# BodyRigid Class

This class is used to simulate rigid bodies that move according to rigid bodies dynamics.

## BodyRigid Class

This class inherits from Body

## BodyRigid ()

Constructor. Creates a rigid body with default properties.

## BodyRigid (Object object)

Constructor. Creates a rigid body with default properties for a given object.

### Arguments

• Object object - Object approximated with the new rigid body.

Applies a force to the radius vector of the body, specified in the world coordinates. This function calculates the cross product of the radius vector and the force vector. It acts like a lever arm that changes both linear and angular velocities of the body.

Unlike impulses, all forces are accumulated first, then the resulting force is calculated and applied to the body (during the physics simulation stage, when the body update() function is called).

Notice
You can call this function only from flush() function in the world script. Do not apply forces in the update() function, because you will get unstable result that varies each rendering frame.

### Arguments

• vec3 radius - radius vector, traced from the center of mass of the body to the point where the force is applied.
• vec3 force - the value of the applied force.

Applies a force to the body's center of mass.

Unlike impulses, all forces are accumulated first, then the resulting force is calculated and applied to the body (during the physics simulation stage, when the body update() function is called).

Notice
You can call this function only from flush() function in the world script. Do not apply forces in the update() function, because you will get unstable result that varies each rendering frame.

### Arguments

• vec3 force - the value of the applied force.

Applies an impulse to the radius vector of the body, specified in the world coordinates.

Unlike forces, impulses immediately affect both linear and angular velocities of the body.

### Arguments

• vec3 radius - radius vector, traced from the center of mass to the point where the impulse is applied.
• vec3 impulse - the value of the applied impulse.

Applies a torque to the radius vector of the body, specified in the world coordinates.

This function calculates the cross product of the radius vector and the force vector.

It acts like a lever arm that changes both angular and linear velocities of the body.

All torque values are accumulated first, then the resulting torque is calculated and applied to the body (during the physics simulation stage, when the body update is called).

Notice
You can call this function only from flush() function in the world script. Do not apply forces in the update() function, because you will get unstable result that varies each rendering frame.

### Arguments

• vec3 radius - Radius vector starting in the body's center of mass in local coordinates. Its end is the point of torque application.
• vec3 torque - the value of the applied torque.

Applies a torque to the body's center of mass.

All torque values are accumulated first, then the resulting torque is calculated and applied to the body (during the physics simulation stage, when the body update() function is called).

Notice
You can call this function only from flush() function in the world script. Do not apply forces in the update() function, because you will get unstable result that varies each rendering frame.

### Arguments

• vec3 torque - the value of the applied torque.

## void addWorldForce (vec3 point, vec3 force)

Applies a force to the given point of the body, that is specified in world coordinates. This function calculates the cross product of the radius vector (a vector from the center of mass to the point where force is applied) and the force vector (the magnitude of the force). It acts like a lever arm that changes both linear and angular velocities of the body.
Unlike impulses, all forces are accumulated first, then the resulting force is calculated and applied to the body (during the physics simulation stage, when the body update is called).
Notice
You can call this function only from within flush() in the world script. Do not apply forces in the update(); otherwise, you will get unstable result that varies each rendering frame.

### Arguments

• vec3 point - Point of the body in world coordinates.
• vec3 force - Amount of force to apply.

## void addWorldImpulse (vec3 point, vec3 impulse)

Applies an impulse to the given point of the body, that is specified in world coordinates. Unlike forces, impulses immediately affect both linear and angular velocities of the body.

### Arguments

• vec3 point - Point of the body in world coordinates.
• vec3 impulse - Amount of impulse to apply.

## void addWorldTorque (vec3 point, vec3 torque)

Applies a torque to the given point of the body, that is specified in world coordinates. This function calculates the cross product of the radius vector (a vector from the center of mass to the point where torque is applied) and the force vector (the magnitude of the torque). It acts like a lever arm that changes both angular and linear velocities of the body.
All torque values are accumulated first, then the resulting torque is calculated and applied to the body (during the physics simulation stage, when the body update is called).
Notice
You can call this function only from within flush() in the world script. Do not apply torques in the update(); otherwise, you will get unstable result that varies each rendering frame.

