Unigine::Plugins::LeapMotion::Bone Struct

struct Bone

Fields

• enum TYPE -
  • TYPE_METACARPAL - metacarpal bone. A bone connected to the wrist inside the palm.
  • TYPE_PROXIMAL - proximal bone. A bone connecting to the palm.
  • TYPE_INTERMEDIATE - intermediate bone. A bone between the tip and the base.
  • TYPE_DISTAL - distal bone. A bone at the tip of the finger.
  • BONE_NUM_TYPES - total number of bone types.
  For example, to specify the proximal bone, write Bone::TYPE_PROXIMAL.
• int type - Bone type. One of the Bone::TYPE_* values.
• float length - Length of the bone, in meters.
• float width - Width of the bone, in meters.
• int is_valid - Value indicating if the bone contains valid tracking data.
• Math::vec3 prev_joint - Coordinates of the end of the bone, closest to the wrist (proximal).
  Notice

  All coordinates are relative to the origin of the Leap Motion coordinate system.
• Math::vec3 next_joint - Coordinates of the end of the bone, closest to the finger tip (distal).
  Notice

  All coordinates are relative to the origin of the Leap Motion coordinate system.
• Math::vec3 center - Coordinates of the center of the bone.
  Notice

  All coordinates are relative to the origin of the Leap Motion coordinate system.
• Math::vec3 direction - Normalized direction of the bone from wrist to tip.
  Notice

  All coordinates are relative to the origin of the Leap Motion coordinate system.
• Math::mat4 basis - Orthonormal basis vectors for this Bone as a Matrix.

  Basis vectors specify the orientation of a bone:

  • X - Perpendicular to the longitudinal axis of the bone; exits the sides of the finger.
  • Y (or up vector) - Perpendicular to the longitudinal axis of the bone; exits the top and bottom of the finger. Increases in the upward direction.
  • Z - Aligned with the longitudinal axis of the bone. Increases 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.

  Notice

  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.