Question

我试图制作某种引擎＆＃39;用C ++ / SDL。所以我遵循了LazyFoo的教程并搜索了其他地方/视频[SDL / C ++]。一切都很好，直到我在2个类中组织我的代码。它只是Game.h / Game.cpp和main.cpp，但我认为将加载和破坏Surfaces / Textures（Game类）的Game类加载Image的代码部分分开是很好的。

所以我将代码复制/粘贴到另一个类。我复制/粘贴的是两个布尔函数textureBMP和textureIMG一切都保持不变。在我将代码复制/粘贴到另一个类之前，一切都运行正常，所以我不知道是什么造成的。

另一个小问题是，我以正确的方式组织代码的方式是什么？我想在一开始就养成良好的习惯，即使是小项目，比如这个小项目只是为了学习。提前谢谢！

image.h的

#pragma once
#include "Game.h"

class Image
{
public:
    Image();
    ~Image();

    Game game;

    SDL_Surface *gBMP = NULL;
    SDL_Texture *tBMP = NULL;
    SDL_Surface *gIMG = NULL;
    SDL_Texture *tIMG = NULL;

    bool textureBMP(char *mediaLocation, bool SetColorKey, int red, int green, int blue);
    bool textureIMG(char *mediaLocation, int imgFlags);
};

Image.cpp

#include "Image.h"

Image::Image()
{
}


Image::~Image()
{
}

bool Image::textureBMP(char *mediaLocation, bool SetColorKey, int red, int green, int blue) {

    gBMP = SDL_LoadBMP(mediaLocation);

    if (gBMP == NULL) {
        printf("Nao foi possivel carregar a imagem %s,por causa do seguinte erro: \n %s \n", mediaLocation, SDL_GetError());
        return false;
    }
    else {

        if (SetColorKey) {

            SDL_SetColorKey(gBMP, 1, SDL_MapRGB(gBMP->format, red, green, blue));

        }

        tBMP = SDL_CreateTextureFromSurface(game.renderer, gBMP);
        SDL_FreeSurface(gBMP);

    }

    return true;
}

bool Image::textureIMG(char *mediaLocation, int imgFlags) {

    if (!(IMG_Init(imgFlags) & imgFlags)) {

        printf("SDL_image não pode ser inicializada! SDL_image Error: %s\n", IMG_GetError());
        return false;
    }
    else {

        gIMG = IMG_Load(mediaLocation);
        tIMG = SDL_CreateTextureFromSurface(game.renderer, gIMG);
        SDL_FreeSurface(gIMG);

    }

    return true;
}

Game.h

#pragma once
#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#include <string>

class Game
{

public:

    const int SCREEN_WIDTH = 800;
    const int SCREEN_HEIGHT = 600;

    bool running;

    SDL_Event event;

    SDL_Window *gWindow = NULL;
    SDL_Renderer *renderer = NULL;
    SDL_Surface *gScreenSurface = NULL;

    Game();
    ~Game();

    bool initEngine(char *windowName);

    void freeSurface(SDL_Surface *surfaceName);
    void freeTexture(SDL_Texture *textureName);
    void destroyRenderer();
    void destroyWindow();

};

Game.cpp

#include "Game.h"

Game::Game()
{
}


Game::~Game()
{
}

bool Game::initEngine(char *windowName) {

    bool initSucess = true;

    if (SDL_Init(SDL_INIT_VIDEO) < 0) {

        printf("A Engine não foi iniciada pelo seguinte erro: \n %s \n", SDL_GetError());
        initSucess = false;
        return initSucess;
    }
    else {

        gWindow = SDL_CreateWindow(windowName, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
        renderer = SDL_CreateRenderer(gWindow, -1, SDL_RENDERER_ACCELERATED);

        if (gWindow == NULL) {

            printf("A janela não pode ser criada pelo seguinte erro: \n %s \n", SDL_GetError());
            initSucess = false;
            return initSucess;

        }
        else {

            gScreenSurface = SDL_GetWindowSurface(gWindow);

        }

    }


    return initSucess;
}

void Game::freeSurface(SDL_Surface *surfaceName) {

    SDL_FreeSurface(surfaceName);
    surfaceName = NULL;

}

void Game::freeTexture(SDL_Texture *textureName) {

    SDL_DestroyTexture(textureName);
    textureName = NULL;

}

void Game::destroyRenderer() {

    SDL_DestroyRenderer(renderer);
    renderer = NULL;

}

void Game::destroyWindow() {

    SDL_DestroyWindow(gWindow); 
    gWindow = NULL;

}

的main.cpp

#include <iostream>
#include <SDL.h>
#include "Game.h"
#include "Image.h"

int main(int argc, char* args[]) {

    Game game;
    Image img;

    if (!game.initEngine("TESTE")) {
        printf("Falha ao iniciar! \n");
        return 0;
    }

    game.running = true;

    if (!img.textureBMP("res/bouncingball.bmp", true, 255, 0, 255))
        printf("Falha ao iniciar imagem!\n");

    if (!img.textureIMG("res/Tulips.jpg", IMG_INIT_JPG))
        printf("Falha ao iniciar imagem! \n");

    SDL_Rect stretchRect{ (game.SCREEN_WIDTH / 2) - 50, (game.SCREEN_HEIGHT / 2) - 50, 100, 100 };

    SDL_Rect stretchRect2{ 0, 0, game.SCREEN_WIDTH, game.SCREEN_HEIGHT };

    while (game.running) {

        while (SDL_PollEvent(&game.event) != 0) {

            switch (game.event.type) {

            case SDL_QUIT:

                game.running = false;
                game.freeSurface(game.gScreenSurface);
                game.freeTexture(img.tBMP);
                game.freeTexture(img.tIMG);
                game.destroyRenderer();
                game.destroyWindow();
                IMG_Quit();
                SDL_Quit();
                break;

            }//Switch Event END


        } // PollEvent END

        SDL_RenderCopy(game.renderer, img.tIMG, nullptr, &stretchRect2);
        SDL_RenderCopy(game.renderer, img.tBMP, nullptr, &stretchRect);
        SDL_RenderPresent(game.renderer);

        SDL_GL_SetSwapInterval(1);

    }// game.running END

    return 0;
}

PrintScreen of the Output

Answer 1

我做了一些更改，现在它正常工作了。我改变了两件事，第一件是给出黑屏的部分，现在功能看起来像这样：

image.h的

bool textureBMP(char *mediaLocation, <...>, SDL_Renderer *render);
bool textureIMG(char *mediaLocation, <...>, SDL_Renderer *render);

的main.cpp

if (!img.textureIMG("res/Tulips.jpg", IMG_INIT_JPG, game.renderer))

另一个变化是，在Image.h包含Game.h之前，在main.cpp中我包含Game.h和Image.h，这会产生错误吗？因为https://en.wikipedia.org/wiki/Include_guard

Obs：我创建了一个答案，因为评论不允许代码

SDL / C ++（加速）黑屏

1 个答案: