c++ - SDL 交叉 header 渲染

Question

注意:使用SDL 2.0，Cross header class问题

我在类之间进行交叉引用，主要是我的类初始化渲染器和我的纹理类引用渲染初始化。现在，我已经能够运行该程序，直到我开始放入纹理类，代码也来自单页代码，它也可以正常工作，我正要将我的代码实现到标题中以中断让它不那么困惑。

首先是 CApp.h。注意:RENDER 在 header 中

#ifndef _CAPP_H_
#define _CAPP_H_

#include <iostream>
#include <stdio.h>

#include <windows.h>

#include <random>
#include <time.h>
#include <string>
#include <cmath>

#include <fstream>

#include <SDL.h>
#include <SDL_image.h>

#include "Texture.h"

class CApp 
{
private:

    bool Running;
    SDL_Renderer* RENDER;
    SDL_Window* WINDOW;

public:

    CApp();
    int OnExecute();

    int SCREEN_WIDTH;   
    int SCREEN_HEIGHT;

    bool OnInit();
    void OnEvent(SDL_Event* Event);
    void OnLoop();
    void OnRender();
    void OnCleanup();
};
#endif

接下来是 CApp.cpp 并不重要，但以防万一

#include "CApp.h"



CApp::CApp()
{
    WINDOW = NULL;
    RENDER = NULL;

    Running = true;
}

int CApp::OnExecute()
{
    if(OnInit() == false)
    {
        return -1;
    }

    SDL_Event Event;

    while(Running)
    {
        while(SDL_PollEvent(&Event))
        {
            OnEvent(&Event);
        }

        OnLoop();
        OnRender();
    }

    OnCleanup();

    return 0;
}

int main(int argc, char* argv[])
{
    CApp theApp;

    return theApp.OnExecute();

    system("pause");
}

现在这是初始化所在的 CApp_OnInit.cpp，请注意第 27 行的 RENDER

#include "CApp.h"

bool CApp::OnInit()
{
    SCREEN_WIDTH = 1300;
    SCREEN_HEIGHT = 750;

    if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
    {
        printf( "INITFAIL 01\n", SDL_GetError() );
        return false;
    }
    else
    {       
        if( !SDL_SetHint( SDL_HINT_RENDER_SCALE_QUALITY, "1" ) )
        {
            printf( "INITFAIL 02/n!" );
        }       
        WINDOW = SDL_CreateWindow( "WINDOW", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );//|| SDL_WINDOW_FULLSCREEN_DESKTOP
        if( WINDOW == NULL )
        {
            printf( "INITFAIL 03\n", SDL_GetError() );
            return false;
        }
        else
        {   
            RENDER = SDL_CreateRenderer( WINDOW, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC );

            if( RENDER == NULL )
            {
                printf( "INITFAIL 04\n", SDL_GetError() );
                return false;
            }
            else
            {   
                SDL_SetRenderDrawColor( RENDER, 0xFF, 0xFF, 0xFF, 0xFF );
                int imgFlags = IMG_INIT_PNG;
                if( !( IMG_Init( imgFlags ) & imgFlags ) )
                {
                    printf( "INITFAIL 05\n", IMG_GetError() );
                    return false;
                }
            }

        }
    }

    return true;
}

Texture header Texture.h

#ifndef _TEXTURE_H_
#define _TEXTURE_H_

#include <SDL.h>
#include <string>

#include "CApp.h"

class TEXTURE
{
public:

    TEXTURE();
    ~TEXTURE();

    bool LOAD_TEXTURE(std::string path);

    void FREE();

    void RGB_TEXTURE(Uint8 red, Uint8 green, Uint8 blue);
    void BLENDMODE(SDL_BlendMode blend);
    void ALPHA(Uint8 alpha);    

    void RENDER_TEXTURE(double x , double y , SDL_Rect* clip = NULL, double angle = 30.0, SDL_Point* center = NULL, SDL_RendererFlip flip = SDL_FLIP_NONE);

    int getWidth();
    int getHeight();

private:    

    SDL_Texture* texture;   

    int imageWidth;
    int imageHeight;
};




#endif

现在是 Texture.cpp 问题的根源行中的RENDER是未声明的标识符
d1d = SDL_CreateTextureFromSurface(RENDER, e1e);

 #include "CApp.h"


TEXTURE::TEXTURE()
{
    texture = NULL;
    imageWidth = 0;
    imageHeight = 0;
}

TEXTURE::~TEXTURE()
{
    FREE();
}

bool TEXTURE::LOAD_TEXTURE(std::string path)
{
    FREE();

    SDL_Texture* d1d = NULL;
    SDL_Surface* e1e = IMG_Load(path.c_str());

    if( e1e == NULL)
    {
        printf("TEXTURE 01\n", path.c_str(), IMG_GetError());
    }
    else
    {
        SDL_SetColorKey(e1e, SDL_TRUE, SDL_MapRGB(e1e->format, 255, 0, 255));
        d1d = SDL_CreateTextureFromSurface(RENDER, e1e);

        if(d1d == NULL)
        {
            printf("TEXTURE 02\n", path.c_str(), SDL_GetError());
        }
        else
        {
            imageWidth = e1e->w;
            imageHeight = e1e->h;
        }
        SDL_FreeSurface(e1e);
    }
    texture = d1d;
    return texture != NULL;
}

我尝试了指向和双指向我只是无法将代码混搭工作。

Answer 1

当它是 CApp 类的成员时，您正尝试在 TEXTURE 类中使用 RENDER...

一个简单的解决方案是进行这些更改:

纹理.h

class TEXTURE
{
public:
    TEXTURE(SDL_Renderer* renderer);
    // [...]

private:
    // [...]
    SDL_Renderer* m_renderer;
};

纹理.cpp

TEXTURE::TEXTURE(SDL_Renderer* renderer)
    :   m_renderer(renderer),
        texture(NULL),
        imageWidth(0),
        imageHeight(0)
{
}

// [...]

bool TEXTURE::LOAD_TEXTURE(std::string path)
{
    // [...]
    d1d = SDL_CreateTextureFromSurface(m_renderer, e1e);
    // [...]
}

并且每次你创建一个TEXTURE对象时，你都用你的CApp类的RENDER成员构造它(例如通过使用getter ).

这应该可以解决您的依赖性问题。