Re: boost bind/lambda

If you want to manage the life time of the data manually (or elsewhere in
code), it's probably easiest to simply not use a shared pointer at all,
and a raw one instead:

GLfloat* givemefloat( .... etc

class_<GLfloat>("GLfloat")

If you really want to use a smart pointer for whatever reason, you can use
a 'null deleter'. See
http://www.boost.org/doc/libs/1_43_0/libs/smart_ptr/sp_techniques.html#static
which explains it.

As said previously by others it would be much better to use
boost::shared_array rather than shared_ptr, which you can use a null
deleter with.

Nigel


On Thu, January 6, 2011 6:27 am, beo wulf wrote:
> This is _almost_ perfect, the only thing I can't figure out is:
>
> #typedef P boost::shared_ptr
> #typedef V std::vector
>
> P<GLfloat> givemefloat(P<V<GLfloat> > p) {
>   return P( & (*v) [0] );
> }
>
> is bad in my case since I don't want the data to be tried to be freed
> when the pointer returned by givemefloat expires. Is there a way to
> have a boost pointer that doesn't reference count? (or if it must
> reference count, reference count on the P<V<GLfloat>> object ?
>
> Thanks!
>
> On Wed, Jan 5, 2011 at 2:55 AM, Nigel Atkinson <[email protected]>
> wrote:
>> You're on the right track. �Perhaps an example will help (and let me
>> make sure it works as advertised!) Attached is a little program which
>> I've tested with gcc 4 and luabind 0.9. �I've added a couple of
>> comments.
>>
>> It should work if GLfloat is a #define rather than a typedef, but I've
>> just checked on my machine (Linux), and it is a typedef.
>>
>> On another note, if you are binding all of OpenGL, are you going to do
>> extensions? �That could be curly! Bound function pointers? That *might*
>> work perhaps. Hmmm.
>>
>> Nigel
>>
>> On Tue, 2011-01-04 at 23:44 -0800, beo wulf wrote:
>>> I've tried
>>>
>>> class_<GLfloat, boost::shared_ptr<GLfloat> > ....
>>>
>>> but I'm not sure what to do with this. Can you explain? (Luabind's
>>> template blackmagicery is a couple levels above my paygrade).
>>> Thanks!
>>>
>>> On Tue, Jan 4, 2011 at 11:26 PM, Nigel Atkinson <[email protected]>
>>> wrote:
>>> > You could bind GLfloat as a class. �I've done this in the past with
>>> > Ogre3d's "Real" witch is a typedef for float or double. �Depending on
>>> > how your using in your scripts, that's all you may need to do, i.e
>>> > without any defined methods. This makes GLfloat in scripts similar to
>>> an
>>> > opaque pointer, where it's allways come from C++ and only really used
>>> by
>>> > C++. You can also add operators and a constructor as well, to get
>>> more
>>> > scripting use out of it.
>>> >
>>> > Using it this way as with pointers (arrays) make take a little
>>> tweaking,
>>> > I'll have to have a play around when I have time.
>>> >
>>> > Nigel
>>> >
>>> > On Wed, 2011-01-05 at 06:17 +0000, Tony Kostanjsek wrote:
>>> >> I might've been mistaken on the function pointer issue, but I've
>>> only used it
>>> >> that way.
>>> >>
>>> >>
>>> >>
>>> >> ----- Urspr�ngliche Mail ----
>>> >> Von: beo wulf <[email protected]>
>>> >> An: [email protected]
>>> >> Gesendet: Mittwoch, den 5. Januar 2011, 6:55:19 Uhr
>>> >> Betreff: Re: [luabind] boost bind/lambda
>>> >>
>>> >> Why does wrapping it on a tag_function work then?
>>> >>
>>> >> Writing wrappers is out of the question -- there are too many
>>> functions.
>>> >>
>>> >> On Tue, Jan 4, 2011 at 9:51 PM, Tony Kostanjsek
>>> <[email protected]> wrote:
>>> >> > "def" requires an address or function pointer, but bind returns a
>>> temporary
>>> >> > functor instance. Try to use a static instance or write a wrapper
>>> function
>>> >> > implementation and pass that.
>>> >> >
>>> >> > Something like <type> func = bind(...)
>>> >> > .def("glLightfv", &func)
>>> >> > I'm not sure what <type> would look like though.
>>> >> >
>>> >> > Alternatively, something like this might work:
>>> >> > void wrappedGlLightfv(GLenum light, GLenum pname, const
>>> >> > boost::shared_ptr<std::vector<GLfloat>> fv)
>>> >> > {
>>> >> > �glLightfv(light, pname, &fv->get()->front()); // not quite sure
>>> about
>>> >> front(),
>>> >> > but you get the idea
>>> >> > }
>>> >> >
>>> >> > ...
>>> >> > .def("glLightfv", wrappedGlLightfv)
>>> >> > ...
>>> >> >
>>> >> > ----- Urspr�ngliche Mail ----
>>> >> > Von: beo wulf <[email protected]>
>>> >> > An: [email protected]
>>> >> > Gesendet: Mittwoch, den 5. Januar 2011, 6:35:09 Uhr
>>> >> > Betreff: [luabind] boost bind/lambda
>>> >> >
>>> >> > Goal: I want to luabind all of OpenGL.
>>> >> > Problem: glLightfv( int, int, GLfloat*)
>>> >> >
>>> >> > Almost solution: �boost::bind
>>> >> >
>>> >> > The following code almost works -- it can use boost::bind to
>>> convert
>>> >> > functions that take arg GLfloat* to take an arg of
>>> >> > boost::shared_ptr<std::vector<GLfloat>> instead. However,
>>> boost::bind
>>> >> > and luabind seem to not work with each other (in particular, the
>>> line
>>> >> >
>>> >> > , def("glLightfv2", bind(glLightfv, _1, _2, _3)) // ths line does
>>> not compile
>>> >> >
>>> >> > Why?
>>> >> >
>>> >> > Full code below:
>>> >> >
>>> >> >
>>> >> >
>>> >> > #include <boost/shared_ptr.hpp>
>>> >> > #include <boost/bind.hpp>
>>> >> >
>>> >> > #include <vector>
>>> >> > #include <iostream>
>>> >> >
>>> >> > #include <luabind/luabind.hpp>
>>> >> > #include <luabind/operator.hpp>
>>> >> > #include <luabind/adopt_policy.hpp>
>>> >> > #include <luabind/copy_policy.hpp>
>>> >> > #include <luabind/class_info.hpp>
>>> >> >
>>> >> > #include <GL/gl.h>
>>> >> >
>>> >> >
>>> >> >
>>> >> > #define P boost::shared_ptr
>>> >> > #define V std::vector
>>> >> >
>>> >> > float foo(int x, int y, float* f) {
>>> >> > �float ans = 0;
>>> >> > �ans = x + y + f[0] + f[1] + f[2];
>>> >> > �return ans;
>>> >> > }
>>> >> >
>>> >> > float* get_raw(P<V<float> > p) {
>>> >> > �return &((*p)[0]);
>>> >> > }
>>> >> >
>>> >> > void test() { // works fine
>>> >> > �P<V<float> > p(new V<float>());
>>> >> > �p->push_back(1);
>>> >> > �p->push_back(2);
>>> >> > �p->push_back(3);
>>> >> >
>>> >> > �// I want this to output 9
>>> >> > �std::cout << bind(foo, _1, _2, bind(get_raw, _3))(1, 2, p) <<
>>> std::endl;
>>> >> > }
>>> >> >
>>> >> >
>>> >> > int main() {
>>> >> > �using namespace luabind;
>>> >> >
>>> >> > �lua_State *L;
>>> >> >
>>> >> > �module( L )
>>> >> > � �[
>>> >> > � �namespace_("gl") [
>>> >> > � � �def( "glLightfv", glLightfv)
>>> >> > � � �// Why do these two lines not compile?
>>> >> > // � �, def( "glLightfv2", bind(glLightfv, _1, _2, _3))
>>> >> > // � �, def( "glLightfv3", bind(glLightfv, _1, _2, bind(get_raw,
>>> _3)))
>>> >> > � �]
>>> >> > � �]
>>> >> >
>>> >> > � �;
>>> >> > }
>>> >> >
>>> >> > ------------------------------------------------------------------------------
>>> >> > Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> >> > to consolidate database storage, standardize their database
>>> environment, and,
>>> >> > should the need arise, upgrade to a full multi-node Oracle RAC
>>> database
>>> >> > without downtime or disruption
>>> >> > http://p.sf.net/sfu/oracle-sfdevnl
>>> >> > _______________________________________________
>>> >> > luabind-user mailing list
>>> >> > [email protected]
>>> >> > https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >> >
>>> >> >
>>> >> >
>>> >> >
>>> >> > ------------------------------------------------------------------------------
>>> >> > Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> >> > to consolidate database storage, standardize their database
>>> environment, and,
>>> >> > should the need arise, upgrade to a full multi-node Oracle RAC
>>> database
>>> >> > without downtime or disruption
>>> >> > http://p.sf.net/sfu/oracle-sfdevnl
>>> >> > _______________________________________________
