GLM :: ivec2는

Question

요즘 내가 더 오전 ++ C보다 스칼라 프로그래밍 언어의 사용자, 그리고 지금은 코드의 아주 간단한 라인을 이식의 좌절은

val map = new HashMap[Vec2i,Entity] 

단순히 거부 이상한 템플릿 오류로 C++로 컴파일하십시오. C++의 Vec2i와 같은 기능은 glm :: ivec2이며, 기본적으로 두 개의 정수가있는 구조체와 수학 연산을위한 구조체입니다.

#include <iostream> 
#include <unordered_map> 
#include <glm/glm.hpp> 

using namespace std; 
using namespace glm; 

struct KeyTraits { 
size_t operator()(const ivec2& k) { 
     return std::hash<int>()(k.x)^std::hash<int>()(k.y); 
    } 

bool operator()(const ivec2& a, const ivec2& b) { 
     return a.x == b.x && a.y == b.y; 
    } 
}; 

typedef unordered_map<ivec2,int,KeyTraits,KeyTraits> MyMap; 

int main(int argc, char **argv) 
{ 
    MyMap map; 

    map[ivec2(2,3)] = 7; 
    map[ivec2(3,4)] = 8; 

    for(auto it = map.begin(); it != map.end(); it++) { 
     cout << it->second << endl; 
    } 
} 

현재 컴파일 오류는 다음과 같습니다 :

이 내가 가지고 얼마나 멀리

In file included from /usr/include/c++/4.5/bits/hashtable.h:35:0, 
      from /usr/include/c++/4.5/unordered_map:45, 
      from /home/arne/codelite/LanguageTest/main.cpp:2: 
/usr/include/c++/4.5/bits/hashtable_policy.h: In member function ‘std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_Hash_code_type std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_M_hash_code(const _Key&) const [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_Hash_code_type = long unsigned int]’: 
/usr/include/c++/4.5/bits/hashtable_policy.h:535:74: instantiated from ‘std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type& std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::operator[](const _Key&) [with _Key = glm::detail::tvec2<int>, _Pair = std::pair<const glm::detail::tvec2<int>, int>, _Hashtable = std::_Hashtable<glm::detail::tvec2<int>, std::pair<const glm::detail::tvec2<int>, int>, std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, KeyTraits, KeyTraits, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, false, false, true>, std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type = int]’ 
/home/arne/codelite/LanguageTest/main.cpp:24:16: instantiated from here 
/usr/include/c++/4.5/bits/hashtable_policy.h:727:25: error: passing ‘const KeyTraits’ as ‘this’ argument of ‘size_t KeyTraits::operator()(const glm::core::type::ivec2&)’ discards qualifiers 
/usr/include/c++/4.5/bits/hashtable_policy.h: In member function ‘bool std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_M_compare(const _Key&, std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_Hash_code_type, std::__detail::_Hash_node<_Value, false>*) const [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_Hash_code_type = long unsigned int]’: 
/usr/include/c++/4.5/bits/hashtable.h:879:2: instantiated from ‘std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Node* std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_M_find_node(std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Node*, const key_type&, typename std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Hash_code_type) const [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _Allocator = std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, _Hash = std::__detail::_Default_ranged_hash, _RehashPolicy = std::__detail::_Prime_rehash_policy, bool __cache_hash_code = false, bool __constant_iterators = false, bool __unique_keys = true, std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Node = std::__detail::_Hash_node<std::pair<const glm::detail::tvec2<int>, int>, false>, key_type = glm::detail::tvec2<int>, typename std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Hash_code_type = long unsigned int]’ 
/usr/include/c++/4.5/bits/hashtable_policy.h:540:53: instantiated from ‘std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type& std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::operator[](const _Key&) [with _Key = glm::detail::tvec2<int>, _Pair = std::pair<const glm::detail::tvec2<int>, int>, _Hashtable = std::_Hashtable<glm::detail::tvec2<int>, std::pair<const glm::detail::tvec2<int>, int>, std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, KeyTraits, KeyTraits, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, false, false, true>, std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type = int]’ 
/home/arne/codelite/LanguageTest/main.cpp:24:16: instantiated from here 
/usr/include/c++/4.5/bits/hashtable_policy.h:742:48: error: passing ‘const KeyTraits’ as ‘this’ argument of ‘bool KeyTraits::operator()(const glm::core::type::ivec2&, const glm::core::type::ivec2&)’ discards qualifiers 
/usr/include/c++/4.5/bits/hashtable_policy.h: In member function ‘size_t std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, std::__detail::_Default_ranged_hash, false>::_M_bucket_index(const std::__detail::_Hash_node<_Value, false>*, size_t) const [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, size_t = long unsigned int]’: 
/usr/include/c++/4.5/bits/hashtable.h:1170:59: instantiated from ‘void std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_M_rehash(std::_Hashtable::size_type) [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _Allocator = std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, _Hash = std::__detail::_Default_ranged_hash, _RehashPolicy = std::__detail::_Prime_rehash_policy, bool __cache_hash_code = false, bool __constant_iterators = false, bool __unique_keys = true, std::_Hashtable::size_type = long unsigned int]’ 
/usr/include/c++/4.5/bits/hashtable.h:911:8: instantiated from ‘std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::iterator std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_M_insert_bucket(const value_type&, std::_Hashtable::size_type, typename std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Hash_code_type) [with _Key = glm::detail::tvec2<int>, _Value = std::pair<const glm::detail::tvec2<int>, int>, _Allocator = std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, _ExtractKey = std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, _Equal = KeyTraits, _H1 = KeyTraits, _H2 = std::__detail::_Mod_range_hashing, _Hash = std::__detail::_Default_ranged_hash, _RehashPolicy = std::__detail::_Prime_rehash_policy, bool __cache_hash_code = false, bool __constant_iterators = false, bool __unique_keys = true, std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::iterator = std::__detail::_Hashtable_iterator<std::pair<const glm::detail::tvec2<int>, int>, false, false>, value_type = std::pair<const glm::detail::tvec2<int>, int>, std::_Hashtable::size_type = long unsigned int, typename std::_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, __cache_hash_code, __constant_iterators, __unique_keys>::_Hash_code_type = long unsigned int]’ 
/usr/include/c++/4.5/bits/hashtable_policy.h:543:24: instantiated from ‘std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type& std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::operator[](const _Key&) [with _Key = glm::detail::tvec2<int>, _Pair = std::pair<const glm::detail::tvec2<int>, int>, _Hashtable = std::_Hashtable<glm::detail::tvec2<int>, std::pair<const glm::detail::tvec2<int>, int>, std::allocator<std::pair<const glm::detail::tvec2<int>, int> >, std::_Select1st<std::pair<const glm::detail::tvec2<int>, int> >, KeyTraits, KeyTraits, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, false, false, true>, std::__detail::_Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>::mapped_type = int]’ 
/home/arne/codelite/LanguageTest/main.cpp:24:16: instantiated from here 
/usr/include/c++/4.5/bits/hashtable_policy.h:737:55: error: passing ‘const KeyTraits’ as ‘this’ argument of ‘size_t KeyTraits::operator()(const glm::core::type::ivec2&)’ discards qualifiers 

