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 flush() 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 set callbacks for a body to handle certain events:
Body Class
Members
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.Body getBody()
Returns the Body class instance.Return value
Body instance.int setID(int id)
Sets the unique ID for the body.Arguments
- int id - Unique ID.
Return value
1 if the ID is set successfully; otherwise, 0.int getID()
Returns the unique ID of the body.Return value
Unique ID.int getType()
Returns the type of the body.Return value
One of the BODY_* pre-defined variables.string getTypeName()
Returns the name of the body type.Return value
Type name.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.void setObject(Object object)
Sets an object, which the body approximates.Arguments
- Object object - Object to approximate.
Object getObject()
Returns the object, which is approximated with the body.Return value
Approximated object.void setEnabled(int enable)
Enables or disables physical interactions with the body.Arguments
- int enable - 1 to enable physical interactions, 0 to disable them.
int isEnabled()
Returns a value indicating if physical interactions with the body are enabled.Return value
1 if physical interactions with the body are enabled; otherwise, 0.int isEnabledSelf()
Returns a value indicating if the body is enabled.Return value
1 if the body is enabled; otherwise, 0.void setFrozen(int frozen)
Freezes or unfreezes the body. When a body is frozen, it is not simulated (though its contacts are still calculated), until a collision with a frozen body occurs or some force is applied.Arguments
- int frozen - 1 to freeze the object, 0 to unfreeze it.
int isFrozen()
Returns a value indicating if the body is frozen. When a body is frozen, it is not simulated (though its contacts are still calculated), until a collision with a frozen body occurs or some force is applied.Return value
1 if the body is frozen; otherwise, 0.void setImmovable(int immovable)
Sets a value indicating if the body is immovable (static).Arguments
- int immovable - 1 if the body is immovable (static); otherwise, 0.
int isImmovable()
Return a value indicating if the body is immovable (static).Return value
1 if the body is immovable (static); otherwise, 0.void setGravity(int gravity)
Sets a value indicating if gravity is affecting the body.Arguments
- int gravity - 1 if the body is affected by gravity; otherwise, 0.
int isGravity()
Returns a value indicating if gravity is affecting the body.Return value
1 if the body is affected by gravity; otherwise, 0.void setName(string name)
Sets the name of the body.Arguments
- string name - Name of the body.
string getName()
Returns the name of the body.Return value
Name of the body.void setPhysicalMask(int mask)
Sets the bit mask for interactions with physicals. Two objects interact, if they both have matching masks.Arguments
- int mask - Integer, each bit of which is a mask.
int getPhysicalMask()
Returns the bit mask for interactions with physicals. Two objects interact, if they both have matching masks.Return value
Integer, each bit of which is a mask.void setTransform(Mat4 transform)
Sets a transformation matrix for the body (in world coordinates). This method resets body's linear and angular velocities to defaults, sets forces and torques to zeros, nullifies counted down frozen frames. It is called, for example, when the node is dragged to a new position in the editor.Arguments
- Mat4 transform - Transformation matrix. This matrix describes position, orientation and scale of the body.
Mat4 getTransform()
Returns the transformation matrix of the body (in world coordinates). This matrix describes position and orientation of the body.Return value
Transformation matrix.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 setPosition(Vec3 pos)
Updates the body position. Body's linear and angular velocities will be reset to 0.Arguments
- Vec3 pos - New position in the world coordinates.
Vec3 getPosition()
Returns the body position.Return value
The body position in the world coordinates.void setRotation(quat rot)
Updates the body rotation.Arguments
- quat rot - New rotation in the world coordinates.
quat getRotation()
Returns the body rotation.Return value
The body rotation in the world coordinates.void setDirection(vec3 dir, vec3 up)
Updates the direction vector of the body. 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.
vec3 getDirection()
Returns the normalized direction vector of the body. By default, a direction vector points along -Z axis. It always has an unit length.Return value
Normalized direction vector in the world coordinates.Body getParent()
Returns the parent of the current body.Return value
Parent body.int isChild(Body body)
Checks if a given body is a child of the current body.Arguments
- Body body - Body to check.
Return value
1 if the provided body is a child; otherwise, 0.int getNumChildren()
Returns the number of child bodies.Return value
Number of children.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.
void addShape(Shape shape)
Adds a shape to the list of shapes comprising the body.Arguments
- Shape shape - New shape to add.
void removeShape(Shape shape)
Removes a given shape from the body.Arguments
- Shape shape - Shape to be removed.
