public static IntegerEncoded CreateEncoding(int MaxVal)
{
while (MaxVal > 0)
{
int Check = MaxVal + 1;
// Is maxVal a power of two?
if ((Check & (Check - 1)) == 0)
{
return(new IntegerEncoded(EIntegerEncoding.JustBits, BitArrayStream.PopCnt(MaxVal)));
}
// Is maxVal of the type 3*2^n - 1?
if ((Check % 3 == 0) && ((Check / 3) & ((Check / 3) - 1)) == 0)
{
return(new IntegerEncoded(EIntegerEncoding.Trit, BitArrayStream.PopCnt(Check / 3 - 1)));
}
// Is maxVal of the type 5*2^n - 1?
if ((Check % 5 == 0) && ((Check / 5) & ((Check / 5) - 1)) == 0)
{
return(new IntegerEncoded(EIntegerEncoding.Quint, BitArrayStream.PopCnt(Check / 5 - 1)));
}
// Apparently it can't be represented with a bounded integer sequence...
// just iterate.
MaxVal--;
}
return(new IntegerEncoded(EIntegerEncoding.JustBits, 0));
}
public static void DecodeIntegerSequence(
List <IntegerEncoded> DecodeIntegerSequence,
BitArrayStream BitStream,
int MaxRange,
int NumberValues)
{
// Determine encoding parameters
IntegerEncoded IntEncoded = CreateEncoding(MaxRange);
// Start decoding
int NumberValuesDecoded = 0;
while (NumberValuesDecoded < NumberValues)
{
switch (IntEncoded.GetEncoding())
{
case EIntegerEncoding.Quint:
{
DecodeQuintBlock(BitStream, DecodeIntegerSequence, IntEncoded.NumberBits);
NumberValuesDecoded += 3;
break;
}
case EIntegerEncoding.Trit:
{
DecodeTritBlock(BitStream, DecodeIntegerSequence, IntEncoded.NumberBits);
NumberValuesDecoded += 5;
break;
}
case EIntegerEncoding.JustBits:
{
IntEncoded.BitValue = BitStream.ReadBits(IntEncoded.NumberBits);
DecodeIntegerSequence.Add(IntEncoded);
NumberValuesDecoded++;
break;
}
}
}
}
short ChangeBitDepth(short Value, byte OldDepth, byte NewDepth)
{
Debug.Assert(NewDepth <= 8);
Debug.Assert(OldDepth <= 8);
if (OldDepth == NewDepth)
{
// Do nothing
return(Value);
}
else if (OldDepth == 0 && NewDepth != 0)
{
return((short)((1 << NewDepth) - 1));
}
else if (NewDepth > OldDepth)
{
return((short)BitArrayStream.Replicate(Value, OldDepth, NewDepth));
}
else
{
// oldDepth > newDepth
if (NewDepth == 0)
{
return(0xFF);
}
else
{
byte BitsWasted = (byte)(OldDepth - NewDepth);
short TempValue = Value;
TempValue = (short)((TempValue + (1 << (BitsWasted - 1))) >> BitsWasted);
TempValue = Math.Min(Math.Max((short)0, TempValue), (short)((1 << NewDepth) - 1));
return((byte)(TempValue));
}
}
}
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;
}
}
}
public static void DecodeTritBlock(
BitArrayStream BitStream,
List <IntegerEncoded> ListIntegerEncoded,
int NumberBitsPerValue)
{
// Implement the algorithm in section C.2.12
int[] m = new int[5];
int[] t = new int[5];
int T;
// Read the trit encoded block according to
// table C.2.14
m[0] = BitStream.ReadBits(NumberBitsPerValue);
T = BitStream.ReadBits(2);
m[1] = BitStream.ReadBits(NumberBitsPerValue);
T |= BitStream.ReadBits(2) << 2;
m[2] = BitStream.ReadBits(NumberBitsPerValue);
T |= BitStream.ReadBits(1) << 4;
m[3] = BitStream.ReadBits(NumberBitsPerValue);
T |= BitStream.ReadBits(2) << 5;
m[4] = BitStream.ReadBits(NumberBitsPerValue);
T |= BitStream.ReadBits(1) << 7;
int C = 0;
BitArrayStream Tb = new BitArrayStream(new BitArray(new int[] { T }));
if (Tb.ReadBits(2, 4) == 7)
{
C = (Tb.ReadBits(5, 7) << 2) | Tb.ReadBits(0, 1);
t[4] = t[3] = 2;
}
else
{
C = Tb.ReadBits(0, 4);
if (Tb.ReadBits(5, 6) == 3)
{
t[4] = 2;
t[3] = Tb.ReadBit(7);
}
else
{
t[4] = Tb.ReadBit(7);
t[3] = Tb.ReadBits(5, 6);
}
}
BitArrayStream Cb = new BitArrayStream(new BitArray(new int[] { C }));
if (Cb.ReadBits(0, 1) == 3)
{
t[2] = 2;
t[1] = Cb.ReadBit(4);
t[0] = (Cb.ReadBit(3) << 1) | (Cb.ReadBit(2) & ~Cb.ReadBit(3));
}
else if (Cb.ReadBits(2, 3) == 3)
{
t[2] = 2;
t[1] = 2;
t[0] = Cb.ReadBits(0, 1);
}
else
{
t[2] = Cb.ReadBit(4);
t[1] = Cb.ReadBits(2, 3);
t[0] = (Cb.ReadBit(1) << 1) | (Cb.ReadBit(0) & ~Cb.ReadBit(1));
}
for (int i = 0; i < 5; i++)
{
IntegerEncoded IntEncoded = new IntegerEncoded(EIntegerEncoding.Trit, NumberBitsPerValue)
