BRDFSlices.DisplayPanel.Convert C# (CSharp) Method

        protected void Convert( double _Theta, double _Phi, out double _ThetaH, out double _ThetaD )
        {
            double	HalfPhi = 0.5 * _Phi;
            // //			_ThetaH = Math.Atan( Math.Cos( _Theta ) / (Math.Sin( _Theta ) * Math.Cos( HalfPhi ) ) );
            // 			_ThetaH = Math.Atan( Math.Tan( _Theta ) * Math.Cos( HalfPhi ) );
            //
            // 			double	SinSq = 2.0 * Math.Sin( _Theta )*Math.Sin( _Theta ) * Math.Sin( HalfPhi )*Math.Sin( HalfPhi );
            // 			_ThetaD = 0.5 * Math.Acos( 1.0 - SinSq );

            _ThetaD = Math.Asin( Math.Sin( HalfPhi ) * Math.Sin( _Theta ) );
            _ThetaH = Math.Atan( Math.Cos( HalfPhi ) * Math.Tan( _Theta ) );
        }