Body Class
This class is used to simulate physical bodies that allow an object to participate in physical interactions. A body can have one or several collision shapes assigned and can be connected together with joints.
To transform a body, one of the following functions can be used:
All of these functions take effect when physics calculations are over and updatePhysics() is performed. Only after that transformations of the body are applied to the rendered node. If a node needs to be transformed immediately after its physical body, flushTransform() is to be called.The simulation of the body can be frozen (if a setFrozen flag is set).
You can subscribe for certain events of a body to handle them:
- Frozen - to perform some actions when a body freezes.
- Position - to perform some actions when a body changes its position.
- ContactEnter - to perform some actions when a contact emerges (body starts touching another body or collidable surface).
- ContactLeave - to perform some actions when a contact ends (body stops touching another body or collidable surface).
- Contacts - to get all contacts of the body including new ones (enter) and the ending ones (leave). Leave contacts are removed after the callback execution stage, so this is the only point where you can still get them.
See Also#
- The Creating and Attaching a Cloth usage example demonstrating how to create objects, assign bodies, and add shapes to them
- A C++ API sample located in the <UnigineSDK>/source/samples/Api/Physics/BodyCallbacks folder
- A C# API sample located in the <UnigineSDK>/source/csharp/samples/Api/Physics/BodyCallbacks folder
- A set of UnigineScript API samples located in the <UnigineSDK>/data/samples/physics/ folder:
- callbacks_00
- callbacks_01
- callbacks_02
- The Handling Contacts on Collision usage example
Body Class
Members
int getNumContacts() const#
Return value
Current number of contacts.int getNumJoints() const#
Return value
Current number of joints in the body.int getNumShapes() const#
Return value
Current number of shapes.int getNumChildren() const#
Return value
Current number of children.void setRotation ( quat rotation ) #
Arguments
- quat rotation - The rotation in the world coordinates.
quat getRotation() const#
Return value
Current rotation in the world coordinates.void setPosition ( Vec3 position ) #
Arguments
- Vec3 position - The position in the world coordinates.
Vec3 getPosition() const#
Return value
Current position in the world coordinates.void setTransform ( Mat4 transform ) #
Arguments
- Mat4 transform - The transformation matrix. This matrix describes position, orientation and scale of the body.
Mat4 getTransform() const#
Return value
Current transformation matrix. This matrix describes position, orientation and scale of the body.void setPhysicalMask ( int mask ) #
Arguments
- int mask - The integer, each bit of which is a mask.
int getPhysicalMask() const#
Return value
Current integer, each bit of which is a mask.void setName ( string name ) #
Arguments
- string name - The name of the body.
string getName() const#
Return value
Current name of the body.void setGravity ( bool gravity ) #
Arguments
- bool gravity - Set true to enable the body is affected by gravity; false - to disable it.
bool isGravity() const#
Return value
true if the body is affected by gravity; otherwise false.void setImmovable ( bool immovable ) #
Arguments
- bool immovable - Set true to enable the body is immovable (static); false - to disable it.
bool isImmovable() const#
Return value
true if the body is immovable (static); otherwise false.void setFrozen ( bool frozen ) #
Arguments
- bool frozen - Set true to enable the body frozen status; false - to disable it.
bool isFrozen() const#
Return value
true if the body frozen status is enabled; otherwise false.bool isEnabledSelf() const#
Return value
true if the body is enabled; otherwise false.void setEnabled ( bool enabled ) #
Arguments
- bool enabled - Set true to enable physical interactions with the body; false - to disable it.
bool isEnabled() const#
Return value
true if physical interactions with the body is enabled; otherwise false.string getTypeName() const#
Return value
Current name of the body type.getType() const#
Return value
Current type of the body, one of the BODY_* pre-defined variables.void setID ( int id ) #
Arguments
- int id - The unique ID of the body.
int getID() const#
Return value
Current unique ID of the body.void setObject ( ) #
Arguments
- object - The object approximated with the body.
