Box2D/Box2D/Common/b2Settings.h File Reference

#include <cassert>
#include <cmath>

Go to the source code of this file.

Classes
struct	b2Version
Defines
#define	B2_NOT_USED(x)   ((void)(x))
#define	b2Assert(A)   assert(A)
#define	b2_maxFloat   FLT_MAX
#define	b2_epsilon   FLT_EPSILON
#define	b2_pi   3.14159265359f
#define	b2_maxManifoldPoints   2
	The maximum number of contact points between two convex shapes.
#define	b2_maxPolygonVertices   8
	The maximum number of vertices on a convex polygon.
#define	b2_aabbExtension   0.1f
#define	b2_aabbMultiplier   2.0f
#define	b2_linearSlop   0.005f
#define	b2_angularSlop   (2.0f / 180.0f * b2_pi)
#define	b2_polygonRadius   (2.0f * b2_linearSlop)
#define	b2_maxTOIContacts   32
	Maximum number of contacts to be handled to solve a TOI impact.
#define	b2_velocityThreshold   1.0f
#define	b2_maxLinearCorrection   0.2f
#define	b2_maxAngularCorrection   (8.0f / 180.0f * b2_pi)
#define	b2_maxTranslation   2.0f
#define	b2_maxTranslationSquared   (b2_maxTranslation * b2_maxTranslation)
#define	b2_maxRotation   (0.5f * b2_pi)
#define	b2_maxRotationSquared   (b2_maxRotation * b2_maxRotation)
#define	b2_contactBaumgarte   0.2f
#define	b2_timeToSleep   0.5f
	The time that a body must be still before it will go to sleep.
#define	b2_linearSleepTolerance   0.01f
	A body cannot sleep if its linear velocity is above this tolerance.
#define	b2_angularSleepTolerance   (2.0f / 180.0f * b2_pi)
	A body cannot sleep if its angular velocity is above this tolerance.
Typedefs
typedef signed char	int8
typedef signed short	int16
typedef signed int	int32
typedef unsigned char	uint8
typedef unsigned short	uint16
typedef unsigned int	uint32
typedef float	float32
Functions
void *	b2Alloc (int32 size)
	Implement this function to use your own memory allocator.
void	b2Free (void *mem)
	If you implement b2Alloc, you should also implement this function.
float32	b2MixFriction (float32 friction1, float32 friction2)
	Friction mixing law. Feel free to customize this.
float32	b2MixRestitution (float32 restitution1, float32 restitution2)
	Restitution mixing law. Feel free to customize this.
Variables
b2Version	b2_version
	Current version.

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Detailed Description

Global tuning constants based on meters-kilograms-seconds (MKS) units.

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Define Documentation

#define b2_aabbExtension   0.1f

This is used to fatten AABBs in the dynamic tree. This allows proxies to move by a small amount without triggering a tree adjustment. This is in meters.

#define b2_aabbMultiplier   2.0f

This is used to fatten AABBs in the dynamic tree. This is used to predict the future position based on the current displacement. This is a dimensionless multiplier.

#define b2_angularSleepTolerance   (2.0f / 180.0f * b2_pi)

A body cannot sleep if its angular velocity is above this tolerance.

#define b2_angularSlop   (2.0f / 180.0f * b2_pi)

A small angle used as a collision and constraint tolerance. Usually it is chosen to be numerically significant, but visually insignificant.

#define b2_contactBaumgarte   0.2f

This scale factor controls how fast overlap is resolved. Ideally this would be 1 so that overlap is removed in one time step. However using values close to 1 often lead to overshoot.

#define b2_epsilon   FLT_EPSILON

#define b2_linearSleepTolerance   0.01f

A body cannot sleep if its linear velocity is above this tolerance.

#define b2_linearSlop   0.005f

A small length used as a collision and constraint tolerance. Usually it is chosen to be numerically significant, but visually insignificant.

#define b2_maxAngularCorrection   (8.0f / 180.0f * b2_pi)

The maximum angular position correction used when solving constraints. This helps to prevent overshoot.

#define b2_maxFloat   FLT_MAX

#define b2_maxLinearCorrection   0.2f

The maximum linear position correction used when solving constraints. This helps to prevent overshoot.

#define b2_maxManifoldPoints   2

The maximum number of contact points between two convex shapes.

#define b2_maxPolygonVertices   8

The maximum number of vertices on a convex polygon.

#define b2_maxRotation   (0.5f * b2_pi)

The maximum angular velocity of a body. This limit is very large and is used to prevent numerical problems. You shouldn't need to adjust this.

#define b2_maxRotationSquared   (b2_maxRotation * b2_maxRotation)

#define b2_maxTOIContacts   32

Maximum number of contacts to be handled to solve a TOI impact.

#define b2_maxTranslation   2.0f

The maximum linear velocity of a body. This limit is very large and is used to prevent numerical problems. You shouldn't need to adjust this.

#define b2_maxTranslationSquared   (b2_maxTranslation * b2_maxTranslation)

#define B2_NOT_USED

(

x

)

((void)(x))

#define b2_pi   3.14159265359f

#define b2_polygonRadius   (2.0f * b2_linearSlop)

The radius of the polygon/edge shape skin. This should not be modified. Making this smaller means polygons will have an insufficient buffer for continuous collision. Making it larger may create artifacts for vertex collision.

#define b2_timeToSleep   0.5f

The time that a body must be still before it will go to sleep.

#define b2_velocityThreshold   1.0f

A velocity threshold for elastic collisions. Any collision with a relative linear velocity below this threshold will be treated as inelastic.

#define b2Assert

(

A

)

assert(A)

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Typedef Documentation

typedef float float32

typedef signed short int16

typedef signed int int32

typedef signed char int8

typedef unsigned short uint16

typedef unsigned int uint32

typedef unsigned char uint8

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Function Documentation

void* b2Alloc

(

int32

size

)

Implement this function to use your own memory allocator.

void b2Free

(

void *

mem

)

If you implement b2Alloc, you should also implement this function.

float32 b2MixFriction	(	float32	friction1,
		float32	friction2
	)			[inline]

Friction mixing law. Feel free to customize this.

float32 b2MixRestitution	(	float32	restitution1,
		float32	restitution2
	)			[inline]

Restitution mixing law. Feel free to customize this.

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Variable Documentation

b2Version b2_version

Current version.