#region --- License ---
/*
Copyright (c) 2006 - 2008 The Open Toolkit library.

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
 */
#endregion

using System;
using System.Runtime.InteropServices;

namespace OpenTK
{
    /// <summary>
    /// Represents a 3x3 Matrix
    /// </summary>
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    public struct Matrix3d : IEquatable<Matrix3d>
    {
        #region Fields
        
        /// <summary>
        /// First row of the matrix.
        /// </summary>
        public Vector3d Row0;
        
        /// <summary>
        /// Second row of the matrix.
        /// </summary>
        public Vector3d Row1;
        
        /// <summary>
        /// Third row of the matrix.
        /// </summary>
        public Vector3d Row2;
        
        /// <summary>
        /// The identity matrix.
        /// </summary>
        public static Matrix3d Identity = new Matrix3d(Vector3d.UnitX, Vector3d.UnitY, Vector3d.UnitZ);
        
#endregion
        
        #region Constructors
        
        /// <summary>
        /// Constructs a new instance.
        /// </summary>
        /// <param name="row0">Top row of the matrix</param>
        /// <param name="row1">Second row of the matrix</param>
        /// <param name="row2">Bottom row of the matrix</param>
        public Matrix3d(Vector3d row0, Vector3d row1, Vector3d row2)
        {
            Row0 = row0;
            Row1 = row1;
            Row2 = row2;
        }
        
        /// <summary>
        /// Constructs a new instance.
        /// </summary>
        /// <param name="m00">First item of the first row of the matrix.</param>
        /// <param name="m01">Second item of the first row of the matrix.</param>
        /// <param name="m02">Third item of the first row of the matrix.</param>
        /// <param name="m10">First item of the second row of the matrix.</param>
        /// <param name="m11">Second item of the second row of the matrix.</param>
        /// <param name="m12">Third item of the second row of the matrix.</param>
        /// <param name="m20">First item of the third row of the matrix.</param>
        /// <param name="m21">Second item of the third row of the matrix.</param>
        /// <param name="m22">Third item of the third row of the matrix.</param>
        public Matrix3d(
            double m00, double m01, double m02,
            double m10, double m11, double m12,
            double m20, double m21, double m22)
        {
            Row0 = new Vector3d(m00, m01, m02);
            Row1 = new Vector3d(m10, m11, m12);
            Row2 = new Vector3d(m20, m21, m22);
        }
        
#endregion
        
        #region Public Members
        
        #region Properties
        
        /// <summary>
        /// Gets the determinant of this matrix.
        /// </summary>
        public double Determinant
        {
            get
            {
                double m11 = Row0.X, m12 = Row0.Y, m13 = Row0.Z,
                m21 = Row1.X, m22 = Row1.Y, m23 = Row1.Z,
                m31 = Row2.X, m32 = Row2.Y, m33 = Row2.Z;
                
                return
                    m11 * m22 * m33 + m12 * m23 * m31 + m13 * m21 * m32
                        - m13 * m22 * m31 - m11 * m23 * m32 - m12 * m21 * m33;
            }
        }
        
        /// <summary>
        /// Gets the first column of this matrix.
        /// </summary>
        public Vector3d Column0
        {
            get { return new Vector3d(Row0.X, Row1.X, Row2.X); }
        }
        
        /// <summary>
        /// Gets the second column of this matrix.
        /// </summary>
        public Vector3d Column1
        {
            get { return new Vector3d(Row0.Y, Row1.Y, Row2.Y); }
        }
        
        /// <summary>
        /// Gets the third column of this matrix.
        /// </summary>
        public Vector3d Column2
        {
            get { return new Vector3d(Row0.Z, Row1.Z, Row2.Z); }
        }
        
        /// <summary>
        /// Gets or sets the value at row 1, column 1 of this instance.
        /// </summary>
        public double M11 { get { return Row0.X; } set { Row0.X = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 1, column 2 of this instance.
        /// </summary>
        public double M12 { get { return Row0.Y; } set { Row0.Y = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 1, column 3 of this instance.
        /// </summary>
        public double M13 { get { return Row0.Z; } set { Row0.Z = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 2, column 1 of this instance.
        /// </summary>
        public double M21 { get { return Row1.X; } set { Row1.X = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 2, column 2 of this instance.
        /// </summary>
        public double M22 { get { return Row1.Y; } set { Row1.Y = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 2, column 3 of this instance.
        /// </summary>
        public double M23 { get { return Row1.Z; } set { Row1.Z = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 3, column 1 of this instance.
        /// </summary>
        public double M31 { get { return Row2.X; } set { Row2.X = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 3, column 2 of this instance.
        /// </summary>
        public double M32 { get { return Row2.Y; } set { Row2.Y = value; } }
        