### Arguments

• vec3 point - Point of the body in world coordinates.
• vec3 torque - Amount of torque to apply.

## int createShapes (int depth = 4, float error = 0.01, float threshold = 0.01)

Removes all previously created shapes and creates one or more convex shapes approximating the mesh.

### Arguments

• int depth = 4 - Degree of decomposition of the mesh. If 0 or a negative value is provided, only one shape will be created. If a positive n is provided, the mesh will be decomposed n times. This is an optional parameter.
• float error = 0.01 - Approximation error, which is used to create convex hulls. This is an optional parameter.
• float threshold = 0.01 - Threshold, which is used to decide, whether two adjoining convex shapes can be replaced with one larger shape. A pair of shapes is replaced with a larger shape, if their volumes are roughly the same. This value is clamped in the range [1 E-6; 1]. This is an optional parameter.

### Return value

1 if the convex shapes are created successfully; otherwise 0.

## float getAngularDamping ()

Returns the angular damping of the body. The default is 0.

Angular damping.

## vec3 getAngularScale ()

Returns a multiplier for the body's angular velocity per axis. If one of vec3 values is set to 0, movement along this axis will be restricted. For example, for 2D physics with movement restricted to a X axis, set the body's angular scale to (1,0,0). The default value is (1,1,1).

### Return value

Angular scale per axis.

## vec3 getAngularVelocity ()

Returns the current angular velocity of the body.

### Return value

Angular velocity in radians per second.

## vec3 getCenterOfMass ()

Returns coordinates of the center of mass of the body.

### Return value

Coordinates of the center of mass.

## float getFrozenAngularVelocity ()

Returns the current angular velocity threshold for freezing body simulation. If body angular velocity remains lower than this threshold during the number of Frozen frames (together with linear one), it stops to be updated. The default is 0.

### Return value

"Freeze" angular velocity.

## float getFrozenLinearVelocity ()

Returns the current linear velocity threshold for freezing body simulation. If body linear velocity remains lower than this threshold during the number of Frozen frames (together with angular one), it stops to be updated. The default is 0.

### Return value

"Freeze" linear velocity.

## float getIMass ()

Returns the inverse mass of the body.

### Return value

Inverse mass of the body.

## float getLinearDamping ()

Returns the linear damping of the body. The default is 0.

Linear damping.

## vec3 getLinearScale ()

Returns a multiplier for the body's linear velocity per axis. If one of vec3 values is set to 0, movement along this axis will be restricted. For example, for 2D physics with movement restricted to a X axis, set the body's linear scale to (0,1,1). The default value is (1,1,1).

### Return value

Linear scale per axis.

## vec3 getLinearVelocity ()

Returns the current linear velocity of the body.

### Return value

Linear velocity in units per second.

## float getMass ()

Returns the body mass.
Notice
If g (Earth's gravity) equals to 9.8 m/s2, and 1 unit equals to 1 m, the mass is measured in kilograms.

### Return value

Mass of the body.

## float getMaxAngularVelocity ()

Returns the maximum angular velocity of the body. The default is infinity.

### Return value

Maximum angular velocity in per second.

## float getMaxLinearVelocity ()

Returns the maximum linear velocity of the body. The default is infinity.

### Return value

Maximum linear velocity in units per second.

Returns the total linear velocity of the point specified in local coordinates.

### Arguments

• vec3 radius - Radius vector starting in the body's center of mass.

### Return value

Total linear velocity in the given point of the body.

## vec3 getWorldCenterOfMass ()

Returns world coordinates of the center of mass of the body.

### Return value

World coordinates of the body's center of mass.

## vec3 getWorldVelocity (vec3 point)

Returns the total linear velocity of the point specified in world coordinates.

### Arguments

• vec3 point - Point of the body in world coordinates.

