78 lines
2.0 KiB
C#
78 lines
2.0 KiB
C#
using OECS;
|
||
|
||
namespace Game.TicTacToe;
|
||
|
||
/// <summary>
|
||
/// After each move, checks whether the game has been won or drawn.
|
||
/// Updates the GameState singleton accordingly.
|
||
/// </summary>
|
||
public class WinCheckSystem : ISystem
|
||
{
|
||
public void RunImpl(World world)
|
||
{
|
||
if (world.ReadSingleton<GameState>().Status != GameStatus.Playing)
|
||
return;
|
||
|
||
ref var state = ref world.GetSingleton<GameState>();
|
||
|
||
// Build a 3×3 grid of marks.
|
||
var grid = new Player[3, 3];
|
||
foreach (var iter in world.Select<Cell, Mark>())
|
||
{
|
||
grid[iter.Val1.Row, iter.Val1.Col] = iter.Val2.Player;
|
||
}
|
||
|
||
// Check rows.
|
||
for (int r = 0; r < 3; r++)
|
||
{
|
||
if (TryGetWinner(grid[r, 0], grid[r, 1], grid[r, 2], out var winner))
|
||
{
|
||
SetWinner(ref state, winner);
|
||
return;
|
||
}
|
||
}
|
||
|
||
// Check columns.
|
||
for (int c = 0; c < 3; c++)
|
||
{
|
||
if (TryGetWinner(grid[0, c], grid[1, c], grid[2, c], out var winner))
|
||
{
|
||
SetWinner(ref state, winner);
|
||
return;
|
||
}
|
||
}
|
||
|
||
// Check diagonals.
|
||
if (TryGetWinner(grid[0, 0], grid[1, 1], grid[2, 2], out var diag1))
|
||
{
|
||
SetWinner(ref state, diag1);
|
||
return;
|
||
}
|
||
if (TryGetWinner(grid[0, 2], grid[1, 1], grid[2, 0], out var diag2))
|
||
{
|
||
SetWinner(ref state, diag2);
|
||
return;
|
||
}
|
||
|
||
// Check draw.
|
||
if (state.MoveCount >= 9)
|
||
state.Status = GameStatus.Draw;
|
||
}
|
||
|
||
private static bool TryGetWinner(Player a, Player b, Player c, out Player winner)
|
||
{
|
||
if (a != Player.None && a == b && b == c)
|
||
{
|
||
winner = a;
|
||
return true;
|
||
}
|
||
winner = Player.None;
|
||
return false;
|
||
}
|
||
|
||
private static void SetWinner(ref GameState state, Player winner)
|
||
{
|
||
state.Status = winner == Player.X ? GameStatus.XWon : GameStatus.OWon;
|
||
}
|
||
}
|