BoneΒΆ

The Bone class represents a tracked bone. More...

Inherits Interface.

Classes

enum  Type
 Enumerates the names of the bones. More...
 

Public Member Functions

Matrix basis ()
 The orthonormal basis vectors for this Bone as a Matrix. More...
 
 Bone ()
 Constructs an invalid Bone object. More...
 
Vector center ()
 The midpoint of the bone. More...
 
Vector direction ()
 The normalized direction of the bone from base to tip. More...
 
boolean equals (Bone arg0)
 Compare Bone object equality. More...
 
boolean isValid ()
 Reports whether this is a valid Bone object. More...
 
float length ()
 The estimated length of the bone in millimeters. More...
 
Vector nextJoint ()
 The end of the bone, closest to the finger tip. More...
 
Vector prevJoint ()
 The base of the bone, closest to the wrist. More...
 
String toString ()
 A string containing a brief, human readable description of the Bone object. More...
 
Bone.Type type ()
 The name of this bone. More...
 
float width ()
 The average width of the flesh around the bone in millimeters. More...
 

Static Public Member Functions

static Bone invalid ()
 Returns an invalid Bone object. More...
 

Detailed Description

The Bone class represents a tracked bone.

All fingers contain 4 bones that make up the anatomy of the finger. Get valid Bone objects from a Finger object.

Bones are ordered from base to tip, indexed from 0 to 3. Additionally, the bone's Type enum may be used to index a specific bone anatomically.

for (Finger finger : hand.fingers()) {
for(Bone.Type boneType : Bone.Type.values()) {
Bone bone = finger.bone(boneType);
// ... Use the bone
}
}

The thumb does not have a base metacarpal bone and therefore contains a valid, zero length bone at that location.

Note that Bone objects can be invalid, which means that they do not contain valid tracking data and do not correspond to a physical bone. Invalid Bone objects can be the result of asking for a Bone object from an invalid finger, indexing a bone out of range, or constructing a new bone. Test for validity with the Bone::isValid() function.

Since
2.0

Constructor & Destructor Documentation

Bone ( )

Constructs an invalid Bone object.

Bone bone = Bone.invalid();

Get valid Bone objects from a Finger object.

Since
2.0

Member Function Documentation

Matrix basis ( )

The orthonormal basis vectors for this Bone as a Matrix.

Basis vectors specify the orientation of a bone.

xBasis Perpendicular to the longitudinal axis of the bone; exits the sides of the finger.

yBasis or up vector Perpendicular to the longitudinal axis of the bone; exits the top and bottom of the finger. More positive in the upward direction.

zBasis Aligned with the longitudinal axis of the bone. More positive toward the base of the finger.

The bases provided for the right hand use the right-hand rule; those for the left hand use the left-hand rule. Thus, the positive direction of the x-basis is to the right for the right hand and to the left for the left hand. You can change from right-hand to left-hand rule by multiplying the z basis vector by -1.

You can use the basis vectors for such purposes as measuring complex finger poses and skeletal animation.

Note that converting the basis vectors directly into a quaternion representation is not mathematically valid. If you use quaternions, create them from the derived rotation matrix not directly from the bases.

Matrix basis = bone.basis();
Vector xBasis = basis.getXBasis();
Vector yBasis = basis.getYBasis();
Vector zBasis = basis.getZBasis();
Vector origin = basis.getOrigin();
Returns
The basis of the bone as a matrix.
Since
2.0
Vector center ( )

The midpoint of the bone.

Vector middle = bone.center();
Returns
The midpoint in the center of the bone.
Since
2.0
Vector direction ( )

The normalized direction of the bone from base to tip.

Vector direction = bone.direction();
Returns
The normalized direction of the bone from base to tip.
Since
2.0
boolean equals ( Bone  arg0)

Compare Bone object equality.

Two Bone objects are equal if and only if both Bone objects represent the exact same physical bone in the same frame and both Bone objects are valid.

Since
2.0
static Bone invalid ( )
static

Returns an invalid Bone object.

You can use the instance returned by this function in comparisons testing whether a given Bone instance is valid or invalid. (You can also use the Bone::isValid() function.)

Bone bone = Bone.invalid();
Returns
The invalid Bone instance.
Since
2.0
boolean isValid ( )

Reports whether this is a valid Bone object.

Bone bone = finger.bone(Bone.Type.TYPE_PROXIMAL);
if(bone.isValid())
{
// ... Use the bone data
}
Returns
True, if this Bone object contains valid tracking data.
Since
2.0
float length ( )

The estimated length of the bone in millimeters.

float length = bone.length();
Returns
The length of the bone in millimeters.
Since
2.0
Vector nextJoint ( )

The end of the bone, closest to the finger tip.

In anatomical terms, this is the distal end of the bone.

Vector boneEnd = bone.nextJoint();
Returns
The Vector containing the coordinates of the next joint position.
Since
2.0
Vector prevJoint ( )

The base of the bone, closest to the wrist.

In anatomical terms, this is the proximal end of the bone.

Vector boneStart = bone.prevJoint();
Returns
The Vector containing the coordinates of the previous joint position.
Since
2.0
String toString ( )

A string containing a brief, human readable description of the Bone object.

String description = bone.toString();
Returns
A description of the Bone object as a string.
Since
2.0
Bone.Type type ( )

The name of this bone.

Bone.Type type = bone.type();
Returns
The anatomical type of this bone as a member of the Bone::Type enumeration.
Since
2.0
float width ( )

The average width of the flesh around the bone in millimeters.

float width = bone.width();
Returns
The width of the flesh around the bone in millimeters.
Since
2.0