3x3 transform matrix More...

#include <SFML/Graphics/Transform.hpp>

Public Member Functions
constexpr	Transform ()=default
	Default constructor.

constexpr	Transform (float a00, float a01, float a02, float a10, float a11, float a12, float a20, float a21, float a22)
	Construct a transform from a 3x3 matrix.

constexpr const float *	getMatrix () const
	Return the transform as a 4x4 matrix.

constexpr Transform	getInverse () const
	Return the inverse of the transform.

constexpr Vector2f	transformPoint (Vector2f point) const
	Transform a 2D point.

constexpr FloatRect	transformRect (const FloatRect &rectangle) const
	Transform a rectangle.

constexpr Transform &	combine (const Transform &transform)
	Combine the current transform with another one.

constexpr Transform &	translate (Vector2f offset)
	Combine the current transform with a translation.

Transform &	rotate (Angle angle)
	Combine the current transform with a rotation.

Transform &	rotate (Angle angle, Vector2f center)
	Combine the current transform with a rotation.

constexpr Transform &	scale (Vector2f factors)
	Combine the current transform with a scaling.

constexpr Transform &	scale (Vector2f factors, Vector2f center)
	Combine the current transform with a scaling.

Static Public Attributes
static const Transform	Identity
	The identity transform (does nothing)

Related Symbols
(Note that these are not member symbols.)
constexpr Transform	operator* (const Transform &left, const Transform &right)
	Overload of binary `operator*` to combine two transforms.

constexpr Transform &	operator*= (Transform &left, const Transform &right)
	Overload of binary `operator*=` to combine two transforms.

constexpr Vector2f	operator* (const Transform &left, Vector2f right)
	Overload of binary `operator*` to transform a point.

constexpr bool	operator== (const Transform &left, const Transform &right)
	Overload of binary `operator==` to compare two transforms.

constexpr bool	operator!= (const Transform &left, const Transform &right)
	Overload of binary `operator!=` to compare two transforms.

Detailed Description

3x3 transform matrix

A sf::Transform specifies how to translate, rotate, scale, shear, project, whatever things.

In mathematical terms, it defines how to transform a coordinate system into another.

For example, if you apply a rotation transform to a sprite, the result will be a rotated sprite. And anything that is transformed by this rotation transform will be rotated the same way, according to its initial position.

Transforms are typically used for drawing. But they can also be used for any computation that requires to transform points between the local and global coordinate systems of an entity (like collision detection).

Example:

// define a translation transform
sf::Transform translation;
translation.translate(20, 50);
 
// define a rotation transform
sf::Transform rotation;
rotation.rotate(45);
 
// combine them
sf::Transform transform = translation * rotation;
 
// use the result to transform stuff...
sf::Vector2f point = transform.transformPoint({10, 20});
sf::FloatRect rect = transform.transformRect(sf::FloatRect({0, 0}, {10, 100}));

See also: sf::Transformable, sf::RenderStates

Definition at line 47 of file Transform.hpp.

Constructor & Destructor Documentation

◆ Transform() [1/2]

sf::Transform::Transform ( )

constexprdefault

Default constructor.

Creates an identity transform (a transform that does nothing).

◆ Transform() [2/2]

sf::Transform::Transform	(	float	a00,
		float	a01,
		float	a02,
		float	a10,
		float	a11,
		float	a12,
		float	a20,
		float	a21,
		float	a22 )

constexpr

Construct a transform from a 3x3 matrix.

Parameters

a00	Element (0, 0) of the matrix
a01	Element (0, 1) of the matrix
a02	Element (0, 2) of the matrix
a10	Element (1, 0) of the matrix
a11	Element (1, 1) of the matrix
a12	Element (1, 2) of the matrix
a20	Element (2, 0) of the matrix
a21	Element (2, 1) of the matrix
a22	Element (2, 2) of the matrix

Member Function Documentation

◆ combine()

Transform & sf::Transform::combine ( const Transform & transform )

constexpr

Combine the current transform with another one.

The result is a transform that is equivalent to applying transform followed by *this. Mathematically, it is equivalent to a matrix multiplication (*this) * transform.

These two statements are equivalent:

left.combine(right);

left *= right;

Parameters

transform Transform to combine with this transform

Returns: Reference to *this

◆ getInverse()

Transform sf::Transform::getInverse ( ) const

nodiscardconstexpr

Return the inverse of the transform.

If the inverse cannot be computed, an identity transform is returned.

Returns: A new transform which is the inverse of self

◆ getMatrix()

const float * sf::Transform::getMatrix ( ) const

nodiscardconstexpr

Return the transform as a 4x4 matrix.

This function returns a pointer to an array of 16 floats containing the transform elements as a 4x4 matrix, which is directly compatible with OpenGL functions.

sf::Transform transform = ...;

glLoadMatrixf(transform.getMatrix());

sf::Transform::getMatrix

constexpr const float * getMatrix() const

Return the transform as a 4x4 matrix.

Returns: Pointer to a 4x4 matrix

◆ rotate() [1/2]

Transform & sf::Transform::rotate ( Angle angle )

Combine the current transform with a rotation.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;

transform.rotate(sf::degrees(90)).translate(50, 20);

sf::degrees

constexpr Angle degrees(float angle)

Construct an angle value from a number of degrees.

