mRoomStartersToAdd[i]);
}
}
}
// Don't want to be hanging onto this data.
mProcessedTiles.Clear();
mRoomStarters.Clear();
mTilesToCheck.Clear();
mTilesToChange.Clear();
mRoomStartersToAdd.Clear();
return success;
}
/// <summary>
/// A somewhat complex check to determine if a tile is what would be considered a doorway.
/// A doorway is an empty tile, surrounded by 2 or more empty tiles on opposite sides. However,
/// it is not quite as simple as that, since some combination block what would be the room after
/// the door way, so we also need to verify that for a given combination of walls, there is a
/// another empty tile at a particular location.
/// </summary>
/// <param name="tile"></param>
/// <returns></returns>
private Boolean IsDoorway(Level.Tile tile)
{
// Build this mapping of walls and empty spaces required to make up a doorway.
/// <todo>Do this once.</todo>
List<DoorwayConfiguration> [] relaventSiblings = BuildDoorwayConfigurationTable();
// We need to loop through every surround tile and see if they are walls. If they ar walls,
// then we start checking the relaventSiblings for the required corrisponding walls and empty tiles
// which mean this tile is a doorway.
for (UInt32 tileIndex = (UInt32)Level.Tile.AdjacentTileDir.START_HORZ; (tileIndex < (UInt32)Level.Tile.AdjacentTileDir.NUM_DIRECTIONS); tileIndex++)
{
// Grab the next tile surrounding the one we are checking.
Level.Tile siblingTile = tile.mAdjecentTiles[tileIndex];
// None of this matters if the adjacent tile is empty.
if (null != siblingTile && siblingTile.mType != Level.Tile.TileTypes.Empty)
{
// Every surrounding tile has a list of corrisponding tiles that when in the proper
// configuration mean that the center tile is a doorway. Loop through those conigurations.
for (Int32 i = 0; i < relaventSiblings[tileIndex].Count; i++)
{
// When siblingTile is Solid, another tile on the opposite side also needs to be solid.
Level.Tile adjTileSolid = tile.mAdjecentTiles[(Int32)relaventSiblings[tileIndex][i].mSolid];
// Is a relavent sibling solid?
if (null != adjTileSolid && adjTileSolid.mType != Level.Tile.TileTypes.Empty)
{
// But it isn't enough to have solid tiles on opposite sides of the center tile.
// There also needs to be an empty tile in the right direction or else this is
// just a dead end and should be considered part of the current room, not the
// start of a new one.
Level.Tile adjEmpty = tile.mAdjecentTiles[(Int32)relaventSiblings[tileIndex][i].mEmpty];
// Is the relavent sibling Empty?
if (null != adjEmpty && adjEmpty.mType == Level.Tile.TileTypes.Empty)
{
// Once this is a doorway in one case, nothing can change that; it can only
// have additional paths, but that will be handled when this Tile becomes
// the starting point of the next room.
return true;
}
}
}
}
}
return false;
}
/// <summary>
/// Is a particular Tile already part of this Cluster, meaning that a GraphNode in this
/// Cluster is wrapping that tile. If it is, then that GraphNode gets returned so that it
/// can be reused.
/// </summary>
/// <param name="tile">The tile to check for.</param>
/// <returns>The GraphNode in this Cluster which wraps the given Tile.</returns>
public GraphNode GetNodeContaining(Level.Tile tile)
{
// Just loop through every GraphNode looking for one that is storing the Tile.
for (Int32 i = 0; i < pNodes.Count; i++)
{
if (pNodes[i].pData as Level.Tile == tile)
{
if (!(pNodes[i] as NavMeshTileGraphNode).pIsTemporary)
{
return pNodes[i];
}
}
else if (pNodes[i].pPosition == tile.mCollisionRect.pCenterPoint)
{
System.Diagnostics.Debug.Assert(false, "Tile at same position but claiming to be different.");
}
}
return null;
}
/// <summary>
/// Checks if a Tile is inside of this cluster (at all).
/// </summary>
/// <param name="tile">The Tile to check for.</param>
/// <returns>True if tile is inside this cluster.</returns>
public Boolean IsInBounds(Level.Tile tile)
{
return (mBounds.Intersects(tile.mCollisionRect));
}
/// <summary>
/// When choosing a path we want to avoid clipping the edges of solid tiles. For example if you are
/// going LEFT_DOWN, there should be no solid tile LEFT or DOWN or else the character would clip
/// into them.
/// It also avoids the problem where the path slips between kitty-cornered tiles.
/// </summary>
/// <param name="dir">The direction we want to move.</param>
/// <param name="rootTile">The tile we are moving from.</param>
/// <returns>True if this is an invalid move.</returns>
static public Boolean IsAttemptingInvalidDiagonalMove(Level.Tile.AdjacentTileDir dir, Level.Tile rootTile)
{
switch ((Int32)dir)
{
// The path wants to move down and to the left...
case (Int32)Level.Tile.AdjacentTileDir.LEFT_DOWN:
{
// But it should only do so if their are no solid tiles to the left and
// no solid tiles below. If there are, it needs to find another way round.
if (IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.LEFT, rootTile) ||
IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.DOWN, rootTile))
{
return true;
}
break;
}
case (Int32)Level.Tile.AdjacentTileDir.LEFT_UP:
{
if (IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.LEFT, rootTile) ||
IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.UP, rootTile))
{
return true;
}
break;
}
case (Int32)Level.Tile.AdjacentTileDir.RIGHT_DOWN:
{
if (IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.RIGHT, rootTile) ||
IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.DOWN, rootTile))
{
return true;
}
break;
}
case (Int32)Level.Tile.AdjacentTileDir.RIGHT_UP:
{
if (IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.RIGHT, rootTile) ||
IsTileInDirectionSolid(Level.Tile.AdjacentTileDir.UP, rootTile))
{
return true;
}
break;
}
};
return false;
}
/// <summary>
/// Checks in an adjecent tile is solid. Safely avoids cases where their is no adjecent tile.
/// </summary>
/// <param name="dir">The direction to check in.</param>
/// <param name="rootTile">The tile to move from.</param>
/// <returns>True if the adjecent tile exists and is solid.</returns>
static private Boolean IsTileInDirectionSolid(Level.Tile.AdjacentTileDir dir, Level.Tile rootTile)
{
return (rootTile.mAdjecentTiles[(Int32)dir] != null && rootTile.mAdjecentTiles[(Int32)dir].mType != Level.Tile.TileTypes.Empty);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="tile">The Tile at this Node's location in the world.</param>
public TileGraphNode(Level.Tile tile)
: base()
{
mTile = tile;
}