Re: kQ3ErrorInfiniteRationalPoint

[James W. <ja...@fr...>]

Edward K. Chew wrote:
> I have been getting reports from users of a -28376 error  
> (kQ3ErrorInfiniteRationalPoint) appearing when they click in a view.   
> I have not been able to reproduce this so far, but I have been looking  
> closely at my picking code.  There doesn't seem to be anything amiss  
> with the coordinates going into the window point pick, so that  
> suggests a geometry object in one of the display groups is acting up.
> 
> Would I see that error if I were unlucky enough to click on a  
> polygonal element edge on, so that it is oriented exactly  
> perpendicular to the plane of view?  I'm just trying to narrow down  
> the possibilities here.  In the event of such an error, would the pick  
> simply not report any hits?  That would be good.  I could simply  
> ignore the error in that case.  :)

Assuming you are not explicitly using rational points, 
kQ3ErrorInfiniteRationalPoint is most likely to be caused by 
transforming a 3D point by a 4x4 matrix.  Furthermore, the matrix would 
need to be not a rigid motion -- for instance not a local-to-world 
matrix, but maybe window-to-world or world-to-frustum or some such.  I 
don't see anything like that in E3Ray3D_IntersectTriangle or 
E3Triangle_InterpolateHit, the key low-level routines used in picking.

You could change your program so that it crashes when it receives 
kQ3ErrorInfiniteRationalPoint, and then the users could send you crash 
logs. :-)
-- 
   James W. Walker, Innoventive Software LLC
   <http://www.frameforge3d.com/>