CSharpImageLibrary.DDS.DDS_BlockHelpers.Compress8BitBlock C# (CSharp) Method

        public static void Compress8BitBlock(byte[] source, int sourcePosition, int sourceLineLength, byte[] destination, int destPosition, int channel, bool isSigned)
        {
            // KFreon: Get min and max
            byte min = byte.MaxValue;
            byte max = byte.MinValue;
            int count = sourcePosition + channel;
            for (int i = 1; i <= 4; i++)
            {
                for (int j= 0; j < 4; j++)
                {
                    byte colour = source[count];
                    if (colour > max)
                        max = colour;
                    else if (colour < min)
                        min = colour;

                    count += 4; // skip to next entry in channel
                }
                count = sourcePosition + channel + sourceLineLength * i;
            }

            // Build Palette
            byte[] Colours = Build8BitPalette(min, max, isSigned);

            // Compress Pixels
            ulong line = 0;
            count = sourcePosition + channel;
            List<int> indicies = new List<int>();
            for (int i = 0; i < 4; i++)
            {
                for (int j = 0; j < 4; j++)
                {
                    int ind = (i << 2) + j;
                    byte colour = source[count];
                    int index = GetClosestValue(Colours, colour);
                    indicies.Add(index);
                    line |= (ulong)index << (ind * 3);
                    count += 4;  // Only need 1 channel
                }

                count = sourcePosition + channel + sourceLineLength * (i + 1);
            }

            byte[] compressed = BitConverter.GetBytes(line);
            destination[destPosition] = min;
            destination[destPosition + 1] = max;
            for (int i = 2; i < 8; i++)
                destination[destPosition + i] = compressed[i - 2];
        }