Support 3D BC4 and BC5 compressed textures (#1655)

* Support 3D BC4 and BC5 compressed textures

* PR feedback

* Fix some typos

Ryujinx.Graphics.GAL/Format.cs

@@ -341,5 +341,25 @@ namespace Ryujinx.Graphics.GAL
         {
             return format.IsUint() || format.IsSint();
         }
+
+        /// <summary>
+        /// Checks if the texture format is a BC4 compressed format.
+        /// </summary>
+        /// <param name="format">Texture format</param>
+        /// <returns>True if the texture format is a BC4 compressed format, false otherwise</returns>
+        public static bool IsBc4(this Format format)
+        {
+            return format == Format.Bc4Unorm || format == Format.Bc4Snorm;
+        }
+
+        /// <summary>
+        /// Checks if the texture format is a BC5 compressed format.
+        /// </summary>
+        /// <param name="format">Texture format</param>
+        /// <returns>True if the texture format is a BC5 compressed format, false otherwise</returns>
+        public static bool IsBc5(this Format format)
+        {
+            return format == Format.Bc5Unorm || format == Format.Bc5Snorm;
+        }
     }
 }

Ryujinx.Graphics.Gpu/Image/Texture.cs

@@ -671,6 +671,9 @@ namespace Ryujinx.Graphics.Gpu.Image
                     data);
             }
 
+            // Handle compressed cases not supported by the host:
+            // - ASTC is usually not supported on desktop cards.
+            // - BC4/BC5 is not supported on 3D textures.
             if (!_context.Capabilities.SupportsAstcCompression && Info.FormatInfo.Format.IsAstc())
             {
                 if (!AstcDecoder.TryDecodeToRgba8(
@@ -691,6 +694,14 @@ namespace Ryujinx.Graphics.Gpu.Image
 
                 data = decoded;
             }
+            else if (Info.Target == Target.Texture3D && Info.FormatInfo.Format.IsBc4())
+            {
+                data = BCnDecoder.DecodeBC4(data, Info.Width, Info.Height, _depth, Info.Levels, _layers, Info.FormatInfo.Format == Format.Bc4Snorm);
+            }
+            else if (Info.Target == Target.Texture3D && Info.FormatInfo.Format.IsBc5())
+            {
+                data = BCnDecoder.DecodeBC5(data, Info.Width, Info.Height, _depth, Info.Levels, _layers, Info.FormatInfo.Format == Format.Bc5Snorm);
+            }
 
             return data;
         }
@@ -707,8 +718,7 @@ namespace Ryujinx.Graphics.Gpu.Image
         public void Flush(bool tracked = true)
         {
             IsModified = false;
-
-            if (Info.FormatInfo.Format.IsAstc())
+            if (TextureCompatibility.IsFormatHostIncompatible(Info, _context.Capabilities))
             {
                 return; // Flushing this format is not supported, as it may have been converted to another host format.
             }
@@ -739,10 +749,9 @@ namespace Ryujinx.Graphics.Gpu.Image
             _context.Renderer.BackgroundContextAction(() =>
             {
                 IsModified = false;
-                if (Info.FormatInfo.Format.IsAstc())
+                if (TextureCompatibility.IsFormatHostIncompatible(Info, _context.Capabilities))
                 {
-                    // ASTC textures are not in their original format, so cannot be flushed.
-                    return;
+                    return; // Flushing this format is not supported, as it may have been converted to another host format.
                 }
 
                 ITexture texture = HostTexture;

Ryujinx.Graphics.Gpu/Image/TextureCompatibility.cs

@@ -26,6 +26,68 @@ namespace Ryujinx.Graphics.Gpu.Image
             Bc7
         }
 
