b2_common.h File Reference

#include "b2_settings.h"
#include <stddef.h>
#include <assert.h>
#include <float.h>

Go to the source code of this file.

Classes
struct	b2Version

Macros
#define	b2DEBUG
#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
#define	b2_aabbExtension   (0.1f * b2_lengthUnitsPerMeter)
#define	b2_aabbMultiplier   4.0f
#define	b2_linearSlop   (0.005f * b2_lengthUnitsPerMeter)
#define	b2_angularSlop   (2.0f / 180.0f * b2_pi)
#define	b2_polygonRadius   (2.0f * b2_linearSlop)
#define	b2_maxSubSteps   8
	Maximum number of sub-steps per contact in continuous physics simulation.
#define	b2_maxTOIContacts   32
	Maximum number of contacts to be handled to solve a TOI impact.
#define	b2_maxLinearCorrection   (0.2f * b2_lengthUnitsPerMeter)
#define	b2_maxAngularCorrection   (8.0f / 180.0f * b2_pi)
#define	b2_maxTranslation   (2.0f * b2_lengthUnitsPerMeter)
#define	b2_maxTranslationSquared   (b2_maxTranslation * b2_maxTranslation)
#define	b2_maxRotation   (0.5f * b2_pi)
#define	b2_maxRotationSquared   (b2_maxRotation * b2_maxRotation)
#define	b2_baumgarte   0.2f
#define	b2_toiBaumgarte   0.75f
#define	b2_timeToSleep   0.5f
	The time that a body must be still before it will go to sleep.
#define	b2_linearSleepTolerance   (0.01f * b2_lengthUnitsPerMeter)
	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.

Functions
void	b2OpenDump (const char *fileName)
	Dump to a file. Only one dump file allowed at a time.
void	b2Dump (const char *string,...)
void	b2CloseDump ()

Variables
B2_API b2Version	b2_version
	Current version.

Detailed Description

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

Macro Definition Documentation

b2_aabbExtension

#define b2_aabbExtension   (0.1f * b2_lengthUnitsPerMeter)

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.

b2_aabbMultiplier

#define b2_aabbMultiplier   4.0f

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.

b2_angularSlop

#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.

b2_baumgarte

#define b2_baumgarte   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.

b2_linearSlop

#define b2_linearSlop   (0.005f * b2_lengthUnitsPerMeter)

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

b2_maxAngularCorrection

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

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

b2_maxLinearCorrection

#define b2_maxLinearCorrection   (0.2f * b2_lengthUnitsPerMeter)

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

b2_maxManifoldPoints

#define b2_maxManifoldPoints   2

The maximum number of contact points between two convex shapes. Do not change this value.

b2_maxRotation

#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.

b2_maxTranslation

#define b2_maxTranslation   (2.0f * b2_lengthUnitsPerMeter)

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

b2_polygonRadius

#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.