        /// <summary>
        /// Gets or sets the value at row 3, column 3 of this instance.
        /// </summary>
        public double M33 { get { return Row2.Z; } set { Row2.Z = value; } }
        
#endregion
        
        #region Instance
        
        #region public void Invert()
        
        public void Invert()
        {
            this = Matrix3d.Invert(this);
        }
        
#endregion
        
        #region public void Transpose()
        
        public void Transpose()
        {
            this = Matrix3d.Transpose(this);
        }
        
#endregion
        
#endregion
        
        #region Static
        
        #region CreateFromAxisAngle
        
        public static void CreateFromAxisAngle(Vector3d axis, double angle, out Matrix3d result)
        {
            //normalize and create a local copy of the vector.
            axis.Normalize();
            double axisX = axis.X, axisY = axis.Y, axisZ = axis.Z;
            
            //calculate angles
            double cos = System.Math.Cos(-angle);
            double sin = System.Math.Sin(-angle);
            double t = 1.0f - cos;
            
            //do the conversion math once
            double tXX = t * axisX * axisX,
            tXY = t * axisX * axisY,
            tXZ = t * axisX * axisZ,
            tYY = t * axisY * axisY,
            tYZ = t * axisY * axisZ,
            tZZ = t * axisZ * axisZ;
            
            double sinX = sin * axisX,
            sinY = sin * axisY,
            sinZ = sin * axisZ;
            
            result.Row0.X = tXX + cos;
            result.Row0.Y = tXY - sinZ;
            result.Row0.Z = tXZ + sinY;
            result.Row1.X = tXY + sinZ;
            result.Row1.Y = tYY + cos;
            result.Row1.Z = tYZ - sinX;
            result.Row2.X = tXZ - sinY;
            result.Row2.Y = tYZ + sinX;
            result.Row2.Z = tZZ + cos;
        }
        
        public static Matrix3d CreateFromAxisAngle(Vector3d axis, double angle)
        {
            Matrix3d result;
            CreateFromAxisAngle(axis, angle, out result);
            return result;
        }
        
#endregion
        
        #region CreateFromQuaternion
        
        public static void CreateFromQuaternion(ref Quaterniond q, out Matrix3d result)
        {
            Vector3d axis;
            double angle;
            q.ToAxisAngle(out axis, out angle);
            CreateFromAxisAngle(axis, angle, out result);
        }
        
        public static Matrix3d CreateFromQuaternion(Quaterniond q)
        {
            Matrix3d result;
            CreateFromQuaternion(ref q, out result);
            return result;
        }
        
#endregion
        
        #region CreateRotation[XYZ]
        
        public static void CreateRotationX(double angle, out Matrix3d result)
        {
            double cos = System.Math.Cos(angle);
            double sin = System.Math.Sin(angle);
            
            result = Identity;
            result.Row1.Y = cos;
            result.Row1.Z = sin;
            result.Row2.Y = -sin;
            result.Row2.Z = cos;
        }
        
        public static Matrix3d CreateRotationX(double angle)
        {
            Matrix3d result;
            CreateRotationX(angle, out result);
            return result;
        }
        
        public static void CreateRotationY(double angle, out Matrix3d result)
        {
            double cos = System.Math.Cos(angle);
            double sin = System.Math.Sin(angle);
            
            result = Identity;
            result.Row0.X = cos;
            result.Row0.Z = -sin;
            result.Row2.X = sin;
            result.Row2.Z = cos;
        }
        
        public static Matrix3d CreateRotationY(double angle)
        {
            Matrix3d result;
            CreateRotationY(angle, out result);
            return result;
        }
        
        public static void CreateRotationZ(double angle, out Matrix3d result)
        {
            double cos = System.Math.Cos(angle);
            double sin = System.Math.Sin(angle);
            
            result = Identity;
            result.Row0.X = cos;
            result.Row0.Y = sin;
            result.Row1.X = -sin;
            result.Row1.Y = cos;
        }
        
        public static Matrix3d CreateRotationZ(double angle)
        {
            Matrix3d result;
            CreateRotationZ(angle, out result);
            return result;
        }
        
