Sifteo::AffineMatrix Struct Reference

An augmented 3x2 matrix, for doing 2D affine transforms. More...

#include <sifteo/math.h>

Public Member Functions
	AffineMatrix ()
	Create an uninitialized matrix.
	AffineMatrix (float _xx, float _yx, float _cx, float _xy, float _yy, float _cy)
	Create a matrix from six scalar values.
void	operator*= (const AffineMatrix &m)
	Matrix multiplication.
void	rotate (float angle)
	Compose this matrix with a rotation by 'angle' radians.
void	scale (float s)
	Compose this matrix with a scale by factor 's'.
void	translate (float x, float y)
	Compose this matrix with a translation by (x, y)
void	translate (Float2 v)
	Compose this matrix with a translation by vector 'v'.

Static Public Member Functions
static AffineMatrix	identity ()
	Create the identity matrix.
static AffineMatrix	rotation (float angle)
	Create a matrix which rotates by 'angle' radians.
static AffineMatrix	scaling (float s)
	Create a matrix which scales by a factor of 's'.
static AffineMatrix	translation (float x, float y)
	Create a matrix which translates by (x, y)
static AffineMatrix	translation (Float2 v)
	Create a matrix which translates by vector 'v'.

Public Attributes
float	cx
	Matrix member cx, the constant offset for X.
float	cy
	Matrix member cy, the constant offset for Y.
float	xx
	Matrix member xx, the horizontal X delta.
float	xy
	Matrix member xy, the horizontal Y delta.
float	yx
	Matrix member yx, the vertical X delta.
float	yy
	Matrix member yy, the vertical Y delta.

Detailed Description

An augmented 3x2 matrix, for doing 2D affine transforms.

[ xx yx cx ] [ xy yy cy ] [ 0 0 1 ]

The way we use affine transforms for background scaling are very similiar to the mechanism used by the GameBoy Advance PPU. There's a great tutorial on this at:

http://www.coranac.com/tonc/text/affine.htm

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

• math.h