Thank you, Paul and Ismail!
I will try Ismail's solution, and will tell you the result.
On Tue, Apr 14, 2009 at 2:27 PM, Ismail Pazarbasi <pazarb...@gmail.com>wrote:
> Hi Lingyun,
>
> std::bad_alloc is thrown when operator new cannot allocate memory,
> which indicates there is not enough memory. You may reserve your array
> before hand, as Paul mentioned, but it may throw as well. This could
> reduce, if nothing, copy operations. It may also prevent exception,
> because when expanding, std::vector will have two large copies at the
> same time. That is:
> e.g. old array length was 1500000
> expand by 500000
> While allocating 2000000 elements, previous 1500000 elements will also
> be alive/allocated, that requires room for 3500000 elements in total.
> Resize may reduce this cost to 2000000 only, because vector will not
> have to expand afterwards (i.e. during push_back), which requires a
> copy operation. Note that C++ standard allocator doesn't do realloc().
> Instead, vector will allocate a block of N * sizeof(T) items (or
> little more), copy existing block into new one, then free existing
> block.
>
> // instantiate vertices normally
> vertices = new osg::Vec3Array;
>
> // if number of parts is greater than 1000,
> // reserve your items before.
> if (NumPart > 1000)
> {
> try
> {
> vertices->reserve(NumPart);
> }
> catch (std::bad_alloc& e)
> {
> // handle exception here; log and return error from this function.
> // alternatively, you can rethrow here, and catch in caller.
> }
> }
>
> // wrap your push_back calls in a try-catch block
> try
> {
> vertices->push_back(...);
> }
> catch (std::exception&)
> {
> }
>
> To be on the safe side, handle your exceptions and wrap your pointers
> in a smart pointer class. If an exception is thrown and you
> rethrow/return from function, you need to delete your Geode, Group and
> other objects. You may get all these for free, if you use a smart
> pointer (osg::ref_ptr<T>, in this case, as osg::Node's destructor is
> protected, IIRC, which prevents it to be "delete"d externally, but
> only when its ref count reaches 0).
>
> HTH
> Ismail
>
> 2009/4/13 Paul Martz <pma...@skew-matrix.com>:
> > Hi Lingyun Yu --
> > You don't have a variable named 'galaxy' defined, so the
> > "addDrawable(galaxy)" is suspicious.
> >
> > I'd so a resize on the vertex and color arrays, rather than a push_back,
> for
> > efficiency reasons.
> >
> > I don't think numParts>1000000 should cause any problems. OpenGL doesn
> not
> > place an upper limit on the number of primitives you can render with a
> > single glDrawArrays call.
> >
> > I don't really see anything that would cause a crash so I guess you
> should
> > use a debugger and look at the call stack, like you would any other
> crash.
> >
> > Paul Martz
> > Skew Matrix Software LLC
> > http://www.skew-matrix.com
> > +1 303 859 9466
> >
> >
> > -----Original Message-----
> > From: osg-users-boun...@lists.openscenegraph.org
> > [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Sent:
> > Monday, April 13, 2009 9:27 AM
> > To: osg-users@lists.openscenegraph.org
> > Subject: [osg-users] Problem of points showing
> >
> > Hi, everybody,
> >
> > I met a problem when I want to show huge amount of points, as you can see
> > the code below, if my NumPart is 1000000, no problem, it shows points
> > properly. But if the NumPart is 2000000, then it shows a lot of lines. If
> > NumPart is even bigger, the program complained like this：Microsoft C++
> > exception: std::bad_alloc at memory location 0x0030e898.
> >
> > I don't know that's because the dataset is too big or not? because while
> it
> > shows not so many points, everything goes well.
> >
> > By the way, the data in P array are all right.
> >
> > osg::Geode *makeGalaxy()
> > {
> > osg::Geode *geode = new osg::Geode();
> > osg::Geometry *geometry= new osg::Geometry();
> > osg::Vec3Array *vertices = new osg::Vec3Array();
> > osg::Vec4Array *colors = new osg::Vec4Array();
> > osg::Vec4 ini(1,0.1,0.55,1);
> > osg::Vec4 fin(0,1,0,1);
> >
> > for (int i = 1; i <= NumPart; i++)
> > {
> >
> > vertices->push_back(osg::Vec3(P[i].Pos[0],P[i].Pos[1],P[i].Pos[2]));
> > colors->push_back(ini+(fin-ini)*(i*1/NumPart));
> > }
> > geometry->setVertexArray(vertices);
> > geometry->setColorArray(colors);
> > geometry->setColorBinding(osg::Geometry::BIND_PER_VERTEX);
> > geometry->addPrimitiveSet(new
> osg::DrawArrays(osg::PrimitiveSet::POINTS,
> > 0, NumPart));
> > geode->addDrawable(galaxy);
> > return geode;
> > }
> >
> > ...
> >
> > Thank you.
> >
> > ------------------
> > Read this topic online here:
> > http://forum.openscenegraph.org/viewtopic.php?p=10166#10166
> >
> >
> >
> >
> >
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> >
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> >
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> >
> >
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>
--
Cheers,
Yun
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