#endregion
        
        #region CreateScale
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="scale">Single scale factor for the x, y, and z axes.</param>
        /// <returns>A scale matrix.</returns>
        public static Matrix3d CreateScale(double scale)
        {
            Matrix3d result;
            CreateScale(scale, out result);
            return result;
        }
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="scale">Scale factors for the x, y, and z axes.</param>
        /// <returns>A scale matrix.</returns>
        public static Matrix3d CreateScale(Vector3d scale)
        {
            Matrix3d result;
            CreateScale(ref scale, out result);
            return result;
        }
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="x">Scale factor for the x axis.</param>
        /// <param name="y">Scale factor for the y axis.</param>
        /// <param name="z">Scale factor for the z axis.</param>
        /// <returns>A scale matrix.</returns>
        public static Matrix3d CreateScale(double x, double y, double z)
        {
            Matrix3d result;
            CreateScale(x, y, z, out result);
            return result;
        }
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="scale">Single scale factor for the x, y, and z axes.</param>
        /// <param name="result">A scale matrix.</param>
        public static void CreateScale(double scale, out Matrix3d result)
        {
            result = Identity;
            result.Row0.X = scale;
            result.Row1.Y = scale;
            result.Row2.Z = scale;
        }
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="scale">Scale factors for the x, y, and z axes.</param>
        /// <param name="result">A scale matrix.</param>
        public static void CreateScale(ref Vector3d scale, out Matrix3d result)
        {
            result = Identity;
            result.Row0.X = scale.X;
            result.Row1.Y = scale.Y;
            result.Row2.Z = scale.Z;
        }
        
        /// <summary>
        /// Creates a scale matrix.
        /// </summary>
        /// <param name="x">Scale factor for the x axis.</param>
        /// <param name="y">Scale factor for the y axis.</param>
        /// <param name="z">Scale factor for the z axis.</param>
        /// <param name="result">A scale matrix.</returns>
        public static void CreateScale(double x, double y, double z, out Matrix3d result)
        {
            result = Identity;
            result.Row0.X = x;
            result.Row1.Y = y;
            result.Row2.Z = z;
        }
        
#endregion
        
        #region Multiply Functions
        
        public static Matrix3d Mult(Matrix3d left, Matrix3d right)
        {
            Matrix3d result;
            Mult(ref left, ref right, out result);
            return result;
        }
        
        public static void Mult(ref Matrix3d left, ref Matrix3d right, out Matrix3d result)
        {
            double lM11 = left.Row0.X, lM12 = left.Row0.Y, lM13 = left.Row0.Z,
            lM21 = left.Row1.X, lM22 = left.Row1.Y, lM23 = left.Row1.Z,
            lM31 = left.Row2.X, lM32 = left.Row2.Y, lM33 = left.Row2.Z,
            rM11 = right.Row0.X, rM12 = right.Row0.Y, rM13 = right.Row0.Z,
            rM21 = right.Row1.X, rM22 = right.Row1.Y, rM23 = right.Row1.Z,
            rM31 = right.Row2.X, rM32 = right.Row2.Y, rM33 = right.Row2.Z;
            
            result.Row0.X = ((lM11 * rM11) + (lM12 * rM21)) + (lM13 * rM31);
            result.Row0.Y = ((lM11 * rM12) + (lM12 * rM22)) + (lM13 * rM32);
            result.Row0.Z = ((lM11 * rM13) + (lM12 * rM23)) + (lM13 * rM33);
            result.Row1.X = ((lM21 * rM11) + (lM22 * rM21)) + (lM23 * rM31);
            result.Row1.Y = ((lM21 * rM12) + (lM22 * rM22)) + (lM23 * rM32);
            result.Row1.Z = ((lM21 * rM13) + (lM22 * rM23)) + (lM23 * rM33);
            result.Row2.X = ((lM31 * rM11) + (lM32 * rM21)) + (lM33 * rM31);
            result.Row2.Y = ((lM31 * rM12) + (lM32 * rM22)) + (lM33 * rM32);
            result.Row2.Z = ((lM31 * rM13) + (lM32 * rM23)) + (lM33 * rM33);
        }
        
#endregion
        
        #region Invert Functions
        
        /// <summary>
        /// Calculate the inverse of the given matrix
        /// </summary>
        /// <param name="mat">The matrix to invert</param>
        /// <param name="result">The inverse of the given matrix if it has one, or the input if it is singular</param>
        /// <exception cref="InvalidOperationException">Thrown if the Matrix3d is singular.</exception>
        public static void Invert(ref Matrix3d mat, out Matrix3d result)
        {
            int[] colIdx = { 0, 0, 0 };
            int[] rowIdx = { 0, 0, 0 };
            int[] pivotIdx = { -1, -1, -1 };
            
            double[,] inverse = {{mat.Row0.X, mat.Row0.Y, mat.Row0.Z},
                {mat.Row1.X, mat.Row1.Y, mat.Row1.Z},
                {mat.Row2.X, mat.Row2.Y, mat.Row2.Z}};
            
            int icol = 0;
            int irow = 0;
            for (int i = 0; i < 3; i++)
            {
                double maxPivot = 0.0;
                for (int j = 0; j < 3; j++)
                {
                    if (pivotIdx[j] != 0)
                    {
                        for (int k = 0; k < 3; ++k)
                        {
                            if (pivotIdx[k] == -1)
                            {
                                double absVal = System.Math.Abs(inverse[j, k]);
                                if (absVal > maxPivot)
                                {
                                    maxPivot = absVal;
                                    irow = j;
                                    icol = k;
                                }
                            }
                            else if (pivotIdx[k] > 0)
                            {
                                result = mat;
                                return;
                            }
                        }
                    }
                }
                