getObject() const#
Return value
Current object approximated with the body.Body getParent() const#
Return value
Current parent of the body.vec3 getDirection() const#
Return value
Current normalized direction vector in the world coordinates.getEventContacts() const#
The event handler signature is as follows: myhandler()Usage Example
Return value
Event reference.getEventContactLeave() const#
The event handler signature is as follows: myhandler()Usage Example
Return value
Event reference.getEventContactEnter() const#
The event handler signature is as follows: myhandler()Usage Example
Return value
Event reference.getEventPosition() const#
The event handler signature is as follows: myhandler()Usage Example
Return value
Event reference.getEventFrozen() const#
The event handler signature is as follows: myhandler()Usage Example
Return value
Event reference.Body createBody ( int type ) #
Creates a new body of the specified type.Arguments
- int type - Body type. One of the BODY_* values.
Return value
New created body instance.Body createBody ( string type_name ) #
Creates a new body of the specified type.Arguments
- string type_name - Body type name.
Return value
New created body instance.string getTypeName ( int type ) #
Returns the name of a body type with a given ID.Arguments
- int type - Body type ID. One of the BODY_* values.
Return value
Body type name.bool setObject ( bool update ) #
Sets an object, which the body approximates.Arguments
- bool update - Update flag: 1 to update the object after assigning the body (by default), 0 not to update right after body assignment.
Return value
1 if the body is assigned to the specified object successfully; otherwise, 0.void setPreserveTransform ( Mat4 transform ) #
Sets a transformation matrix for the body (in world coordinates). This method safely preserves body's linear and angular velocities. It changes only body coordinates - all other body parameters stay the same.Arguments
- Mat4 transform - Transformation matrix. This matrix describes position, orientation and scale of the body.
void setVelocityTransform ( Mat4 transform ) #
Sets a transformation matrix (in world coordinates) and computes linear and angular velocities of the body depending on its trajectory from the current position to the specified one. The time used in calculations corresponds to physics ticks. It clears forces and torques to zeros and nullifies counted down frozen frames.Arguments
- Mat4 transform - Transformation matrix. This matrix describes position, orientation and scale of the body.
void flushTransform ( ) #
Forces to set the transformations of the body for the node.void setDirection ( vec3 dir, vec3 up ) #
Updates the direction vector of the body (in world coordinates). By default, a direction vector points along -Z axis. This function changes its direction and reorients the body.Arguments
- vec3 dir - New direction vector in the world coordinates. The direction vector always has unit length.
- vec3 up - New up vector in the world coordinates.
int isChild ( Body body ) #
Checks if a given body is a child of the body.Arguments
- Body body - Body to check.
Return value
1 if the provided body is a child; otherwise, 0.int findChild ( string name ) #
Searches for a child body with a given name.Arguments
- string name - Name of the child body.
Return value
Number of the child in the list of children, if it is found; otherwise, -1.Body getChild ( int num ) #
Returns a given child body.Arguments
- int num - Child number.
Return value
Corresponding body.void addShape ( Shape shape, mat4 transform ) #
Adds a shape to the list of shapes comprising the body.Arguments
- Shape shape - New shape to add.
- mat4 transform - Shape transformation matrix (in the body's coordinate system).
void addShape ( Shape shape ) #
Adds a shape to the list of shapes comprising the body.Arguments
- Shape shape - New shape to add.
void clearShapes ( int destroy = 0 ) #
Clears all shapes from the body.Arguments
- int destroy - Flag indicating whether shapes are to be destroyed after removal: use 1 to destroy shapes after removal, or 0 if you plan to use them later. The default value is 0.
int isShape ( Shape shape ) #
Checks if a given shape belongs to the body.Arguments
- Shape shape - Shape to check.
Return value
1 if the shape belongs to the body; otherwise, 0.int insertShape ( int pos, Shape shape ) #
Inserts a given shape at the specified position in the list of body's shapes.Arguments
- int pos - Position in the list at which the shape is to be inserted in the range from 0 to the number of shapes.
- Shape shape - Shape to be inserted.
