Alter the vanishing point?

[jeff]

Is there a way to alter the vanishing point in Away3D? I am not
looking to move the camera, just the vanishing point. As I understand
it the scenes origin is the vanishing point, and have experimented
with moving the scene within the ViewPort3D, but did not get the
results I was after.

If you are wondering, "why not move the camera?" the effect I am after
is slightly different. If looking trough a window(the viewport) into
a room(the scene), moving the camera would be like moving the window
along the the wall of the room. I am trying to move the viewer to the
side of the window.

Rotating the camera, gave a effect close to this when dealing with
very small values, but not quite on the money.

If there is not way to change the vanishing point, any ideas of how to
fake this would be super welcome.

I searched and did not find anything on this, but if it has been
discussed before using different terminology, I apologize and please
let me know.

Thanks

[Karim Beyrouti]

how about changing the FOV ?

[jeff]

Thanks for the idea.

Is there a way I can use the FOV to shift things right or left?

If not that certainly seams like a the place to start if I hack into
Away3D for a solution.

[Michael Iv]

FOV is not a vanishing point . It is the view angle of your eyes ( camera). In Away3d 3x I guess you should moderate it by your own . In Away lite you do it via generic Flash Perspective Projection class. In Broomstick I am still not proficient to say how it is done .

Sent from my iPhone

[Michael Iv]

Btw , you don't need the vanishing point to shift things left right. Camera matrix does this job

Sent from my iPhone

On May 2, 2011, at 10:10 PM, jeff <fej...@gmail.com> wrote:

[Li]

I think that you would need to alter the projection matrix (PespectiveLens) so that the homogeneous clip space relates to a non-symmetrical frustum. Am I right or am I saying crazy stuff?

If not, I know that Broomstick assumes symmetrical frustums always.

[Peter Kapelyan]

A simple way to do that is just move the view itself on the stage left/right/up/down etc. Your vanishing point will no longer be in the exact middle of the stage (like the view is in the middle). Not sure if it will do exactly what you want, or if it is too simple.

-Pete

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[jeff]

Li, I think you may be right and I'll need to find someway to fake the
effect. Peter thanks for the idea, I had played with that a little,
but was not satisfied. However reading your post made me think I
might be able to combine moving the view with moving the objects in
the scene to simulate the effect. I'll see what I can paste together
and report back.

[Li]

If you want to go the hard way, ping me in Gtalk and I'll help you set up that non-symmetrical projection matrix.