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 getNumShapes()
Returns the number of shapes comprising the body.Return value
Number of shapes.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.
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(Joint joint)
Removes a given joint from the body.Arguments
- Joint joint - Joint to be removed.
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 a joint is to be inserted.
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 getNumJoints()
Returns the number of joints in the body.Return value
Number of joints.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.Shape getIntersection(vec3 p0, vec3 p1, int mask, variable v)
Performs tracing from the p0 point to the p1 point to find a body shape located on that line. Intersection is found only for objects with a matching mask.
Notice
World space coordinates are used for this function.
Depending on the variable passed as an argument, the result can be presented as the PhysicsIntersection or PhysicsIntersectionNormal node.
Arguments
- vec3 p0 - Start point of the line.
- vec3 p1 - End point of the line.
- int mask - Intersection mask.
- variable v - Variable defining which type of intersection object will be returned:
- PhysicsIntersection intersection — The PhysicsIntersection node.
- PhysicsIntersectionNormal normal — The PhysicsIntersectionNormal node.
Return value
Reference to the first intersected shape, if found; otherwise, 0.int getNumContacts()
Returns the number of contacts in which the body participates and which it handles.Notice
A contact can be handled by any of the bodies that participate in it. To which body it will be assigned is completely random. If the contact is assigned to and handled by another body, the number of contacts for the current body is not incremented.
To detect all contacts in which the body participates setContactCallback() should be used.
To detect all contacts in which the body participates setContactCallback() should be used.
Return value
Number of contacts.int getContactID(int num)
Returns the contact ID by the contact number.Arguments
- int num - Contact number.
Return value
Contact ID.Vec3 getContactPoint(int num)
Returns world coordinates of the contact point.Arguments
- int num - Contact number.
Return value
Contact point.vec3 getContactNormal(int num)
Returns a normal of the contact point, in world coordinates.Arguments
- int num - Contact number.
Return value
Contact normal.vec3 getContactVelocity(int num)
Returns relative velocity in the point of a given contact.Arguments
- int num - Contact number.
Return value
Velocity vector.float getContactImpulse(int num)
Returns the relative impulse arising in the point of a given contact.Arguments
- int num - Contact number.
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.
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.
Return value
Penetration depth in units.float getContactFriction(int num)
Returns relative friction arising in the point of a given contact.Arguments
- int num - Contact number.
Return value
Friction value.float getContactRestitution(int num)
Returns relative restitution arising in the point of a given contact.Arguments
- int num - Contact number.
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.
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.
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.
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.
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.
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.
Return value
Surface number.void setFrozenCallback(string func)
Adds a callback function to be called when a given body freezes.
Notice
The signature of the frozen callback function must be as follows:
Source code (UnigineScript)
void frozen_callback_function_name(Body body);You can set a callback function as follows:
Source code (UnigineScript)
setFrozenCallback("frozen_callback_function_name");Notice
Physics-based callbacks are executed in parallel with the main tread, so you should not modify nodes inside these functions. If you want to reposition, transform, create or delete nodes captured by your callback function, you can store them in the array and then perform all necessary operations in the update(). See the example for contact callbacks
Example: Setting a body frozen callback function for a certain class:
Source code (UnigineScript)
class SomeClass
{
// body for which a frozen callback function is to be set
Body body;
/*...*/
// callback function
void on_frozen(Body body)
{
// insert your code handling freezing here
}
void registerCallback()
{
// setting the on_frozen() function to handle freezing for the body
body.setFrozenCallback("SomeClass::on_frozen");
}
/*...*/
};Arguments
- string func - Callback function name.
void setPositionCallback(string func)
Adds a callback function to be called when a given body moves a certain distance (rotation is not taken into account).
Notice
The signature of the position callback function must be as follows:
Source code (UnigineScript)
void position_callback_function_name(Body body);You can set a callback function as follows:
Source code (UnigineScript)
setPositionCallback("position_callback_function_name");Notice
Physics-based callbacks are executed in parallel with the main tread, so you should not modify nodes inside these functions. If you want to reposition, transform, create or delete nodes captured by your callback function, you can store them in the array and then perform all necessary operations in the update(). See the example for contact callbacks
Example: Setting a body position callback function for a certain class:
Source code (UnigineScript)
class SomeClass
{
// body for which a position callback function is to be set
Body body;
/*...*/
// callback function
void on_position(Body body)
{
// insert your code handling position changes here
}
void registerCallback()
{
// setting the on_position() function to handle position changes for the body
body.setPositionCallback("SomeClass::on_position");
}
/*...*/
};Arguments
- string func - Callback function name.
