Rent a coder: camera routine

this example do what you want..set it up for your own purpose..it cant be more simple..

Type CSys

Field cx#, cy#, cz#
Field mx#, my#, sps%

End Type

Function ChaseCam(cam, Entity, XOff#, YOff# = 2, ZOff# = -5, Spd# = 0.8)

Local sys.csys = First csys
Local nx#, ny#, nz#
Local dx#, dy#, dz#
Local ex#, ey#, ez#
Local hit%

If sys = Null
sys = New cSys
sys\sps = CreatePivot()
EndIf

sys\mx = MouseX()
sys\my = MouseY()
sps = sys\sps
PositionEntity sps, EntityX(entity), EntityY(entity), EntityZ(entity)
TFormVector xOff, yOff, zOff, entity, 0
ex# = EntityX(entity)
ey# = EntityY(entity)
ez# = EntityZ(entity)
nx# = ex+TFormedX()
ny# = ey+TFormedY()
nz# = ez+TFormedZ()
dx# = nx-ex
dy# = ny-ey
dz# = nz-ez
hit = LinePick(ex, ey, ez, dx, dy, dz, 0.2)

If hit
nx = PickedX()
ny = PickedY()
nz = PickedZ()
EndIf

sys\cx = sys\cx+(nx-sys\cx)*spd
sys\cy = sys\cy+(ny-sys\cy)*spd
sys\cz = sys\cz+(nz-sys\cz)*Spd

PositionEntity cam, sys\cx, sys\cy, sys\cz
PointEntity Cam, Entity, 0

End Function


Graphics3D 800, 600, 0, 2
SetBuffer BackBuffer()

Global cube = CreateCube()
Global cam = CreateCamera()
Global ops = CreateCube()
ScaleEntity ops, 10, 10, 1
MoveEntity ops, 0, 0, -5
EntityPickMode ops, 2

While Not KeyHit(1)

Cls

ChaseCam(cam, cube, 0, 2, -20, .1)

MoveEntity ops, KeyDown(205) - KeyDown(203), 0, 0

UpdateWorld
RenderWorld

Flip

Wend