### Return value

Total linear velocity in the given point.

## int isFreezable ()

Returns a value indicating if the object is not simulated if both its linear and angular velocities are below "freeze" ones (see setFrozenLinearVelocity and setFrozenAngularVelocity functions). The default is 1.

### Return value

Positive number if the body "freezes" when necessary; 0 if its physical state is always updated.

## int isShapeBased ()

Returns a value indicating if mass and inertia of the body are bound to its shape properties or not. The default is 1.

### Return value

Positive number if mass and inertia are calculated based on shape properties; otherwise, 0.

## void setAngularDamping (float damping)

Sets an angular damping of the body.

### Arguments

• float damping - Angular damping. If a negative value is provided, 0 will be used instead.

## void setAngularScale (vec3 scale)

Sets a multiplier for the body's angular velocity per axis. If one of vec3 values is set to 0, movement along this axis will be restricted. For example, for 2D physics with movement restricted to a X axis, set the body's angular scale to (1,0,0). The default value is (1,1,1).

### Arguments

• vec3 scale - Angular scale per axis.

## void setAngularVelocity (vec3 velocity)

Sets an angular velocity of the body.

### Arguments

• vec3 velocity - Angular velocity in radians per second.

## void setCenterOfMass (vec3 center)

Sets coordinates of the center of mass of the body.

### Arguments

• vec3 center - Coordinates of the center of mass.

## void setFreezable (int frozenable)

Sets a value indicating if the body should not be simulated if both its linear and angular velocities are below "freeze" ones (see setFrozenLinearVelocity and setFrozenAngularVelocity functions). The default is 1.

### Arguments

• int frozenable - Positive number to "freeze" the body when necessary; 0 for its physical state to be always updated.

## void setFrozenAngularVelocity (float velocity)

Sets angular velocity threshold for freezing body simulation. If body angular velocity remains lower than this threshold during the number of Frozen frames (together with linear one), it stops to be updated.

## void setFrozenLinearVelocity (float velocity)

Sets linear velocity threshold for freezing body simulation. If body linear velocity remains lower than this threshold during the number of Frozen frames (together with angular one), it stops to be updated.

## void setInertia (mat4 inertia)

Sets an inertia tensor of the body. The inertia tensor describes the distribution of the mass over the body relative to the body's center of mass.

### Arguments

• mat4 inertia - Inertia tensor. (In fact, here the engine will handle mat4 as mat3.)

## void setLinearDamping (float damping)

Sets a linear damping of the body.

### Arguments

• float damping - Linear damping. If a negative value is provided, 0 will be used instead.

## void setLinearScale (vec3 scale)

Sets a multiplier for the body's linear velocity per axis. If one of vec3 values is set to 0, movement along this axis will be restricted. For example, for 2D physics with movement restricted to a X axis, set the body's linear scale to (0,1,1). The default value is (1,1,1).

### Arguments

• vec3 scale - Linear scale per axis.

## void setLinearVelocity (vec3 velocity)

Sets a linear velocity of the body.

### Arguments

• vec3 velocity - Linear velocity in units per second.

## void setMass (float mass)

Sets a mass of the body.
Notice
If g (Earth's gravity) equals to 9.8 m/s2, and 1 unit equals to 1 m, the mass is measured in kilograms.

### Arguments

• float mass - Mass of the body.

## void setMaxAngularVelocity (float velocity)

Sets a maximum angular velocity of the body.

### Arguments

• float velocity - Maximum angular velocity in radians per second. If a negative value is provided, 0 will be used instead.

## void setMaxLinearVelocity (float velocity)

Sets a maximum linear velocity of the body.

### Arguments

• float velocity - Maximum linear velocity in units per second. If a negative value is provided, 0 will be used instead.

## void setShapeBased (int mode)

Sets a value indicating if mass and inertia of the body are bound to its shape properties or not.

### Arguments

• int mode - Positive number to bind mass and inertia of the body to its shape properties, 0 to allow arbitrary values.
Last update: 2017-07-03