Class: Three::Matrix3

Inherits:
Object
  • Object
show all
Defined in:
lib/three/math/matrix3.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*values) ⇒ Matrix3

Returns a new instance of Matrix3.



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# File 'lib/three/math/matrix3.rb', line 7

def initialize(*values)
  @elements = [
    1, 0, 0,
    0, 1, 0,
    0, 0, 1
  ]

  set(*values) unless values.empty?
end

Instance Attribute Details

#elements ⇒ Object (readonly)

Returns the value of attribute elements.



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# File 'lib/three/math/matrix3.rb', line 5

def elements
  @elements
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 247

def ==(other)
  other.is_a?(self.class) && equals?(other)
end

#clone ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 38

def clone
  self.class.new.from_array(@elements)
end

#copy(matrix) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 42

def copy(matrix)
  @elements = matrix.elements.dup
  self
end

#determinant ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 107

def determinant
  a = @elements[0]
  b = @elements[1]
  c = @elements[2]
  d = @elements[3]
  e = @elements[4]
  f = @elements[5]
  g = @elements[6]
  h = @elements[7]
  i = @elements[8]

  a * e * i - a * f * h - b * d * i + b * f * g + c * d * h - c * e * g
end

#equals?(matrix, epsilon: 0.0) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/three/math/matrix3.rb', line 241

def equals?(matrix, epsilon: 0.0)
  @elements.each_with_index.all? do |value, index|
    (value - matrix.elements[index]).abs <= epsilon
  end
end

#from_array(array, offset = 0) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 227

def from_array(array, offset = 0)
  9.times { |index| @elements[index] = array[index + offset] }
  self
end

#get_normal_matrix(matrix4) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 159

def get_normal_matrix(matrix4)
  set_from_matrix4(matrix4).invert.transpose
end

#identity ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 30

def identity
  set(
    1, 0, 0,
    0, 1, 0,
    0, 0, 1
  )
end

#inspect ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 251

def inspect
  "#<#{self.class} elements=#{@elements.inspect}>"
end

#invert ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 121

def invert
  n11 = @elements[0]
  n21 = @elements[1]
  n31 = @elements[2]
  n12 = @elements[3]
  n22 = @elements[4]
  n32 = @elements[5]
  n13 = @elements[6]
  n23 = @elements[7]
  n33 = @elements[8]

  t11 = n33 * n22 - n32 * n23
  t12 = n32 * n13 - n33 * n12
  t13 = n23 * n12 - n22 * n13
  det = n11 * t11 + n21 * t12 + n31 * t13
  return set(0, 0, 0, 0, 0, 0, 0, 0, 0) if det.zero?

  det_inv = 1.0 / det

  @elements[0] = t11 * det_inv
  @elements[1] = (n31 * n23 - n33 * n21) * det_inv
  @elements[2] = (n32 * n21 - n31 * n22) * det_inv
  @elements[3] = t12 * det_inv
  @elements[4] = (n33 * n11 - n31 * n13) * det_inv
  @elements[5] = (n31 * n12 - n32 * n11) * det_inv
  @elements[6] = t13 * det_inv
  @elements[7] = (n21 * n13 - n23 * n11) * det_inv
  @elements[8] = (n22 * n11 - n21 * n12) * det_inv
  self
end

#multiply(matrix) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 56

def multiply(matrix)
  multiply_matrices(self, matrix)
end

#multiply_matrices(a, b) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 64

def multiply_matrices(a, b)
  ae = a.elements
  be = b.elements

  a11 = ae[0]
  a12 = ae[3]
  a13 = ae[6]
  a21 = ae[1]
  a22 = ae[4]
  a23 = ae[7]
  a31 = ae[2]
  a32 = ae[5]
  a33 = ae[8]

  b11 = be[0]
  b12 = be[3]
  b13 = be[6]
  b21 = be[1]
  b22 = be[4]
  b23 = be[7]
  b31 = be[2]
  b32 = be[5]
  b33 = be[8]

  @elements[0] = a11 * b11 + a12 * b21 + a13 * b31
  @elements[3] = a11 * b12 + a12 * b22 + a13 * b32
  @elements[6] = a11 * b13 + a12 * b23 + a13 * b33