Answer 1

typedef에 해시 클래스와 비교기 클래스를 지정해야합니다. 여기 참조 템플릿 PARAMS 해시 및 KeyEqual : http://en.cppreference.com/w/cpp/container/unordered_map

이 (메소드 서명의 끝 부분에 CONST 예선을 고려) 그 모양을 다음 있기 때문에, 내 문제가 조금 변경

struct KeyFuncs 
{ 
    size_t operator()(const ivec2& k)const 
    { 
     return std::hash<int>()(k.x)^std::hash<int>()(k.y); 
    } 

    bool operator()(const ivec2& a, const ivec2& b)const 
    { 
      return a.x == b.x && a.y == b.y; 
    } 
}; 


typedef unordered_map<ivec2,int,KeyFuncs,KeyFuncs> MyMap; 

Answer 2

그냥 당신이 구현하거나 목록에 제공해야하는지 당신을 알려줍니다, 링커 오류보고 템플릿 인수 :

std::hash<glm::detail::tvec2<int> >::operator()(glm::detail::tvec2<int>) const 

프로그램은 벡터를 기반으로 해시를 만드는 방법을 모릅니다. 목적. 지도 코드가 벡터를 구별 할 수 있도록 자신 만의 해시를 계산해야합니다.

편집 : 벡터에 대한 포인터를 사용하는 경향이 있습니다. 일부 요소를 추가하고 나중에 변경하면 (const 개체를 추가해야 함)이 문제가 발생할 수 있습니다.

---

편집 2 : 당신이 그들의 this 포인터 타입 KeyTraits*이다, 그래서 KeyTaits const를 내부의 방법을 잊어 버렸 같은 업데이트 된 코드/오류 메시지와 함께 , 그것은 보이지만, 전달 된 값은 const KeyTraits* 될 것을 의미한다 .