using Ryujinx.Common.Utilities; using System; using System.Diagnostics; using System.Linq; using System.Runtime.CompilerServices; using System.Runtime.InteropServices; namespace Ryujinx.Graphics.Texture.Astc { // https://github.com/GammaUNC/FasTC/blob/master/ASTCEncoder/src/Decompressor.cpp public class AstcDecoder { private ReadOnlyMemory InputBuffer { get; } private Memory OutputBuffer { get; } private int BlockSizeX { get; } private int BlockSizeY { get; } private AstcLevel[] Levels { get; } private bool Success { get; set; } public int TotalBlockCount { get; } public AstcDecoder( ReadOnlyMemory inputBuffer, Memory outputBuffer, int blockWidth, int blockHeight, int width, int height, int depth, int levels) { if ((uint)blockWidth > 12) { throw new ArgumentOutOfRangeException(nameof(blockWidth)); } if ((uint)blockHeight > 12) { throw new ArgumentOutOfRangeException(nameof(blockHeight)); } InputBuffer = inputBuffer; OutputBuffer = outputBuffer; BlockSizeX = blockWidth; BlockSizeY = blockHeight; Levels = new AstcLevel[levels]; Success = true; TotalBlockCount = 0; int currentInputBlock = 0; int currentOutputOffset = 0; for (int i = 0; i < levels; i++) { ref AstcLevel level = ref Levels[i]; level.ImageSizeX = Math.Max(1, width >> i); level.ImageSizeY = Math.Max(1, height >> i); level.ImageSizeZ = Math.Max(1, depth >> i); level.BlockCountX = (level.ImageSizeX + blockWidth - 1) / blockWidth; level.BlockCountY = (level.ImageSizeY + blockHeight - 1) / blockHeight; level.StartBlock = currentInputBlock; level.OutputByteOffset = currentOutputOffset; currentInputBlock += level.TotalBlockCount; currentOutputOffset += level.PixelCount * 4; } TotalBlockCount = currentInputBlock; } private struct AstcLevel { public int ImageSizeX { get; set; } public int ImageSizeY { get; set; } public int ImageSizeZ { get; set; } public int BlockCountX { get; set; } public int BlockCountY { get; set; } public int StartBlock { get; set; } public int OutputByteOffset { get; set; } public int TotalBlockCount => BlockCountX * BlockCountY * ImageSizeZ; public int PixelCount => ImageSizeX * ImageSizeY * ImageSizeZ; } public static int QueryDecompressedSize(int sizeX, int sizeY, int sizeZ, int levelCount) { int size = 0; for (int i = 0; i < levelCount; i++) { int levelSizeX = Math.Max(1, sizeX >> i); int levelSizeY = Math.Max(1, sizeY >> i); int levelSizeZ = Math.Max(1, sizeZ >> i); size += levelSizeX * levelSizeY * levelSizeZ; } return size * 4; } public void ProcessBlock(int index) { Buffer16 inputBlock = MemoryMarshal.Cast(InputBuffer.Span)[index]; Span decompressedData = stackalloc int[144]; try { DecompressBlock(inputBlock, decompressedData, BlockSizeX, BlockSizeY); } catch (Exception) { Success = false; } Span decompressedBytes = MemoryMarshal.Cast(decompressedData); AstcLevel levelInfo = GetLevelInfo(index); WriteDecompressedBlock(decompressedBytes, OutputBuffer.Span.Slice(levelInfo.OutputByteOffset), index - levelInfo.StartBlock, levelInfo); } private AstcLevel GetLevelInfo(int blockIndex) { foreach (AstcLevel levelInfo in Levels) { if (blockIndex < levelInfo.StartBlock + levelInfo.TotalBlockCount) { return levelInfo; } } throw new AstcDecoderException("Invalid block index."); } private void WriteDecompressedBlock(ReadOnlySpan block, Span outputBuffer, int blockIndex, AstcLevel level) { int stride = level.ImageSizeX * 4; int blockCordX = blockIndex % level.BlockCountX; int blockCordY = blockIndex / level.BlockCountX; int pixelCordX = blockCordX * BlockSizeX; int pixelCordY = blockCordY * BlockSizeY; int outputPixelsX = Math.Min(pixelCordX + BlockSizeX, level.ImageSizeX) - pixelCordX; int outputPixelsY = Math.Min(pixelCordY + BlockSizeY, level.ImageSizeY * level.ImageSizeZ) - pixelCordY; int outputStart = pixelCordX * 4 + pixelCordY * stride; int outputOffset = outputStart; int inputOffset = 0; for (int i = 0; i < outputPixelsY; i++) { ReadOnlySpan blockRow = block.Slice(inputOffset, outputPixelsX * 4); Span outputRow = outputBuffer.Slice(outputOffset); blockRow.CopyTo(outputRow); inputOffset += BlockSizeX * 4; outputOffset += stride; } } struct TexelWeightParams { public int Width; public int Height; public int MaxWeight; public bool DualPlane; public bool Error; public bool VoidExtentLdr; public bool VoidExtentHdr; public int GetPackedBitSize() { // How many indices do we have? int indices = Height * Width; if (DualPlane) { indices *= 2; } IntegerEncoded intEncoded = IntegerEncoded.CreateEncoding(MaxWeight); return intEncoded.GetBitLength(indices); } public int GetNumWeightValues() { int ret = Width * Height; if (DualPlane) { ret *= 2; } return ret; } } public static bool TryDecodeToRgba8( ReadOnlyMemory data, int blockWidth, int blockHeight, int width, int height, int depth, int levels, out Span decoded) { byte[] output = new byte[QueryDecompressedSize(width, height, depth, levels)]; AstcDecoder decoder = new AstcDecoder(data, output, blockWidth, blockHeight, width, height, depth, levels); for (int i = 0; i < decoder.TotalBlockCount; i++) { decoder.ProcessBlock(i); } decoded = output; return decoder.Success; } public static bool TryDecodeToRgba8( ReadOnlyMemory data, Memory outputBuffer, int blockWidth, int blockHeight, int width, int height, int depth, int levels) { AstcDecoder decoder = new AstcDecoder(data, outputBuffer, blockWidth, blockHeight, width, height, depth, levels); for (int i = 0; i < decoder.TotalBlockCount; i++) { decoder.ProcessBlock(i); } return decoder.Success; } public static bool TryDecodeToRgba8P( ReadOnlyMemory data, Memory outputBuffer, int blockWidth, int blockHeight, int width, int height, int depth, int levels) { AstcDecoder decoder = new AstcDecoder(data, outputBuffer, blockWidth, blockHeight, width, height, depth, levels); // Lazy parallelism Enumerable.Range(0, decoder.TotalBlockCount).AsParallel().ForAll(x => decoder.ProcessBlock(x)); return decoder.Success; } public static bool TryDecodeToRgba8P( ReadOnlyMemory data, int blockWidth, int blockHeight, int width, int height, int depth, int levels, out Span decoded) { byte[] output = new byte[QueryDecompressedSize(width, height, depth, levels)]; AstcDecoder decoder = new AstcDecoder(data, output, blockWidth, blockHeight, width, height, depth, levels); Enumerable.Range(0, decoder.TotalBlockCount).AsParallel().ForAll(x => decoder.ProcessBlock(x)); decoded = output; return decoder.Success; } public static bool DecompressBlock( Buffer16 inputBlock, Span outputBuffer, int blockWidth, int blockHeight) { BitStream128 bitStream = new BitStream128(inputBlock); DecodeBlockInfo(ref bitStream, out TexelWeightParams texelParams); if (texelParams.Error) { throw new AstcDecoderException("Invalid block mode"); } if (texelParams.VoidExtentLdr) { FillVoidExtentLdr(ref bitStream, outputBuffer, blockWidth, blockHeight); return true; } if (texelParams.VoidExtentHdr) { throw new AstcDecoderException("HDR void extent blocks are not supported."); } if (texelParams.Width > blockWidth) { throw new AstcDecoderException("Texel weight grid width should be smaller than block width."); } if (texelParams.Height > blockHeight) { throw new AstcDecoderException("Texel weight grid height should be smaller than block height."); } // Read num partitions int numberPartitions = bitStream.ReadBits(2) + 1; Debug.Assert(numberPartitions <= 4); if (numberPartitions == 4 && texelParams.DualPlane) { throw new AstcDecoderException("Dual plane mode is incompatible with four partition blocks."); } // Based on the number of partitions, read the color endpoint mode for // each partition. // Determine partitions, partition index, and color endpoint modes int planeIndices; int partitionIndex; Span colorEndpointMode = stackalloc uint[4]; BitStream128 colorEndpointStream = new BitStream128(); // Read extra config data... uint baseColorEndpointMode = 0; if (numberPartitions == 1) { colorEndpointMode[0] = (uint)bitStream.ReadBits(4); partitionIndex = 0; } else { partitionIndex = bitStream.ReadBits(10); baseColorEndpointMode = (uint)bitStream.ReadBits(6); } uint baseMode = (baseColorEndpointMode & 3); // Remaining bits are color endpoint data... int numberWeightBits = texelParams.GetPackedBitSize(); int remainingBits = bitStream.BitsLeft - numberWeightBits; // Consider