                ++(pivotIdx[icol]);
                
                if (irow != icol)
                {
                    for (int k = 0; k < 3; ++k)
                    {
                        double f = inverse[irow, k];
                        inverse[irow, k] = inverse[icol, k];
                        inverse[icol, k] = f;
                    }
                }
                
                rowIdx[i] = irow;
                colIdx[i] = icol;
                
                double pivot = inverse[icol, icol];
                
                if (pivot == 0.0)
                {
                    throw new InvalidOperationException("Matrix is singular and cannot be inverted.");
                }
                
                double oneOverPivot = 1.0 / pivot;
                inverse[icol, icol] = 1.0;
                for (int k = 0; k < 3; ++k)
                    inverse[icol, k] *= oneOverPivot;
                
                for (int j = 0; j < 3; ++j)
                {
                    if (icol != j)
                    {
                        double f = inverse[j, icol];
                        inverse[j, icol] = 0.0;
                        for (int k = 0; k < 3; ++k)
                            inverse[j, k] -= inverse[icol, k] * f;
                    }
                }
            }
            
            for (int j = 2; j >= 0; --j)
            {
                int ir = rowIdx[j];
                int ic = colIdx[j];
                for (int k = 0; k < 3; ++k)
                {
                    double f = inverse[k, ir];
                    inverse[k, ir] = inverse[k, ic];
                    inverse[k, ic] = f;
                }
            }
            
            result.Row0.X = inverse[0, 0];
            result.Row0.Y = inverse[0, 1];
            result.Row0.Z = inverse[0, 2];
            result.Row1.X = inverse[1, 0];
            result.Row1.Y = inverse[1, 1];
            result.Row1.Z = inverse[1, 2];
            result.Row2.X = inverse[2, 0];
            result.Row2.Y = inverse[2, 1];
            result.Row2.Z = inverse[2, 2];
        }
        
        /// <summary>
        /// Calculate the inverse of the given matrix
        /// </summary>
        /// <param name="mat">The matrix to invert</param>
        /// <returns>The inverse of the given matrix if it has one, or the input if it is singular</returns>
        /// <exception cref="InvalidOperationException">Thrown if the Matrix4 is singular.</exception>
        public static Matrix3d Invert(Matrix3d mat)
        {
            Matrix3d result;
            Invert(ref mat, out result);
            return result;
        }
        
#endregion
        
        #region Transpose
        
        public static Matrix3d Transpose(Matrix3d mat)
        {
            return new Matrix3d(mat.Column0, mat.Column1, mat.Column2);
        }
        
        public static void Transpose(ref Matrix3d mat, out Matrix3d result)
        {
            result.Row0 = mat.Column0;
            result.Row1 = mat.Column1;
            result.Row2 = mat.Column2;
        }
        
#endregion
        
#endregion
        
        #region Operators
        
        public static Matrix3d operator *(Matrix3d left, Matrix3d right)
        {
            return Matrix3d.Mult(left, right);
        }
        
        public static bool operator ==(Matrix3d left, Matrix3d right)
        {
            return left.Equals(right);
        }
        
        public static bool operator !=(Matrix3d left, Matrix3d right)
        {
            return !left.Equals(right);
        }
        
#endregion
        
        #region Overrides
        
        #region public override string ToString()
        
        /// <summary>
        /// Returns a System.String that represents the current Matrix3d.
        /// </summary>
        /// <returns>The string representation of the matrix.</returns>
        public override string ToString()
        {
            return String.Format("{0}\n{1}\n{2}", Row0, Row1, Row2);
        }
        
#endregion
        
        #region public override int GetHashCode()
        
        /// <summary>
        /// Returns the hashcode for this instance.
        /// </summary>
        /// <returns>A System.Int32 containing the unique hashcode for this instance.</returns>
        public override int GetHashCode()
        {
            return Row0.GetHashCode() ^ Row1.GetHashCode() ^ Row2.GetHashCode();
        }
        
#endregion
        
        #region public override bool Equals(object obj)
        
        /// <summary>
        /// Indicates whether this instance and a specified object are equal.
        /// </summary>
        /// <param name="obj">The object to compare to.</param>
        /// <returns>True if the instances are equal; false otherwise.</returns>
        public override bool Equals(object obj)
        {
            if (!(obj is Matrix3d))
                return false;
            
            return this.Equals((Matrix3d)obj);
        }
        
#endregion
        
#endregion
        
#endregion
        
        #region IEquatable<Matrix3d> Members
        
        public bool Equals(Matrix3d other)
        {
            return
                Row0 == other.Row0 &&
                    Row1 == other.Row1 &&
                    Row2 == other.Row2;
        }
        
#endregion
    }
}