Return value
1 if a shape was successfully inserted; otherwise, 0.int insertShape ( int pos, Shape shape, mat4 transform ) #
Inserts a given shape at the specified position in the list of body's shapes and sets the specified transformation for it.Arguments
- int pos - Position in the list at which the shape is to be inserted in the range from 0 to the number of shapes.
- Shape shape - Shape to be inserted.
- mat4 transform - Shape's transformation (in the body's coordinate system).
Return value
1 if a shape was successfully inserted; otherwise, 0.int findShape ( string name ) #
Searches for a shape with a given name.Arguments
- string name - Name of the shape.
Return value
Number of the shape in the list of shapes, if it is found; otherwise, -1.Shape getShape ( int num ) #
Returns a given shape.Arguments
- int num - Shape number.
Return value
Corresponding shape object.void setShapeTransform ( int num, mat4 transform ) #
Sets a transformation matrix for a given shape (in local coordinates). This matrix describes position and orientation of the shape.Arguments
- int num - Shape number.
- mat4 transform - Transformation matrix (in the body's coordinate system).
mat4 getShapeTransform ( int num ) #
Returns the transformation matrix of a given shape (in local coordinates). This matrix describes position and orientation of the shape.Arguments
- int num - Shape number.
Return value
Transformation matrix.void updateShapes ( ) #
Updates all shapes of the body.void addJoint ( Joint joint ) #
Adds a joint to the body.Arguments
- Joint joint - New joint to add.
void removeJoint ( ) #
Removes a given joint from the body.Arguments
void insertJoint ( Joint joint, int num ) #
Inserts a given joint at the specified position in the list of body's joints.Arguments
- Joint joint - Joint to be inserted.
- int num - Position in the list at which the joint is to be inserted in the range from 0 to the number of joints.
int isJoint ( Joint joint ) #
Checks if a given joint belongs to the body.Arguments
- Joint joint - Joint to check.
Return value
1 if the joint belongs to the body; otherwise, 0.int findJoint ( string name ) #
Searches for a joint with a given name.Arguments
- string name - Name of the joint.
Return value
Number of the joint in the list of joints, if it is found; otherwise, -1.Joint getJoint ( int num ) #
Returns a given joint.Arguments
- int num - Joint number.
Return value
Corresponding joint.getIntersection ( int mask, variable v ) #
Performs tracing from the p0 point to the p1 point to find a body shape intersected by this line. Intersection is found only for objects with a matching intersection mask. On success ret_point and ret_normal shall contain information about intersection.
Depending on the variable passed as an argument, the result can be presented as a PhysicsIntersection or PhysicsIntersectionNormal class instance.
Arguments
- int mask - Intersection mask.
- variable v - Variable defining which type of intersection object will be returned:
- PhysicsIntersection intersection — PhysicsIntersection class instance containing intersection information (contact point coordinates).
- PhysicsIntersectionNormal normal — PhysicsIntersectionNormal class instance containing intersection information (contact point and normal coordinates).
Return value
First intersected shape, if found; otherwise, 0.long getContactID ( int num ) #
Returns the contact ID by the contact number.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Contact ID.int findContactByID ( long id ) #
Returns the number of the contact by its ID.Arguments
- long id - Contact ID.
