Class: Geo3d::Quaternion

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Quaternion

Returns a new instance of Quaternion.



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# File 'lib/quaternion.rb', line 5

def initialize
  @x = @y = @z = @w = 0.0
end

Instance Attribute Details

#w ⇒ Object

Returns the value of attribute w.



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# File 'lib/quaternion.rb', line 3

def w
  @w
end

#x ⇒ Object

Returns the value of attribute x.



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# File 'lib/quaternion.rb', line 3

def x
  @x
end

#y ⇒ Object

Returns the value of attribute y.



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# File 'lib/quaternion.rb', line 3

def y
  @y
end

#z ⇒ Object

Returns the value of attribute z.



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# File 'lib/quaternion.rb', line 3

def z
  @z
end

Class Method Details

.from_axis(rotation_axis, radians = 0) ⇒ Object 



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# File 'lib/quaternion.rb', line 25

def self.from_axis rotation_axis, radians = 0
  normalized_rotation_axis = rotation_axis.normalize
  #const float radians = GeoConvertToRadians( degrees );

  q = self.new
  q.x = Math.sin(radians / 2.0) * normalized_rotation_axis.x
  q.y = Math.sin(radians / 2.0) * normalized_rotation_axis.y
  q.z = Math.sin(radians / 2.0) * normalized_rotation_axis.z
  q.w = Math.cos(radians / 2.0)
  q
end

.from_matrix(pm) ⇒ Object 



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# File 'lib/quaternion.rb', line 37

def self.from_matrix pm
  pout = self.new

  trace = pm._11 + pm._22 + pm._33 + 1.0
  if trace > 0
    pout.x = (pm._23 - pm._32) / (2.0 * Math.sqrt(trace))
    pout.y = (pm._31 - pm._13) / (2.0 * Math.sqrt(trace))
    pout.z = (pm._12- pm._21) / (2.0 * Math.sqrt(trace))
    pout.w = Math.sqrt(trace) / 2.0
    return pout
  end
  maxi = 0
  maxdiag = pm._11


  for i in 1..2
    if pm[i, i] > maxdiag #todo: indexing might need to be fixed > maxdiag
      maxi = i
      maxdiag = pm[i, i] #todo: indexing might need to be fixed
    end
  end
  case maxi
    when 0
      s = 2.0 * Math.sqrt(1.0 + pm._11 - pm._22 - pm._33)
      pout.x = 0.25 * s
      pout.y = (pm._12 + pm._21) / s
      pout.z = (pm._13 + pm._31) / s
      pout.w = (pm._23 - pm._32) / s

    when 1
      s = 2.0 * Math.sqrt(1.0 + pm._22 - pm._11 - pm._33)
      pout.x = (pm._12 + pm._21) / s
      pout.y = 0.25 * s
      pout.z = (pm._23 + pm._32) / s
      pout.w = (pm._31 - pm._13) / s

    when 2
      s = 2.0 * Math.sqrt(1.0 + pm._33 - pm._11 - pm._22)
      pout.x = (pm._13 + pm._31) / s
      pout.y = (pm._23 + pm._32) / s
      pout.z = 0.25 * s
      pout.w = (pm._12 - pm._21) / s
  end
  pout
end

Instance Method Details

#*(quat) ⇒ Object 



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# File 'lib/quaternion.rb', line 83

def * quat
  out = Quat.new
  out.w = w * quat.w - x * quat.x - y * quat.y - z * quat.z
  out.x = w * quat.x + x * quat.w + y * quat.z - z * quat.y
  out.y = w * quat.y - x * quat.z + y * quat.w + z * quat.x
  out.z = w * quat.z + x * quat.y - y * quat.x + z * quat.w
  out
end

#angle ⇒ Object 



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# File 'lib/quaternion.rb', line 115

def angle
  Math.acos(w) * 2.0
end

#axis ⇒ Object 



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# File 'lib/quaternion.rb', line 107

def axis
  v = Vector.new
  v.x = x / Math.sqrt(1-w*w)
  v.y = y / Math.sqrt(1-w*w)
  v.z = z / Math.sqrt(1-w*w)
  v
end

#to_matrix ⇒ Object 



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# File 'lib/quaternion.rb', line 92

def to_matrix
  v = Vector.new(x, y, z, w); ## Normalize();
  matrix = Matrix.identity
  matrix._11 = 1.0 - 2.0 * (v.y * v.y + v.z * v.z)
  matrix._12 = 2.0 * (v.x * v.y + v.z * v.w)
  matrix._13 = 2.0 * (v.x * v.z - v.y * v.w)
  matrix._21 = 2.0 * (v.x * v.y - v.z * v.w)
  matrix._22 = 1.0 - 2.0 * (v.x * v.x + v.z * v.z)
  matrix._23 = 2.0 * (v.y * v.z + v.x * v.w)
  matrix._31 = 2.0 * (v.x * v.z + v.y * v.w)
  matrix._32 = 2.0 * (v.y * v.z - v.x * v.w)
  matrix._33 = 1.0 - 2.0 * (v.x * v.x + v.y * v.y)
  matrix
end