extra bits prior to texel data... uint extraColorEndpointModeBits = 0; if (baseMode != 0) { switch (numberPartitions) { case 2: extraColorEndpointModeBits += 2; break; case 3: extraColorEndpointModeBits += 5; break; case 4: extraColorEndpointModeBits += 8; break; default: Debug.Assert(false); break; } } remainingBits -= (int)extraColorEndpointModeBits; // Do we have a dual plane situation? int planeSelectorBits = 0; if (texelParams.DualPlane) { planeSelectorBits = 2; } remainingBits -= planeSelectorBits; // Read color data... int colorDataBits = remainingBits; while (remainingBits > 0) { int numberBits = Math.Min(remainingBits, 8); int bits = bitStream.ReadBits(numberBits); colorEndpointStream.WriteBits(bits, numberBits); remainingBits -= 8; } // Read the plane selection bits planeIndices = bitStream.ReadBits(planeSelectorBits); // Read the rest of the CEM if (baseMode != 0) { uint extraColorEndpointMode = (uint)bitStream.ReadBits((int)extraColorEndpointModeBits); uint tempColorEndpointMode = (extraColorEndpointMode << 6) | baseColorEndpointMode; tempColorEndpointMode >>= 2; Span c = stackalloc bool[4]; for (int i = 0; i < numberPartitions; i++) { c[i] = (tempColorEndpointMode & 1) != 0; tempColorEndpointMode >>= 1; } Span m = stackalloc byte[4]; for (int i = 0; i < numberPartitions; i++) { m[i] = (byte)(tempColorEndpointMode & 3); tempColorEndpointMode >>= 2; Debug.Assert(m[i] <= 3); } for (int i = 0; i < numberPartitions; i++) { colorEndpointMode[i] = baseMode; if (!(c[i])) colorEndpointMode[i] -= 1; colorEndpointMode[i] <<= 2; colorEndpointMode[i] |= m[i]; } } else if (numberPartitions > 1) { uint tempColorEndpointMode = baseColorEndpointMode >> 2; for (int i = 0; i < numberPartitions; i++) { colorEndpointMode[i] = tempColorEndpointMode; } } // Make sure everything up till here is sane. for (int i = 0; i < numberPartitions; i++) { Debug.Assert(colorEndpointMode[i] < 16); } Debug.Assert(bitStream.BitsLeft == texelParams.GetPackedBitSize()); // Decode both color data and texel weight data Span colorValues = stackalloc int[32]; // Four values * two endpoints * four maximum partitions DecodeColorValues(colorValues, ref colorEndpointStream, colorEndpointMode, numberPartitions, colorDataBits); EndPointSet endPoints; unsafe { _ = &endPoints; } // Skip struct initialization int colorValuesPosition = 0; for (int i = 0; i < numberPartitions; i++) { ComputeEndpoints(endPoints.Get(i), colorValues, colorEndpointMode[i], ref colorValuesPosition); } // Read the texel weight data. Buffer16 texelWeightData = inputBlock; // Reverse everything for (int i = 0; i < 8; i++) { byte a = ReverseByte(texelWeightData[i]); byte b = ReverseByte(texelWeightData[15 - i]); texelWeightData[i] = b; texelWeightData[15 - i] = a; } // Make sure that higher non-texel bits are set to zero int clearByteStart = (texelParams.GetPackedBitSize() >> 3) + 1; texelWeightData[clearByteStart - 1] &= (byte)((1 << (texelParams.GetPackedBitSize() % 8)) - 1); int cLen = 16 - clearByteStart; for (int i = clearByteStart; i < clearByteStart + cLen; i++) texelWeightData[i] = 0; IntegerSequence texelWeightValues; unsafe { _ = &texelWeightValues; } // Skip struct initialization texelWeightValues.Reset(); BitStream128 weightBitStream = new BitStream128(texelWeightData); IntegerEncoded.DecodeIntegerSequence(ref texelWeightValues, ref weightBitStream, texelParams.MaxWeight, texelParams.GetNumWeightValues()); // Blocks can be at most 12x12, so we can have as many as 144 weights Weights weights; unsafe { _ = &weights; } // Skip struct initialization UnquantizeTexelWeights(ref weights, ref texelWeightValues, ref texelParams, blockWidth, blockHeight); ushort[] table = Bits.Replicate8_16Table; // Now that we have endpoints and weights, we can interpolate and generate // the proper decoding... for (int j = 0; j < blockHeight; j++) { for (int i = 0; i < blockWidth; i++) { int partition = Select2dPartition(partitionIndex, i, j, numberPartitions, ((blockHeight * blockWidth) < 32)); Debug.Assert(partition < numberPartitions); AstcPixel pixel = new AstcPixel(); for (int component = 