StandardizedDiffuseAlbedoMaps.Form1.IntegrateLuminance C# (CSharp) Method

        private ImageUtility.float3 IntegrateLuminance( float _X, float _Y, float _Radius, out ImageUtility.float3 _MinXYZ, out ImageUtility.float3 _MaxXYZ, out float _PercentOfBlackValues, out float _PercentOfSaturatedValues )
        {
            float	Radius = Math.Max( 1, _Radius * m_BitmapXYZ.Width );
            float	CenterX = _X * m_BitmapXYZ.Width;
            float	CenterY = _Y * m_BitmapXYZ.Height;
            float	SqRadius = Radius*Radius;

            int		X0 = Math.Max( 0, Math.Min( m_BitmapXYZ.Width-1, (int) Math.Floor( CenterX - Radius ) ) );
            int		X1 = Math.Max( 0, Math.Min( m_BitmapXYZ.Width-1, (int) Math.Ceiling( CenterX + Radius ) ) );
            int		Y0 = Math.Max( 0, Math.Min( m_BitmapXYZ.Height-1, (int) Math.Floor( CenterY - Radius ) ) );
            int		Y1 = Math.Max( 0, Math.Min( m_BitmapXYZ.Height-1, (int) Math.Ceiling( CenterY + Radius ) ) );

            const float	SMOOTHSTEP_MAX_RADIUS = 0.2f;	// We reach max weight 1 at 20% of the border of the circle

            bool	ApplySpatialCorrection = checkBoxSpatialLuminanceCorrection.Checked;

            int		TotalBlackValuesCount = 0;
            int		TotalSaturatedValuesCount = 0;
            int		TotalValuesCount = 0;
            ImageUtility.float3	SumXYZ = new ImageUtility.float3( 0, 0, 0 );
            _MinXYZ = new ImageUtility.float3( 0, +float.MaxValue, 0 );
            _MaxXYZ = new ImageUtility.float3( 0, 0, 0 );
            float	SumWeights = 0.0f;
            for ( int Y=Y0; Y < Y1; Y++ )
                for ( int X=X0; X < X1; X++ )
                {
                    float	SqR = (X-CenterX)*(X-CenterX) + (Y-CenterY)*(Y-CenterY);
                    if ( SqR > SqRadius )
                        continue;

                    float	r = (float) Math.Sqrt( SqR ) / Radius;	// Nomalized radius
            //					float	Weight = Math.Min( 1.0f, floatTrackbarControl1.Value * (float) Math.Exp( -floatTrackbarControl2.Value * r ) );

                    float	x = Math.Max( 0.0f, Math.Min( 1.0f, (1.0f - r) / SMOOTHSTEP_MAX_RADIUS ) );
                    float	Weight = x*x*(3.0f - 2.0f*x);

            //DEBUG					m_BitmapXYZ.ContentXYZ[X,Y].y = Weight;
                    ImageUtility.float3	XYZ = (ImageUtility.float3) m_BitmapXYZ.ContentXYZ[X,Y];
                    if ( ApplySpatialCorrection )
                    {
                        ImageUtility.float3	xyY = ImageUtility.ColorProfile.XYZ2xyY( XYZ );
                        xyY.z *= m_CalibrationDatabase.GetSpatialLuminanceCorrectionFactor( (float) X / m_BitmapXYZ.Width, (float) Y / m_BitmapXYZ.Height );
                        XYZ = ImageUtility.ColorProfile.xyY2XYZ( xyY );
                    }

                    if ( XYZ.y < 0.001f )
                        TotalBlackValuesCount++;		// Warning!
                    if ( XYZ.y > 0.999f )
                        TotalSaturatedValuesCount++;	// Warning!
                    TotalValuesCount++;

                    if ( XYZ.y < _MinXYZ.y )
                        _MinXYZ = XYZ;
                    if ( XYZ.y > _MaxXYZ.y )
                        _MaxXYZ = XYZ;
                    SumXYZ += Weight * XYZ;
                    SumWeights += Weight;
                }

            //DEBUG			RebuildImage();

            _PercentOfBlackValues = (float) TotalBlackValuesCount / TotalValuesCount;
            _PercentOfSaturatedValues = (float) TotalSaturatedValuesCount / TotalValuesCount;

            SumXYZ = (1.0f/SumWeights) * SumXYZ;
            return SumXYZ;
        }