feat: show next piece

src/AvaloniaTetris/Game.cs

@@ -17,11 +17,22 @@ public Game()
                 Positions[x, y] = new GridPoint();
             }
         }
+
+        for (int y = 0; y <= 1; y++)
+        {
+            for (int x = 0; x <= 3; x++)
+            {
+                NextPiecePositions[x, y] = new GridPoint();
+            }
+        }
     }
 
     [ObservableProperty]
     private GridPoint[,] _positions = new GridPoint[10,20];
 
+    [ObservableProperty]
+    private GridPoint[,] _nextPiecePositions = new GridPoint[4, 2];
+
     [ObservableProperty]
     private int _level;
 
@@ -43,34 +54,50 @@ public Game()
 
     private Piece? activePiece;
 
+    private Piece? nextPiece;
+
     private void Timer_Tick(object? sender, EventArgs e)
     {
         MoveDown();
     }
 
     readonly Random randomPiece = new();
 
-    private void AddNewPiece()
+    private Piece GetRandom()
     {
         // Pick random Piece
         Piece? newPiece = randomPiece.Next(1, 6) switch
         {
             1 => new Straight(),
             2 => new Square(),
             3 => new T(),
-            4 => randomPiece.Next(1,3) switch
+            4 => randomPiece.Next(1, 3) switch
             {
                 1 => new L1(),
-                2=> new L2(),
-            } ,
+                2 => new L2(),
+            },
             5 => randomPiece.Next(1, 3) switch
             {
                 1 => new S1(),
                 2 => new S2(),
             },
             _ => throw new Exception(),
         };
-        activePiece = newPiece;
+
+        return newPiece;
+    }
+
+    private void AddNewPiece()
+    {
+        if (nextPiece == null)
+        {
+            nextPiece = GetRandom();
+        }
+
+        activePiece = nextPiece;
+
+        nextPiece = GetRandom();
+        SetNextPiece();
     }
 
     private void ClearActivePiece()
@@ -115,6 +142,42 @@ private void SetActivePiece(bool isActive = true)
         }
     }
 
+    private void SetNextPiece()
+    {
+        int shape = 0;
+        if (nextPiece is Straight)
+        {
+            shape = 1;
+        }
+        else if (nextPiece is Square)
+        {
+            shape = 2;
+        }
+        else if (nextPiece is S1 or S2)
+        {
+            shape = 3;
+        }
+        else if (nextPiece is T)
+        {
+            shape = 4;
+        }
+        else if (nextPiece is L1 or L2)
+        {
+            shape = 5;
+        }
+
+        foreach (var item in NextPiecePositions)
+        {
+            item.Type = 0;
+        }
+
+        foreach (var point in nextPiece.GetUsedCoords(-nextPiece.X, -nextPiece.Y))
+        {
+            var pos = NextPiecePositions[(int)point.X, (int)point.Y];
+            pos.Type = shape;
+        }
+    }
+
     private void RemoveFullRow()
     {
         //Check if a row needs to be removed

src/AvaloniaTetris/ViewModels/MainViewModel.cs

@@ -5,6 +5,7 @@ namespace AvaloniaTetris.ViewModels;
 public partial class MainViewModel : ViewModelBase
 {
     public IEnumerable<GridPoint> OrderedPoints => OrderPoints();
+    public IEnumerable<GridPoint> OrderedNextPoints => OrderNextPoints();
 
     public Game Game { get; set; } = new Game();
 
@@ -25,4 +26,15 @@ private IEnumerable<GridPoint> OrderPoints()
             }
         }
     }
+
+    private IEnumerable<GridPoint> OrderNextPoints()
+    {
+        for (int y = 1; y >= 0; y--)
+        {
+            for (int x = 0; x <= 3; x++)
+            {
+                yield return Game.NextPiecePositions[x, y];
+            }
+        }
+    }
 }

src/AvaloniaTetris/Views/MainView.axaml

@@ -84,6 +84,30 @@
                 <Button Command="{Binding Game.MoveDownCommand}" HotKey="Down">↓</Button>
                 <Button Command="{Binding Game.MoveRightCommand}" HotKey="Right">→</Button>
             </StackPanel>
+
+            <TextBlock></TextBlock>
+
+            <TextBlock>Next Piece</TextBlock>
+            <ItemsControl ItemsSource="{Binding OrderedNextPoints}" Padding="2" >
+                    <ItemsControl.ItemTemplate>
+                        <DataTemplate>
+                            <Border Height="30"
+                                    Width="30"
+                                    BorderThickness="1"
+                                    BorderBrush="White"
+                                    CornerRadius="4"
+                                    BoxShadow="inset 1 1 1 1 DarkGray"
+                                    Background="{Binding Type, Converter={StaticResource intToColorConverter}}"
+                                >
+                            </Border>
+                        </DataTemplate>
+                    </ItemsControl.ItemTemplate>
+                    <ItemsControl.ItemsPanel>
+                        <ItemsPanelTemplate>
+                            <UniformGrid Rows="2" Columns="4" HorizontalAlignment="Left" VerticalAlignment="Top" />
+                        </ItemsPanelTemplate>
+                    </ItemsControl.ItemsPanel>
+                </ItemsControl>
         </StackPanel>
 
     </Grid>