Class: Geom::Intersection

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

Constant Summary collapse

INTERSECTION = 
1
NO_INTERSECTION = 
0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(status = NO_INTERSECTION) ⇒ Intersection

Returns a new instance of Intersection.



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# File 'lib/geom/intersection.rb', line 6

def initialize(status=NO_INTERSECTION)
  @alpha  = Array.new
  @points = Array.new
  @status = status
end

Instance Attribute Details

#alpha ⇒ Object

Returns the value of attribute alpha.



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# File 'lib/geom/intersection.rb', line 5

def alpha
  @alpha
end

#points ⇒ Object

Returns the value of attribute points.



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# File 'lib/geom/intersection.rb', line 5

def points
  @points
end

#status ⇒ Object

Returns the value of attribute status.



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# File 'lib/geom/intersection.rb', line 5

def status
  @status
end

Class Method Details

.line_line(a1, a2, b1, b2, infinite = true) ⇒ Object 



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# File 'lib/geom/intersection.rb', line 12

def self.line_line(a1,a2,b1,b2,infinite=true)
  result = Intersection.new

  x1, y1 = a1.x, a1.y
  x2, y2 = a2.x, a2.y
  x3, y3 = b1.x, b1.y
  x4, y4 = b2.x, b2.y

  d = ((y4-y3)*(x2-x1)-(x4-x3)*(y2-y1))

  unless d.zero?
    # The lines intersect at a point somewhere
    ua = ((x4-x3)*(y1-y3)-(y4-y3)*(x1-x3)) / d
    ub = ((x2-x1)*(y1-y3)-(y2-y1)*(x1-x3)) / d

    result.alpha.push(ua,ub)
    if infinite || ((ua > 0 && ua < 1) && (ub > 0 && ub < 1))
      x = x1 + ua*(x2-x1)
      y = y1 + ua*(y2-y1)
      result.points << Number3D.new(x,y)
      result.status = INTERSECTION;
    end
  end
  result
end