Box2D/Box2D/Common/b2Math.h File Reference

#include <Box2D/Common/b2Settings.h>
#include <cmath>
#include <cfloat>
#include <cstddef>
#include <limits>

Go to the source code of this file.

Classes
struct	b2Vec2
	A 2D column vector. More...
struct	b2Vec3
	A 2D column vector with 3 elements. More...
struct	b2Mat22
	A 2-by-2 matrix. Stored in column-major order. More...
struct	b2Mat33
	A 3-by-3 matrix. Stored in column-major order. More...
struct	b2Transform
struct	b2Sweep
Defines
#define	b2Sqrt(x)   sqrtf(x)
#define	b2Atan2(y, x)   atan2f(y, x)
Functions
bool	b2IsValid (float32 x)
float32	b2InvSqrt (float32 x)
	This is a approximate yet fast inverse square-root.
float32	b2Abs (float32 a)
float32	b2Dot (const b2Vec2 &a, const b2Vec2 &b)
	Perform the dot product on two vectors.
float32	b2Cross (const b2Vec2 &a, const b2Vec2 &b)
	Perform the cross product on two vectors. In 2D this produces a scalar.
b2Vec2	b2Cross (const b2Vec2 &a, float32 s)
b2Vec2	b2Cross (float32 s, const b2Vec2 &a)
b2Vec2	b2Mul (const b2Mat22 &A, const b2Vec2 &v)
b2Vec2	b2MulT (const b2Mat22 &A, const b2Vec2 &v)
b2Vec2	operator+ (const b2Vec2 &a, const b2Vec2 &b)
	Add two vectors component-wise.
b2Vec2	operator- (const b2Vec2 &a, const b2Vec2 &b)
	Subtract two vectors component-wise.
b2Vec2	operator* (float32 s, const b2Vec2 &a)
bool	operator== (const b2Vec2 &a, const b2Vec2 &b)
float32	b2Distance (const b2Vec2 &a, const b2Vec2 &b)
float32	b2DistanceSquared (const b2Vec2 &a, const b2Vec2 &b)
b2Vec3	operator* (float32 s, const b2Vec3 &a)
b2Vec3	operator+ (const b2Vec3 &a, const b2Vec3 &b)
	Add two vectors component-wise.
b2Vec3	operator- (const b2Vec3 &a, const b2Vec3 &b)
	Subtract two vectors component-wise.
float32	b2Dot (const b2Vec3 &a, const b2Vec3 &b)
	Perform the dot product on two vectors.
b2Vec3	b2Cross (const b2Vec3 &a, const b2Vec3 &b)
	Perform the cross product on two vectors.
b2Mat22	operator+ (const b2Mat22 &A, const b2Mat22 &B)
b2Mat22	b2Mul (const b2Mat22 &A, const b2Mat22 &B)
b2Mat22	b2MulT (const b2Mat22 &A, const b2Mat22 &B)
b2Vec3	b2Mul (const b2Mat33 &A, const b2Vec3 &v)
	Multiply a matrix times a vector.
b2Vec2	b2Mul (const b2Transform &T, const b2Vec2 &v)
b2Vec2	b2MulT (const b2Transform &T, const b2Vec2 &v)
b2Vec2	b2Abs (const b2Vec2 &a)
b2Mat22	b2Abs (const b2Mat22 &A)
template<typename T >
T	b2Min (T a, T b)
b2Vec2	b2Min (const b2Vec2 &a, const b2Vec2 &b)
template<typename T >
T	b2Max (T a, T b)
b2Vec2	b2Max (const b2Vec2 &a, const b2Vec2 &b)
template<typename T >
T	b2Clamp (T a, T low, T high)
b2Vec2	b2Clamp (const b2Vec2 &a, const b2Vec2 &low, const b2Vec2 &high)
template<typename T >
void	b2Swap (T &a, T &b)
uint32	b2NextPowerOfTwo (uint32 x)
bool	b2IsPowerOfTwo (uint32 x)
Variables
const b2Vec2	b2Vec2_zero
const b2Mat22	b2Mat22_identity
const b2Transform	b2Transform_identity

---

Define Documentation

#define b2Atan2	(	y,
		x		)	atan2f(y, x)

#define b2Sqrt

(

x

)

sqrtf(x)

---

Function Documentation

b2Mat22 b2Abs

(

const b2Mat22 &

A

)

[inline]

b2Vec2 b2Abs

(

const b2Vec2 &

a

)

