Float2x2

A 2x2 matrix of floating-point values.

A Float2x2 can represent any linear transformation on the 2D plane without a translation component, such as rotation, scale or shear.

The matrix is stored in column-major order. In other words, it's an array of two Float2 column vectors.

Header File

#include <ply-math/Matrix.h>

Also included from <ply-math/Base.h>.

Constructors

  Float2x2::Float2x2() [code]

Constructs an uninitialized Float2x2.

  Float2x2::Float2x2(const Float2& col0, const Float2& col1) [code]

Constructs a 2x2 matrix from the given column vectors.

Float2x2 m = {{1, 0}, {0, 1}};

Element Access

Float2& Float2x2::operator[](ureg i) [code]

const Float2& Float2x2::operator[](ureg i) const [code]

Accesses the column vector at the specified index.

Float2x2 m = {{1, 0}, {0, 1}};
m[0].x = -1;
StdOut::text() << m[1];  // "{0, 1}"

Comparison Functions

bool operator==(const Float2x2& a, const Float2x2& b) [code]

bool operator!=(const Float2x2& a, const Float2x2& b) [code]

Returns true if the matrices are equal (or not equal) using floating-point comparison. In particular, a component with a value of 0.f is equal to a component with a value of -0.f.

Creation Functions

 static Float2x2 Float2x2::identity() [code]

Returns the identity matrix {{1, 0}, {0, 1}}.

 static Float2x2 Float2x2::makeScale(const Float2& scale) [code]

Returns a scale matrix.

 static Float2x2 Float2x2::makeRotation(float radians) [code]

Returns a counter-clockwise rotation matrix. The angle is specified in radians.

 static Float2x2 Float2x2::fromComplex(const Float2& c) [code]

Returns a rotation and scale matrix whose first column is given by c. Transforming a vector by this matrix is equivalent to premultiplying by the vector by c on the complex plane.

Float2x2::fromComplex({1, 0})  // returns the identity matrix

Matrix Operations

 Float2x2 Float2x2::transposed() const [code]

Returns the transpose of the 2x2 matrix. If the matrix is orthogonal (in other words, it consists only of a rotation and/or reflection), this function also returns the inverse matrix.

Float2 operator*(const Float2x2& m, const Float2& v) [code]

Transform a vector using a matrix. v is treated as a column vector and premultiplied by the matrix m.

Float2x2 operator*(const Float2x2& a, const Float2x2& b) [code]

Matrix multiplication.