PolyLine library

[1micha.elok]

Problem
How to make closed loop and curved polyline ?
It makes sharp turn at X.

Code:

'===============================================
'                 TEST DRIVE
'
'Problem :
'- How to make closed loop and curved polyline ?
'  It makes sharp turn at X.
'===============================================

'------------------
'  INITIALIZATION
'------------------
#win32
include "polyline.n7"

set window "Test Drive", 160, 120,false,5
set redraw off

'color definition
white       = [255,255,255]
gray        = [128,128,128,50]
black       = [0,0,0]
black_alpha = [0,0,0,24]
red         = [168,0,0]
green       = [0,255,0]

'points' coordinates
points = []
points[0] = [20,60]
points[1] = [50,30]
points[2] = [80,60]
points[3] = [110,90]
points[4] = [140,60]
points[5] = [110,30]
points[6] = [80,60]
points[7] = [50,90]
points[8] = [20,60]

' Create a polyline
path = PolyLine(points)

' Variables
distance    = 1
move_pixel  = 4
radius      = 2

'-------------
'  MAIN LOOP
'-------------
while not keydown(KEY_ESCAPE, true)

    ' Title
    set caret width(primary)/2, 6; center "Test Drive"
    set caret width(primary)/2, height(primary)-20; center "Sharp turn at X"

    ' Racing Track
    set color gray  ; draw ellipse 50-1,60, 32,32,1;draw ellipse 110+2,60, 32,32,1
    set color black ; draw ellipse 50-1,60, 21,21,1;draw ellipse 110+2,60, 21,21,1
    set color white ; set caret 20-8,60-6; wln "x"

    'Polyline functions : .GetLength(), .GetPoint()
    distance = (distance + move_pixel)%path.GetLength()
    pos = path.GetPoint(distance,true) 'false = sharp, true = curved

    ' Draw circle that moves along path.
    set color black_alpha; cls 'clear background screen
    set color green; draw ellipse pos[0], pos[1], radius, radius, 1

    redraw
    fwait 10
wend