Implemented simple connected textures example in RedCottonBlockDefini…

…tion (#325)

OctoAwesome/OctoAwesome.Basics/Definitions/Blocks/RedCottonBlockDefinition.cs

@@ -1,5 +1,8 @@
-using OctoAwesome.Basics.Definitions.Materials;
+using System;
+using OctoAwesome.Basics.Definitions.Materials;
+using OctoAwesome.Chunking;
 using OctoAwesome.Definitions;
+using OctoAwesome.Location;
 
 namespace OctoAwesome.Basics.Definitions.Blocks
 {
@@ -15,7 +18,25 @@ public sealed class RedCottonBlockDefinition : BlockDefinition
         public override string Icon => "cotton_red";
 
         /// <inheritdoc />
-        public override string[] Textures { get; } = { "cotton_red" };
+        public override string[] Textures =>
+            new[]{
+                "cotton_red_0",
+                "cotton_red_1",
+                "cotton_red_2",
+                "cotton_red_3",
+                "cotton_red_4",
+                "cotton_red_5",
+                "cotton_red_6",
+                "cotton_red_7",
+                "cotton_red_8",
+                "cotton_red_9",
+                "cotton_red_10",
+                "cotton_red_11",
+                "cotton_red_12",
+                "cotton_red_13",
+                "cotton_red_14",
+                "cotton_red_15",
+            };
 
         /// <inheritdoc />
         public override IMaterialDefinition Material { get; }
@@ -28,5 +49,46 @@ public RedCottonBlockDefinition(CottonMaterialDefinition material)
         {
             Material = material;
         }
+
+        /// <inheritdoc />
+        public override int GetTextureIndex(Wall wall, ILocalChunkCache manager, int x, int y, int z)
+        {
+            int fullBlockTextureIndex = 15;
+            var centerBlock = new Index3(x, y, z);
+            var baseBlockIndex = manager.GetBlock(centerBlock);
+
+            var (firstAxis, secondAxis) = wall switch
+            {
+                Wall.Top => (Index3.UnitX, Index3.UnitY),
+                Wall.Bottom => (-Index3.UnitX, Index3.UnitY),
+                Wall.Left => (Index3.UnitY, -Index3.UnitZ),
+                Wall.Right => (-Index3.UnitY, -Index3.UnitZ),
+                Wall.Front => (Index3.UnitX, -Index3.UnitZ),
+                Wall.Back => (-Index3.UnitX, -Index3.UnitZ),
+                _ => throw new ArgumentOutOfRangeException(nameof(wall), wall, null)
+            };
+
+            fullBlockTextureIndex = RemoveEdgesOnAxis(manager, centerBlock, firstAxis, 0, baseBlockIndex, fullBlockTextureIndex);
+            fullBlockTextureIndex = RemoveEdgesOnAxis(manager, centerBlock, secondAxis, 1, baseBlockIndex, fullBlockTextureIndex);
+
+            return fullBlockTextureIndex;
+        }
+
+        private static int RemoveEdgesOnAxis(ILocalChunkCache manager, Index3 centerBlock, Index3 axis, int sideOffset, ushort baseBlockIndex,
+            int fullBlockTextureIndex)
+        {
+            for (int i = -1; i <= 1; i+=2)
+            {
+                var otherIndex = manager.GetBlock(centerBlock + axis * i);
+
+                if (otherIndex == baseBlockIndex)
+                {
+                    var bitOffset = (i + 1) + sideOffset;
+                    fullBlockTextureIndex &= ~(1 << bitOffset);
+                }
+            }
+
+            return fullBlockTextureIndex;
+        }
     }
 }

OctoAwesome/OctoAwesome/Location/Index3.cs

@@ -280,6 +280,16 @@ public double Length()
         public int LengthSquared()
             => X * X + Y * Y + Z * Z;
 
+        /// <summary>
+        /// Calculates the componentwise factorization with -1.
+        /// </summary>
+        /// <param name="val">The calculated factorization with -1.</param>
+        /// <returns>The componentwise factorized result.</returns>
+        public static Index3 operator -(Index3 val)
+        {
+            return new Index3(-val.X, -val.Y, -val.Z);
+        }
+
         /// <summary>
         /// Calculates the sum of two <see cref="Index3"/> componentwise.
         /// </summary>