static void FillVoidExtentLDR(BitArrayStream BitStream, int[] 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 TexelWeightParams DecodeBlockInfo(BitArrayStream BitStream) { TexelWeightParams 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(TexelParams); } // First check if the last four bits are zero if ((ModeBits & 0xF) == 0) { TexelParams.Error = true; return(TexelParams); } // 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(TexelParams); } // 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 = 0; 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) { int[] MaxWeights = { 9, 11, 15, 19, 23, 31 }; TexelParams.MaxWeight = MaxWeights[R - 2]; } else { int[] MaxWeights = { 1, 2, 3, 4, 5, 7 }; TexelParams.MaxWeight = MaxWeights[R - 2]; } TexelParams.DualPlane = D; return(TexelParams); }
public static bool DecompressBlock( byte[] InputBuffer, int[] OutputBuffer, int BlockWidth, int BlockHeight) { BitArrayStream BitStream = new BitArrayStream(new BitArray(InputBuffer)); TexelWeightParams TexelParams = DecodeBlockInfo(BitStream); if (TexelParams.Error) { throw new Exception("Invalid block mode"); } // Console.WriteLine($"BlockWidth {BlockWidth} {BlockHeight} BlockHeight"); // Console.WriteLine($"TexelParams {TexelParams.Width} X {TexelParams.Height}"); if (TexelParams.VoidExtentLDR) { FillVoidExtentLDR(BitStream, OutputBuffer, BlockWidth, BlockHeight); return(true); } if (TexelParams.VoidExtentHDR) { throw new Exception("HDR void extent blocks are unsupported!"); } if (TexelParams.Width > BlockWidth) { throw new Exception("Texel weight grid width should be smaller than block width"); } if (TexelParams.Height > BlockHeight) { throw new Exception("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 Exception("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 = -1; int PartitionIndex; uint[] ColorEndpointMode = { 0, 0, 0, 0 }; BitArrayStream ColorEndpointStream = new BitArrayStream(new BitArray(16 * 8)); // 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 = 128 - NumberWeightBits - BitStream.Position; // 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; bool[] C = new bool[4]; for (int i = 0; i < NumberPartitions; i++) { C[i] = (TempColorEndpointMode & 1) != 0; TempColorEndpointMode >>= 1; } byte[] M = new 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 (uint 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.Position + TexelParams.GetPackedBitSize() == 128); // Decode both color data and texel weight data int[] ColorValues = new int[32]; // Four values * two endpoints * four maximum partitions DecodeColorValues(ColorValues, ColorEndpointStream.ToByteArray(), ColorEndpointMode, NumberPartitions, ColorDataBits); ASTCPixel[][] EndPoints = new ASTCPixel[4][]; EndPoints[0] = new ASTCPixel[2]; EndPoints[1] = new ASTCPixel[2]; EndPoints[2] = new ASTCPixel[2]; EndPoints[3] = new ASTCPixel[2]; int ColorValuesPosition = 0; for (int i = 0; i < NumberPartitions; i++) { ComputeEndpoints(EndPoints[i], ColorValues, ColorEndpointMode[i], ref ColorValuesPosition); } // Read the texel weight data. byte[] TexelWeightData = (byte[])InputBuffer.Clone(); // 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; } List <IntegerEncoded> TexelWeightValues = new List <IntegerEncoded>(); BitArrayStream WeightBitStream = new BitArrayStream(new BitArray(TexelWeightData)); IntegerEncoded.DecodeIntegerSequence(TexelWeightValues, WeightBitStream, TexelParams.MaxWeight, TexelParams.GetNumWeightValues()); // Blocks can be at most 12x12, so we can have as many as 144 weights int[][] Weights = new int[2][]; Weights[0] = new int[144]; Weights[1] = new int[144]; UnquantizeTexelWeights(Weights, TexelWeightValues, TexelParams, BlockWidth, BlockHeight); // 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(0, 0, 0, 0); for (int Component = 0; Component < 4; Component++) { int Component0 = EndPoints[Partition][0].GetComponent(Component); Component0 = BitArrayStream.Replicate(Component0, 8, 16); int Component1 = EndPoints[Partition][1].GetComponent(Component); Component1 = BitArrayStream.Replicate(Component1, 8, 16); int Plane = 0; if (TexelParams.DualPlane && (((PlaneIndices + 1) & 3) == Component)) { Plane = 1; } int Weight = Weights[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); }