我正在尝试使用 SFML 库在 C++ 中制作一个在屏幕上移动的角色。 每次制作项目时,我都会遇到相同的 LNK 2001 错误。
请向我解释我做错了什么以及我该如何解决。我仍然是初学者,所以如果您有任何关于修复错误或编写代码的建议,我会非常乐意。
main.cpp :
#include "Game.cpp"
#include "Game.h"
int main ()
{
Game Game;
Game.GameRun();
}
游戏.h:
#pragma once
#include <SFML\Window.hpp>
#include "Character.h"
class Game
{
public:
void GameRun ();
void UpdateGame(Character player);
void Controls(int sourceX, int sourceY, Character player);
};
Character.h:
#pragma once
#include <SFML\Graphics.hpp>
#include <SFML\System.hpp>
#include <SFML\Window.hpp>
#include "Game.h"
class Character
{
public:
enum Direction {Down, Left, Right, Up};
int characterX;
int characterY;
sf::Texture txt_character;
sf::Sprite spr_character;
};
游戏.cpp:
#include "Game.h"
#include "Character.h"
#include <iostream>
inline void Game::GameRun()
{
sf::RenderWindow window(sf::VideoMode(800, 600), "SFML test");
Character player;
player.characterX = 1;
player.characterY = Character::Down;
player.txt_character.loadFromFile("character sprite sheet.png");
player.spr_character.setTexture(player.txt_character);
while(window.isOpen())
{
Game::UpdateGame(player);
}
}
inline void Game::UpdateGame(Character player)
{
sf::Event event;
sf::RenderWindow window(sf::VideoMode(800, 600), "SFML test");
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed)
window.close();
}
Game::Controls(player.characterX, player.characterY, player);
player.spr_character.setTextureRect(sf::IntRect(player.characterX * 32, player.characterY * 32, 32, 32));
window.draw(player.spr_character);
window.display();
window.clear();
}
inline void Game::Controls(int sourceX, int sourceY, Character player)
{
if (sf::Keyboard::isKeyPressed(sf::Keyboard::W))
{
sourceY = Character::Up;
sourceX++;
if (sourceX * 32 >= player.txt_character.getSize().x)
sourceX = 0;
player.spr_character.move(0, -2);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::S))
{
sourceY = Character::Down;
sourceX++;
if (sourceX * 32 >= player.txt_character.getSize().x)
sourceX = 0;
player.spr_character.move(0, 2);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::A))
{
sourceY = Character::Left;
sourceX++;
if (sourceX * 32 >= player.txt_character.getSize().x)
sourceX = 0;
player.spr_character.move(-2, 0);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::D))
{
sourceY = Character::Right;
sourceX++;
if (sourceX * 32 >= player.txt_character.getSize().x)
sourceX = 0;
player.spr_character.move(2, 0);
}
}
错误:
1>main.obj:错误 LNK2001:未解析的外部符号“public:static int Character::characterY”(?characterY@Character@@2HA)
1>main.obj:错误 LNK2001:未解析的外部符号“public:static int Character::characterX”(?characterX@Character@@2HA)
1>C:\Users\SONY\Documents\Visual Studio 2010\Projects\Top Down Game\Debug\Game.exe : fatal error LNK1120: 2 unresolved externals
谢谢:D
编辑:仅供引用,我有没有类的代码并且它工作得很好,它只是 main.cpp 中的一大块代码
编辑:程序文件夹链接:https://www.dropbox.com/s/3yyjti8zwu019s7/Top%20Down%20Game%20With%20Classes.rar
最佳答案
编辑 2014/03/08: 我尝试了您的来源。删除 #include "Game.cpp"
在Main.cpp
里面文件和 inline
Game.cpp
中的关键字文件。
背后的逻辑不起作用,所以我对其进行了最低限度的修复,以便在修复编译(链接)错误后立即运行。您应该尝试我的代码,看看它是否有开箱即用的帮助。
先解释一下
按值传递播放器对象(当您有 void someMethod(Character player)
时)会将对象的拷贝发送到方法。因此,当您对播放器对象进行更改时,这些更改只会对拷贝进行,而不会对实际播放器进行更改。我更改了您的代码,因此它改为发送一个指针 ( void someMethod(Character * player)
。该方法接收指向实际播放器对象的指针,对该对象所做的更改反射(reflect)在实际播放器对象上。
除了使用指针(有些人可能会说这太过分或太危险)之外,还有几个解决方案。
它可以代替:
- 引用
void someMethod(Character& player)
- 或返回值
Character someMethod(Character player)
- 或两者的混合
Character someMethod(const Character& player)
- 或者一个成员变量(定义在头文件中)
另一件事是您在 Character 类中按值保留一个 sf::Texture。 sf::Texture 是真正的“重”对象,所以它们不应该按值传递,应该作为指针保存。你能做的最好的事情(我没有在下面的代码中做)是从 Character 类中完全删除 sf::Texture 并且只保留已经包含 sf::Texture 的 sf::Sprite(在一种优化的方式,因此您不必为此烦恼)。
这是代码
main.cpp
#include "Game.h"
int main ()
{
Game Game;
Game.GameRun();
}
游戏.h
#ifndef GAME_H_
#define GAME_H_
//#include <SFML/Window.hpp> /* you don't need this */
#include <SFML/Graphics/RenderWindow.hpp>
// forward declaration, this prevents recursive/circular dependencies.