+        /// <summary>
+        /// Checks if a format is host incompatible.
+        /// </summary>
+        /// <remarks>
+        /// Host incompatible formats can't be used directly, the texture data needs to be converted
+        /// to a compatible format first.
+        /// </remarks>
+        /// <param name="info">Texture information</param>
+        /// <param name="caps">Host GPU capabilities</param>
+        /// <returns>True if the format is incompatible, false otherwise</returns>
+        public static bool IsFormatHostIncompatible(TextureInfo info, Capabilities caps)
+        {
+            Format originalFormat = info.FormatInfo.Format;
+            return ToHostCompatibleFormat(info, caps).Format != originalFormat;
+        }
+
+        /// <summary>
+        /// Converts a incompatible format to a host compatible format, or return the format directly
+        /// if it is already host compatible.
+        /// </summary>
+        /// <remarks>
+        /// This can be used to convert a incompatible compressed format to the decompressor
+        /// output format.
+        /// </remarks>
+        /// <param name="info">Texture information</param>
+        /// <param name="caps">Host GPU capabilities</param>
+        /// <returns>A host compatible format</returns>
+        public static FormatInfo ToHostCompatibleFormat(TextureInfo info, Capabilities caps)
+        {
+            if (!caps.SupportsAstcCompression)
+            {
+                if (info.FormatInfo.Format.IsAstcUnorm())
+                {
+                    return new FormatInfo(Format.R8G8B8A8Unorm, 1, 1, 4, 4);
+                }
+                else if (info.FormatInfo.Format.IsAstcSrgb())
+                {
+                    return new FormatInfo(Format.R8G8B8A8Srgb, 1, 1, 4, 4);
+                }
+            }
+
+            if (info.Target == Target.Texture3D)
+            {
+                // The host API does not support 3D BC4/BC5 compressed formats.
+                // We assume software decompression will be done for those textures,
+                // and so we adjust the format here to match the decompressor output.
+                switch (info.FormatInfo.Format)
+                {
+                    case Format.Bc4Unorm:
+                        return new FormatInfo(Format.R8Unorm, 1, 1, 1, 1);
+                    case Format.Bc4Snorm:
+                        return new FormatInfo(Format.R8Snorm, 1, 1, 1, 1);
+                    case Format.Bc5Unorm:
+                        return new FormatInfo(Format.R8G8Unorm, 1, 1, 2, 2);
+                    case Format.Bc5Snorm:
+                        return new FormatInfo(Format.R8G8Snorm, 1, 1, 2, 2);
+                }
+            }
+
+            return info.FormatInfo;
+        }
+
         /// <summary>
         /// Finds the appropriate depth format for a copy texture if the source texture has a depth format.
         /// </summary>

Ryujinx.Graphics.Gpu/Image/TextureManager.cs

@@ -1058,19 +1058,7 @@ namespace Ryujinx.Graphics.Gpu.Image
         /// <returns>The texture creation information</returns>
         public static TextureCreateInfo GetCreateInfo(TextureInfo info, Capabilities caps, float scale)
         {
-            FormatInfo formatInfo = info.FormatInfo;
-
-            if (!caps.SupportsAstcCompression)
-            {
-                if (formatInfo.Format.IsAstcUnorm())
-                {
-                    formatInfo = new FormatInfo(Format.R8G8B8A8Unorm, 1, 1, 4, 4);
-                }
-                else if (formatInfo.Format.IsAstcSrgb())
-                {
-                    formatInfo = new FormatInfo(Format.R8G8B8A8Srgb, 1, 1, 4, 4);
-                }
-            }
+            FormatInfo formatInfo = TextureCompatibility.ToHostCompatibleFormat(info, caps);
 
             if (info.Target == Target.TextureBuffer)
             {
@@ -1079,12 +1067,24 @@ namespace Ryujinx.Graphics.Gpu.Image
                 // The shader will need the appropriate conversion code to compensate.
                 switch (formatInfo.Format)
                 {
-                    case Format.R8Snorm:           formatInfo = new FormatInfo(Format.R8Sint,           1, 1, 1, 1); break;
-                    case Format.R16Snorm:          formatInfo = new FormatInfo(Format.R16Sint,          1, 1, 2, 1); break;
-                    case Format.R8G8Snorm:         formatInfo = new FormatInfo(Format.R8G8Sint,         1, 1, 2, 2); break;
-                    case Format.R16G16Snorm:       formatInfo = new FormatInfo(Format.R16G16Sint,       1, 1, 4, 2); break;
-                    case Format.R8G8B8A8Snorm:     formatInfo = new FormatInfo(Format.R8G8B8A8Sint,     1, 1, 4, 4); break;
-                    case Format.R16G16B16A16Snorm: formatInfo = new FormatInfo(Format.R16G16B16A16Sint, 1, 1, 8, 4); break;
+                    case Format.R8Snorm:
+                        formatInfo = new FormatInfo(Format.R8Sint, 1, 1, 1, 1);
+                        break;
+                    case Format.R16Snorm:
+                        formatInfo = new FormatInfo(Format.R16Sint, 1, 1, 2, 1);
+                        break;
+                    case Format.R8G8Snorm:
+                        formatInfo = new FormatInfo(Format.R8G8Sint, 1, 1, 2, 2);
+                        break;
+                    case Format.R16G16Snorm:
+                        formatInfo = new FormatInfo(Format.R16G16Sint, 1, 1, 4, 2);
+                        break;
+                    case Format.R8G8B8A8Snorm:
+                        formatInfo = new FormatInfo(Format.R8G8B8A8Sint, 1, 1, 4, 4);
+                        break;
+                    case Format.R16G16B16A16Snorm:
+                        formatInfo = new FormatInfo(Format.R16G16B16A16Sint, 1, 1, 8, 4);
+                        break;
                 }
             }
 

