static void ComputeEndpoints(
ASTCPixel[] EndPoints,
int[] ColorValues,
uint ColorEndpointMode,
ref int ColorValuesPosition)
{
switch (ColorEndpointMode)
{
case 0:
{
uint[] 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:
{
uint[] 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:
{
uint[] 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:
{
int[] Val = ReadIntColorValues(4, ColorValues, ref ColorValuesPosition);
BitArrayStream.BitTransferSigned(ref Val[1], ref Val[0]);
BitArrayStream.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:
{
uint[] 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:
{
uint[] 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:
{
int[] Val = ReadIntColorValues(6, ColorValues, ref ColorValuesPosition);
BitArrayStream.BitTransferSigned(ref Val[1], ref Val[0]);
BitArrayStream.BitTransferSigned(ref Val[3], ref Val[2]);
BitArrayStream.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:
{
uint[] 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:
{
uint[] 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:
{
int[] Val = ReadIntColorValues(8, ColorValues, ref ColorValuesPosition);
BitArrayStream.BitTransferSigned(ref Val[1], ref Val[0]);
BitArrayStream.BitTransferSigned(ref Val[3], ref Val[2]);
BitArrayStream.BitTransferSigned(ref Val[5], ref Val[4]);
BitArrayStream.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?)");
}
}
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);
}
