没有匹配函数来调用spriteSheet :: spriteSheet()'

时间:2016-02-14 00:15:53

标签: c++ sdl sdl-2

我最近开始学习C ++,而且我已经暂时停留在这个错误上了一段时间。寻找类似的问题并没有给我一个答案。

main.cpp的一部分:

#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#include <string>
#include "spritesheet.h"
using namespace std;

spriteSheet charimage("../img/char.png");
spriteSheet bgimage("../img/bg.png");

class playerSprite
{
    public:
        playerSprite(int xpos, int ypos, spriteSheet sheet);

        int pos[2]; // player postition
        spriteSheet image;
};

playerSprite::playerSprite(int xpos, int ypos, spriteSheet sheet)
{
    pos[0] = xpos;
    pos[1] = ypos;
    image = sheet;
}

playerSprite player(0, 0, charimage);

spritesheet.h:

#ifndef LTEXTURE_H
#define LTEXTURE_H
using namespace std;

extern SDL_Renderer* screen;

class spriteSheet //Texture wrapper for all game objects
{
    SDL_Texture* sheet;
    SDL_Rect ssize;

    public:
        spriteSheet(string path);
        ~spriteSheet();
        void setClip(int x = 0, int y = 0, int w = 0, int h = 0);
        void render(int x = 0, int y = 0);
        void free();

        SDL_Rect sclip;

};

#endif // LTEXTURE_H

spritesheet.cpp的一部分:

#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#include <string>
#include "spritesheet.h"
using namespace std;

spriteSheet::spriteSheet(string path)
{
    SDL_Texture* newTexture = NULL;
    SDL_Surface* loadedSurface = IMG_Load(path.c_str());

    if(loadedSurface == NULL)
    {
        cout << IMG_GetError() << endl;
    }
    else
    {
        newTexture = SDL_CreateTextureFromSurface(screen, loadedSurface);
        if(newTexture == NULL)
        {
            cout << SDL_GetError() << endl;
        }
        else
        {
            ssize.w, sclip.w = loadedSurface->w;
            ssize.h, sclip.h = loadedSurface->h;
        }
        SDL_FreeSurface(loadedSurface);
    }
    sheet = newTexture;
}

当我构造我的playerSprite对象时,我想为它传入一个spriteSheet对象。我已经通过使用像playerSprite :: setSheet()和spriteSheet :: setImage()这样的函数来编译这些代码,但是我无法让它与构造函数一起工作。每次我尝试编译时都会收到此错误:

C:\Users\Platino\Documents\C++\Dragorogue\main.cpp  In constructor 'playerSprite::playerSprite(int, int, spriteSheet)':
20  65  C:\Users\Platino\Documents\C++\Dragorogue\main.cpp  [Error] no matching function for call to 'spriteSheet::spriteSheet()'
20  65  C:\Users\Platino\Documents\C++\Dragorogue\main.cpp  [Note] candidates are:
5   0   C:\Users\Platino\Documents\C++\Dragorogue\main.cpp  In file included from main.cpp
13  3   C:\Users\Platino\Documents\C++\Dragorogue\spritesheet.h [Note] spriteSheet::spriteSheet(std::string)
13  3   C:\Users\Platino\Documents\C++\Dragorogue\spritesheet.h [Note] candidate expects 1 argument, 0 provided
7   7   C:\Users\Platino\Documents\C++\Dragorogue\spritesheet.h [Note] spriteSheet::spriteSheet(const spriteSheet&)
7   7   C:\Users\Platino\Documents\C++\Dragorogue\spritesheet.h [Note] candidate expects 1 argument, 0 provided

编辑:

LogicStuff建议的方法会强制我在每次构造一个新的playerSprite对象时初始化一个新的SpriteSheet对象。我想创建一个SpriteSheet对象,让所有的playerSprite对象都使用它。

1 个答案:

答案 0 :(得分:0)

由于您的spriteSheet对象没有默认构造函数,因此问题是spriteSheet类中有一个playerSprite成员,需要使用一个参数构造。该成员是image

class spriteSheet 
{
        spriteSheet(string path);  // <-- This is your constructor
};

class playerSprite
{
    public:
        playerSprite(int xpos, int ypos, spriteSheet sheet);  
        spriteSheet image;  // <-- This member has to be initialized on construction.
};

构建playerSprite时,必须初始化spriteSheet成员。初始化image成员的唯一方法是在成员初始化列表中使用一个参数构造它:

playerSprite::playerSprite(int xpos, int ypos, spriteSheet sheet) :
                           image("somestring") 
{
  //...
}

注意 - 构造函数体内的代码({ }之间)是不是初始化。这是任务 - 一个很大的不同。要初始化,必须使用成员初始化列表。

此外,您应该通过const引用传递spriteSheet,而不是通过值传递:

playerSprite::playerSprite(int xpos, int ypos, const spriteSheet& sheet) :
                           image("somestring") 
{
   image = sheet;  // now we can assign.
}

进入构造函数后,您就可以对成员进行分配:

Here is a small sample