org.jbox2d.common
Class Settings

java.lang.Object
  org.jbox2d.common.Settings

public class Settings
extends Object

Global tuning constants based on MKS units and various integer maximums (vertices per shape, pairs, etc.).

Field Summary

static float	aabbExtension This is used to fatten AABBs in the dynamic tree.
static float	aabbMultiplier This is used to fatten AABBs in the dynamic tree.
static float	angularSleepTolerance A body cannot sleep if its angular velocity is above this tolerance.
static float	angularSlop A small angle used as a collision and constraint tolerance.
static float	baumgarte This scale factor controls how fast overlap is resolved.
static int	CONTACT_STACK_INIT_SIZE
static float	EPSILON A "close to zero" float epsilon value for use
static boolean	FAST_ABS
static boolean	FAST_ATAN2
static boolean	FAST_CEIL
static boolean	FAST_FLOOR
static boolean	FAST_ROUND
static float	linearSleepTolerance A body cannot sleep if its linear velocity is above this tolerance.
static float	linearSlop A small length used as a collision and constraint tolerance.
static float	maxAngularCorrection The maximum angular position correction used when solving constraints.
static float	maxLinearCorrection The maximum linear position correction used when solving constraints.
static int	maxManifoldPoints The maximum number of contact points between two convex shapes.
static int	maxPolygonVertices The maximum number of vertices on a convex polygon.
static float	maxRotation The maximum angular velocity of a body.
static float	maxRotationSquared
static int	maxSubSteps Maximum number of sub-steps per contact in continuous physics simulation.
static int	maxTOIContacts Maximum number of contacts to be handled to solve a TOI island.
static float	maxTranslation The maximum linear velocity of a body.
static float	maxTranslationSquared
static float	PI Pi.
static float	polygonRadius The radius of the polygon/edge shape skin.
static boolean	SINCOS_LUT_ENABLED
static int	SINCOS_LUT_LENGTH
static boolean	SINCOS_LUT_LERP Use if the table's precision is large (eg .006 or greater).
static float	SINCOS_LUT_PRECISION smaller the precision, the larger the table.
static float	timeToSleep The time that a body must be still before it will go to sleep.
static float	toiBaugarte
static float	velocityThreshold A velocity threshold for elastic collisions.

Constructor Summary

Settings()

Method Summary

static float	mixFriction(float friction1, float friction2) Friction mixing law.
static float	mixRestitution(float restitution1, float restitution2) Restitution mixing law.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EPSILON

public static final float EPSILON

A "close to zero" float epsilon value for use

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Constant Field Values

PI

public static final float PI

Pi.

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Constant Field Values

FAST_ABS

public static boolean FAST_ABS

FAST_FLOOR

public static boolean FAST_FLOOR

FAST_CEIL

public static boolean FAST_CEIL

FAST_ROUND

public static boolean FAST_ROUND

FAST_ATAN2

public static boolean FAST_ATAN2

CONTACT_STACK_INIT_SIZE

public static int CONTACT_STACK_INIT_SIZE

SINCOS_LUT_ENABLED

public static boolean SINCOS_LUT_ENABLED

SINCOS_LUT_PRECISION

public static final float SINCOS_LUT_PRECISION

smaller the precision, the larger the table. If a small table is used (eg, precision is .006 or greater), make sure you set the table to lerp it's results. Accuracy chart is in the MathUtils source. Or, run the tests yourself in SinCosTest.

Good lerp precision values:

• .0092
• .008201
• .005904
• .005204
• .004305
• .002807
• .001508
• 9.32500E-4
• 7.48000E-4
• 8.47000E-4
• .0005095
• .0001098
• 9.50499E-5
• 6.08500E-5
• 3.07000E-5
• 1.53999E-5

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Constant Field Values

SINCOS_LUT_LENGTH

public static final int SINCOS_LUT_LENGTH

SINCOS_LUT_LERP

public static boolean SINCOS_LUT_LERP

Use if the table's precision is large (eg .006 or greater). Although it is more expensive, it greatly increases accuracy. Look in the MathUtils source for some test results on the accuracy and speed of lerp vs non lerp. Or, run the tests yourself in SinCosTest.

maxManifoldPoints

public static final int maxManifoldPoints

The maximum number of contact points between two convex shapes.

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Constant Field Values

maxPolygonVertices

public static final int maxPolygonVertices

The maximum number of vertices on a convex polygon.

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Constant Field Values

aabbExtension

public static final float aabbExtension

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.

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Constant Field Values

aabbMultiplier

public static final float aabbMultiplier

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.

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Constant Field Values

linearSlop

public static final float linearSlop

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

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Constant Field Values

angularSlop

public static final float angularSlop

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

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Constant Field Values

polygonRadius

public static final float polygonRadius

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

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Constant Field Values

maxSubSteps

public static final int maxSubSteps

Maximum number of sub-steps per contact in continuous physics simulation.

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Constant Field Values

maxTOIContacts

public static final int maxTOIContacts

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

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Constant Field Values

velocityThreshold

public static final float velocityThreshold

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

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Constant Field Values

maxLinearCorrection

public static final float maxLinearCorrection

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

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Constant Field Values

maxAngularCorrection

public static final float maxAngularCorrection

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

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Constant Field Values

maxTranslation

public static final float maxTranslation

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.

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Constant Field Values

maxTranslationSquared

public static final float maxTranslationSquared

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Constant Field Values

maxRotation

public static final float maxRotation

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.

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Constant Field Values

maxRotationSquared

public static float maxRotationSquared

baumgarte

public static final float baumgarte

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.

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Constant Field Values

toiBaugarte

public static final float toiBaugarte

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Constant Field Values

timeToSleep

public static final float timeToSleep

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

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Constant Field Values

linearSleepTolerance

public static final float linearSleepTolerance

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

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Constant Field Values

angularSleepTolerance

public static final float angularSleepTolerance

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

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Constant Field Values

Constructor Detail

Settings

public Settings()

Method Detail

mixFriction

public static final float mixFriction(float friction1,
                                      float friction2)

Friction mixing law. Feel free to customize this. TODO djm: add customization

Parameters:

friction1 -

friction2 -

Returns:

mixRestitution

public static final float mixRestitution(float restitution1,
                                         float restitution2)

Restitution mixing law. Feel free to customize this. TODO djm: add customization

Parameters:

restitution1 -

restitution2 -

Returns: