Re: [ggt-devel] Patch Intersection.h

[Patrick H. <pa...@13...>]

On Feb 12, 2009, at 3:54 AM, Sebastian Messerschmidt wrote:

> Hi,
>
> as I've written some weeks ago, I've fixed some float/double/  
> DATA_TYPE issues and  corrected some intersection functions, that  
> were return false positives.
>
> The changes in detail:
>
> Line 318:
> Fixed the box / lineseg intersection, which was missing an early out  
> for the case were the ray hit the box. but the line didn't (some  
> simple early out test by checking tin,tout between 0 and 1)

This change breaks one of the tests (see  
gmtlTest::IntersectionTest::testIntersectAABoxLineSeg() at line 199 of  
Test/TestSuite/TestCases/IntersectionTest.cpp). As far as I can tell,  
the expectation of the test is correct. Specifically, there is a line  
segment that starts within the axis-aligned bounding box and ends  
outside the box. In this case, tIn has a value of -0.5, and tOut is  
0.5. Should the test be a logical AND instead of an OR?

> Lines 584, 616, 649, 706:
>
> changed the declaration of tIN and tOUT parameters consitently to  
> DATA_TYPE instead of fixed float.
> addiditionally the numHits were mixed int/unsigned int which I've  
> corrected to unsigned int everywhere
>
> Line 745:
> Same as above, double/float DATA_TYPE corrections

These changes have been committed. Thanks very much.

> Here I've corrected the intersection test between plane an ray, that  
> failed due to missing check in tIn/tOut - range

This change breaks another test in Test/TestSuite/TestCases/ 
IntersectionTest.cpp. This one is at line 874 where a plane is  
constructed with a ray pointing down through it. The test expects that  
t will be 5. Is the expectation of the test invalid?

> I've also added the proposed intersectDoubleSided-Test for ray/ 
> triangle, that ignores the triangle orientation.


This has been committed. Thanks!

  -Patrick


--
Patrick L. Hartling
Senior Software Engineer, Priority 5
http://www.priority5.com/