Fixed sprites 8x16 processing

1 files changed, 16 insertions, 15 deletions

diff --git a/NesTiler/Tile.cs b/NesTiler/Tile.cs
index e20d81d..f77352a 100644
--- a/NesTiler/Tile.cs
+++ b/NesTiler/Tile.cs
@@ -7,34 +7,35 @@ namespace com.clusterrr.Famicom.NesTiler
     sealed record Tile : IEquatable<Tile>

     {

         public readonly byte[] Pixels;

-        public readonly int Width;

+        public const int Width = 8;

         public readonly int Height;

         private int? hash;

         private byte[] data = null;

 

-        public Tile(byte[] data, int width, int height)

+        public Tile(byte[] data, int height)

         {

-            (Pixels, Width, Height) = (data, width, height);

+            (Pixels, Height) = (data, height);

         }

 

-        public byte[] GetAsTileData()

+        public byte[] GetAsPatternData()

         {

             if (data != null) return data;

-            data = new byte[Width * Height / 8 * 2];

+            data = new byte[Height * 2]; // two bits per pixel

             lock (data)

             {

-                int pixel = 0;

-                byte bit = 7;

+                int pixel = 0; // total pixels counter

+                byte bit = 7;  // bit number

                 for (int y = 0; y < Height; y++)

                 {

                     for (int x = 0; x < Width; x++)

                     {

-                        if ((Pixels[(y * Width) + x] & 1) != 0)

-                            data[(pixel / 64 * 2) + y] |= (byte)(1 << bit);

-                        if ((Pixels[(y * Width) + x] & 2) != 0)

-                            data[(pixel / 64 * 2) + y + 8] |= (byte)(1 << bit);

+                        // for each pixel

+                        if ((Pixels[(y * Width) + x] & 1) != 0) // check bit 0

+                            data[y / 8 * 16 + (y % 8)] |= (byte)(1 << bit);

+                        if ((Pixels[(y * Width) + x] & 2) != 0) // check bit 1

+                            data[y / 8 * 16 + (y % 8) + 8] |= (byte)(1 << bit);

                         pixel++;

-                        bit = (byte)((byte)(bit - 1) % 8);

+                        bit = (byte)((byte)(bit - 1) % 8); // decrease bit number, wrap around if need

                     }

                 }

             }

@@ -43,8 +44,8 @@ namespace com.clusterrr.Famicom.NesTiler
 

         public bool Equals(Tile other)

         {

-            var data1 = GetAsTileData();

-            var data2 = other.GetAsTileData();

+            var data1 = GetAsPatternData();

+            var data2 = other.GetAsPatternData();

             return Enumerable.SequenceEqual(data1, data2);

         }

 

@@ -52,7 +53,7 @@ namespace com.clusterrr.Famicom.NesTiler
         {

             if (hash != null) return hash.Value;

             var crc = new Crc32();

-            crc.Append(GetAsTileData());

+            crc.Append(GetAsPatternData());

             var hashBytes = crc.GetCurrentHash();

             hash = BitConverter.ToInt32(hashBytes, 0);

             return hash.Value;