// Clears all active tiles on the grid and re-initializes it with fresh randomized tiles from the tile pool.
public void ResetGrid()
{
_grid.Clear(_tilePool);
GameSettings.LevelSettings settings = GameSettings.currentLevelSettings;
_grid.ResizeGrid(settings.gridSize.x + 2, settings.gridSize.y + 2);
int tileCount = settings.gridSize.x * settings.gridSize.y;
SpriteTileInfo[] tiles = GetRandomTilePairs(settings.uniqueTileCount, tileCount);
// Fill the grid leaving cells around the border empty
for (int x = 1; x < _grid.columns - 1; x++)
{
for (int y = 1; y < _grid.rows - 1; y++)
{
int i = (y - 1) * (_grid.columns - 2) + (x - 1);
if (tiles[i] != null)
{
// Grab a new tile from the pool and initalize it
SpriteTile tile = _tilePool.Pop();
tile.SetSpriteTileInfo(tiles[i]);
tile.SetGridNode(_grid[x, y]);
tile.SetHighlighted(false);
tile.SetColliderEnabled(true);
}
}
}
// Make sure we haven't spawned a grid with an unwinnable pattern of tiles
FixUnwinnables();
}
// Looks for an 'x' pattern of tiles in the grid and swaps the tiles in any it finds so that it can be completed.
void FixUnwinnables()
{
bool done = false;
// Repeat until no cross patterns are detected
do
{
done = true;
for (int x = 1; x < _grid.columns - 2; x++)
{
for (int y = 1; y < _grid.rows - 2; y++)
{
// Check for 'crosses' of tiles that result in an unwinnable puzzle.
// [ n3, n4 ]
// [ n1, n2 ]
GridNode n1 = _grid[x, y];
GridNode n2 = _grid[x + 1, y];
GridNode n3 = _grid[x, y + 1];
GridNode n4 = _grid[x + 1, y + 1];
// Pattern is unwinnable if n1 == n4 and n2 == n3
if (n1.tile != null && n2.tile != null && n3.tile != null && n4.tile != null && n1.tile.Matches(n4.tile) && n2.tile.Matches(n3.tile))
{
// Swap n1 and n2 to move the pattern
SpriteTile t = n2.tile;
n1.tile.SetGridNode(n2);
t.SetGridNode(n1);
done = false;
}
}
}
} while(!done);
}