Class: Mittsu::Spline

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

Defined Under Namespace

Classes: Length, Point

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(points) ⇒ Spline

Returns a new instance of Spline.



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# File 'lib/mittsu/math/spline.rb', line 8

def initialize(points)
  @points = points
  @c = []
  @v3 = Point.new(0.0, 0.0, 0.0)
end

Instance Attribute Details

#points ⇒ Object

Returns the value of attribute points.



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# File 'lib/mittsu/math/spline.rb', line 6

def points
  @points
end

Instance Method Details

#control_points_array ⇒ Object 



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# File 'lib/mittsu/math/spline.rb', line 45

def control_points_array
  @points.map do |p|
    [ p.x, p.y, p.z ]
  end
end

#init_from_array(a) ⇒ Object 



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# File 'lib/mittsu/math/spline.rb', line 14

def init_from_array(a)
  @points = a.map do |p|
    Point.new(*p.take(3))
  end
end

#length(n_sub_divisions = 100) ⇒ Object 



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# File 'lib/mittsu/math/spline.rb', line 51

def length(n_sub_divisions = 100)
  point, int_point, old_int_point = 0, 0, 0
  old_position = Mittsu::Vector3.new
  tmp_vec = Mittsu::Vector3.new
  chunk_lengths = []
  total_length = 0

  # first point has 0 length
  chunk_lengths << 0
  n_samples = @points.length * n_sub_divisions
  old_position.copy(@points.first)

  (1...n_samples).each do |i|
    index = i.to_f / n_samples.to_f

    position = self.point(index)
    tmp_vec.copy(position)

    total_length += tmp_vec.distance_to(old_position)

    old_position.copy(position)

    point = (@points.length - 1) * index
    int_point = point.floor

    if (int_point != old_int_point)
      chunk_lengths[int_point] = total_length
      old_int_point = int_point
    end
  end

  # last point ends with total length
  chunk_lengths << total_length
  Length.new(chunk_lengths, total_length)
end

#point(k) ⇒ Object 



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

def point(k)
  point = (@points.length - 1) * k
  int_point = point.floor
  weight = point - int_point

  @c[0] = int_point.zero? ? int_point : int_point - 1
  @c[1] = int_point
  @c[2] = int_point > @points.length - 1 ? @points.length - 1 : int_point + 1
  @c[3] = int_point > @points.length - 3 ? @points.length - 1 : int_point + 2

  pa = @points[c[0]]
  pb = @points[c[1]]
  pc = @points[c[2]]
  pd = @points[c[3]]

  w2 = weight * weight
  w3 = weight * w2

  v3.x = interpolate(pa.x, pb.x, pc.x, pd.x, weight, w2, w3)
  v3.y = interpolate(pa.y, pb.y, pc.y, pd.y, weight, w2, w3)
  v3.z = interpolate(pa.z, pb.z, pc.z, pd.z, weight, w2, w3)

  v3
end

#reparametrize_by_arc_length(sampling_coef) ⇒ Object 



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# File 'lib/mittsu/math/spline.rb', line 87

def reparametrize_by_arc_length(sampling_coef)
  new_points = []
  tmp_vec = Mittsu::Vector3.new
  sl = self.length

  new_points << tmp_vec.copy(@points[0]).clone

  @points.each_with_index do |p,i|
    #tmp_vec.copy(@points[i-1])
    #linear_distance = tmp_vec.distance_to(p)

    real_distance = sl.chunks[i] - sl.chunks[i - 1]

    sampling = (sampling_coef * real_distance / sl.total).ceil

    index_current = (i.to_f - 1.0) / (@points.length.to_f - 1.0)
    index_next = i.to_f / (@points.length.to_f - 1.0)

    (1...sampling-1).each do |j|
      index = index_current + j * (1.0 / sampling) * (index_next - index_current)

      position = self.point(index)
      new_points << tmp_vec.copy(position).clone
    end

    new_points << tmp_vec.copy(p).clone
  end
  @points = new_points
end