BRDFSlices.DisplayForm.PhiDiff_index C# (CSharp) Метод

        public static int PhiDiff_index( double _PhiDiff, out double _Interpolant )
        {
            // Because of reciprocity, the BRDF is unchanged under
            // _PhiDiff -> _PhiDiff + PI
            if ( _PhiDiff < 0.0 )
                _PhiDiff += Math.PI;

            // In: _PhiDiff in [0 .. PI]
            // Out: tmp in [0 .. 179]
            double	fIndex = 2*_PhiDiff / Math.PI * BRDF_SAMPLING_RES_PHI_D;
            int		Index = (int) Math.Floor( fIndex );
            _Interpolant = fIndex - Index;
                    Index = Math.Max( 0, Math.Min( Index, BRDF_SAMPLING_RES_PHI_D/2-1 ) );
            return Index;
        }