>>> >> > luabind-user mailing list
>>> >> > [email protected]
>>> >> > https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >> >
>>> >>
>>> >> ------------------------------------------------------------------------------
>>> >> Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> >> to consolidate database storage, standardize their database
>>> environment, and,
>>> >> should the need arise, upgrade to a full multi-node Oracle RAC
>>> database
>>> >> without downtime or disruption
>>> >> http://p.sf.net/sfu/oracle-sfdevnl
>>> >> _______________________________________________
>>> >> luabind-user mailing list
>>> >> [email protected]
>>> >> https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> ------------------------------------------------------------------------------
>>> >> Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> >> to consolidate database storage, standardize their database
>>> environment, and,
>>> >> should the need arise, upgrade to a full multi-node Oracle RAC
>>> database
>>> >> without downtime or disruption
>>> >> http://p.sf.net/sfu/oracle-sfdevnl
>>> >> _______________________________________________
>>> >> luabind-user mailing list
>>> >> [email protected]
>>> >> https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >
>>> >
>>> >
>>> > ------------------------------------------------------------------------------
>>> > Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> > to consolidate database storage, standardize their database
>>> environment, and,
>>> > should the need arise, upgrade to a full multi-node Oracle RAC
>>> database
>>> > without downtime or disruption
>>> > http://p.sf.net/sfu/oracle-sfdevnl
>>> > _______________________________________________
>>> > luabind-user mailing list
>>> > [email protected]
>>> > https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >
>>>
>>> ------------------------------------------------------------------------------
>>> Learn how Oracle Real Application Clusters (RAC) One Node allows
>>> customers
>>> to consolidate database storage, standardize their database
>>> environment, and,
>>> should the need arise, upgrade to a full multi-node Oracle RAC database
>>> without downtime or disruption
>>> http://p.sf.net/sfu/oracle-sfdevnl
>>> _______________________________________________
>>> luabind-user mailing list
>>> [email protected]
>>> https://lists.sourceforge.net/lists/listinfo/luabind-user
>>
>>
>> ------------------------------------------------------------------------------
>> Learn how Oracle Real Application Clusters (RAC) One Node allows
>> customers
>> to consolidate database storage, standardize their database environment,
>> and,
>> should the need arise, upgrade to a full multi-node Oracle RAC database
>> without downtime or disruption
>> http://p.sf.net/sfu/oracle-sfdevnl
>> _______________________________________________
>> luabind-user mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/luabind-user
>>
>>
>
> ------------------------------------------------------------------------------
> Learn how Oracle Real Application Clusters (RAC) One Node allows customers
> to consolidate database storage, standardize their database environment,
> and,
> should the need arise, upgrade to a full multi-node Oracle RAC database
> without downtime or disruption
> http://p.sf.net/sfu/oracle-sfdevnl
> _______________________________________________
> luabind-user mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/luabind-user
>



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Learn how Oracle Real Application Clusters (RAC) One Node allows customers
to consolidate database storage, standardize their database environment, and, 
should the need arise, upgrade to a full multi-node Oracle RAC database 
without downtime or disruption
http://p.sf.net/sfu/oracle-sfdevnl
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