Class: Mittsu::Vector4

Inherits:
Vector
  • Object
show all
Defined in:
lib/mittsu/math/vector4.rb

Constant Summary collapse

ELEMENTS = 
{ x: 0, y: 1, z: 2, w: 3 }
DIMENSIONS = 
ELEMENTS.count

Instance Attribute Summary

Attributes inherited from Vector

#elements, #index, #uv

Instance Method Summary collapse

Methods inherited from Vector

#==, #[], #[]=, #add, #add_scalar, #add_vectors, #angle_to, #ceil, #clamp, #clamp_scalar, #clone, #copy, #distance_to, #divide, #each_dimension, #floor, #from_array, #length, #length_sq, #lerp, #lerp_vectors, #max, #min, #multiply, #multiply_scalar, #multiply_vectors, #negate, #normalize, #project_on_plane, #project_on_vector, #reflect, #round, #round_to_zero, #set_length, #sub, #sub_scalar, #sub_vectors, #to_array, #to_s

Constructor Details

#initialize(x = 0, y = 0, z = 0, w = 1) ⇒ Vector4

Returns a new instance of Vector4.



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# File 'lib/mittsu/math/vector4.rb', line 9

def initialize(x = 0, y = 0, z = 0, w = 1)
  super [x.to_f, y.to_f, z.to_f, w.to_f]
end

Instance Method Details

#apply_matrix4(m) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 27

def apply_matrix4(m)
  _x, _y, _z, _w = *@elements
  e = m.elements
  @elements[0] = e[0] * _x + e[4] * _y + e[8]  * _z + e[12] * _w
  @elements[1] = e[1] * _x + e[5] * _y + e[9]  * _z + e[13] * _w
  @elements[2] = e[2] * _x + e[6] * _y + e[10] * _z + e[14] * _w
  @elements[3] = e[3] * _x + e[7] * _y + e[11] * _z + e[15] * _w
  self
end

#divide_scalar(scalar) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 37

def divide_scalar(scalar)
  if scalar != 0.0
    inv_scalar = 1.0 / scalar
    @elements[0] *= inv_scalar
    @elements[1] *= inv_scalar
    @elements[2] *= inv_scalar
    @elements[3] *= inv_scalar
  else
    @elements = [0.0, 0.0, 0.0, 1.0]
  end
  self
end

#dot(v) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 147

def dot(v)
  x * v.x + y * v.y + z * v.z + w * v.w
end

#from_attribute(attribute, index, offset = 0) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 155

def from_attribute(attribute, index, offset = 0)
  index = index * attribute.itemSize + offset
  @elements[0] = attribute.array[index]
  @elements[1] = attribute.array[index + 1]
  @elements[2] = attribute.array[index + 2]
  @elements[3] = attribute.array[index + 3]
  self
end

#length_manhattan ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 151

def length_manhattan
  x.abs + y.abs + z.abs + w.abs
end

#set(x, y, z, w) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 13

def set(x, y, z, w)
  super [x.to_f, y.to_f, z.to_f, w.to_f]
end

#set_axis_angle_from_quaternion(q) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 50

def set_axis_angle_from_quaternion(q)
  # http:#www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToAngle/index.htm
  # q is assumed to be normalized
  @elements[3] = 2.0 * Math.acos(q.w)
  s = Math.sqrt(1.0 - q.w * q.w)
  if s < 0.0001
     @elements[0] = 1.0
     @elements[1] = 0.0
     @elements[2] = 0.0
  else
     @elements[0] = q.x / s
     @elements[1] = q.y / s
     @elements[2] = q.z / s
  end
  self
end

#set_axis_angle_from_rotation_matrix(m) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 67

def set_axis_angle_from_rotation_matrix(m)
  # http:#www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToAngle/index.htm
  # assumes the upper 3x3 of m is a pure rotation matrix (i.e, unscaled)
  angle, x1, y1, z1 = nil    # variables for result
  epsilon = 0.01    # margin to allow for rounding errors
  epsilon2 = 0.1    # margin to distinguish between 0 and 180 degrees
  te = m.elements
  m11, m12, m13 = te[0], te[4], te[8]
  m21, m22, m23 = te[1], te[5], te[9]
  m31, m32, m33 = te[2], te[6], te[10]
  if (((m12 - m21).abs < epsilon) &&
      ((m13 - m31).abs < epsilon) &&
      ((m23 - m32).abs < epsilon))
    # singularity found
    # first check for identity matrix which must have +1 for all terms
    # in leading diagonal and zero in other terms
    if (((m12 + m21).abs < epsilon2) &&
        ((m13 + m31).abs < epsilon2) &&
        ((m23 + m32).abs < epsilon2) &&
        ((m11 + m22 + m33 - 3).abs < epsilon2))
      # self singularity is identity matrix so angle = 0
      @elements = [1.0, 0.0, 0.0, 0.0]
      return self # zero angle, arbitrary axis
    end
    # otherwise self singularity is angle = 180
    angle = Math::PI
    xx = (m11 + 1.0) / 2.0
    yy = (m22 + 1.0) / 2.0
    zz = (m33 + 1.0) / 2.0
    xy = (m12 + m21) / 4.0
    xz = (m13 + m31) / 4.0
    yz = (m23 + m32) / 4.0
    if (xx > yy) && (xx > zz) # m11 is the largest diagonal term
      if xx < epsilon
        x1 = 0.0
        y1 = 0.707106781
        z1 = 0.707106781
      else
        x1 = Math.sqrt(xx)
        y1 = xy / x1
        z1 = xz / x1
      end
    elsif yy > zz # m22 is the largest diagonal term
      if yy < epsilon
        x1 = 0.707106781
        y1 = 0.0
        z1 = 0.707106781
      else
        y1 = Math.sqrt(yy)
        x1 = xy / y1
        z1 = yz / y1
      end
    else # m33 is the largest diagonal term so base result on self
      if zz < epsilon
        x1 = 0.707106781
        y1 = 0.707106781
        z1 = 0.0
      else
        z1 = Math.sqrt(zz)
        x1 = xz / z1
        y1 = yz / z1
      end
    end
    @elements = [x1, y1, z1, angle]
    return self # return 180 deg rotation
  end
  # as we have reached here there are no singularities so we can handle normally
  s = Math.sqrt((m32 - m23) * (m32 - m23) +
    (m13 - m31) * (m13 - m31) +
    (m21 - m12) * (m21 - m12)) # used to normalize
  s = 1.0 if (s.abs < 0.001)
  # prevent divide by zero, should not happen if matrix is orthogonal and should be
  # caught by singularity test above, but I've left it in just in case
  @elements[0] = (m32 - m23) / s
  @elements[1] = (m13 - m31) / s
  @elements[2] = (m21 - m12) / s
  @elements[3] = Math.acos((m11 + m22 + m33 - 1.0) / 2.0)
  self
end

#w ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 20

def w; @elements[3]; end

#w=(value) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 25

def w=(value); @elements[3] = value.to_f; end

#x ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 17

def x; @elements[0]; end

#x=(value) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 22

def x=(value); @elements[0] = value.to_f; end

#y ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 18

def y; @elements[1]; end

#y=(value) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 23

def y=(value); @elements[1] = value.to_f; end

#z ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 19

def z; @elements[2]; end

#z=(value) ⇒ Object 



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# File 'lib/mittsu/math/vector4.rb', line 24

def z=(value); @elements[2] = value.to_f; end