move backend to subfolder

tanks-backend/TanksServer/Graphics/DrawPowerUpsStep.cs

@@ -0,0 +1,52 @@
+using System.Diagnostics;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+using TanksServer.GameLogic;
+
+namespace TanksServer.Graphics;
+
+internal sealed class DrawPowerUpsStep : IDrawStep
+{
+    private readonly MapEntityManager _entityManager;
+    private readonly bool?[,] _explosiveSprite;
+
+    public DrawPowerUpsStep(MapEntityManager entityManager)
+    {
+        _entityManager = entityManager;
+
+        using var tankImage = Image.Load<Rgba32>("assets/powerup_explosive.png");
+        Debug.Assert(tankImage.Width == tankImage.Height && tankImage.Width == MapService.TileSize);
+        _explosiveSprite = new bool?[tankImage.Width, tankImage.Height];
+
+        var whitePixel = new Rgba32(byte.MaxValue, byte.MaxValue, byte.MaxValue, byte.MaxValue);
+        for (var y = 0; y < tankImage.Height; y++)
+        for (var x = 0; x < tankImage.Width; x++)
+        {
+            var pixelValue = tankImage[x, y];
+            _explosiveSprite[x, y] = pixelValue.A == 0
+                ? null
+                : pixelValue == whitePixel;
+        }
+    }
+
+    public void Draw(GamePixelGrid pixels)
+    {
+        foreach (var powerUp in _entityManager.PowerUps)
+        {
+            var position = powerUp.Bounds.TopLeft;
+
+            for (byte dy = 0; dy < MapService.TileSize; dy++)
+            for (byte dx = 0; dx < MapService.TileSize; dx++)
+            {
+                var pixelState = _explosiveSprite[dx, dy];
+                if (!pixelState.HasValue)
+                    continue;
+
+                var (x, y) = position.GetPixelRelative(dx, dy);
+                pixels[x, y].EntityType = pixelState.Value
+                    ? GamePixelEntityType.PowerUp
+                    : null;
+            }
+        }
+    }
+}