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Subject: Re: backface culling w/ camera question

In article ,
dfgkkdfjgddfgd@gmail.com says...
> Say I have a cube in my 3D scene. The camera is being moved around via
> camera matrix transformations. Its possible to "fly" the camera towards and
> past the cube so that the cube is then behind the camera.
> It seems like backface culling will not totally hide the cube since some of
> its faces still "face" the camera even though the camera is not pointing at
> it. How can I totally hide things behind the camera? It would seem fairly
> obvious I need to know which way the camera is pointing, but Im not sure how
> to derive this from the position and rotation information I give my camera,
> and then use it to hide faces if theyre not being viewed by the camera.

Oops, I misunderstood your question at the first posting.

As Hans points out, you need view frustum culling. This is most
conveniently done in homogeneous screen coordinates. For those polygons
that are both outside and inside the view frustum, you need view frustum
clipping. Also in hom.scr.coord.

Btw, are you constructing a software renderer?

Kalle Rutanen


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Re: backface culling w/ camera question

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