plib-devel

[Plib-devel] Sphere intersection tests, and ssgaSpheres.

[Bram S. <br...@sa...>]

Hello,

Attached is sphere_isect.cxx test program, which demonstrates the
difficulties I experience when trying to line up ssgaSpheres with
sgSpheres.

The test program shows a sphere, and a cube. If the sgSphere
intersects the cube, the sphere is rendered in red, else it is
rendered using a blue colour.

I need to scale the ssgaSphere to a very strange size before I
get results which are visually roughly correct.

  Bram

Re: [Plib-devel] Sphere intersection tests, and ssgaSpheres.

[Bram S. <br...@sa...>]

On 02/02/05 15:15:36, Bram Stolk wrote:

> I need to scale the ssgaSphere to a very strange size before I
> get results which are visually roughly correct.

Ah... I found the problem in my test program.
When using this ssg func:

int  ssgIsect ( ssgBranch *root, sgSphere*s,sgMat4 m, ssgHit =20
**results ) ;

the relative position of intersector and intersectee can be
in either the inverse mat for the root, or in the 'center'
member data of the sphere.

I had put the sphere pos both in the inverse-math *and* in
the sphere itself -> incorrect results.

   bram