Class: Bvh::Skeleton::Bone

Inherits:
Object
  • Object
show all
Defined in:
lib/bvh/skeleton.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name = nil, parent = nil) ⇒ Bone

Returns a new instance of Bone.



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# File 'lib/bvh/skeleton.rb', line 25

def initialize(name = nil, parent = nil)
  @name, @parent = name, parent
  @channels, @offset, @joints = [], [], []
  @frames = []
end

Instance Attribute Details

#channels ⇒ Object (readonly)

the channels, or degrees of freedom, that this bone allows – and the order that they appear in



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# File 'lib/bvh/skeleton.rb', line 17

def channels
  @channels
end

#joints ⇒ Object (readonly)

an array of joints, or child bones. Each should have its parent set to this bone. See also #add_joint!



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# File 'lib/bvh/skeleton.rb', line 23

def joints
  @joints
end

#name ⇒ Object

the name of this bone



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# File 'lib/bvh/skeleton.rb', line 11

def name
  @name
end

#offset ⇒ Object (readonly)

the offset of this bone in relation to its parent



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# File 'lib/bvh/skeleton.rb', line 20

def offset
  @offset
end

#parent ⇒ Object (readonly)

this bone’s parent bone, if any (if nil, this bone is a root)



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# File 'lib/bvh/skeleton.rb', line 14

def parent
  @parent
end

Instance Method Details

#add_joint!(joint) ⇒ Object

Adds the specified bone to this bone’s list of joints, setting its parent equal to this bone. This bone is returned.



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# File 'lib/bvh/skeleton.rb', line 33

def add_joint!(joint)
  joint.instance_variable_set("@parent", self)
  raise "Cannot add joint: name '#{joint.name}' already exists" if self / joint.name
  joints << joint unless joints.include? joint
  self
end

#end_site? ⇒ Boolean

returns true if this is a “leaf” node; that is, there are no joints

Returns:

  • (Boolean) 


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# File 'lib/bvh/skeleton.rb', line 41

def end_site?
  joints.length == 0
end

#find_by_name(name) ⇒ Object Also known as: /

returns the descendant joint (or self) with the specified name.



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# File 'lib/bvh/skeleton.rb', line 46

def find_by_name(name)
  return self if self.name == name
  joints.each { |j| r = j.find_by_name(name); return r unless r.nil? }
  nil
end

#length ⇒ Object

Returns the length of this bone, inferred from the offset of its first joint.



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# File 'lib/bvh/skeleton.rb', line 53

def length
  if end_site? then 0
  else
    ofs = joints.first.offset
    # ofs is a vector, so we need its magnitude
    if ofs.nil? then 0
    else Math.sqrt(ofs[0]**2) + Math.sqrt(ofs[1]**2) + Math.sqrt(ofs[2]**2)
    end
  end
end

#orientation ⇒ Object

Returns a unit vector representing the orientation of this bone, inferred from the offset of its first joint.



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# File 'lib/bvh/skeleton.rb', line 65

def orientation
  if end_site? then [0,0,0]
  else
    ofs = joints.first.offset
    if ofs.nil? then [0,0,0]
    else
      # ofs is a vector, so we need to normalize it
      max = proc { |a,b| a.to_f.abs > b.to_f.abs ? a.to_f.abs : b.to_f.abs }
      max = max.call(ofs[0], max.call(ofs[1], ofs[2]))
      if max > 0 then [ofs[0].to_f / max, ofs[1].to_f / max, ofs[2].to_f / max]
      else [0,0,0]
      end
    end
  end
end