0; component < 4; component++) { int component0 = endPoints.Get(partition)[0].GetComponent(component); component0 = table[component0]; int component1 = endPoints.Get(partition)[1].GetComponent(component); component1 = table[component1]; int plane = 0; if (texelParams.DualPlane && (((planeIndices + 1) & 3) == component)) { plane = 1; } int weight = weights.Get(plane)[j * blockWidth + i]; int finalComponent = (component0 * (64 - weight) + component1 * weight + 32) / 64; if (finalComponent == 65535) { pixel.SetComponent(component, 255); } else { double finalComponentFloat = finalComponent; pixel.SetComponent(component, (int)(255.0 * (finalComponentFloat / 65536.0) + 0.5)); } } outputBuffer[j * blockWidth + i] = pixel.Pack(); } } return true; } // Blocks can be at most 12x12, so we can have as many as 144 weights [StructLayout(LayoutKind.Sequential, Size = 144 * sizeof(int) * Count)] private struct Weights { private int _start; public const int Count = 2; public Span this[int index] { get { if ((uint)index >= Count) { throw new ArgumentOutOfRangeException(); } ref int start = ref Unsafe.Add(ref _start, index * 144); return MemoryMarshal.CreateSpan(ref start, 144); } } [MethodImpl(MethodImplOptions.AggressiveInlining)] public Span Get(int index) { ref int start = ref Unsafe.Add(ref _start, index * 144); return MemoryMarshal.CreateSpan(ref start, 144); } } private static int Select2dPartition(int seed, int x, int y, int partitionCount, bool isSmallBlock) { return SelectPartition(seed, x, y, 0, partitionCount, isSmallBlock); } private static int SelectPartition(int seed, int x, int y, int z, int partitionCount, bool isSmallBlock) { if (partitionCount == 1) { return 0; } if (isSmallBlock) { x <<= 1; y <<= 1; z <<= 1; } seed += (partitionCount - 1) * 1024; int rightNum = Hash52((uint)seed); byte seed01 = (byte)(rightNum & 0xF); byte seed02 = (byte)((rightNum >> 4) & 0xF); byte seed03 = (byte)((rightNum >> 8) & 0xF); byte seed04 = (byte)((rightNum >> 12) & 0xF); byte seed05 = (byte)((rightNum >> 16) & 0xF); byte seed06 = (byte)((rightNum >> 20) & 0xF); byte seed07 = (byte)((rightNum >> 24) & 0xF); byte seed08 = (byte)((rightNum >> 28) & 0xF); byte seed09 = (byte)((rightNum >> 18) & 0xF); byte seed10 = (byte)((rightNum >> 22) & 0xF); byte seed11 = (byte)((rightNum >> 26) & 0xF); byte seed12 = (byte)(((rightNum >> 30) | (rightNum << 2)) & 0xF); seed01 *= seed01; seed02 *= seed02; seed03 *= seed03; seed04 *= seed04; seed05 *= seed05; seed06 *= seed06; seed07 *= seed07; seed08 *= seed08; seed09 *= seed09; seed10 *= seed10; seed11 *= seed11; seed12 *= seed12; int seedHash1, seedHash2, seedHash3; if ((seed & 1) != 0) { seedHash1 = (seed & 2) != 0 ? 4 : 5; seedHash2 = (partitionCount == 3) ? 6 : 5; } else { seedHash1 = (partitionCount == 3) ? 6 : 5; seedHash2 = (seed & 2) != 0 ? 4 : 5; } seedHash3 = (seed & 0x10) != 0 ? seedHash1 : seedHash2; seed01 >>= seedHash1; seed02 >>= seedHash2; seed03 >>= seedHash1; seed04 >>= seedHash2; seed05 >>= seedHash1; seed06 >>= seedHash2; seed07 >>= seedHash1; seed08 >>= seedHash2; seed09 >>= seedHash3; seed10 >>= seedHash3; seed11 >>= seedHash3; seed12 >>= seedHash3; int a = seed01 * x + seed02 * y + seed11 * z + (rightNum >> 14); int b = seed03 * x + seed04 * y + seed12 * z + (rightNum >> 10); int c = seed05 * x + seed06 * y + seed09 * z + (rightNum >> 6); int d = seed07 * x + seed08 * y + seed10 * z + (rightNum >> 2); a &= 0x3F; b &= 0x3F; c &= 0x3F; d &= 0x3F; if (partitionCount < 4) d = 0; if (partitionCount < 3) c = 0; if (a >= b && a >= c && a >= d) return 0; else if (b >= c && b >= d) return 1; else if (c >= d) return 2; return 3; } static int Hash52(uint val) { val ^= val >> 15; val -= val << 17; val += val << 7; val += val << 4; val ^= val >> 5; val += val << 16; val ^= val >> 7; val ^= val >> 3; val ^= val << 6; val ^= val >> 17; return (int)val; } static void UnquantizeTexelWeights( ref Weights outputBuffer, ref IntegerSequence weights, ref TexelWeightParams texelParams, int blockWidth, int blockHeight) { int weightIndices = 0; Weights unquantized; unsafe { _ = &unquantized; } // Skip struct initialization