mertan/test/test.js

geometrical operations

require('better-stack-traces')
var gm = require('../')
    , expect = require('expect.js')
    , R = require('rationals')
    , V = require('momentum')

describe('Lines', function() {
    var line2D_1 = gm.line(V([2,0]),V([4,2]))
      , point2D_1 = V([0,-1])
      , point2D_2 = [R(3,4),R(-5,8)]
      , point2D_3 = [R(5),R(3,2)]
      , point2D_4 = [R(-2),R(2)]
      , line2D_2 = gm.line([R(0),R(3,2)],[R(6),R(-3)])
      , point2D_5 = [R(5),R(-1)]
      , point2D_6 = [R(-1),R(2)]
      , point2D_7 = [R(-5),R(4)]
      , point2D_8 = [R(1),R(1)]
      , point2D_9 = [R(-3),R(-21)]
      , line2D_3 = gm.line([R(2),R(1)],[R(3),R(0)])
      , point2D_10 = [R(-10),R(1)]
      , line2D_4 = gm.line([R(-3),R(-3)],[R(-20),R(0)])
      , line2D_5 = gm.line([R(3),R(-3)],[R(0),R(20)])
      , line3D_1 = gm.line(V([3,6,1]),V([3,-4,-1]))
      , line3D_2 = gm.line(V([-6,18,4]),V([9,-12,-3]))
      , line3D_3 = gm.line(V([-1,2,-3]),V([5,-1,2]))
      , line3D_4 = gm.line(V([6,-5,4]),V([3,-11,-13]))
      , line3D_5 = gm.joinPoints(V([1,4,-2]),V([3,8,6]))
      , line3D_6 = gm.joinPoints(V([0,4,8]),V([6,10,-10]))
      , line4D_1 = gm.line(V([1,2,-3,-4]),V([35,42,-49,-56]))
      , line4D_2 = gm.line(V([9,10,11,12]),V([-13,-14,-7,-8]))



    it('checks if point lies on line', function() {
        // check for data mismatch ?
        expect(line2D_1.has(point2D_1)).to.be(true)
        expect(line2D_1.has(point2D_2)).to.be(true)
        expect(line2D_1.has(point2D_3)).to.be(true)
        expect(line2D_1.has(point2D_4)).to.be(false)
        expect(line2D_2.has(point2D_5)).to.be(true)
        expect(line2D_2.has(point2D_6)).to.be(true)
        expect(line2D_2.has(point2D_7)).to.be(true)
        expect(line2D_2.has(point2D_8)).to.be(true)
        expect(line2D_2.has(point2D_9)).to.be(false)
        expect(line2D_3.has(point2D_10)).to.be(true)
        expect(gm.line([R(3),R(-2)],[R(4),R(-3)])
                    .has([R(0),R(1,4)]))
                        .to.be(true)
    })

    it('checks if line is parallel to another line', function() {
        // check for data mismatch ?
        expect(line2D_1.parallel(line2D_2)).to.be(false)
        expect(line2D_3.parallel(line2D_4)).to.be(true)
        expect(gm.line([R(3),R(-2)],[R(4),R(-3)])
                    .parallel(gm.line([R(0),R(-5,8)],[R(-5,6),R(5,8)])))
                        .to.be(true)
    })

    it('checks if line is perpendicular to another line', function() {
        // check for data mismatch ?
        expect(line2D_1.perpendicularTo(line2D_2)).to.be(false)
        expect(line2D_5.perpendicularTo(line2D_4)).to.be(true)
        expect(line3D_3.perpendicularTo(line3D_4)).to.be(true)
        expect(line3D_2.perpendicularTo(line3D_4)).to.be(false)
        expect(gm.line([R(3),R(-2)],[R(4),R(-3)])
                    .perpendicularTo(gm.line([R(0),R(-2,3)],[R(1,2),R(2,3)])))
                        .to.be(true)
    })

    it('returns quadrance between two points', function(){
        expect(gm.Q([R(3),R(-12)],[R(15),R(4)])).to
            .be(R(12).times(R(12)).add(R(16).times(R(16))))
    })
    it('returns spread between two vectors', function(){
        //spread is 1 when perpendicular
        expect(gm.S(line2D_4.vector, line2D_5.vector)).to.be(R(1))
        //spread is 0 when parallel
        expect(gm.S(line3D_1.vector, line3D_2.vector)).to.be(R(0))
    })

    it('check if lines are identical', function(){
        expect(line3D_1.identical(line3D_2)).to.be(true)
        expect(line2D_1.identical(line2D_2)).to.be(false)
    })

    it('check if lines are skew', function(){
        expect(line3D_1.skewing(line3D_3)).to.be(true)
        expect(line3D_1.skewing(line3D_2)).to.be(false)
    })

    it('check if lines are intersecting', function(){
        expect(line2D_1.intersecting(line2D_2)).to.be(true)
        expect(line3D_5.intersecting(line3D_6)).to.be(true)
        expect(line3D_1.intersecting(line3D_4)).to.be(false)
    })

    it('returns meet of two lines', function(){
        expect(gm.meetLines(line2D_1,line2D_2)).to.eql([R(5,2),R(1,4)])
        expect(gm.meetLines(gm.line(V([3,0]),V([1,0])),gm.line(V([0,-3]),V([0,1])))).to.eql([R(0),R(0)])
        expect(gm.meetLines(line3D_5,line3D_6)).to.eql(V([2,6,2]))
        expect(gm.meetLines(line4D_1,line4D_2)).to.eql(V([-4,-4,4,4]))
    })
})