Re: [osg-users] LineSegmentIntersector and MODEL Frame

[OpenSceneGraph Users]

I found the problem, and it was mine. It helps if I attach my root node to 
the scene BEFORE I try to insect with it. ;)

On Monday, February 3, 2020 at 1:04:10 PM UTC-5, Nonsanity wrote:
>
> Thanks. I had thought to apply the visitor to the scene, but GetScene() 
> didn't have Accept(). With your confirmation that using the scene was 
> correct, I found that viewer.getSceneData()->accept( iv ) did exist.
>
> However, calling that line just results in a segfault. The rest of the 
> code is the same as before. I'm going to search to see if I'm doing 
> something obviously wrong, but in case I got the above line incorrect, I 
> wanted to post my failed results here for further comment.
>
>
> On Monday, February 3, 2020 at 3:06:33 AM UTC-5, OpenSceneGraph Users 
> wrote:
>>
>> Hi Chris,
>> I guess you want the scene to accept the IntersectionVisitor, not the 
>> camera.
>> Laurens.
>>
>> On Sat, Feb 1, 2020 at 1:18 PM OpenSceneGraph Users <
>> osg-...@lists.openscenegraph.org> wrote:
>>
>>> I have a scene built with a few objects loaded, the most pertinent one 
>>> being a large plane surface centered at the origin. I want to cast a ray 
>>> from a particular point at a particular angle inside the scene and get a 
>>> list of everything it intersects—both the point of intersection and the 
>>> Node object. Most examples of using intersectors involve picking from the 
>>> window, so I haven't seen exactly what I wanted. But from what I've read, 
>>> the following should at least be close:
>>>
>>> Vec3d start( 0.0, 0.0, 100.0 );
>>> Vec3d end( 0.0, 0.0, -100.0 );
>>> ref_ptr intsec = new LineSegmentIntersector( 
>>> Intersector::MODEL, start, end );
>>> IntersectionVisitor iv( intsec.get() );
>>> viewer.getCamera()->accept( iv );
>>> cout << intsec->containsIntersections() << endl;
>>>
>>> My start and end points in this snippet are well above and well below 
>>> the surface object. So that plane object should definitely be intersected 
>>> by a line running between them. However the containsIntersections function 
>>> always returns false.
>>>
>>> Immediately after making this preliminary test pick, the program calls 
>>> viewer.run() so I know everything is arranged as expected in the scene. So 
>>> my guess is that I'm missunderstanding how the visitor works. Perhaps the 
>>> accept() function is not what I should be using to execute the intersector?
>>>
>>>  ~ Chris
>>>
>>>
>>>
>>> -- 
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>>> Groups "OpenSceneGraph Users" group.
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>>>  
>>> 
>>> .
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>>>
>>

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Re: [osg-users] LineSegmentIntersector and MODEL Frame

[OpenSceneGraph Users]

Thanks. I had thought to apply the visitor to the scene, but GetScene() 
didn't have Accept(). With your confirmation that using the scene was 
correct, I found that viewer.getSceneData()->accept( iv ) did exist.

However, calling that line just results in a segfault. The rest of the code 
is the same as before. I'm going to search to see if I'm doing something 
obviously wrong, but in case I got the above line incorrect, I wanted to 
post my failed results here for further comment.


On Monday, February 3, 2020 at 3:06:33 AM UTC-5, OpenSceneGraph Users wrote:
>
> Hi Chris,
> I guess you want the scene to accept the IntersectionVisitor, not the 
> camera.
> Laurens.
>
> On Sat, Feb 1, 2020 at 1:18 PM OpenSceneGraph Users <
> osg-...@lists.openscenegraph.org > wrote:
>
>> I have a scene built with a few objects loaded, the most pertinent one 
>> being a large plane surface centered at the origin. I want to cast a ray 
>> from a particular point at a particular angle inside the scene and get a 
>> list of everything it intersects—both the point of intersection and the 
>> Node object. Most examples of using intersectors involve picking from the 
>> window, so I haven't seen exactly what I wanted. But from what I've read, 
>> the following should at least be close:
>>
>> Vec3d start( 0.0, 0.0, 100.0 );
>> Vec3d end( 0.0, 0.0, -100.0 );
>> ref_ptr intsec = new LineSegmentIntersector( 
>> Intersector::MODEL, start, end );
>> IntersectionVisitor iv( intsec.get() );
>> viewer.getCamera()->accept( iv );
>> cout << intsec->containsIntersections() << endl;
>>
>> My start and end points in this snippet are well above and well below the 
>> surface object. So that plane object should definitely be intersected by a 
>> line running between them. However the containsIntersections function 
>> always returns false.
>>
>> Immediately after making this preliminary test pick, the program calls 
>> viewer.run() so I know everything is arranged as expected in the scene. So 
>> my guess is that I'm missunderstanding how the visitor works. Perhaps the 
>> accept() function is not what I should be using to execute the intersector?
>>
>>  ~ Chris
>>
>>
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "OpenSceneGraph Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to osg-...@googlegroups.com .
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/osg-users/58d20034-cb65-4bef-937f-f85a1fa92030%40googlegroups.com
>>  
>> 
>> .
>> ___
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>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>
>

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Re: [osg-users] LineSegmentIntersector and MODEL Frame

[OpenSceneGraph Users]

Hi Chris,
I guess you want the scene to accept the IntersectionVisitor, not the
camera.
Laurens.

On Sat, Feb 1, 2020 at 1:18 PM OpenSceneGraph Users <
osg-users@lists.openscenegraph.org> wrote:

> I have a scene built with a few objects loaded, the most pertinent one
> being a large plane surface centered at the origin. I want to cast a ray
> from a particular point at a particular angle inside the scene and get a
> list of everything it intersects—both the point of intersection and the
> Node object. Most examples of using intersectors involve picking from the
> window, so I haven't seen exactly what I wanted. But from what I've read,
> the following should at least be close:
>
> Vec3d start( 0.0, 0.0, 100.0 );
> Vec3d end( 0.0, 0.0, -100.0 );
> ref_ptr intsec = new LineSegmentIntersector(
> Intersector::MODEL, start, end );
> IntersectionVisitor iv( intsec.get() );
> viewer.getCamera()->accept( iv );
> cout << intsec->containsIntersections() << endl;
>
> My start and end points in this snippet are well above and well below the
> surface object. So that plane object should definitely be intersected by a
> line running between them. However the containsIntersections function
> always returns false.
>
> Immediately after making this preliminary test pick, the program calls
> viewer.run() so I know everything is arranged as expected in the scene. So
> my guess is that I'm missunderstanding how the visitor works. Perhaps the
> accept() function is not what I should be using to execute the intersector?
>
>  ~ Chris
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "OpenSceneGraph Users" group.
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> To view this discussion on the web visit
> https://groups.google.com/d/msgid/osg-users/58d20034-cb65-4bef-937f-f85a1fa92030%40googlegroups.com
> 
> .
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[osg-users] LineSegmentIntersector and MODEL Frame

[OpenSceneGraph Users]

I have a scene built with a few objects loaded, the most pertinent one 
being a large plane surface centered at the origin. I want to cast a ray 
from a particular point at a particular angle inside the scene and get a 
list of everything it intersects—both the point of intersection and the 
Node object. Most examples of using intersectors involve picking from the 
window, so I haven't seen exactly what I wanted. But from what I've read, 
the following should at least be close:

Vec3d start( 0.0, 0.0, 100.0 );
Vec3d end( 0.0, 0.0, -100.0 );
ref_ptr intsec = new LineSegmentIntersector( 
Intersector::MODEL, start, end );
IntersectionVisitor iv( intsec.get() );
viewer.getCamera()->accept( iv );
cout << intsec->containsIntersections() << endl;

My start and end points in this snippet are well above and well below the 
surface object. So that plane object should definitely be intersected by a 
line running between them. However the containsIntersections function 
always returns false.

Immediately after making this preliminary test pick, the program calls 
viewer.run() so I know everything is arranged as expected in the scene. So 
my guess is that I'm missunderstanding how the visitor works. Perhaps the 
accept() function is not what I should be using to execute the intersector?

 ~ Chris



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