private static int LeastDistance(byte[][] palette, byte[] colour, int offset)
{
if (colour[offset + 3] < (byte)8)
{
return(3);
}
int num1 = int.MaxValue;
int num2 = 0;
for (int index = 0; index < palette.Length && palette[index][3] == byte.MaxValue; ++index)
{
int num3 = ImageDataFormat.Distance(palette[index], 0, colour, offset);
if (num3 < num1)
{
if (num3 == 0)
{
return(index);
}
num1 = num3;
num2 = index;
}
}
return(num2);
}
private static byte[] ConvertBlockToQuaterCmpr(byte[] block)
{
int num1;
int num2 = num1 = -1;
int num3 = num1;
int num4 = num1;
bool flag = false;
byte[] numArray = new byte[8];
for (int index1 = 0; index1 < 15; ++index1)
{
if (block[index1 * 4 + 3] < (byte)16)
{
flag = true;
}
else
{
for (int index2 = index1 + 1; index2 < 16; ++index2)
{
int num5 = ImageDataFormat.Distance(block, index1 * 4, block, index2 * 4);
if (num5 > num4)
{
num4 = num5;
num3 = index1;
num2 = index2;
}
}
}
}
byte[][] palette;
if (num4 == -1)
{
palette = new byte[4][]
{
new byte[4] {
(byte)0, (byte)0, (byte)0, byte.MaxValue
},
new byte[4]
{
byte.MaxValue,
byte.MaxValue,
byte.MaxValue,
byte.MaxValue
},
null,
null
};
}
else
{
palette = new byte[4][]
{
new byte[4],
new byte[4],
null,
null
};
Array.Copy((Array)block, num3 * 4, (Array)palette[0], 0, 3);
palette[0][3] = byte.MaxValue;
Array.Copy((Array)block, num2 * 4, (Array)palette[1], 0, 3);
palette[1][3] = byte.MaxValue;
if ((int)palette[0][0] >> 3 == (int)palette[1][0] >> 3 && (int)palette[0][1] >> 2 == (int)palette[1][1] >> 2 && (int)palette[0][2] >> 3 == (int)palette[1][2] >> 3)
{
int num5 = (int)palette[0][0] >> 3 != 0 || (int)palette[0][1] >> 2 != 0 ? 1 : ((int)palette[0][2] >> 3 != 0 ? 1 : 0);
palette[1][0] = num5 != 0 ? (palette[1][1] = palette[1][2] = (byte)0) : (palette[1][1] = palette[1][2] = byte.MaxValue);
}
}
numArray[0] = (byte)((int)palette[0][2] & 248 | (int)palette[0][1] >> 5);
numArray[1] = (byte)((int)palette[0][1] << 3 & 224 | (int)palette[0][0] >> 3);
numArray[2] = (byte)((int)palette[1][2] & 248 | (int)palette[1][1] >> 5);
numArray[3] = (byte)((int)palette[1][1] << 3 & 224 | (int)palette[1][0] >> 3);
if (((int)numArray[0] > (int)numArray[2] ? 1 : ((int)numArray[0] != (int)numArray[2] ? 0 : ((int)numArray[1] >= (int)numArray[3] ? 1 : 0))) == (flag ? 1 : 0))
{
Array.Copy((Array)numArray, 0, (Array)numArray, 4, 2);
Array.Copy((Array)numArray, 2, (Array)numArray, 0, 2);
Array.Copy((Array)numArray, 4, (Array)numArray, 2, 2);
palette[2] = palette[0];
palette[0] = palette[1];
palette[1] = palette[2];
}
if (!flag)
{
palette[2] = new byte[4]
{
(byte)((((int)palette[0][0] << 1) + (int)palette[1][0]) / 3),
(byte)((((int)palette[0][1] << 1) + (int)palette[1][1]) / 3),
(byte)((((int)palette[0][2] << 1) + (int)palette[1][2]) / 3),
byte.MaxValue
};
palette[3] = new byte[4]
{
(byte)(((int)palette[0][0] + ((int)palette[1][0] << 1)) / 3),
(byte)(((int)palette[0][1] + ((int)palette[1][1] << 1)) / 3),
(byte)(((int)palette[0][2] + ((int)palette[1][2] << 1)) / 3),
byte.MaxValue
};
}
else
{
palette[2] = new byte[4]
{
(byte)((int)palette[0][0] + (int)palette[1][0] >> 1),
(byte)((int)palette[0][1] + (int)palette[1][1] >> 1),
(byte)((int)palette[0][2] + (int)palette[1][2] >> 1),
byte.MaxValue
};
palette[3] = new byte[4];
}
for (int index = 0; index < block.Length >> 4; ++index)
{
numArray[4 + index] = (byte)(ImageDataFormat.LeastDistance(palette, block, index * 16) << 6 | ImageDataFormat.LeastDistance(palette, block, index * 16 + 4) << 4 | ImageDataFormat.LeastDistance(palette, block, index * 16 + 8) << 2 | ImageDataFormat.LeastDistance(palette, block, index * 16 + 12));
}
return(numArray);
}