rem Vectors - OpenDBC tutorial (DarkBASIC Professional)
sync on : sync rate 60
autocam off
color backdrop rgb(14, 16, 28)

rem Vectors live in numbered slots, like objects
r = make vector3(1)  : rem position of the chaser
r = make vector3(2)  : rem position of the target
r = make vector3(3)  : rem direction from chaser to target

make object cone 1, 10 : color object 1, rgb(255, 120, 60)
xrotate object 1, 90 : fix object pivot 1
make object sphere 2, 8 : color object 2, rgb(90, 220, 255)
set vector3 1, 0, 0, 0

position camera 0, 55, -60
point camera 0, 0, 0

do
   t = wrapvalue(t + 1)
   rem The target moves on a figure of eight
   set vector3 2, sin(t) * 40, 0, sin(t * 2) * 20
   position object 2, x vector3(2), y vector3(2), z vector3(2)

   rem direction = target - chaser, then normalised to length 1
   subtract vector3 3, 2, 1
   distance# = length vector3(3)
   normalize vector3 3, 3

   rem Step 0.8 units along the direction unless already there
   if distance# > 5
      multiply vector3 3, 0.8
      add vector3 1, 1, 3
   endif
   position object 1, x vector3(1), y vector3(1), z vector3(1)
   point object 1, x vector3(2), y vector3(2), z vector3(2)

   text 10, 10, "Distance: " + str$(distance#, 1)
   sync
loop