SharpMath.float3x3.ComputeRotationMatrix C# (CSharp) Method

        public static float3x3 ComputeRotationMatrix( float3 _Source, float3 _Target )
        {
            SharpMath.float3x3	Result = new float3x3();
                            Result.MakeIdentity();

            float	e = _Source | _Target;
            bool	bReverse = e < 0.0f;
            if ( bReverse )
            {	// Revert target
                _Target = -_Target;
                e = -e;
            }

            if ( e > 1.0f - 0.000001f )
            {
                if ( bReverse )
                {	// Reverse final matrix
             					Result.SetRow0( -Result.GetRow0() );
             					Result.SetRow1( -Result.GetRow1() );
             					Result.SetRow2( -Result.GetRow2() );
                }

                return	Result;					// No rotation needed...
            }

            float3	Ortho = _Source ^ _Target;

            float	h = 1.0f / (1.0f + e);      // Optimization by Gottfried Chen

            Result.SetRow0(	new float3( e + h * Ortho.x * Ortho.x,
                                        h * Ortho.x * Ortho.y + Ortho.z,
                                        h * Ortho.x * Ortho.z - Ortho.y ) );

            Result.SetRow1( new float3( h * Ortho.x * Ortho.y - Ortho.z,
                                        e + h * Ortho.y * Ortho.y,
                                        h * Ortho.y * Ortho.z + Ortho.x ) );

            Result.SetRow2(	new float3( h * Ortho.x * Ortho.z + Ortho.y,
                                        h * Ortho.y * Ortho.z - Ortho.x,
                                        e + h * Ortho.z * Ortho.z ) );

            if ( bReverse )
            {	// Reverse final matrix
             				Result.SetRow0( -Result.GetRow0() );
             				Result.SetRow1( -Result.GetRow1() );
             				Result.SetRow2( -Result.GetRow2() );
            }

            return	Result;
        }