Span weightsList = weights.List; Span unquantized0 = unquantized[0]; Span unquantized1 = unquantized[1]; for (int i = 0; i < weightsList.Length; i++) { unquantized0[weightIndices] = UnquantizeTexelWeight(weightsList[i]); if (texelParams.DualPlane) { i++; unquantized1[weightIndices] = UnquantizeTexelWeight(weightsList[i]); if (i == weightsList.Length) { break; } } if (++weightIndices >= texelParams.Width * texelParams.Height) break; } // Do infill if necessary (Section C.2.18) ... int ds = (1024 + blockWidth / 2) / (blockWidth - 1); int dt = (1024 + blockHeight / 2) / (blockHeight - 1); int planeScale = texelParams.DualPlane ? 2 : 1; for (int plane = 0; plane < planeScale; plane++) { Span unquantizedSpan = unquantized.Get(plane); Span outputSpan = outputBuffer.Get(plane); for (int t = 0; t < blockHeight; t++) { for (int s = 0; s < blockWidth; s++) { int cs = ds * s; int ct = dt * t; int gs = (cs * (texelParams.Width - 1) + 32) >> 6; int gt = (ct * (texelParams.Height - 1) + 32) >> 6; int js = gs >> 4; int fs = gs & 0xF; int jt = gt >> 4; int ft = gt & 0x0F; int w11 = (fs * ft + 8) >> 4; int v0 = js + jt * texelParams.Width; int weight = 8; int wxh = texelParams.Width * texelParams.Height; if (v0 < wxh) { weight += unquantizedSpan[v0] * (16 - fs - ft + w11); if (v0 + 1 < wxh) { weight += unquantizedSpan[v0 + 1] * (fs - w11); } } if (v0 + texelParams.Width < wxh) { weight += unquantizedSpan[v0 + texelParams.Width] * (ft - w11); if (v0 + texelParams.Width + 1 < wxh) { weight += unquantizedSpan[v0 + texelParams.Width + 1] * w11; } } outputSpan[t * blockWidth + s] = weight >> 4; } } } } static int UnquantizeTexelWeight(IntegerEncoded intEncoded) { int bitValue = intEncoded.BitValue; int bitLength = intEncoded.NumberBits; int a = Bits.Replicate1_7(bitValue & 1); int b = 0, c = 0, d = 0; int result = 0; switch (intEncoded.GetEncoding()) { case IntegerEncoded.EIntegerEncoding.JustBits: result = Bits.Replicate(bitValue, bitLength, 6); break; case IntegerEncoded.EIntegerEncoding.Trit: { d = intEncoded.TritValue; Debug.Assert(d < 3); switch (bitLength) { case 0: { result = d switch { 0 => 0, 1 => 32, 2 => 63, _ => 0 }; break; } case 1: { c = 50; break; } case 2: { c = 23; int b2 = (bitValue >> 1) & 1; b = (b2 << 6) | (b2 << 2) | b2; break; } case 3: { c = 11; int cb = (bitValue >> 1) & 3; b = (cb << 5) | cb; break; } default: throw new AstcDecoderException("Invalid trit encoding for texel weight."); } break; } case IntegerEncoded.EIntegerEncoding.Quint: { d = intEncoded.QuintValue; Debug.Assert(d < 5); switch (bitLength) { case 0: { result = d switch { 0 => 0, 1 => 16, 2 => 32, 3 => 47, 4 => 63, _ => 0 }; break; } case 1: { c = 28; break; } case 2: { c = 13; int b2 = (bitValue >> 1) & 1; b = (b2 << 6) | (b2 << 1); break; } default: throw new AstcDecoderException("Invalid quint encoding for texel weight."); } break; } } if (intEncoded.GetEncoding() != IntegerEncoded.EIntegerEncoding.JustBits && bitLength > 0) { // Decode the value... result = d * c + b; result ^= a; result = (a & 0x20) | (result >> 2); } Debug.Assert(result < 64); // Change from [0,63] to [0,64] if (result > 32) { result += 1; } return result; } static byte ReverseByte(byte b) { // Taken from http://graphics.stanford.edu/~seander/bithacks.html#ReverseByteWith64Bits return (byte)((((b) * 0x80200802L) & 0x0884422110L) * 0x0101010101L >> 32); } static Span ReadUintColorValues(int number, Span colorValues, ref int colorValuesPosition) { Span ret = colorValues.Slice(colorValuesPosition, number); colorValuesPosition += number; return MemoryMarshal.Cast(ret); } static Span ReadIntColorValues(int number, Span colorValues, ref int colorValuesPosition) { Span ret = colorValues.Slice(colorValuesPosition, number); colorValuesPosition += number; return ret; } static void ComputeEndpoints( Span endPoints, Span colorValues, uint colorEndpointMode, ref int colorValuesPosition) { switch (colorEndpointMode) { case 0: { Span val = ReadUintColorValues(2, colorValues, ref colorValuesPosition); endPoints[0] = new AstcPixel(0xFF, (short)val[0], (short)val[0], (short)val[0]); endPoints[1] = new