Struct Matrix3x3

Represents a 3x3 matrix. Assimp docs say their matrices are always row-major, and it looks like they're only describing the memory layout. Matrices are treated as column vectors however (X base in the first column, Y base the second, and Z base the third)

Implements

IEquatable<Matrix3x3>

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: SharpAssimp

Assembly: SharpAssimp.dll

Syntax

public record struct Matrix3x3 : IEquatable<Matrix3x3>

Constructors

Matrix3x3(Matrix4x4)

Constructs a new Matrix3x3.

Declaration

public Matrix3x3(Matrix4x4 rotMatrix)

Parameters

Type	Name	Description
Matrix4x4	rotMatrix	A 4x4 matrix to construct from, only taking the rotation/scaling part.

Matrix3x3(float, float, float, float, float, float, float, float, float)

Represents a 3x3 matrix. Assimp docs say their matrices are always row-major, and it looks like they're only describing the memory layout. Matrices are treated as column vectors however (X base in the first column, Y base the second, and Z base the third)

Declaration

public Matrix3x3(float A1, float A2, float A3, float B1, float B2, float B3, float C1, float C2, float C3)

Parameters

Type	Name	Description
float	A1	Value at row 1, column 1 of the matrix.
float	A2	Value at row 1, column 2 of the matrix.
float	A3	Value at row 1, column 3 of the matrix.
float	B1	Value at row 2, column 1 of the matrix.
float	B2	Value at row 2, column 2 of the matrix.
float	B3	Value at row 2, column 3 of the matrix.
float	C1	Value at row 3, column 1 of the matrix.
float	C2	Value at row 3, column 2 of the matrix.
float	C3	Value at row 3, column 3 of the matrix.

Properties

A1

Value at row 1, column 1 of the matrix.

Declaration

public float A1 { readonly get; set; }

Property Value

Type	Description
float

A2

Value at row 1, column 2 of the matrix.

Declaration

public float A2 { readonly get; set; }

Property Value

Type	Description
float

A3

Value at row 1, column 3 of the matrix.

Declaration

public float A3 { readonly get; set; }

Property Value

Type	Description
float

B1

Value at row 2, column 1 of the matrix.

Declaration

public float B1 { readonly get; set; }

Property Value

Type	Description
float

B2

Value at row 2, column 2 of the matrix.

Declaration

public float B2 { readonly get; set; }

Property Value

Type	Description
float

B3

Value at row 2, column 3 of the matrix.

Declaration

public float B3 { readonly get; set; }

Property Value

Type	Description
float

C1

Value at row 3, column 1 of the matrix.

Declaration

public float C1 { readonly get; set; }

Property Value

Type	Description
float

C2

Value at row 3, column 2 of the matrix.

Declaration

public float C2 { readonly get; set; }

Property Value

Type	Description
float

C3

Value at row 3, column 3 of the matrix.

Declaration

public float C3 { readonly get; set; }

Property Value

Type	Description
float

Identity

Gets the identity matrix.

Declaration

public static Matrix3x3 Identity { get; }

Property Value

Type	Description
Matrix3x3

IsIdentity

Gets if this matrix is an identity matrix.

Declaration

public bool IsIdentity { get; }

Property Value

Type	Description
bool

this[int, int]

Gets or sets the value at the specific one-based row, column index. E.g. i = 1, j = 2 gets the value in row 1, column 2 (MA2). Indices out of range return a value of zero.

Declaration

public float this[int i, int j] { get; set; }

Parameters

Type	Name	Description
int	i	One-based Row index
int	j	One-based Column index

Property Value

Type	Description
float	Matrix value

Methods

Determinant()

Compute the determinant of this matrix.

Declaration

public float Determinant()

Returns

Type	Description
float	The determinant

FromAngleAxis(float, Vector3)

Creates a rotation matrix for a rotation about an arbitrary axis.

Declaration

public static Matrix3x3 FromAngleAxis(float radians, Vector3 axis)

Parameters

Type	Name	Description
float	radians	Rotation angle, in radians
Vector3	axis	Rotation axis, which should be a normalized vector.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromEulerAnglesXYZ(Vector3)

Creates a rotation matrix from a set of euler angles.

