Raycast node technique

#include once "fbgfx.bi"
screenres 640,480, 32


dim as integer mx, my, mb

dim as single posX, posY, dx,dy,steps
dim as integer x1, x2, y1, y2


do

    getmouse(mx,my,,mb)

    if mb and fb.button_left then

        x1 = mx
        y1 = my

    end if

    if mb and fb.button_right then

        x2 = mx
        y2 = my

    end if


    dx = (x2 - x1)
    dy = (y2 - y1)

    if abs(dx)>=abs(dy) then

        steps = abs(dx)

    else

        steps = abs(dy)

    end if

    dx = dx / steps
    dy = dy / steps
    posX = x1
    posY = y1

    screenlock

    cls

    for i as integer = 1 to steps

        pset(posX, posY)

        posX += dx

        posY += dy

    next

    screenunlock

    sleep(3, 1)

loop until multikey(fb.sc_escape)

sleep