Add support for swizzled Switch textures

Co-Authored-By: nesrak1 <12544505+nesrak1@users.noreply.github.com>

AssetStudio/Classes/Texture2D.cs

@@ -14,12 +14,13 @@ namespace AssetStudio
         public int m_MipCount;
         public GLTextureSettings m_TextureSettings;
         public int m_ImageCount;
+        public byte[] m_PlatformBlob;
         public ResourceReader image_data;
         public StreamingInfo m_StreamData;
 
         public Texture2D() { }
 
-        public Texture2D(Texture2DArray m_Texture2DArray, int layer)
+        public Texture2D(Texture2DArray m_Texture2DArray, int layer) // Texture2DArrayImage
         {
             reader = m_Texture2DArray.reader;
             assetsFile = m_Texture2DArray.assetsFile;
@@ -63,6 +64,7 @@ namespace AssetStudio
             m_ImageCount = parsedTex2d.m_ImageCount;
             m_TextureSettings = parsedTex2d.m_TextureSettings;
             m_StreamData = parsedTex2d.m_StreamData;
+            m_PlatformBlob = parsedTex2d.m_PlatformBlob ?? Array.Empty<byte>();
 
             image_data = !string.IsNullOrEmpty(m_StreamData?.path)
                 ? new ResourceReader(m_StreamData.path, assetsFile, m_StreamData.offset, m_StreamData.size)
@@ -141,9 +143,13 @@ namespace AssetStudio
             }
             if (version[0] > 2020 || (version[0] == 2020 && version[1] >= 2)) //2020.2 and up
             {
-                var m_PlatformBlob = reader.ReadUInt8Array();
+                m_PlatformBlob = reader.ReadUInt8Array();
                 reader.AlignStream();
             }
+            else
+            {
+                m_PlatformBlob = Array.Empty<byte>();
+            }
             var image_data_size = reader.ReadInt32();
             if (image_data_size == 0 && ((version[0] == 5 && version[1] >= 3) || version[0] > 5))//5.3.0 and up
             {

AssetStudioGUI/AssetStudioGUIForm.cs

@@ -932,6 +932,8 @@ namespace AssetStudioGUI
                         }
                     }
                 }
+                var switchSwizzled = m_Texture2D.m_PlatformBlob.Length != 0;
+                assetItem.InfoText += assetItem.Asset.platform == BuildTarget.Switch ? $"\nUses texture swizzling: {switchSwizzled}" : "";
                 PreviewTexture(bitmap);
 
                 StatusStripUpdate("'Ctrl'+'R'/'G'/'B'/'A' for Channel Toggle");

AssetStudioUtility/Texture2DConverter.cs

@@ -9,20 +9,74 @@ namespace AssetStudio
         private ResourceReader reader;
         private int m_Width;
         private int m_Height;
+        private int m_WidthCrop;
+        private int m_HeightCrop;
         private TextureFormat m_TextureFormat;
+        private byte[] m_PlatformBlob;
         private int[] version;
         private BuildTarget platform;
-        public int outPutSize;
+        private int outPutDataSize;
+
+        private bool switchSwizzled;
+        private int gobsPerBlock;
+        private SixLabors.ImageSharp.Size blockSize;
+
+        public int OutputDataSize => outPutDataSize;
+        public bool UsesSwitchSwizzle => switchSwizzled;
 
