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POHow to cast to it boost::bind(&myClass::fun, this, _1, _2, _3) to typedef void (*fun)(arg1, arg2, arg3)?
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copied!<p>In lib Bullet there is defined a type:</p> <pre><code>typedef void (*btNearCallback)(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo); </code></pre> <p>in there docs there is presented a <a href="http://www.bulletphysics.com/ftp/pub/test/physics/Bullet_User_Manual.pdf" rel="nofollow noreferrer">sample of usage (page 23)</a>:</p> <pre><code>void MyNearCallback(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo) { // Do your collision logic here // Only dispatch the Bullet collision information if you want the physics to continue dispatcher.defaultNearCallback(collisionPair, dispatcher, dispatchInfo); } </code></pre> <p>I copied this sample code into my class defention so my class got this function and I shall be capable to do such casts like:</p> <pre><code> dispatcher->setNearCallback(boost::bind(&BulletAPIWrapper::MyNearCallback, this, _1, _2, _3)); </code></pre> <p>instead of C like <code>dispatcher->setNearCallback(MyNearCallback);</code> from Bullet tutorial.</p> <p>Yet my VS2010 sp1 gives me an error:</p> <pre><code>Error 44 error C2664: 'btCollisionDispatcher::setNearCallback' : cannot convert parameter 1 from 'boost::_bi::bind_t<R,F,L>' to 'btNearCallback' </code></pre> <p>So I wonder how to cast boost::bind to such typedef?</p> <p>Is it possible having having static class function (or at least global function like):</p> <pre><code>void MyNearCallback(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo, BulletAPI* api) { } </code></pre> <p>call <code>dispatcher->setNearCallback( boost::bind(MyNearCallback, _1, _2, _3, this));</code></p> <p>because it results in nearly same error for me:</p> <pre><code>Error 44 error C2664: 'btCollisionDispatcher::setNearCallback' : cannot convert parameter 1 from 'boost::_bi::bind_t<R,F,L>' to 'btNearCallback' </code></pre> <p>I also tried <a href="https://stackoverflow.com/a/13238113/1973207">as described here</a>:</p> <pre><code>template<unsigned ID,typename Functor> boost::optional<Functor> &get_local() { static boost::optional<Functor> local; return local; } template<unsigned ID,typename Functor> typename Functor::result_type wrapper(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo) { return get_local<ID,Functor>().get()(collisionPair, dispatcher, dispatchInfo); } template<typename ReturnType> struct Func { typedef ReturnType (*type)(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo); }; template<unsigned ID,typename Functor> typename Func<typename Functor::result_type>::type get_wrapper(Functor f) { (get_local<ID,Functor>()) = f; return wrapper<ID,Functor>; } struct NearCallbackWrapper { class BulletAPI; void MyNearCallback(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo) { std::cout << "called" << std::endl; } }; //.... dispatcher->setNearCallback( get_wrapper<0>( boost::bind(&NearCallbackWrapper::MyNearCallback,this) ) ); </code></pre> <p>yet I got such error out from it:</p> <pre><code>error C2664: 'btCollisionDispatcher::setNearCallback' : cannot convert parameter 1 from 'void (__cdecl *)(btBroadphasePair &,btCollisionDispatcher &,const btDispatcherInfo &)' to 'btNearCallback' </code></pre>

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