LOGO-L> Multi-Turtle in 3D

["Olga Tuzova" <olgatu@hotmail.com>]

Hello everybody!

First of all--many thanks to those, who have made the archive look so 
great. I would like very much to contribute a GIF there compatible with 
those of Ray Catzel and Yehuda, but it will take some time, may be the 
hole life. :-)
Instead, I'm sending just a code for ants chasing each other in 3d 
space. Hope, you'll enjoy it as much as I do.

The changing in position of -1 turtle leads to quite different pictures. 
I offer to make changes using SELECTBOX. It would be better to give a 
name to the turtle position, not pointing the coordinates ("high above 
the cube", for example), but I'm not sure how it should sound in 
English.

--- Chasing Ants in 3D -----------

to ants_3d.main
cs
perspective
setturtle -1
localmake "choice selectbox[Choose position for turtle # -1]~
                            [[20 1000 50]
                             [300 500 500]
                             [-200 -100 800] ]
if :choice=1 [setposxyz [20 1000 50]]
if :choice=2 [setposxyz [300 500 500]]
if :choice=3 [setposxyz [-200 -100 800]]
if :choice=0 [stop]

ants_set

; initial positions of four ants

ants_cube

; a drawing of a cube, on the tops of which
; the ants are placed

ants_move

; recursive procedure imitating the ants' movement 
; towards each other

end

to ants_cube
setturtle 0 setpc [255 0 0]
repeat 4[repeat 4[fd 200 rt 90] fd 200 downpitch 90]
setpc [0 0 0]
end 

to ants_move
if dist_0_3 < 4 [stop]
for [i 0 3][localmake "num remainder :i+1 4 setturtle :num
            localmake "place posxyz
            setturtle :i
            setorientation towardsxyz :place fd 2]
ants_move
end   

to ants_set
setturtle 0
pu setxyz -100 0 100 pd label "0
setturtle 1
pu setxyz 100 200 100 pd label "1
setturtle 2
pu setxyz 100 0 -100 pd label "2
setturtle 3
pu setxyz -100 200 -100 pd label "3
end

to dist_0_3

;estimates the distance between two turtles (#0 and #3)
 
setturtle 3 
localmake "pos1 posxyz
setturtle 0
localmake "dx2 (xcor-first :pos1)*(xcor-first :pos1)
localmake "dy2 (ycor-first bf :pos1)*(ycor-first bf :pos1)
localmake "dz2 (zcor-last :pos1)*(zcor-last :pos1)
op sqrt :dx2+:dy2+:dz2
end  

--------------------------

All the best,
Olga


______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
---------------------------------------------------------------
Please post messages to the Logo forum to logo-l@gsn.org.  Mail
questions about the list administration to logofdn@gsn.org.  To
unsubscribe send    unsubscribe logo-l    to majordomo@gsn.org.