         public Texture2DConverter(Texture2D m_Texture2D)
         {
             reader = m_Texture2D.image_data;
-            m_Width = m_Texture2D.m_Width;
+            m_WidthCrop = m_Texture2D.m_Width;
-            m_Height = m_Texture2D.m_Height;
+            m_HeightCrop = m_Texture2D.m_Height;
             m_TextureFormat = m_Texture2D.m_TextureFormat;
+            m_PlatformBlob = m_Texture2D.m_PlatformBlob;
             version = m_Texture2D.version;
             platform = m_Texture2D.platform;
-            outPutSize = m_Width * m_Height * 4;
+            // not guaranteed, you can have a swizzled texture without m_PlatformBlob
+            // but officially, I don't think this can happen. maybe check which engine
+            // version this started happening in...
+            switchSwizzled = platform == BuildTarget.Switch && m_PlatformBlob.Length != 0;
+            if (switchSwizzled)
+            {
+                SetupSwitchSwizzle();
+            }
+            else
+            {
+                m_Width = m_WidthCrop;
+                m_Height = m_HeightCrop;
+            }
+            outPutDataSize = m_Width * m_Height * 4;
+        }
+
+        private void SetupSwitchSwizzle()
+        {
+            //apparently there is another value to worry about, but seeing as it's
+            //always 0 and I have nothing else to test against, this will probably
+            //work fine for now
+            gobsPerBlock = 1 << BitConverter.ToInt32(m_PlatformBlob, 8);
+
+            //in older versions of unity, rgb24 has a platformBlob which shouldn't
+            //be possible. it turns out in this case, the image is just rgba32.
+            //probably shouldn't be modifying the texture2d here, but eh, who cares
+            if (m_TextureFormat == TextureFormat.RGB24)
+            {
+                m_TextureFormat = TextureFormat.RGBA32;
+            }
+            else if (m_TextureFormat == TextureFormat.BGR24)
+            {
+                m_TextureFormat = TextureFormat.BGRA32;
+            }
+
+            blockSize = Texture2DSwitchDeswizzler.GetTextureFormatBlockSize(m_TextureFormat);
+            var realSize = Texture2DSwitchDeswizzler.GetPaddedTextureSize(m_WidthCrop, m_HeightCrop, blockSize.Width, blockSize.Height, gobsPerBlock);
+            m_Width = realSize.Width;
+            m_Height = realSize.Height;
+        }
+
+        public SixLabors.ImageSharp.Size GetUncroppedSize()
+        {
+            return new SixLabors.ImageSharp.Size(m_Width, m_Height);
         }
 
         public bool DecodeTexture2D(byte[] bytes)
@@ -36,6 +90,11 @@ namespace AssetStudio
             try
             {
                 reader.GetData(buff);
+                if (switchSwizzled)
+                {
+                    buff = Texture2DSwitchDeswizzler.Unswizzle(buff, GetUncroppedSize(), blockSize, gobsPerBlock);
+                }
+
                 switch (m_TextureFormat)
                 {
                     case TextureFormat.Alpha8: //test pass
@@ -275,7 +334,7 @@ namespace AssetStudio
 
         private bool DecodeRGBA32(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = image_data[i + 2];
                 buff[i + 1] = image_data[i + 1];
@@ -287,7 +346,7 @@ namespace AssetStudio
 
         private bool DecodeARGB32(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = image_data[i + 3];
                 buff[i + 1] = image_data[i + 2];
@@ -354,7 +413,7 @@ namespace AssetStudio
 
         private bool DecodeBGRA32(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = image_data[i];
                 buff[i + 1] = image_data[i + 1];
@@ -366,7 +425,7 @@ namespace AssetStudio
 
         private bool DecodeRHalf(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = 0;
                 buff[i + 1] = 0;
@@ -378,7 +437,7 @@ namespace AssetStudio
 
         private bool DecodeRGHalf(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = 0;
                 buff[i + 1] = (byte)Math.Round(Half.ToHalf(image_data, i + 2) * 255f);
@@ -390,7 +449,7 @@ namespace AssetStudio
 
         private bool DecodeRGBAHalf(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = (byte)Math.Round(Half.ToHalf(image_data, i * 2 + 4) * 255f);
                 buff[i + 1] = (byte)Math.Round(Half.ToHalf(image_data, i * 2 + 2) * 255f);
@@ -402,7 +461,7 @@ namespace AssetStudio
 
         private bool DecodeRFloat(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = 0;
                 buff[i + 1] = 0;
@@ -414,7 +473,7 @@ namespace AssetStudio
 
         private bool DecodeRGFloat(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = 0;
                 buff[i + 1] = (byte)Math.Round(BitConverter.ToSingle(image_data, i * 2 + 4) * 255f);
@@ -426,7 +485,7 @@ namespace AssetStudio
 
         private bool DecodeRGBAFloat(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = (byte)Math.Round(BitConverter.ToSingle(image_data, i * 4 + 8) * 255f);
                 buff[i + 1] = (byte)Math.Round(BitConverter.ToSingle(image_data, i * 4 + 4) * 255f);
@@ -474,7 +533,7 @@ namespace AssetStudio
 
         private bool DecodeRGB9e5Float(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 var n = BitConverter.ToInt32(image_data, i);
                 var scale = n >> 27 & 0x1f;
@@ -652,7 +711,7 @@ namespace AssetStudio
 
         private bool DecodeRG32(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = 0;                                                                          //b
                 buff[i + 1] = DownScaleFrom16BitTo8Bit(BitConverter.ToUInt16(image_data, i + 2));     //g
@@ -677,7 +736,7 @@ namespace AssetStudio
 
         private bool DecodeRGBA64(byte[] image_data, byte[] buff)
         {
-            for (var i = 0; i < outPutSize; i += 4)
+            for (var i = 0; i < outPutDataSize; i += 4)
             {
                 buff[i] = DownScaleFrom16BitTo8Bit(BitConverter.ToUInt16(image_data, i * 2 + 4));     //b
                 buff[i + 1] = DownScaleFrom16BitTo8Bit(BitConverter.ToUInt16(image_data, i * 2 + 2)); //g

