ColorEncoding.cs

using UnityEngine;
namespace AirControl
{
    public class ColorEncoding
    {
        public static byte ReverseBits(byte value)
        {
            return (byte)((value * 0x0202020202 & 0x010884422010) % 1023);
        }
 
        public static int SparsifyBits(byte value, int sparse)
        {
            int retVal = 0;
            for (int bits = 0; bits < 8; bits++, value >>= 1)
            {
                retVal |= (value & 1);
                retVal <<= sparse;
            }
            return retVal >> sparse;
        }
 
        public static Color EncodeIDAsColor(int instanceId)
        {
            var uid = instanceId * 2;
            if (uid < 0)
                uid = -uid + 1;
 
            var sid =
                (SparsifyBits((byte)(uid >> 16), 3) << 2) |
                (SparsifyBits((byte)(uid >> 8), 3) << 1) |
                SparsifyBits((byte)(uid), 3);
            //Debug.Log(uid + " >>> " + System.Convert.ToString(sid, 2).PadLeft(24, '0'));
 
            var r = (byte)(sid >> 8);
            var g = (byte)(sid >> 16);
            var b = (byte)(sid);
 
            //Debug.Log(r + " " + g + " " + b);
            return new Color32(r, g, b, 255);
        }
 
        public static Color EncodeTagAsColor(string tag)
        {
            var hash = tag.GetHashCode();
            var a = (byte)(hash >> 24);
            var r = (byte)(hash >> 16);
            var g = (byte)(hash >> 8);
            var b = (byte)(hash);
            return new Color32(r, g, b, a);
        }
 
        public static Color EncodeLayerAsColor(int layer)
        {
            // Following value must be in the range (0.5 .. 1.0)
            // in order to avoid color overlaps when using 'divider' in this func
            var z = .7f;
 
            // First 8 layers are Unity Builtin layers
            // Unity supports up to 32 layers in total
 
            // Lets create palette of unique 16 colors
            var uniqueColors = new Color[] {
                new Color(1,1,1,1), new Color(z,z,z,1),                     // 0
                new Color(1,1,z,1), new Color(1,z,1,1), new Color(z,1,1,1), // 
                new Color(1,z,0,1), new Color(z,0,1,1), new Color(0,1,z,1), // 7
 
                new Color(1,0,0,1), new Color(0,1,0,1), new Color(0,0,1,1), // 8
                new Color(1,1,0,1), new Color(1,0,1,1), new Color(0,1,1,1), // 
                new Color(1,z,z,1), new Color(z,1,z,1)                      // 15
            };
 
            // Create as many colors as necessary by using base 16 color palette
            // To create more than 16 - will simply adjust brightness with 'divider'
            var color = uniqueColors[layer % uniqueColors.Length];
            var divider = 1.0f + Mathf.Floor(layer / uniqueColors.Length);
            color /= divider;
 
            return color;
        }
    }
}