Documentation de SFML 2.1

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sf::Transform Class Reference

Define a 3x3 transform matrix. More...

`#include <Transform.hpp>`

Public Member Functions

Transform ()
Default constructor.

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.

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

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

Vector2f transformPoint (float x, float y) const
Transform a 2D point.

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

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

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

Transformtranslate (float x, float y)
Combine the current transform with a translation.

Transformtranslate (const Vector2f &offset)
Combine the current transform with a translation.

Transformrotate (float angle)
Combine the current transform with a rotation.

Transformrotate (float angle, float centerX, float centerY)
Combine the current transform with a rotation.

Transformrotate (float angle, const Vector2f &center)
Combine the current transform with a rotation.

Transformscale (float scaleX, float scaleY)
Combine the current transform with a scaling.

Transformscale (float scaleX, float scaleY, float centerX, float centerY)
Combine the current transform with a scaling.

Transformscale (const Vector2f &factors)
Combine the current transform with a scaling.

Transformscale (const Vector2f &factors, const Vector2f &center)
Combine the current transform with a scaling.

Static Public Attributes

static const Transform Identity
The identity transform (does nothing)

Related Functions

(Note that these are not member functions.)

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

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

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

Detailed Description

Define a 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));
sf::Transformable, sf::RenderStates

Definition at line 42 of file Transform.hpp.

Constructor & Destructor Documentation

 sf::Transform::Transform ( )

Default constructor.

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

 sf::Transform::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.

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

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

Combine the current transform with another one.

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

Parameters
 transform Transform to combine with this transform
Returns
Reference to *this
 Transform sf::Transform::getInverse ( ) const

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

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 = ...;
Returns
Pointer to a 4x4 matrix
 Transform& sf::Transform::rotate ( float 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(90).translate(50, 20);
Parameters
 angle Rotation angle, in degrees
Returns
Reference to *this
translate, scale
 Transform& sf::Transform::rotate ( float angle, float centerX, float centerY )

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(90, 8, 3).translate(50, 20);
Parameters
 angle Rotation angle, in degrees centerX X coordinate of the center of rotation centerY Y coordinate of the center of rotation
Returns
Reference to *this
translate, scale
 Transform& sf::Transform::rotate ( float angle, const 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(90, sf::Vector2f(8, 3)).translate(sf::Vector2f(50, 20));
Parameters
 angle Rotation angle, in degrees center Center of rotation
Returns
Reference to *this
translate, scale
 Transform& sf::Transform::scale ( float scaleX, float scaleY )

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(2, 1).rotate(45);
Parameters
 scaleX Scaling factor on the X axis scaleY Scaling factor on the Y axis
Returns
Reference to *this
translate, rotate
 Transform& sf::Transform::scale ( float scaleX, float scaleY, float centerX, float centerY )

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(2, 1, 8, 3).rotate(45);
Parameters
 scaleX Scaling factor on X axis scaleY Scaling factor on Y axis centerX X coordinate of the center of scaling centerY Y coordinate of the center of scaling
Returns
Reference to *this
translate, rotate
 Transform& sf::Transform::scale ( const Vector2f & factors )

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(45);
Parameters
 factors Scaling factors
Returns
Reference to *this
translate, rotate
 Transform& sf::Transform::scale ( const Vector2f & factors, const Vector2f & center )

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
translate, rotate
 Vector2f sf::Transform::transformPoint ( float x, float y ) const

Transform a 2D point.

Parameters
 x X coordinate of the point to transform y Y coordinate of the point to transform
Returns
Transformed point
 Vector2f sf::Transform::transformPoint ( const Vector2f & point ) const

Transform a 2D point.

Parameters
 point Point to transform
Returns
Transformed point
 FloatRect sf::Transform::transformRect ( const FloatRect & rectangle ) const

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
 Transform& sf::Transform::translate ( float x, float y )

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(100, 200).rotate(45);
Parameters
 x Offset to apply on X axis y Offset to apply on Y axis
Returns
Reference to *this
rotate, scale
 Transform& sf::Transform::translate ( const Vector2f & offset )

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(45);
Parameters
 offset Translation offset to apply
Returns
Reference to *this
rotate, scale

Friends And Related Function Documentation

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

Overload of binary operator * to combine two transforms.

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

Overload of binary operator * to transform a point.

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

Overload of binary operator *= to combine two transforms.

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

Member Data Documentation

 const Transform sf::Transform::Identity
static

The identity transform (does nothing)

Definition at line 354 of file Transform.hpp.

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