Ray-casting algorithm: Difference between revisions

 

=={{header|Ada}}==

polygons.ads:

<lang Ada>package Polygons is

=={{header|AutoHotkey}}==

{{incomplete|AutoHotkey}}

{

count := 0

else

return true ; P is in the polygon

 

=={{header|C}}==

 

=={{header|CoffeeScript}}==

Takes a polygon as a list of points joining segments, and creates segments between them.

 

pointInPoly = (point,poly) ->

mAB = (b.y - a.y) / (b.x - a.x)

mAP = (p.y - a.y) / (p.x - a.x)

 

=={{header|Common Lisp}}==

Points are represented as cons cells whose car is an x value and whose cdr is a y value. A line segment is a cons cell of two points. A polygon is a list of line segments.

<lang lisp>(defun point-in-polygon (point polygon)

(do ((in-p nil)) ((endp polygon) in-p)

 

Testing code

<lang lisp>(defparameter *points*

#((0 . 0) (10 . 0) (10 . 10) (0 . 10)

test-point

(point-in-polygon test-point polygon)))))</lang>

 

=={{header|Fortran}}==

{{works with|Fortran|95 and later}}

The following code uses the <tt>Points_Module</tt> defined [[Closest pair problem#Fortran|here]].

 

This module ''defines'' "polygons".

<lang fortran>module Polygons

use Points_Module

 

The ray casting algorithm module:

<lang fortran>module Ray_Casting_Algo

use Polygons

 

'''Testing'''

<lang fortran>program Pointpoly

use Points_Module

 

end program Pointpoly</lang>

=={{header|Go}}==

<lang go>package main

 

=={{header|Liberty BASIC}}==

Displays interactively on-screen.

Global sw, sh, verts

 

Function rand(loNum,hiNum)

rand = Int(Rnd(0)*(hiNum-loNum+1)+loNum)

 

=={{header|OCaml}}==

{{Trans|C}}

<lang ocaml>type point = { x:float; y:float }

 

Testing:

<lang perl># the following are utilities to use the same Fortran data...

sub point

: (inside (10.0 . 10.0) Exagon)

-> NIL</pre>

=={{header|PureBasic}}==

The code below is includes a GUI for drawing a polygon with the mouse that constantly tests whether the mouse is inside or outside the polygon. It displays a message and changes the windows color slightly to indicate if the pointer is inside or outside the polygon being drawn. The routine that does the checking is called inpoly() and it returns a value of one if the point is with the polygon and zero if it isn't.

 

=={{header|Python}}==

from pprint import pprint as pp

import sys

for p in testpoints[3:6])

print ' ', '\t'.join("%s: %s" % (p, ispointinside(p, poly))

 

'''Sample output'''

 

'''Helper routine to convert Fortran Polygons and points to Python'''

<lang python>def _convert_fortran_shapes():

point = Pt

print ' ', ',\n '.join(str(e) for e in p.edges) + '\n )),'

print ' ]'

 

=={{header|R}}==

=={{header|Smalltalk}}==

{{works with|GNU Smalltalk}}

The class Segment holds the code to test if a ray starting from a point (and going towards "right") intersects the segment (method <tt>doesIntersectRayFrom</tt>); while the class Polygon hosts the code to test if a point is inside the polygon (method <tt>pointInside</tt>).

<lang smalltalk>Object subclass: Segment [

|pts|

 

'''Testing'''

<lang smalltalk>|points names polys|