look at the 3rd person camera example:
Rem * Title : Third Person Camera
Rem * Author : DBS-LB
Rem * Date : 1st Sept 99
rem ===========================================
rem DARK BASIC EXAMPLE PROGRAM 3
rem ===========================================
rem This program operates a third person camera
rem -------------------------------------------
rem Make a simple scene for the camera to look at
make matrix 1,10000.0,10000.0,25,25
load bitmap "floor1.bmp",1
get image 1,0,0,256,256
delete bitmap 1
prepare matrix texture 1,1,2,2
randomize matrix 1,50.0
set matrix height 1,12,12,300.0
update matrix 1
rem Create blob character to follow
make object sphere 1,100.0
rem Set variables for character position
x#=500
z#=500
rem Activate manual sync
sync on
rem Begin loop
do
rem Control camera with arrow keys
if upkey()=1 then x#=newxvalue(x#,a#,10) : z#=newzvalue(z#,a#,10)
if downkey()=1 then x#=newxvalue(x#,a#,-10) : z#=newzvalue(z#,a#,-10)
if leftkey()=1 then a#=wrapvalue(a#-10.0)
if rightkey()=1 then a#=wrapvalue(a#+10.0)
rem Update character
y#=get ground height(1,x#,z#)+50.0
position object 1,x#,y#,z#
yrotate object 1,a#
rem Position camera to the back of the character
cx#=newxvalue(x#,wrapvalue(a#+180),300)
cz#=newzvalue(z#,wrapvalue(a#+180),300)
cy#=get ground height(1,cx#,cz#)+100.0
position camera cx#,cy#,cz#
rem Point camera at object
point camera x#,y#,z#
rem Syncronise
sync
rem End loop
loop
