internal static IReadOnlyList <TetriminoNode> GetTetriminoDependencyGraph(IReadOnlyList <ITetrimino> tetriminos,
int playAreaWidth, int playAreaHeight)
{
// Build block map
var tetriminoNodes = new List <TetriminoNode>(tetriminos.Count);
var memoizedMap = new MemoizedBlock[playAreaHeight, playAreaWidth];
foreach (var tetrimino in tetriminos)
{
var tetriminoNode = new TetriminoNode
{
Kind = tetrimino.Kind,
Position = tetrimino.Position,
FacingDirection = tetrimino.FacingDirection
};
tetriminoNode.MemoizedBlocks = GetMemoizedBlocksForTetriminoNode(tetriminoNode, tetrimino);
foreach (var block in tetriminoNode.MemoizedBlocks)
{
memoizedMap[block.Position.Y, block.Position.X] = block;
}
tetriminoNodes.Add(tetriminoNode);
}
// Get dependency relationship
foreach (var tetriminoNode in tetriminoNodes)
{
foreach (var block in tetriminoNode.MemoizedBlocks)
{
// if a blocker under the current block is occupied then
// this tetrimino can not be placed until the underlying block's
// owner is placed, i.e., this tetrimino depends on the underlying
// block's owner.
var dependedBlockRow = block.Position.Y + 1;
var dependedBlockCol = block.Position.X;
if (TryGetOccupiedTetriminoNode(
memoizedMap,
dependedBlockRow, dependedBlockCol,
playAreaWidth, playAreaHeight,
out var dependOn
) &&
dependOn != tetriminoNode)
{
dependOn.DependedBy.Add(tetriminoNode);
tetriminoNode.Depending.Add(dependOn);
}
}
}
return(tetriminoNodes);
}
private static bool TryGetOccupiedTetriminoNode(MemoizedBlock[,] map,
int row, int col,
int playAreaWidth, int playAreaHeight,
out TetriminoNode result)
{
if (row < 0 || row >= playAreaHeight || col < 0 || col >= playAreaWidth)
{
result = null;
return(false);
}
var cell = map[row, col];
if (cell == null ||
cell.FilledBy == TetriminoKind.AvailableToFill ||
cell.FilledBy == TetriminoKind.UnavailableToFill)
{
result = null;
return(false);
}
result = cell.Owner;
return(true);
}
private static IReadOnlyList <MemoizedBlock> GetMemoizedBlocksForTetriminoNode(TetriminoNode node,
ITetrimino tetrimino)
{
var memoizedBlocks = new List <MemoizedBlock>();
foreach (var block in tetrimino.Blocks)
{
var newBlock = new MemoizedBlock
{
Position = block.Position,
FilledBy = block.FilledBy,
Owner = node
};
memoizedBlocks.Add(newBlock);
}
return(memoizedBlocks);
}