Class: NDPointList

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

Overview

require ‘kamelopard_classes’

Direct Known Subclasses

OneDPointList, ThreeDPointList, TwoDPointList

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(num) ⇒ NDPointList

Returns a new instance of NDPointList.



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# File 'lib/kamelopard/pointlist.rb', line 10

def initialize(num)
    raise "Can't have an NDPointList with #{num} dimensions -- must be 1 or more" if num < 1
    @dim = num
    @points = []
end

Instance Attribute Details

#dim ⇒ Object (readonly)

Contains a list of N-dimensional numeric arrays



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# File 'lib/kamelopard/pointlist.rb', line 8

def dim
  @dim
end

Instance Method Details

#<<(a) ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 20

def <<(a)
    # Append points to our list
    if a.kind_of? Kamelopard::Point then
        if self.dim == 3 then
            @points << [a.longitude, a.latitude, a.altitude]
        else
            @points << [a.longitude, a.latitude]
        end
    elsif a.respond_to? 'dim' and @dim != a.dim then
        raise "Argument's dimension #{a.dim} must agree with our dimension #{@dim} to append to an NDPointList"
    else
        @points << a
    end
end

#[](i) ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 39

def [](i)
    @points[i]
end

#each(&blk) ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 63

def each(&blk)
    @points.each(&blk)
end

#interpolate(resolution = nil) ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 67

def interpolate(resolution = nil)
    # XXX Figure out how to implement the "resolution" argument
    STDERR.puts "resolution argument to NDPointList.interpolate is ignored" if resolution.nil?
    # Ruby implementation of Catmull-Rom splines (http://www.cubic.org/docs/hermite.htm)
    # Return NDPointList interpolating a path along all points in this list

    h = Matrix[
        [ 2,  -2,   1,   1 ],
        [-3,   3,  -2,  -1 ],
        [ 0,   0,   1,   0 ],
        [ 1,   0,   0,   0 ],
    ]

    result = NDPointList.new(@dim)

    # Calculate spline between every two points
    (0..(self.size-2)).each do |i|
        p1 = self[i]
        p2 = self[i+1]
        
        # Get surrounding points for calculating tangents
        if i <= 0 then pt1 = p1 else pt1 = self[i-1] end
        if i == self.size - 2 then pt2 = p2 else pt2 = self[i+2] end

        # Build tangent points into matrices to calculate tangents.
        t1 = 0.5 * ( Matrix[p2]  - Matrix[pt1] )
        t2 = 0.5 * ( Matrix[pt2] - Matrix[p1] )

        # Build matrix of Hermite parameters
        c = Matrix[p1, p2, t1.row(0), t2.row(0)]

        # Make a set of points
        (0..10).each do |t|
            r = t/10.0
            s = Matrix[[r**3, r**2, r, 1]]
            tmp = s * h
            p = tmp * c
            result << p.row(0).to_a
        end
    end
    result
end

#last ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 35

def last
    @points.last
end

#size ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 16

def size
    return @points.size
end

#x ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 43

def x
    @points.collect do |a| a[0] end
end

#y ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 47

def y
    if @dim >= 2 then
        @points.collect do |a| a[1] end
    else
        raise "NDPointList of size #{@dim} has no Y element"
    end
end

#z ⇒ Object 



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# File 'lib/kamelopard/pointlist.rb', line 55

def z
    if @dim >= 2 then
        @points.collect do |a| a[2] end
    else
        raise "NDPointList of size #{@dim} has no Z element"
    end
end