I am reading the source code and found code like this:

```
// Octahedron Normal Vectors
// [Cigolle 2014, "A Survey of Efficient Representations for Independent Unit Vectors"]
// Mean Max
// oct 8:8 0.33709 0.94424
// snorm 8:8:8 0.17015 0.38588
// oct 10:10 0.08380 0.23467
// snorm 10:10:10 0.04228 0.09598
// oct 12:12 0.02091 0.05874
float2 UnitVectorToOctahedron( float3 N )
{
N.xy /= dot( 1, abs(N) );
if( N.z <= 0 )
{
N.xy = ( 1 - abs(N.yx) ) * ( N.xy >= 0 ? float2(1,1) : float2(-1,-1) );
}
return N.xy;
}
```

Wanna know what those values mean……