AssetStudioUtility/Texture2DExtensions.cs

@@ -10,20 +10,30 @@ namespace AssetStudio
         public static Image<Bgra32> ConvertToImage(this Texture2D m_Texture2D, bool flip)
         {
             var converter = new Texture2DConverter(m_Texture2D);
-            var buff = BigArrayPool<byte>.Shared.Rent(converter.outPutSize);
+            var uncroppedSize = converter.GetUncroppedSize();
+            var buff = BigArrayPool<byte>.Shared.Rent(converter.OutputDataSize);
             try
             {
-                if (converter.DecodeTexture2D(buff))
+                if (!converter.DecodeTexture2D(buff)) 
+                    return null;
+
+                Image<Bgra32> image;
+                if (converter.UsesSwitchSwizzle)
                 {
-                    var image = Image.LoadPixelData<Bgra32>(buff, m_Texture2D.m_Width, m_Texture2D.m_Height);
+                    image = Image.LoadPixelData<Bgra32>(buff, uncroppedSize.Width, uncroppedSize.Height);
+                    image.Mutate(x => x.Crop(m_Texture2D.m_Width, m_Texture2D.m_Height));
+                }
+                else
+                {
+                    image = Image.LoadPixelData<Bgra32>(buff, m_Texture2D.m_Width, m_Texture2D.m_Height);
+                }
+
                 if (flip)
                 {
                     image.Mutate(x => x.Flip(FlipMode.Vertical));
                 }
                 return image;
             }
-                return null;
-            }
             finally
             {
                 BigArrayPool<byte>.Shared.Return(buff, clearArray: true);