Parameters

angle Rotation angle

Returns: Reference to *this

See also: translate, scale

◆ rotate() [2/2]

Transform & sf::Transform::rotate	(	Angle	angle,
		Vector2f	center )

Combine the current transform with a rotation.

The center of rotation is provided for convenience as a second argument, so that you can build rotations around arbitrary points more easily (and efficiently) than the usual translate(-center).rotate(angle).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;

transform.rotate(sf::degrees(90), sf::Vector2f(8, 3)).translate(sf::Vector2f(50, 20));

Parameters

angle	Rotation angle
center	Center of rotation

Returns: Reference to *this

See also: translate, scale

◆ scale() [1/2]

Transform & sf::Transform::scale ( Vector2f factors )

constexpr

Combine the current transform with a scaling.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;

transform.scale(sf::Vector2f(2, 1)).rotate(sf::degrees(45));

sf::Transform::scale

constexpr Transform & scale(Vector2f factors)

Combine the current transform with a scaling.

Parameters

factors Scaling factors

Returns: Reference to *this

See also: translate, rotate

◆ scale() [2/2]

Transform & sf::Transform::scale	(	Vector2f	factors,
		Vector2f	center )

constexpr

Combine the current transform with a scaling.

The center of scaling is provided for convenience as a second argument, so that you can build scaling around arbitrary points more easily (and efficiently) than the usual translate(-center).scale(factors).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;

transform.scale(sf::Vector2f(2, 1), sf::Vector2f(8, 3)).rotate(45);

Parameters

factors	Scaling factors
center	Center of scaling

Returns: Reference to *this

See also: translate, rotate

◆ transformPoint()

Vector2f sf::Transform::transformPoint ( Vector2f point ) const

nodiscardconstexpr

Transform a 2D point.

These two statements are equivalent:

sf::Vector2f transformedPoint = matrix.transformPoint(point);

sf::Vector2f transformedPoint = matrix * point;

Parameters

point Point to transform

Returns: Transformed point

◆ transformRect()

FloatRect sf::Transform::transformRect ( const FloatRect & rectangle ) const

nodiscardconstexpr

Transform a rectangle.

Since SFML doesn't provide support for oriented rectangles, the result of this function is always an axis-aligned rectangle. Which means that if the transform contains a rotation, the bounding rectangle of the transformed rectangle is returned.

Parameters

rectangle Rectangle to transform

Returns: Transformed rectangle

◆ translate()

Transform & sf::Transform::translate ( Vector2f offset )

constexpr

Combine the current transform with a translation.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;

transform.translate(sf::Vector2f(100, 200)).rotate(sf::degrees(45));

Parameters

offset Translation offset to apply

Returns: Reference to *this

See also: rotate, scale

Friends And Related Symbol Documentation

◆ operator!=()

bool operator!=	(	const Transform &	left,
		const Transform &	right )

This call is equivalent to !(left == right).

Parameters

left	Left operand (the first transform)
right	Right operand (the second transform)

Returns: true if the transforms are not equal, false otherwise

◆ operator*() [1/2]

Transform operator*	(	const Transform &	left,
		const Transform &	right )

This call is equivalent to calling Transform(left).combine(right).

Parameters

left	Left operand (the first transform)
right	Right operand (the second transform)

Returns: New combined transform

◆ operator*() [2/2]

Vector2f operator*	(	const Transform &	left,
		Vector2f	right )

This call is equivalent to calling left.transformPoint(right).

Parameters

left	Left operand (the transform)
right	Right operand (the point to transform)

Returns: New transformed point

◆ operator*=()

Transform & operator*=	(	Transform &	left,
		const Transform &	right )

This call is equivalent to calling left.combine(right).

Parameters

left	Left operand (the first transform)
right	Right operand (the second transform)

Returns: The combined transform

◆ operator==()

bool operator==	(	const Transform &	left,
		const Transform &	right )

Performs an element-wise comparison of the elements of the left transform with the elements of the right transform.

Parameters

left	Left operand (the first transform)
right	Right operand (the second transform)

Returns: true if the transforms are equal, false otherwise

Member Data Documentation

◆ Identity

const Transform sf::Transform::Identity

static

The identity transform (does nothing)

Definition at line 265 of file Transform.hpp.

The documentation for this class was generated from the following file:

Transform.hpp

Public Member Functions

Static Public Attributes

Related Symbols

Detailed Description

Constructor & Destructor Documentation

◆ Transform() [1/2]

◆ Transform() [2/2]

Member Function Documentation

◆ combine()

◆ getInverse()

◆ getMatrix()

◆ rotate() [1/2]

◆ rotate() [2/2]

◆ scale() [1/2]

◆ scale() [2/2]

◆ transformPoint()

◆ transformRect()

◆ translate()

Friends And Related Symbol Documentation

◆ operator!=()

◆ operator*() [1/2]

◆ operator*() [2/2]

◆ operator*=()

◆ operator==()

Member Data Documentation

◆ Identity