/// <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>
/// 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);
}
}