void setContactCallback(string func)
Adds a callback function to be called when a contact with the body emerges. The body might have no information on some of its contacts with other physical bodies, as these contacts can be handled by other bodies. The contact callback function is to be used to detect all contacts in which the body participates.Notice
The signature of the contact callback function must be one of the following:
Source code (UnigineScript)
You can set a callback function as follows:
contact_callback_function_name(Body body);
contact_callback_function_name(Body body,int num); // num is the contact ID
contact_callback_function_name(Body body,int num,variable arg0); // num is the contact ID
contact_callback_function_name(Body body,int num,variable arg0,variable arg1); // num is the contact IDSource code (UnigineScript)
This function
contact_callback_function_name() must have the following signature:
setContactCallback("contact_callback_function_name",arg0,arg1);Source code (UnigineScript)
contact_callback_function_name(Body body,int num,variable arg0,variable arg1);Notice
Physics-based callbacks are executed in parallel with the main tread, so you should not modify nodes inside these functions.
If you want to reposition, transform, create or delete nodes captured by your callback function, you can store them in the array and then perform all necessary operations in the update():
Source code (UnigineScript)
// list of collisions that were processed by other bodies
Body unregistered_collisions[0];
// flag indicating if collisions were detected
int collision_detected = 0;
/*...*/
void contact_callback(Body body, int num)
{
// collision was detected
collision_detected = 1;
// if the collision is processed by other body, adding it to the list
if (body != this_body)
unregistered_collisions.append(body);
}
/*...*/
int update()
{
if (collision_detected)
{
// resetting collision flag
collision_detected = 0;
for (int i = 0; i < body.getNumContacts(); i++)
{
// process all nodes with which collisions were registered
Node node = class_cast("Node",body.getContactObject(i));
// changing node's rotation
if (node != NULL)
node.setRotation(quat(0.0f, 1.0f, 0.0f, 90.0f));
}
for (int i = 0; i < unregistered_collisions.size(); i++)
{
// process all unregistered collisions
Node node = class_cast("Node", unregistered_collisions[i].getObject());
// deleting a node
if (node != NULL)
engine.editor.removeNode(node);
}
// clearing the list of unregistered collisions after processing them
unregistered_collisions.clear();
}
}Arguments
- string func - Callback function name.
void renderContacts()
Renders contact points of the body.void renderJoints()
Renders joints in the body.void renderShapes()
Renders shapes comprising the body.void renderVisualizer()
Renders shapes, joints and contact points of the body.Notice
You should enable the engine visualizer by the show_visualizer 1 console command.
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 node into a binary stream.- If a node is a parent for other nodes, states of these child nodes need to be saved manually.
- To save the state from a buffer, file or a message from a socket, make sure the stream is opened. For buffers and files, you also need to set the proper position for reading.
Warning
This function is deprecated and will be removed in the next release.
Arguments
- Stream stream - Stream to save node state data.
Return value
1 if node state is successfully saved; otherwise, 0.int restoreState(Stream stream)
Restores the state of a given node from a binary stream.- If a node is a parent for other nodes, states of these child nodes need to be restored manually.
- To save the state into a buffer, file or a message from a socket, make sure the stream is opened. If necessary, you can set a position for writing for buffers and files.
Warning
This function is deprecated and will be removed in the next release.
Arguments
- Stream stream - Stream with saved node state data.
Return value
1 if node state is successfully restored; otherwise, 0.int BODY_CLOTH
Description
This body simulates cloth.int BODY_DUMMY
Description
This body is used to create an immovable collider for an object.int BODY_FRACTURE
Description
This body simulates breakable objects.int BODY_PATH
Description
This body simulates a path along which rigid bodies are moving, for example, like a train along the railtrack.int BODY_RAGDOLL
Description
This body contains joints connecting parts of the body (represented with rigid bodies).int BODY_RIGID
Description
This is a basictype of body describing a rigid object.int BODY_ROPE
Description
This body simulates ropes.int BODY_WATER
Description
This body simulates water and other fluids.int NUM_BODIES
Description
The number of bodies.Last update: 2018-08-10
Help improve this article
Was this article helpful?
(or select a word/phrase and press Ctrl+Enter)