AstcPixel(0xFF, (short)val[1], (short)val[1], (short)val[1]); break; } case 1: { Span val = ReadUintColorValues(2, colorValues, ref colorValuesPosition); int l0 = (int)((val[0] >> 2) | (val[1] & 0xC0)); int l1 = (int)Math.Max(l0 + (val[1] & 0x3F), 0xFFU); endPoints[0] = new AstcPixel(0xFF, (short)l0, (short)l0, (short)l0); endPoints[1] = new AstcPixel(0xFF, (short)l1, (short)l1, (short)l1); break; } case 4: { Span val = ReadUintColorValues(4, colorValues, ref colorValuesPosition); endPoints[0] = new AstcPixel((short)val[2], (short)val[0], (short)val[0], (short)val[0]); endPoints[1] = new AstcPixel((short)val[3], (short)val[1], (short)val[1], (short)val[1]); break; } case 5: { Span val = ReadIntColorValues(4, colorValues, ref colorValuesPosition); Bits.BitTransferSigned(ref val[1], ref val[0]); Bits.BitTransferSigned(ref val[3], ref val[2]); endPoints[0] = new AstcPixel((short)val[2], (short)val[0], (short)val[0], (short)val[0]); endPoints[1] = new AstcPixel((short)(val[2] + val[3]), (short)(val[0] + val[1]), (short)(val[0] + val[1]), (short)(val[0] + val[1])); endPoints[0].ClampByte(); endPoints[1].ClampByte(); break; } case 6: { Span val = ReadUintColorValues(4, colorValues, ref colorValuesPosition); endPoints[0] = new AstcPixel(0xFF, (short)(val[0] * val[3] >> 8), (short)(val[1] * val[3] >> 8), (short)(val[2] * val[3] >> 8)); endPoints[1] = new AstcPixel(0xFF, (short)val[0], (short)val[1], (short)val[2]); break; } case 8: { Span val = ReadUintColorValues(6, colorValues, ref colorValuesPosition); if (val[1] + val[3] + val[5] >= val[0] + val[2] + val[4]) { endPoints[0] = new AstcPixel(0xFF, (short)val[0], (short)val[2], (short)val[4]); endPoints[1] = new AstcPixel(0xFF, (short)val[1], (short)val[3], (short)val[5]); } else { endPoints[0] = AstcPixel.BlueContract(0xFF, (short)val[1], (short)val[3], (short)val[5]); endPoints[1] = AstcPixel.BlueContract(0xFF, (short)val[0], (short)val[2], (short)val[4]); } break; } case 9: { Span val = ReadIntColorValues(6, colorValues, ref colorValuesPosition); Bits.BitTransferSigned(ref val[1], ref val[0]); Bits.BitTransferSigned(ref val[3], ref val[2]); Bits.BitTransferSigned(ref val[5], ref val[4]); if (val[1] + val[3] + val[5] >= 0) { endPoints[0] = new AstcPixel(0xFF, (short)val[0], (short)val[2], (short)val[4]); endPoints[1] = new AstcPixel(0xFF, (short)(val[0] + val[1]), (short)(val[2] + val[3]), (short)(val[4] + val[5])); } else { endPoints[0] = AstcPixel.BlueContract(0xFF, val[0] + val[1], val[2] + val[3], val[4] + val[5]); endPoints[1] = AstcPixel.BlueContract(0xFF, val[0], val[2], val[4]); } endPoints[0].ClampByte(); endPoints[1].ClampByte(); break; } case 10: { Span val = ReadUintColorValues(6, colorValues, ref colorValuesPosition); endPoints[0] = new AstcPixel((short)val[4], (short)(val[0] * val[3] >> 8), (short)(val[1] * val[3] >> 8), (short)(val[2] * val[3] >> 8)); endPoints[1] = new AstcPixel((short)val[5], (short)val[0], (short)val[1], (short)val[2]); break; } case 12: { Span val = ReadUintColorValues(8, colorValues, ref colorValuesPosition); if (val[1] + val[3] + val[5] >= val[0] + val[2] + val[4]) { endPoints[0] = new AstcPixel((short)val[6], (short)val[0], (short)val[2], (short)val[4]); endPoints[1] = new AstcPixel((short)val[7], (short)val[1], (short)val[3], (short)val[5]); } else { endPoints[0] = AstcPixel.BlueContract((short)val[7], (short)val[1], (short)val[3], (short)val[5]); endPoints[1] = AstcPixel.BlueContract((short)val[6], (short)val[0], (short)val[2], (short)val[4]); } break; } case 13: { Span val = ReadIntColorValues(8, colorValues, ref colorValuesPosition); Bits.BitTransferSigned(ref val[1], ref val[0]); Bits.BitTransferSigned(ref val[3], ref val[2]); Bits.BitTransferSigned(ref val[5], ref val[4]); Bits.BitTransferSigned(ref val[7], ref val[6]); if (val[1] + val[3] + val[5] >= 0) { endPoints[0] = new AstcPixel((short)val[6], (short)val[0], (short)val[2], (short)val[4]); endPoints[1] = new AstcPixel((short)(val[7] + val[6]), (short)(val[0] + val[1]), (short)(val[2] + val[3]), (short)(val[4] + val[5])); } else { endPoints[0] = AstcPixel.BlueContract(val[6] + val[7], val[0] + val[1], val[2] + val[3], val[4] + val[5]); endPoints[1] = AstcPixel.BlueContract(val[6], val[0], val[2], val[4]); } endPoints[0].ClampByte(); endPoints[1].ClampByte(); break; } default: throw new AstcDecoderException("Unsupported color endpoint mode (is it HDR?)"); } } static void DecodeColorValues( Span outputValues, ref BitStream128 colorBitStream, Span modes, int numberPartitions, int numberBitsForColorData) { // First figure out how many color values we have int numberValues = 0; for (int i = 0; i < numberPartitions; i++) { numberValues += (int)((modes[i] >> 2) + 1) << 1; } // Then based on the number of values and the remaining number of bits, // figure out the max value for each of them... int range = 256; while (--range > 0) { IntegerEncoded intEncoded = IntegerEncoded.CreateEncoding(range); int bitLength = intEncoded.GetBitLength(numberValues); if (bitLength <= numberBitsForColorData) { // Find the smallest possible range that matches the given encoding while (--range > 0) { IntegerEncoded newIntEncoded = IntegerEncoded.CreateEncoding(range); if (!newIntEncoded.MatchesEncoding(intEncoded)) { break; } } // Return to last matching range. range++; break; } } // We now have enough to decode our integer sequence. IntegerSequence integerEncodedSequence; unsafe { _ = &integerEncodedSequence; } // Skip struct initialization integerEncodedSequence.Reset(); IntegerEncoded.DecodeIntegerSequence(ref integerEncodedSequence, ref colorBitStream, range, numberValues); // Once we have the decoded values, we need to dequantize them to the 0-255 range // This procedure is outlined in ASTC spec C.2.13 int outputIndices = 0; foreach (ref IntegerEncoded intEncoded in integerEncodedSequence.List) { int bitLength = intEncoded.NumberBits; int bitValue = intEncoded.BitValue; Debug.Assert(bitLength >= 1); int a = 0, b = 0, c = 0, d = 0; // A is just the lsb replicated 9 times. a = Bits.Replicate(bitValue & 1, 1, 9); switch (intEncoded.GetEncoding()) { case IntegerEncoded.EIntegerEncoding.JustBits: { outputValues[outputIndices++] = Bits.Replicate(bitValue, bitLength, 8); break; } case IntegerEncoded.EIntegerEncoding.Trit: { d = intEncoded.TritValue; switch (bitLength) { case 1: { c = 204; break; } case 2: { c = 93; // B = b000b0bb0 int b2 = (bitValue >> 1) & 1; b = (b2 << 8) | (b2 << 4) | (b2 << 2) | (b2 << 1); break; } case 3: { c = 44; // B = cb000cbcb int cb = (bitValue >> 1) & 3; b = (cb << 7) | (cb << 2) | cb; break; } case 4: { c = 22; // B = dcb000dcb int dcb = (bitValue >> 1) & 7; b = (dcb << 6) | dcb; break; } case 5: { c = 11; // B = edcb000ed int edcb = (bitValue >> 1) & 0xF; b = (edcb << 5) | (edcb >> 2); break; } case 6: { c = 5; // B = fedcb000f int fedcb = (bitValue >> 1) & 0x1F; b = (fedcb << 4) | (fedcb >> 4); break; } default: throw new AstcDecoderException("Unsupported trit encoding for color values."); } break; } case IntegerEncoded.EIntegerEncoding.Quint: { d = intEncoded.QuintValue; switch (bitLength) { case 1: { c = 113; break; } case 2: { c = 54; // B = b0000bb00 int b2 = (bitValue >> 1) & 1; b = (b2 << 8) | (b2 << 3) | (b2 << 2); break; } case 3: { c = 26; // B = cb0000cbc int cb = (bitValue >> 1) & 3; b = (cb << 7) | (cb << 1) | (cb >> 1); break; } case 4: { c = 13; // B = dcb0000dc int dcb = (bitValue >> 1) & 7; b = (dcb << 6) | (dcb >> 1); break; } case 5: { c = 6; // B = edcb0000e int edcb = (bitValue >> 1) & 0xF; b = (edcb << 5) | (edcb >> 3); break; } default: throw new AstcDecoderException("Unsupported quint encoding for color values."); } break; } } if (intEncoded.GetEncoding() != IntegerEncoded.EIntegerEncoding.JustBits) { int T = d * c + b; T ^= a; T = (a & 0x80) | (T >> 2); outputValues[outputIndices++] = T; } } // Make sure that each of our values is in the proper range... for (int i = 0; i < numberValues; i++) { Debug.Assert(outputValues[i] <= 255); } } static void FillVoidExtentLdr(ref BitStream128 bitStream, Span outputBuffer, int blockWidth, int blockHeight) { // Don't actually care about the void extent, just read the bits... for (int i = 0; i < 4; ++i) { bitStream.ReadBits(13); } // Decode the RGBA