A prismatic joint allows for translation along a single axis with no rotation. More...

Collaboration diagram for Prismatic Joint:

Data Structures
struct	b2PrismaticJointDef
	Prismatic joint definition. More...

Functions
b2JointId	b2CreatePrismaticJoint (b2WorldId worldId, const b2PrismaticJointDef *def)
	Create a prismatic (slider) joint.

void	b2PrismaticJoint_EnableSpring (b2JointId jointId, bool enableSpring)
	Enable/disable the joint spring.

bool	b2PrismaticJoint_IsSpringEnabled (b2JointId jointId)
	Is the prismatic joint spring enabled or not?

void	b2PrismaticJoint_SetSpringHertz (b2JointId jointId, float hertz)
	Set the prismatic joint stiffness in Hertz.

float	b2PrismaticJoint_GetSpringHertz (b2JointId jointId)
	Get the prismatic joint stiffness in Hertz.

void	b2PrismaticJoint_SetSpringDampingRatio (b2JointId jointId, float dampingRatio)
	Set the prismatic joint damping ratio (non-dimensional)

float	b2PrismaticJoint_GetSpringDampingRatio (b2JointId jointId)
	Get the prismatic spring damping ratio (non-dimensional)

void	b2PrismaticJoint_EnableLimit (b2JointId jointId, bool enableLimit)
	Enable/disable a prismatic joint limit.

bool	b2PrismaticJoint_IsLimitEnabled (b2JointId jointId)
	Is the prismatic joint limit enabled?

float	b2PrismaticJoint_GetLowerLimit (b2JointId jointId)
	Get the prismatic joint lower limit.

float	b2PrismaticJoint_GetUpperLimit (b2JointId jointId)
	Get the prismatic joint upper limit.

void	b2PrismaticJoint_SetLimits (b2JointId jointId, float lower, float upper)
	Set the prismatic joint limits.

void	b2PrismaticJoint_EnableMotor (b2JointId jointId, bool enableMotor)
	Enable/disable a prismatic joint motor.

bool	b2PrismaticJoint_IsMotorEnabled (b2JointId jointId)
	Is the prismatic joint motor enabled?

void	b2PrismaticJoint_SetMotorSpeed (b2JointId jointId, float motorSpeed)
	Set the prismatic joint motor speed, typically in meters per second.

float	b2PrismaticJoint_GetMotorSpeed (b2JointId jointId)
	Get the prismatic joint motor speed, typically in meters per second.

void	b2PrismaticJoint_SetMaxMotorForce (b2JointId jointId, float force)
	Set the prismatic joint maximum motor force, typically in newtons.

float	b2PrismaticJoint_GetMaxMotorForce (b2JointId jointId)
	Get the prismatic joint maximum motor force, typically in newtons.

float	b2PrismaticJoint_GetMotorForce (b2JointId jointId)
	Get the prismatic joint current motor force, typically in newtons.

Detailed Description

A prismatic joint allows for translation along a single axis with no rotation.

The prismatic joint is useful for things like pistons and moving platforms, where you want a body to translate along an axis and have no rotation. Also called a slider joint.

Data Structure Documentation

◆ b2PrismaticJointDef

struct b2PrismaticJointDef

Prismatic joint definition.

This requires defining a line of motion using an axis and an anchor point. The definition uses local anchor points and a local axis so that the initial configuration can violate the constraint slightly. The joint translation is zero when the local anchor points coincide in world space.

Collaboration diagram for b2PrismaticJointDef:

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Data Fields
b2BodyId	bodyIdA	The first attached body.
b2BodyId	bodyIdB	The second attached body.
bool	collideConnected	Set this flag to true if the attached bodies should collide.
float	dampingRatio	The spring damping ratio, non-dimensional.
bool	enableLimit	Enable/disable the joint limit.
bool	enableMotor	Enable/disable the joint motor.
bool	enableSpring	Enable a linear spring along the prismatic joint axis.
float	hertz	The spring stiffness Hertz, cycles per second.
int32_t	internalValue	Used internally to detect a valid definition. DO NOT SET.
b2Vec2	localAnchorA	The local anchor point relative to bodyA's origin.
b2Vec2	localAnchorB	The local anchor point relative to bodyB's origin.
b2Vec2	localAxisA	The local translation unit axis in bodyA.
float	lowerTranslation	The lower translation limit.
float	maxMotorForce	The maximum motor force, typically in newtons.
float	motorSpeed	The desired motor speed, typically in meters per second.
float	referenceAngle	The constrained angle between the bodies: bodyB_angle - bodyA_angle.
float	upperTranslation	The upper translation limit.
void *	userData	User data pointer.

Function Documentation

◆ b2CreatePrismaticJoint()

b2JointId b2CreatePrismaticJoint	(	b2WorldId	worldId,
		const b2PrismaticJointDef *	def )

Create a prismatic (slider) joint.

See also: b2PrismaticJointDef for details

◆ b2PrismaticJoint_SetSpringHertz()

void b2PrismaticJoint_SetSpringHertz	(	b2JointId	jointId,
		float	hertz )

Set the prismatic joint stiffness in Hertz.

This should usually be less than a quarter of the simulation rate. For example, if the simulation runs at 60Hz then the joint stiffness should be 15Hz or less.