// only works with pointer or referenced type.
class Character;
class Game
{
public:
void GameRun ();
// I change the param to pointer to Character for logic reasons.
// You were doing changes on a Character COPY of the player,
// which was deleted when leaving the scope of the functions.
void UpdateGame(Character * player);
void Controls(Character * player);
private:
// I added this here, so you can create the window in the
// GameRun and UpdateGame methods where needed.
sf::RenderWindow window;
};
#endif
游戏.cpp
#include "Game.h"
#include "Character.h"
#include <SFML/Window/Event.hpp> /* you only need this */
#include <iostream>
void Game::GameRun()
{
// I moved the window creation here because you were
// creating a new window each update which made the windows
// flickers each frame, making it impossible to close properly.
window.create(sf::VideoMode(800, 600), "SFML test");
Character * player = new Character();
player->characterX = 1;
player->characterY = Character::Down;
// if the file isn't available, this will prevent further problems.
if (player->txt_character.loadFromFile("character.png"))
{
player->spr_character.setTexture(player->txt_character);
}
while (window.isOpen())
{
Game::UpdateGame(player);
}
}
void Game::UpdateGame(Character * player)
{
sf::Event event;
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed){
window.close();
}
}
Controls(player);
// player.spr_character.setTextureRect(
// sf::IntRect(player.characterX * 32, player.characterY * 32, 32,
// 32));
window.clear();
window.draw(player->spr_character);
window.display();
}
// You were already sending the player so I removed the other
// params and used the player instead.
void Game::Controls(Character * player)
{
int sourceX = player->characterX;
if (sf::Keyboard::isKeyPressed(sf::Keyboard::W))
{
player->characterY = Character::Up;
sourceX++;
if (sourceX * 32 >= player->txt_character.getSize().x)
sourceX = 0;
player->spr_character.move(0, -2);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::S))
{
player->characterY = Character::Down;
sourceX++;
if (sourceX * 32 >= player->txt_character.getSize().x)
sourceX = 0;
player->spr_character.move(0, 2);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::A))
{
player->characterY = Character::Left;
sourceX++;
if (sourceX * 32 >= player->txt_character.getSize().x)
sourceX = 0;
player->spr_character.move(-2, 0);
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::D))
{
player->characterY = Character::Right;
sourceX++;
if (sourceX * 32 >= player->txt_character.getSize().x)
sourceX = 0;
player->spr_character.move(2, 0);
}
player->characterX = sourceX;
}
Character.h
#ifndef CHARACTER_H_
#define CHARACTER_H_
//#include <SFML\Graphics.hpp>
//#include <SFML\System.hpp>
//#include <SFML\Window.hpp>
//#include "Game.h"
#include <SFML/Graphics/Sprite.hpp> /* Don't include more than you need */
#include <SFML/Graphics/Texture.hpp>
class Character
{
public:
enum Direction {Down, Left, Right, Up};
int characterX;
int characterY;
sf::Texture txt_character; // Don't keep the texture value, it's really heavy.
sf::Sprite spr_character;
};
#endif
一般 C++ 信息
- What's the difference between passing by reference vs. passing by value?
- When to use forward declaration?
- 可选 What causes the need to forward declare types.
- What are the differences between pointer variable and reference variable in C++?
- 可选 In depth explanations of pointers
- 可选 Why is “using namespace std;” considered bad practice?
关于c++ - 使用 C++ SFML Unresolved LNK 2001,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22236632/