Declaration

public static Matrix3x3 FromEulerAnglesXYZ(Vector3 angles)

Parameters

Type	Name	Description
Vector3	angles	Vector containing the rotation angles about the x, y, z axes, in radians.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromEulerAnglesXYZ(float, float, float)

Creates a rotation matrix from a set of euler angles.

Declaration

public static Matrix3x3 FromEulerAnglesXYZ(float x, float y, float z)

Parameters

Type	Name	Description
float	x	Rotation angle about the x-axis, in radians.
float	y	Rotation angle about the y-axis, in radians.
float	z	Rotation angle about the z-axis, in radians.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromRotationX(float)

Creates a rotation matrix for a rotation about the x-axis.

Declaration

public static Matrix3x3 FromRotationX(float radians)

Parameters

Type	Name	Description
float	radians	Rotation angle in radians.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromRotationY(float)

Creates a rotation matrix for a rotation about the y-axis.

Declaration

public static Matrix3x3 FromRotationY(float radians)

Parameters

Type	Name	Description
float	radians	Rotation angle in radians.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromRotationZ(float)

Creates a rotation matrix for a rotation about the z-axis.

Declaration

public static Matrix3x3 FromRotationZ(float radians)

Parameters

Type	Name	Description
float	radians	Rotation angle in radians.

Returns

Type	Description
Matrix3x3	The rotation matrix

FromScaling(Vector3)

Creates a scaling matrix.

Declaration

public static Matrix3x3 FromScaling(Vector3 scaling)

Parameters

Type	Name	Description
Vector3	scaling	Scaling vector

Returns

Type	Description
Matrix3x3	The scaling vector

FromToMatrix(Vector3, Vector3)

Creates a rotation matrix that rotates a vector called "from" into another vector called "to". Based on an algorithm by Tomas Moller and John Hudges:

"Efficiently Building a Matrix to Rotate One Vector to Another" Journal of Graphics Tools, 4(4):1-4, 1999

Declaration

public static Matrix3x3 FromToMatrix(Vector3 from, Vector3 to)

Parameters

Type	Name	Description
Vector3	from	Starting vector
Vector3	to	Ending vector

Returns

Type	Description
Matrix3x3	Rotation matrix to rotate from the start to end.

Inverse()

Inverts the matrix. If the matrix is not invertible all elements are set to NaN.

Declaration

public void Inverse()

ToString()

Returns a string that represents this instance.

Declaration

public override string ToString()

Returns

Type	Description
string	A string that represents this instance.

Overrides

ValueType.ToString()

Transform(Vector3)

Performs matrix-vector multiplication identical to the way Assimp does it.

Declaration

public Vector3 Transform(Vector3 v)

Parameters

Type	Name	Description
Vector3	v	Vector to transform

Returns

Type	Description
Vector3	Transformed vector

Transpose()

Transposes this matrix (rows become columns, vice versa).

Declaration

public void Transpose()

Operators

implicit operator Matrix4x4(Matrix3x3)

Implicit conversion from a 3x3 matrix to a 4x4 matrix.

Declaration

public static implicit operator Matrix4x4(Matrix3x3 mat)

Parameters

Type	Name	Description
Matrix3x3	mat	3x3 matrix

Returns

Type	Description
Matrix4x4	4x4 matrix

implicit operator Matrix3x3(Matrix4x4)

Implicit conversion from a 4x4 matrix to a 3x3 matrix.

Declaration

public static implicit operator Matrix3x3(Matrix4x4 mat)

Parameters

Type	Name	Description
Matrix4x4	mat	4x4 matrix

Returns

Type	Description
Matrix3x3	3x3 matrix

operator *(Matrix3x3, Matrix3x3)

Performs matrix multiplication.Multiplication order is B x A. That way, SRT concatenations are left to right.

Declaration

public static Matrix3x3 operator *(Matrix3x3 a, Matrix3x3 b)

Parameters

Type	Name	Description
Matrix3x3	a	First matrix
Matrix3x3	b	Second matrix

Returns

Type	Description
Matrix3x3	Multiplied matrix

Implements

IEquatable<T>