He doesn't want to create a screen object. In his case, for performance
reasons, but there are some problems with the screen object approach too
that I found.
Wanting to do this is a common enough problem and comes up a lot if you go
looking for a solution in these forums. Not so many good answers to be
found though. It'd be great if some functionality was added to Away3D to
handle it correctly so people could quit asking.
For my app, I wound up hacking some code from View3D:
*private* *function* mouseTo3D(screenX:Number, screenY:Number,
screenZ:Number = 0):Number3D
{
* var* persp:Number = view.camera.zoom / view.camera.focus;
* var* inv:Matrix3D = *new* Matrix3D();
inv = view.camera.invViewMatrix;
* var* n3D:Number3D = *new* Number3D;
n3D.x = screenX / persp * inv.sxx + screenY / persp * inv.sxy + screenZ
* inv.sxz + inv.tx;
n3D.y = screenX / persp * inv.syx + screenY / persp * inv.syy + screenZ
* inv.syz + inv.ty;
n3D.z = screenX / persp * inv.szx + screenY / persp * inv.szy + screenZ
* inv.szz + inv.tz;
* return* n3D;
}
I was trying to create a continuous display of the coordinates of the mouse
cursor. I had several problems creating transparent planes for this
purpose. First, mouse move events are apparently not processed unless you
are rendering. I'm not rendering unless something changed because I have a
lot of other things to process and don't want to overhead. Second, the
View3D code hardwires the perspective model of PerspectiveLens and I'm using
the OrthogonalLens (reflected in the code above). It'd be nice if it would
get the info from the lens and not hardwire it.
The biggest problem with this code is coming up with the right screenZ for
the mouse cursor. As you can see, I assume it is 0 most of the time, but if
the camera is in certain positions (haven't tracked it down) this gives a
way wrong answer.
Cheers,
BW
On Fri, Jun 18, 2010 at 7:49 AM, savagelook <[email protected]>wrote:
> Are the away3d clipping/culling methods not working for you?
>
>
> http://groups.google.com/group/away3d-dev/browse_thread/thread/ccbcab2aa2156b87?hl=en
> The Camera3D.screen() method says in the source that the screen object
> can be passed for the first argument in place of an object. So for
> you it would be:
>
> var sv:ScreenVertex = view.camera.screen(view.scene, yourVector3D);
> var x:Number = sv.x + view.x;
> var y:Number = sv.y + view.y;
>
> On Jun 18, 10:26 am, Th3Sh33p <[email protected]> wrote:
> > I understand that a function such as this ...
> >
> > private function getScreenPos(ob:Object3D):Point{
> > var posn:Vector3D = ob.viewMatrix3D.position
> > var screenX:Number = posn.x / posn.z;
> > var screenY:Number = posn.y / posn.z;
> > return new Point(screenX,screenY)
> >
> > }
> >
> > ...can find the 2D position of the 3D object, but how would I go about
> > finding the 2D position of a vector3D that hasn't been added to the
> > scene?
> >
> > I'm using this to find if a 3d object will appear on the screen if I
> > add it, that way I won't waste precious processing power on a unseen
> > object.
> >
> > Any help appreciated :)
>