[inline]

float32 b2Abs

(

float32

a

)

[inline]

b2Vec2 b2Clamp	(	const b2Vec2 &	a,
		const b2Vec2 &	low,
		const b2Vec2 &	high
	)			[inline]

template<typename T >

T b2Clamp	(	T	a,
		T	low,
		T	high
	)			[inline]

b2Vec3 b2Cross	(	const b2Vec3 &	a,
		const b2Vec3 &	b
	)			[inline]

Perform the cross product on two vectors.

b2Vec2 b2Cross	(	float32	s,
		const b2Vec2 &	a
	)			[inline]

Perform the cross product on a scalar and a vector. In 2D this produces a vector.

b2Vec2 b2Cross	(	const b2Vec2 &	a,
		float32	s
	)			[inline]

Perform the cross product on a vector and a scalar. In 2D this produces a vector.

float32 b2Cross	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

Perform the cross product on two vectors. In 2D this produces a scalar.

float32 b2Distance	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

float32 b2DistanceSquared	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

float32 b2Dot	(	const b2Vec3 &	a,
		const b2Vec3 &	b
	)			[inline]

Perform the dot product on two vectors.

float32 b2Dot	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

Perform the dot product on two vectors.

float32 b2InvSqrt

(

float32

x

)

[inline]

This is a approximate yet fast inverse square-root.

bool b2IsPowerOfTwo

(

uint32

x

)

[inline]

bool b2IsValid

(

float32

x

)

[inline]

This function is used to ensure that a floating point number is not a NaN or infinity.

b2Vec2 b2Max	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

template<typename T >

T b2Max	(	T	a,
		T	b
	)			[inline]

b2Vec2 b2Min	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

template<typename T >

T b2Min	(	T	a,
		T	b
	)			[inline]

b2Vec2 b2Mul	(	const b2Transform &	T,
		const b2Vec2 &	v
	)			[inline]

b2Vec3 b2Mul	(	const b2Mat33 &	A,
		const b2Vec3 &	v
	)			[inline]

Multiply a matrix times a vector.

b2Mat22 b2Mul	(	const b2Mat22 &	A,
		const b2Mat22 &	B
	)			[inline]

b2Vec2 b2Mul	(	const b2Mat22 &	A,
		const b2Vec2 &	v
	)			[inline]

Multiply a matrix times a vector. If a rotation matrix is provided, then this transforms the vector from one frame to another.

b2Vec2 b2MulT	(	const b2Transform &	T,
		const b2Vec2 &	v
	)			[inline]

b2Mat22 b2MulT	(	const b2Mat22 &	A,
		const b2Mat22 &	B
	)			[inline]

b2Vec2 b2MulT	(	const b2Mat22 &	A,
		const b2Vec2 &	v
	)			[inline]

Multiply a matrix transpose times a vector. If a rotation matrix is provided, then this transforms the vector from one frame to another (inverse transform).

uint32 b2NextPowerOfTwo

(

uint32

x

)

[inline]

"Next Largest Power of 2 Given a binary integer value x, the next largest power of 2 can be computed by a SWAR algorithm that recursively "folds" the upper bits into the lower bits. This process yields a bit vector with the same most significant 1 as x, but all 1's below it. Adding 1 to that value yields the next largest power of 2. For a 32-bit value:"

template<typename T >

void b2Swap	(	T &	a,
		T &	b
	)			[inline]

b2Vec3 operator*	(	float32	s,
		const b2Vec3 &	a
	)			[inline]

b2Vec2 operator*	(	float32	s,
		const b2Vec2 &	a
	)			[inline]

b2Mat22 operator+	(	const b2Mat22 &	A,
		const b2Mat22 &	B
	)			[inline]

b2Vec3 operator+	(	const b2Vec3 &	a,
		const b2Vec3 &	b
	)			[inline]

Add two vectors component-wise.

b2Vec2 operator+	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

Add two vectors component-wise.

b2Vec3 operator-	(	const b2Vec3 &	a,
		const b2Vec3 &	b
	)			[inline]

Subtract two vectors component-wise.

b2Vec2 operator-	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

Subtract two vectors component-wise.

bool operator==	(	const b2Vec2 &	a,
		const b2Vec2 &	b
	)			[inline]

---

Variable Documentation

const b2Mat22 b2Mat22_identity

const b2Transform b2Transform_identity

const b2Vec2 b2Vec2_zero