{
BitValue = m[i],
TritValue = t[i]
};
ListIntegerEncoded.Add(IntEncoded);
}
}
public static void DecodeQuintBlock(
BitArrayStream BitStream,
List <IntegerEncoded> ListIntegerEncoded,
int NumberBitsPerValue)
{
// Implement the algorithm in section C.2.12
int[] m = new int[3];
int[] q = new int[3];
int Q;
// Read the trit encoded block according to
// table C.2.15
m[0] = BitStream.ReadBits(NumberBitsPerValue);
Q = BitStream.ReadBits(3);
m[1] = BitStream.ReadBits(NumberBitsPerValue);
Q |= BitStream.ReadBits(2) << 3;
m[2] = BitStream.ReadBits(NumberBitsPerValue);
Q |= BitStream.ReadBits(2) << 5;
BitArrayStream Qb = new BitArrayStream(new BitArray(new int[] { Q }));
if (Qb.ReadBits(1, 2) == 3 && Qb.ReadBits(5, 6) == 0)
{
q[0] = q[1] = 4;
q[2] = (Qb.ReadBit(0) << 2) | ((Qb.ReadBit(4) & ~Qb.ReadBit(0)) << 1) | (Qb.ReadBit(3) & ~Qb.ReadBit(0));
}
else
{
int C = 0;
if (Qb.ReadBits(1, 2) == 3)
{
q[2] = 4;
C = (Qb.ReadBits(3, 4) << 3) | ((~Qb.ReadBits(5, 6) & 3) << 1) | Qb.ReadBit(0);
}
else
{
q[2] = Qb.ReadBits(5, 6);
C = Qb.ReadBits(0, 4);
}
BitArrayStream Cb = new BitArrayStream(new BitArray(new int[] { C }));
if (Cb.ReadBits(0, 2) == 5)
{
q[1] = 4;
q[0] = Cb.ReadBits(3, 4);
}
else
{
q[1] = Cb.ReadBits(3, 4);
q[0] = Cb.ReadBits(0, 2);
}
}
for (int i = 0; i < 3; i++)
{
IntegerEncoded IntEncoded = new IntegerEncoded(EIntegerEncoding.Quint, NumberBitsPerValue)
{
BitValue = m[i],
QuintValue = q[i]
};
ListIntegerEncoded.Add(IntEncoded);
}
}
static void DecodeColorValues(
int[] OutputValues,
byte[] InputData,
uint[] 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.
List <IntegerEncoded> IntegerEncodedSequence = new List <IntegerEncoded>();
BitArrayStream ColorBitStream = new BitArrayStream(new BitArray(InputData));
IntegerEncoded.DecodeIntegerSequence(IntegerEncodedSequence, 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 (IntegerEncoded IntEncoded in IntegerEncodedSequence)
{
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 = BitArrayStream.Replicate(BitValue & 1, 1, 9);
switch (IntEncoded.GetEncoding())
{
case IntegerEncoded.EIntegerEncoding.JustBits:
{
OutputValues[OutputIndices++] = BitArrayStream.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 b = (BitValue >> 1) & 1;
B = (b << 8) | (b << 4) | (b << 2) | (b << 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 b = (BitValue >> 1) & 1;
B = (b << 8) | (b << 3) | (b << 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 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?)");
}
}
static int UnquantizeTexelWeight(IntegerEncoded IntEncoded)
{
int BitValue = IntEncoded.BitValue;
int BitLength = IntEncoded.NumberBits;
int A = BitArrayStream.Replicate(BitValue & 1, 1, 7);
int B = 0, C = 0, D = 0;
int Result = 0;
switch (IntEncoded.GetEncoding())
{
case IntegerEncoded.EIntegerEncoding.JustBits:
Result = BitArrayStream.Replicate(BitValue, BitLength, 6);
break;
case IntegerEncoded.EIntegerEncoding.Trit:
{
D = IntEncoded.TritValue;
Debug.Assert(D < 3);
switch (BitLength)
{
case 0:
{
int[] Results = { 0, 32, 63 };
Result = Results[D];
break;
}
case 1:
{
C = 50;
break;
}
case 2:
{
C = 23;
int b = (BitValue >> 1) & 1;
B = (b << 6) | (b << 2) | b;
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:
{
int[] Results = { 0, 16, 32, 47, 63 };
Result = Results[D];
break;
}
case 1:
{
C = 28;
break;
}
case 2:
{
C = 13;
int b = (BitValue >> 1) & 1;
B = (b << 6) | (b << 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 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 ASTCDecoderException("Invalid block mode");
}
if (TexelParams.VoidExtentLDR)
{
FillVoidExtentLDR(BitStream, OutputBuffer, BlockWidth, BlockHeight);
return(true);
}
if (TexelParams.VoidExtentHDR)
{
throw new ASTCDecoderException("HDR void extent blocks are unsupported!");
}
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 = -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);
}