  @elements[1] = a21 * b11 + a22 * b21 + a23 * b31
  @elements[4] = a21 * b12 + a22 * b22 + a23 * b32
  @elements[7] = a21 * b13 + a22 * b23 + a23 * b33

  @elements[2] = a31 * b11 + a32 * b21 + a33 * b31
  @elements[5] = a31 * b12 + a32 * b22 + a33 * b32
  @elements[8] = a31 * b13 + a32 * b23 + a33 * b33
  self
end

#multiply_scalar(scalar) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 102

def multiply_scalar(scalar)
  @elements.map! { |value| value * scalar }
  self
end

#premultiply(matrix) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 60

def premultiply(matrix)
  multiply_matrices(matrix, self)
end

#rotate(theta) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 184

def rotate(theta)
  c = Math.cos(theta)
  s = Math.sin(theta)

  a11 = @elements[0]
  a12 = @elements[3]
  a13 = @elements[6]
  a21 = @elements[1]
  a22 = @elements[4]
  a23 = @elements[7]

  @elements[0] = c * a11 + s * a21
  @elements[3] = c * a12 + s * a22
  @elements[6] = c * a13 + s * a23
  @elements[1] = -s * a11 + c * a21
  @elements[4] = -s * a12 + c * a22
  @elements[7] = -s * a13 + c * a23
  self
end

#scale(sx, sy) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 174

def scale(sx, sy)
  @elements[0] *= sx
  @elements[3] *= sx
  @elements[6] *= sx
  @elements[1] *= sy
  @elements[4] *= sy
  @elements[7] *= sy
  self
end

#set(n11, n12, n13, n21, n22, n23, n31, n32, n33) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 17

def set(n11, n12, n13, n21, n22, n23, n31, n32, n33)
  @elements[0] = n11
  @elements[3] = n12
  @elements[6] = n13
  @elements[1] = n21
  @elements[4] = n22
  @elements[7] = n23
  @elements[2] = n31
  @elements[5] = n32
  @elements[8] = n33
  self
end

#set_from_matrix4(matrix) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 47

def set_from_matrix4(matrix)
  me = matrix.elements
  set(
    me[0], me[4], me[8],
    me[1], me[5], me[9],
    me[2], me[6], me[10]
  )
end

#set_uv_transform(tx, ty, sx, sy, rotation, cx, cy) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 163

def set_uv_transform(tx, ty, sx, sy, rotation, cx, cy)
  c = Math.cos(rotation)
  s = Math.sin(rotation)

  set(
    sx * c, sx * s, -sx * (c * cx + s * cy) + cx + tx,
    -sy * s, sy * c, -sy * (-s * cx + c * cy) + cy + ty,
    0, 0, 1
  )
end

#to_a ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 232

def to_a
  @elements.dup
end

#to_array(array = [], offset = 0) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 236

def to_array(array = [], offset = 0)
  9.times { |index| array[index + offset] = @elements[index] }
  array
end

#translate(tx, ty) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 204

def translate(tx, ty)
  @elements[0] += tx * @elements[2]
  @elements[3] += tx * @elements[5]
  @elements[6] += tx * @elements[8]
  @elements[1] += ty * @elements[2]
  @elements[4] += ty * @elements[5]
  @elements[7] += ty * @elements[8]
  self
end

#transpose ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 152

def transpose
  @elements[1], @elements[3] = @elements[3], @elements[1]
  @elements[2], @elements[6] = @elements[6], @elements[2]
  @elements[5], @elements[7] = @elements[7], @elements[5]
  self
end

#transpose_into_array(array = []) ⇒ Object 



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# File 'lib/three/math/matrix3.rb', line 214

def transpose_into_array(array = [])
  array[0] = @elements[0]
  array[1] = @elements[3]
  array[2] = @elements[6]
  array[3] = @elements[1]
  array[4] = @elements[4]
  array[5] = @elements[7]
  array[6] = @elements[2]
  array[7] = @elements[5]
  array[8] = @elements[8]
  array
end