Return value
Number of the contact with the specified ID if it exists, otherwise -1.int isContactInternal ( int num ) #
Returns a value indicating whether the contact with the specified number is internal (handled by the body) or not (handled by another body). A contact can be handled by any of the bodies that participate in it. To which body a contact is assigned is random. If the contact is assigned to and handled by the body it is called an internal one, otherwise it is called external (handled by another body). The total number of contacts for the body includes all, internal and external ones. Iterating through internal contacts is much faster than through external ones, thus you might want a certain body to handle most of the contacts it participates in. This can be done for a rigid body by raising a priority for the body via the setHighPriorityContacts() method.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
1 if the contact with the specified number is internal; otherwise 0.int isContactEnter ( int num ) #
Returns a value indicating if the body has begun touching another body at the contact point with the specified number (the contact has just occurred).Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
1 if the body has begun touching another body at the contact point with the specified number (the contact has just occurred); otherwise 0.int isContactLeave ( int num ) #
Returns a value indicating if the body has stopped touching another body at the contact point with the specified number.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
1 if the body has stopped touching another body at the contact point with the specified number; otherwise 0.int isContactStay ( int num ) #
Returns a value indicating if the body keeps touching another body at the contact point with the specified number (the contact lasts).Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
1 if the body keeps touching another body at the contact point with the specified number (the contact lasts); otherwise 0.Vec3 getContactPoint ( int num ) #
Returns world coordinates of the contact point.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Contact point (in world coordinates).vec3 getContactNormal ( int num ) #
Returns a normal of the contact point, in world coordinates.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Contact normal (in world coordinates).vec3 getContactVelocity ( int num ) #
Returns relative velocity at the given contact point.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Velocity vector.float getContactImpulse ( int num ) #
Returns the relative impulse at the given contact point.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Impulse value.float getContactTime ( int num ) #
Returns the time when the given contact occurs. By CCD (for spheres or capsules), it returns the time starting from the current physics simulation tick to the moment when the calculated contact is bound to happen. By non-continuous collision detection, 0 is always returned.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Time of the calculated contact to happen, in seconds.float getContactDepth ( int num ) #
Returns the depth by which the body penetrated with an obstacle by the given contact. This distance is measured along the contact normal.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Penetration depth, in units.float getContactFriction ( int num ) #
Returns relative friction at the given contact point.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Friction value.float getContactRestitution ( int num ) #
Returns relative restitution at the given contact point.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Restitution.Body getContactBody0 ( int num ) #
Returns the first body participating in a given contact. This is not necessarily the current body.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
First body.Body getContactBody1 ( int num ) #
Returns the second body participating in a given contact. This is not necessarily the current body.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Second body.Shape getContactShape0 ( int num ) #
Returns the first shape participating in a given contact. This shape does not necessarily belong to the current body.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
First shape.Shape getContactShape1 ( int num ) #
Returns the second shape participating in a given contact. This shape does not necessarily belong to the current body.Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Second shape.Object getContactObject ( int num ) #
Returns an object participating in the contact (used for collisions with non-physical object).Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Object in contact.int getContactSurface ( int num ) #
Returns the surface of the current object, which is in contact (used for collisions with non-physical object).Arguments
- int num - Contact number in the range from 0 to the total number of contacts.
Return value
Surface number.void renderContacts ( ) #
Renders all contact points of the body including internal and external ones (handled by other bodies).void renderExternalContacts ( ) #
Renders all external contacts of the body (handled by other bodies).void renderInternalContacts ( ) #
Renders all internal contacts of the body (handled by it).void renderJoints ( ) #
Renders joints to which the body is connected.void renderShapes ( ) #
Renders shapes comprising the body.void renderVisualizer ( ) #
Renders shapes, joints and contact points of the body.Body clone ( Object object ) #
Clones the body and assigns a copy to a given object.Arguments
- Object object - Object, to which the copy will be assigned.
Return value
Copy of the body.void swap ( Body body ) #
Swaps the bodies saving the pointers.Arguments
- Body body - Body to swap.
int saveState ( Stream stream ) #
Saves the state of a given body into a binary stream.Example using saveState() and restoreState() methods:
// set the body state
body.setPosition(vec3(1, 1, 0));
// save state
Blob blob_state = new Blob();
body.saveState(blob_state);
// change state
body.setPosition(vec3(0, 0, 0));
// restore state
blob_state.seekSet(0); // returning the carriage to the start of the blob
body.restoreState(blob_state);
Arguments
- Stream stream - Stream to save body state data.
Return value
1 if the body state is successfully saved; otherwise, 0.int restoreState ( Stream stream ) #
Restores the state of a given body from a binary stream.Example using saveState() and restoreState() methods:
// set the body state
body.setPosition(vec3(1, 1, 0));
// save state
Blob blob_state = new Blob();
body.saveState(blob_state);
// change state
body.setPosition(vec3(0, 0, 0));
// restore state
blob_state.seekSet(0); // returning the carriage to the start of the blob
body.restoreState(blob_state);
Arguments
- Stream stream - Stream with saved body state data.