Ryujinx.Graphics.Texture/BCnDecoder.cs

@@ -0,0 +1,242 @@
+using Ryujinx.Common;
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.Texture
+{
+    public static class BCnDecoder
+    {
+        private const int BlockWidth = 4;
+        private const int BlockHeight = 4;
+
+        public static byte[] DecodeBC4(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers, bool signed)
+        {
+            int size = 0;
+
+            for (int l = 0; l < levels; l++)
+            {
+                size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers;
+            }
+
+            byte[] output = new byte[size];
+
+            ReadOnlySpan<ulong> data64 = MemoryMarshal.Cast<byte, ulong>(data);
+
+            Span<byte> rPal = stackalloc byte[8];
+
+            int baseOOffs = 0;
+
+            for (int l = 0; l < levels; l++)
+            {
+                int w = BitUtils.DivRoundUp(width, BlockWidth);
+                int h = BitUtils.DivRoundUp(height, BlockHeight);
+
+                for (int l2 = 0; l2 < layers; l2++)
+                {
+                    for (int z = 0; z < depth; z++)
+                    {
+                        for (int y = 0; y < h; y++)
+                        {
+                            int baseY = y * BlockHeight;
+
+                            for (int x = 0; x < w; x++)
+                            {
+                                int baseX = x * BlockWidth;
+                                int lineBaseOOffs = baseOOffs + baseX;
+
+                                ulong block = data64[0];
+
+                                rPal[0] = (byte)block;
+                                rPal[1] = (byte)(block >> 8);
+
+                                if (signed)
+                                {
+                                    CalculateBC3AlphaS(rPal);
+                                }
+                                else
+                                {
+                                    CalculateBC3Alpha(rPal);
+                                }
+
+                                ulong rI = block >> 16;
+
+                                for (int texel = 0; texel < BlockWidth * BlockHeight; texel++)
+                                {
+                                    int tX = texel & 3;
+                                    int tY = texel >> 2;
+
+                                    if (baseX + tX >= width || baseY + tY >= height)
+                                    {
+                                        continue;
+                                    }
+
+                                    int shift = texel * 3;
+
+                                    byte r = rPal[(int)((rI >> shift) & 7)];
+
+                                    int oOffs = lineBaseOOffs + tY * width + tX;
+
+                                    output[oOffs] = r;
+                                }
+
+                                data64 = data64.Slice(1);
+                            }
+
+                            baseOOffs += width * (baseY + BlockHeight > height ? (height & (BlockHeight - 1)) : BlockHeight);
+                        }
+                    }
+                }
+
+                width  = Math.Max(1, width  >> 1);
+                height = Math.Max(1, height >> 1);
+                depth  = Math.Max(1, depth  >> 1);
+            }
+
+            return output;
+        }
+
+        public static byte[] DecodeBC5(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers, bool signed)
+        {
+            int size = 0;
+
+            for (int l = 0; l < levels; l++)
+            {
+                size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers * 2;
+            }
+
+            byte[] output = new byte[size];
+
+            ReadOnlySpan<ulong> data64 = MemoryMarshal.Cast<byte, ulong>(data);
+
+            Span<byte> rPal = stackalloc byte[8];
+            Span<byte> gPal = stackalloc byte[8];
+
+            int baseOOffs = 0;
+
+            for (int l = 0; l < levels; l++)
+            {
+                int w = BitUtils.DivRoundUp(width, BlockWidth);
+                int h = BitUtils.DivRoundUp(height, BlockHeight);
+
+                for (int l2 = 0; l2 < layers; l2++)
+                {
+                    for (int z = 0; z < depth; z++)
+                    {
+                        for (int y = 0; y < h; y++)
+                        {
+                            int baseY = y * BlockHeight;
+
+                            for (int x = 0; x < w; x++)
+                            {
+                                int baseX = x * BlockWidth;
+                                int lineBaseOOffs = baseOOffs + baseX;
+
