Re: boost bind/lambda

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.
> >>
> >>
> >>
> >> ----- Ursprüngliche 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)
> >> > ...
> >> >
> >> > ----- Ursprüngliche 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
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> >> > _______________________________________________
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> >> >
> >> >
> >> >
> >> >
> >> > ------------------------------------------------------------------------------
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> >> > to consolidate database storage, standardize their database environment, and,
> >> > should the need arise, upgrade to a full multi-node Oracle RAC database
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> >>
> >> ------------------------------------------------------------------------------
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> >> 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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> >>
> >>
> >>
> >>
> >> ------------------------------------------------------------------------------
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> >> 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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> >
> >
> >
> > ------------------------------------------------------------------------------
> > 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

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#include <luabind/luabind.hpp>
#include <boost/shared_ptr.hpp>
#include <iostream>
#include <lua.hpp>

using namespace luabind;
using namespace std;

typedef float GLfloat;
typedef boost::shared_ptr<GLfloat> GLfloatPtr;

// Poor mans constructor.
// Use a shared pointer so we don't have to worry
// about deletion.
GLfloatPtr givemefloat( float x, float y, float z)
{
    GLfloat *f = new GLfloat[3];
    f[0] = x;
    f[1] = y;
    f[2] = z;

    GLfloatPtr ptr( f );

    return ptr;
}

// Some wierd new OpenGL command ;-)
// Notice the parameter type, luabind will
// automagicly change a boost shared pointer 
// to a raw one.
void floaty( GLfloat* fv )
{
    cout << "3 Floats in a row: " << 
        fv[0] << ", " << 
        fv[1] << ", " <<
        fv[2] << endl;
}

int main()
{
    lua_State* L = lua_open();

    luaL_openlibs( L );
    luabind::open(L);

    module(L)
    [
        class_<GLfloat, GLfloatPtr >( "GLfloat" ),
        def( "floaty", floaty ),
        def( "givemefloat", givemefloat )
    ];

    const char *script =
        "vec = givemefloat( 4, 5, 6 )\n"
        "vec2 = vec -- Just for fun\n"
        "floaty( vec2 )\n";

    if( luaL_dostring( L, script ) )
        cout << lua_tostring( L, -1 ) << endl;

    lua_close( L );

    return 0;
}