Re: [Algorithms] octree and HSR

[A. J. C. <Alb...@te...>]

----- Original Message -----
From: "Dave Eberly" <eb...@ma...>
To: <gda...@li...>
Sent: Thursday, August 31, 2000 7:47 PM
Subject: Re: [Algorithms] octree and HSR


> From: "A. Jeffrey Cahyono" <Alb...@te...>
>
> > > 4. How can I check if the view frustrum and a cube intersect? (or if the
> cube is inside
> > the view frustrum)
> > This is easy once you've created the view frustum.
> > Just test the eight corners of the cube against the six frustum plane like
> this.
> <snip of code>
>
> I do not believe your code handles the case when the eight
> corners of the box are outside the frustum, but the box
> still intersects the frustum (or completely contains the frustum).
> If you can guarantee that your bounding boxes are small
> enough relative to the frustum (for example a rectangular
> face can never be large enough to contain the near face
> of the frustum), then not a problem.

I've tested that kind of case and  the testing function returns IC_STRADDLE.
This algorithm is a conservative testing.

BTW I've checked out tour intersection library and it really cool!

I also would like to apologize because I forget to mention that the original idea of this
algorithm was came from Thatcher Ulrich's terrain demo.