components and renormalize them to the range [0, 255] ushort r = (ushort)bitStream.ReadBits(16); ushort g = (ushort)bitStream.ReadBits(16); ushort b = (ushort)bitStream.ReadBits(16); ushort a = (ushort)bitStream.ReadBits(16); int rgba = (r >> 8) | (g & 0xFF00) | ((b) & 0xFF00) << 8 | ((a) & 0xFF00) << 16; for (int j = 0; j < blockHeight; j++) { for (int i = 0; i < blockWidth; i++) { outputBuffer[j * blockWidth + i] = rgba; } } } static void DecodeBlockInfo(ref BitStream128 bitStream, out TexelWeightParams texelParams) { texelParams = new TexelWeightParams(); // Read the entire block mode all at once ushort modeBits = (ushort)bitStream.ReadBits(11); // Does this match the void extent block mode? if ((modeBits & 0x01FF) == 0x1FC) { if ((modeBits & 0x200) != 0) { texelParams.VoidExtentHdr = true; } else { texelParams.VoidExtentLdr = true; } // Next two bits must be one. if ((modeBits & 0x400) == 0 || bitStream.ReadBits(1) == 0) { texelParams.Error = true; } return; } // First check if the last four bits are zero if ((modeBits & 0xF) == 0) { texelParams.Error = true; return; } // If the last two bits are zero, then if bits // [6-8] are all ones, this is also reserved. if ((modeBits & 0x3) == 0 && (modeBits & 0x1C0) == 0x1C0) { texelParams.Error = true; return; } // Otherwise, there is no error... Figure out the layout // of the block mode. Layout is determined by a number // between 0 and 9 corresponding to table C.2.8 of the // ASTC spec. int layout; if ((modeBits & 0x1) != 0 || (modeBits & 0x2) != 0) { // layout is in [0-4] if ((modeBits & 0x8) != 0) { // layout is in [2-4] if ((modeBits & 0x4) != 0) { // layout is in [3-4] if ((modeBits & 0x100) != 0) { layout = 4; } else { layout = 3; } } else { layout = 2; } } else { // layout is in [0-1] if ((modeBits & 0x4) != 0) { layout = 1; } else { layout = 0; } } } else { // layout is in [5-9] if ((modeBits & 0x100) != 0) { // layout is in [7-9] if ((modeBits & 0x80) != 0) { // layout is in [7-8] Debug.Assert((modeBits & 0x40) == 0); if ((modeBits & 0x20) != 0) { layout = 8; } else { layout = 7; } } else { layout = 9; } } else { // layout is in [5-6] if ((modeBits & 0x80) != 0) { layout = 6; } else { layout = 5; } } } Debug.Assert(layout < 10); // Determine R int r = (modeBits >> 4) & 1; if (layout < 5) { r |= (modeBits & 0x3) << 1; } else { r |= (modeBits & 0xC) >> 1; } Debug.Assert(2 <= r && r <= 7); // Determine width & height switch (layout) { case 0: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 7) & 0x3; texelParams.Width = b + 4; texelParams.Height = a + 2; break; } case 1: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 7) & 0x3; texelParams.Width = b + 8; texelParams.Height = a + 2; break; } case 2: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 7) & 0x3; texelParams.Width = a + 2; texelParams.Height = b + 8; break; } case 3: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 7) & 0x1; texelParams.Width = a + 2; texelParams.Height = b + 6; break; } case 4: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 7) & 0x1; texelParams.Width = b + 2; texelParams.Height = a + 2; break; } case 5: { int a = (modeBits >> 5) & 0x3; texelParams.Width = 12; texelParams.Height = a + 2; break; } case 6: { int a = (modeBits >> 5) & 0x3; texelParams.Width = a + 2; texelParams.Height = 12; break; } case 7: { texelParams.Width = 6; texelParams.Height = 10; break; } case 8: { texelParams.Width = 10; texelParams.Height = 6; break; } case 9: { int a = (modeBits >> 5) & 0x3; int b = (modeBits >> 9) & 0x3; texelParams.Width = a + 6; texelParams.Height = b + 6; break; } default: // Don't know this layout... texelParams.Error = true; break; } // Determine whether or not we're using dual planes // and/or high precision layouts. bool d = ((layout != 9) && ((modeBits & 0x400) != 0)); bool h = (layout != 9) && ((modeBits & 0x200) != 0); if (h) { ReadOnlySpan maxWeights = new byte[] { 9, 11, 15, 19, 23, 31 }; texelParams.MaxWeight = maxWeights[r - 2]; } else { ReadOnlySpan maxWeights = new byte[] { 1, 2, 3, 4, 5, 7 }; texelParams.MaxWeight = maxWeights[r - 2]; } texelParams.DualPlane = d; } } }