+                                ulong blockL = data64[0];
+                                ulong blockH = data64[1];
+
+                                rPal[0] = (byte)blockL;
+                                rPal[1] = (byte)(blockL >> 8);
+                                gPal[0] = (byte)blockH;
+                                gPal[1] = (byte)(blockH >> 8);
+
+                                if (signed)
+                                {
+                                    CalculateBC3AlphaS(rPal);
+                                    CalculateBC3AlphaS(gPal);
+                                }
+                                else
+                                {
+                                    CalculateBC3Alpha(rPal);
+                                    CalculateBC3Alpha(gPal);
+                                }
+
+                                ulong rI = blockL >> 16;
+                                ulong gI = blockH >> 16;
+
+                                for (int texel = 0; texel < BlockWidth * BlockHeight; texel++)
+                                {
+                                    int tX = texel & 3;
+                                    int tY = texel >> 2;
+
+                                    if (baseX + tX >= width || baseY + tY >= height)
+                                    {
+                                        continue;
+                                    }
+
+                                    int shift = texel * 3;
+
+                                    byte r = rPal[(int)((rI >> shift) & 7)];
+                                    byte g = gPal[(int)((gI >> shift) & 7)];
+
+                                    int oOffs = (lineBaseOOffs + tY * width + tX) * 2;
+
+                                    output[oOffs + 0] = r;
+                                    output[oOffs + 1] = g;
+                                }
+
+                                data64 = data64.Slice(2);
+                            }
+
+                            baseOOffs += width * (baseY + BlockHeight > height ? (height & (BlockHeight - 1)) : BlockHeight);
+                        }
+                    }
+                }
+
+                width  = Math.Max(1, width  >> 1);
+                height = Math.Max(1, height >> 1);
+                depth  = Math.Max(1, depth  >> 1);
+            }
+
+            return output;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+         private static void CalculateBC3Alpha(Span<byte> alpha)
+        {
+            for (int i = 2; i < 8; i++)
+            {
+                if (alpha[0] > alpha[1])
+                {
+                    alpha[i] = (byte)(((8 - i) * alpha[0] + (i - 1) * alpha[1]) / 7);
+                }
+                else if (i < 6)
+                {
+                    alpha[i] = (byte)(((6 - i) * alpha[0] + (i - 1) * alpha[1]) / 7);
+                }
+                else if (i == 6)
+                {
+                    alpha[i] = 0;
+                }
+                else /* i == 7 */
+                {
+                    alpha[i] = 0xff;
+                }
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static void CalculateBC3AlphaS(Span<byte> alpha)
+        {
+            for (int i = 2; i < 8; i++)
+            {
+                if ((sbyte)alpha[0] > (sbyte)alpha[1])
+                {
+                    alpha[i] = (byte)(((8 - i) * (sbyte)alpha[0] + (i - 1) * (sbyte)alpha[1]) / 7);
+                }
+                else if (i < 6)
+                {
+                    alpha[i] = (byte)(((6 - i) * (sbyte)alpha[0] + (i - 1) * (sbyte)alpha[1]) / 7);
+                }
+                else if (i == 6)
+                {
+                    alpha[i] = 0x80;
+                }
+                else /* i == 7 */
+                {
+                    alpha[i] = 0x7f;
+                }
+            }
+        }
+    }
+}

Ryujinx.sln

@@ -87,14 +87,6 @@ Global
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-		{8E7D36DD-9626-47E2-8EF5-8F2F66751C9C}.Debug|Any CPU.Build.0 = Debug|Any CPU
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-		{8E7D36DD-9626-47E2-8EF5-8F2F66751C9C}.Profile Release|Any CPU.ActiveCfg = Profile Release|Any CPU
-		{8E7D36DD-9626-47E2-8EF5-8F2F66751C9C}.Profile Release|Any CPU.Build.0 = Profile Release|Any CPU
-		{8E7D36DD-9626-47E2-8EF5-8F2F66751C9C}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{8E7D36DD-9626-47E2-8EF5-8F2F66751C9C}.Release|Any CPU.Build.0 = Release|Any CPU
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 		{5FD4E4F6-8928-4B3C-BE07-28A675C17226}.Debug|Any CPU.Build.0 = Debug|Any CPU
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