feat: make Sand/Snow opaque and register Sand/Snow/Water blocks

World/Blocks/BlockRegistry.cs

@@ -8,11 +8,15 @@ public sealed class BlockRegistry
     public StoneBlock Stone { get; } = new();
     public DirtBlock Dirt { get; } = new();
     public GrassBlock Grass { get; } = new();
+    public SandBlock Sand { get; } = new();
+    public SnowBlock Snow { get; } = new();
+    public WaterBlock Water { get; } = new();
 
     public BlockRegistry()
     {
         // Index by id. Order does not matter; slot = block.Id.
-        IBlock[] blocks = new IBlock[] { this.Air, this.Stone, this.Dirt, this.Grass };
+        IBlock[] blocks = new IBlock[]
+            { this.Air, this.Stone, this.Dirt, this.Grass, this.Sand, this.Snow, this.Water };
         this._byId = new IBlock[blocks.Length];
         foreach (IBlock block in blocks)
         {

World/Blocks/SandBlock.cs

@@ -0,0 +1,10 @@
+namespace VoxelEngine.World.Blocks;
+
+public class SandBlock : IBlock
+{
+    public ushort Id => 4;
+    public string Name => "Sand";
+    public bool IsOpaque => true;
+    public bool IsSolid => true;
+    public TileCoord GetTextureTile(BlockFace face) => new(2, 1);
+}

World/Blocks/SnowBlock.cs

@@ -0,0 +1,16 @@
+namespace VoxelEngine.World.Blocks;
+
+public class SnowBlock : IBlock
+{
+    public ushort Id => 5;
+    public string Name => "Snow Block";
+    public bool IsOpaque => true;
+    public bool IsSolid => true;
+
+    public TileCoord GetTextureTile(BlockFace face) => face switch
+    {
+        BlockFace.Top => new TileCoord(2, 0),
+        BlockFace.Bottom => new TileCoord(0, 0),
+        _ => new TileCoord(3, 0)
+    };
+}

World/Blocks/WaterBlock.cs

@@ -0,0 +1,6 @@
+namespace VoxelEngine.World.Blocks;
+
+public class WaterBlock
+{
+    
+}