AssetStudioUtility/Texture2DSwitchDeswizzler.cs

@@ -0,0 +1,129 @@
+// https://github.com/nesrak1/AssetStudio/tree/switch-tex-deswizzle
+
+using SixLabors.ImageSharp;
+using System;
+
+namespace AssetStudio
+{
+    public class Texture2DSwitchDeswizzler
+    {
+        // referring to block here as a compressed texture block, not a gob one
+        const int GOB_X_TEXEL_COUNT = 4;
+        const int GOB_Y_TEXEL_COUNT = 8;
+        const int TEXEL_BYTE_SIZE = 16;
+        const int BLOCKS_IN_GOB = GOB_X_TEXEL_COUNT * GOB_Y_TEXEL_COUNT;
+        static readonly int[] GOB_X_POSES = {
+            0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 2, 2, 3, 3, 2, 2, 3, 3, 2, 2, 3, 3, 2, 2, 3, 3
+        };
+        static readonly int[] GOB_Y_POSES = {
+            0, 1, 0, 1, 2, 3, 2, 3, 4, 5, 4, 5, 6, 7, 6, 7, 0, 1, 0, 1, 2, 3, 2, 3, 4, 5, 4, 5, 6, 7, 6, 7
+        };
+
+        /*
+        sector:
+        A
+        B
+         
+        gob (made of sectors):
+        ABIJ
+        CDKL
+        EFMN
+        GHOP
+
+        gob blocks (example with height 2):
+        ACEGIK... from left to right of image
+        BDFHJL...
+        --------- start new row of blocks
+        MOQSUW...
+        NPRTVX...
+        */
+
+        private static int CeilDivide(int a, int b)
+        {
+            return (a + b - 1) / b;
+        }
+
+        internal static byte[] Unswizzle(byte[] data, Size imageSize, Size blockSize, int gobsPerBlock)
+        {
+            byte[] newData = new byte[data.Length];
+
+            int width = imageSize.Width;
+            int height = imageSize.Height;
+
+            int blockCountX = CeilDivide(width, blockSize.Width);
+            int blockCountY = CeilDivide(height, blockSize.Height);
+
+            int gobCountX = blockCountX / GOB_X_TEXEL_COUNT;
+            int gobCountY = blockCountY / GOB_Y_TEXEL_COUNT;
+
+            int srcPos = 0;
+            for (int i = 0; i < gobCountY / gobsPerBlock; i++)
+            {
+                for (int j = 0; j < gobCountX; j++)
+                {
+                    for (int k = 0; k < gobsPerBlock; k++)
+                    {
+                        for (int l = 0; l < BLOCKS_IN_GOB; l++)
+                        {
+                            int gobX = GOB_X_POSES[l];
+                            int gobY = GOB_Y_POSES[l];
+                            int gobDstX = j * GOB_X_TEXEL_COUNT + gobX;
+                            int gobDstY = (i * gobsPerBlock + k) * GOB_Y_TEXEL_COUNT + gobY;
+                            int gobDstLinPos = gobDstY * blockCountX * TEXEL_BYTE_SIZE + gobDstX * TEXEL_BYTE_SIZE;
+
+                            Array.Copy(data, srcPos, newData, gobDstLinPos, TEXEL_BYTE_SIZE);
+
+                            srcPos += TEXEL_BYTE_SIZE;
+                        }
+                    }
+                }
+            }
+            return newData;
+        }
+
+        //this should be the amount of pixels that can fit 16 bytes
+        internal static Size GetTextureFormatBlockSize(TextureFormat m_TextureFormat)
+        {
+            switch (m_TextureFormat)
+            {
+                case TextureFormat.Alpha8: return new Size(16, 1); // 1 byte per pixel
+                case TextureFormat.ARGB4444: return new Size(8, 1); // 2 bytes per pixel
+                case TextureFormat.RGBA32: return new Size(4, 1); // 4 bytes per pixel
+                case TextureFormat.ARGB32: return new Size(4, 1); // 4 bytes per pixel
+                case TextureFormat.ARGBFloat: return new Size(1, 1); // 16 bytes per pixel (?)
+                case TextureFormat.RGB565: return new Size(8, 1); // 2 bytes per pixel
+                case TextureFormat.R16: return new Size(8, 1); // 2 bytes per pixel
+                case TextureFormat.DXT1: return new Size(8, 4); // 8 bytes per 4x4=16 pixels
+                case TextureFormat.DXT5: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.RGBA4444: return new Size(8, 1); // 2 bytes per pixel
+                case TextureFormat.BGRA32: return new Size(4, 1); // 4 bytes per pixel
+                case TextureFormat.BC6H: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.BC7: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.BC4: return new Size(8, 4); // 8 bytes per 4x4=16 pixels
+                case TextureFormat.BC5: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.ASTC_RGB_4x4: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.ASTC_RGB_5x5: return new Size(5, 5); // 16 bytes per 5x5=25 pixels
+                case TextureFormat.ASTC_RGB_6x6: return new Size(6, 6); // 16 bytes per 6x6=36 pixels
+                case TextureFormat.ASTC_RGB_8x8: return new Size(8, 8); // 16 bytes per 8x8=64 pixels
+                case TextureFormat.ASTC_RGB_10x10: return new Size(10, 10); // 16 bytes per 10x10=100 pixels
+                case TextureFormat.ASTC_RGB_12x12: return new Size(12, 12); // 16 bytes per 12x12=144 pixels
+                case TextureFormat.ASTC_RGBA_4x4: return new Size(4, 4); // 16 bytes per 4x4=16 pixels
+                case TextureFormat.ASTC_RGBA_5x5: return new Size(5, 5); // 16 bytes per 5x5=25 pixels
+                case TextureFormat.ASTC_RGBA_6x6: return new Size(6, 6); // 16 bytes per 6x6=36 pixels
+                case TextureFormat.ASTC_RGBA_8x8: return new Size(8, 8); // 16 bytes per 8x8=64 pixels
+                case TextureFormat.ASTC_RGBA_10x10: return new Size(10, 10); // 16 bytes per 10x10=100 pixels
+                case TextureFormat.ASTC_RGBA_12x12: return new Size(12, 12); // 16 bytes per 12x12=144 pixels
+                case TextureFormat.RG16: return new Size(8, 1); // 2 bytes per pixel
+                case TextureFormat.R8: return new Size(16, 1); // 1 byte per pixel
+                default: throw new NotImplementedException();
+            };
+        }
+
+        internal static Size GetPaddedTextureSize(int width, int height, int blockWidth, int blockHeight, int gobsPerBlock)
+        {
+            width = CeilDivide(width, blockWidth * GOB_X_TEXEL_COUNT) * blockWidth * GOB_X_TEXEL_COUNT;
+            height = CeilDivide(height, blockHeight * GOB_Y_TEXEL_COUNT * gobsPerBlock) * blockHeight * GOB_Y_TEXEL_COUNT * gobsPerBlock;
+            return new Size(width, height);
+        }
+    }
+}