个人中心
gpt4 book ai didi

c++ - 在多文件项目中正确#include SDL

转载 作者：行者123 更新时间：2023-11-30 02:25:52 25 4
gpt4 key购买 nike

<分区>

我刚刚开始使用 C++ 和 SDL，并且我已经开始创建一个基本的 Breakout 克隆来了解语义。为了模块化我目前拥有的内容，我创建了两个头文件 core.h 和 paddle.h。

我很难正确地将 SDL 包含在这些模块中。最初，项目编译时我只有主文件 breakout.cpp、paddle.h 和 paddle.cpp。在此阶段，“核心”类位于 breakout.cpp 中，当我将其迁移到自己的文件中时，编译器开始变得不安。

就目前而言，这是一个非常简单的设置，可以说明如下:

breakout ---> core ---> paddle

这让我相信我正在犯一个菜鸟疏忽。或者我在 Makefile 中错误地链接了文件。

代码如下:

突破.cpp

#include "SDL2/SDL.h"
#include "SDL2/SDL_image.h"
#include <stdio.h>
#include <string>
#include "core.h"

int main(int argc, char* args[]) {
    Core gCore;
    gCore.runGame();

    return 0;
}

核心.h

#pragma once

#include "paddle.h"

class Core {
public:
    Core();
    ~Core();
    void runGame();

private:
    static const int SCREEN_WIDTH = 640, SCREEN_HEIGHT = 480;

    SDL_Window* gWindow;
    SDL_Renderer* gRenderer;

    Paddle* p1;

    void render();
};

paddle.h

#pragma once

#include <string>

class Paddle {

    friend class Core;

public:
    Paddle( SDL_Renderer* gRenderer );
    ~Paddle();

    void free();

private:
    static const int VELOCITY = 5;
    int xPos, yPos, pWidth, pHeight;

    SDL_Texture* pSprite;
    SDL_Rect* pRect;

    bool loadFromFile( SDL_Renderer* gRenderer, std::string path );

    int getXPos();  int getYPos();
    int getWidth(); int getHeight();
};

核心.cpp

#include "SDL2/SDL.h"
#include "SDL2/SDL_image.h"
#include <stdio.h>
#include "paddle.h"
#include "core.h"

Core::Core() {

    // Set up SDL
    if ( SDL_Init( SDL_INIT_VIDEO ) < 0 ) {
        printf( "SDL could not initialise! SDL Error: %s\n", SDL_GetError() ); 
    }
    else {
        if ( !SDL_SetHint( SDL_HINT_RENDER_SCALE_QUALITY, "1" ) ) {
            printf( "Warning: Linear texture filtering not enabled!" );
        }
        else {
            gWindow = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT,
                                        SDL_WINDOW_SHOWN );
            if ( gWindow == NULL ) {
                printf( "Could not create window. SDL Error: %s\n", SDL_GetError() ); 
            }
            else {
                gRenderer = SDL_CreateRenderer( gWindow, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC );
                if ( gRenderer == NULL ) {
                    printf( "Renderer could not be created! SDL Error: %s\n", SDL_GetError() );
                }
                else {
                    // Initialise renderer colour
                    SDL_SetRenderDrawColor( gRenderer, 0xFF, 0xFF, 0xFF, 0xFF );

                    // Initialise PNG loading
                    int imgFlags = IMG_INIT_PNG;
                    if ( !( IMG_Init( imgFlags ) & imgFlags ) ) {
                        printf( "SDL_image could not be initialised! SDL_image Error: %s\n", IMG_GetError() );
                    }
                }
            }
        }
    }
}

Core::~Core() {
    SDL_DestroyRenderer( gRenderer );    gRenderer = NULL;
    SDL_DestroyWindow( gWindow );        gWindow = NULL;

    // Quit SDL subsystems
    IMG_Quit();
    SDL_Quit();
}

void Core::runGame() {
    // Main loop flag
    bool quit = false;

    // Event handler
    SDL_Event e;

    // p1 = new Paddle( gRenderer );

    while ( !quit ) {
        while( SDL_PollEvent( &e ) != 0 ) {
            //User requests quit
            if( e.type == SDL_QUIT ) {
                quit = true;
            }
        }

        // Clear screen
        SDL_SetRenderDrawColor( gRenderer, 0xFF, 0xFF, 0xFF, 0xFF );
        SDL_RenderClear( gRenderer );

        // Render game assets
        render();

        // Update screen
        SDL_RenderPresent( gRenderer );
    }   
}

void Core::render() {
    // Set rendering space and render to screen
    SDL_Rect pRenderQuad = { p1->xPos, p1->yPos, p1->pWidth, p1->pHeight };

    // Render to screen
    SDL_RenderCopy( gRenderer, p1->pSprite, NULL, &pRenderQuad );
}

paddle.cpp

#include "SDL2/SDL.h"
#include "SDL2/SDL_image.h"
#include <stdio.h>
#include <string>
#include "paddle.h"

Paddle::Paddle(SDL_Renderer* gRenderer) {

    xPos =   300;  yPos =    400;
    pWidth =   0;  pHeight =   0;

    loadFromFile( gRenderer, "paddle.png" );
}

Paddle::~Paddle() {
    free();
}

bool Paddle::loadFromFile(SDL_Renderer* gRenderer, std::string path) {
    // Get rid of preexisting texture
    free();

    SDL_Texture* nTexture = NULL;

    SDL_Surface* lSurface = IMG_Load( path.c_str() );
    if ( lSurface == NULL ) { printf( "Unable to load image %s! SDL_image Error: %s\n", path.c_str(), IMG_GetError() ); }
    else {
        nTexture = SDL_CreateTextureFromSurface( gRenderer, lSurface );
        if ( nTexture == NULL ) { printf( "Unable to load texture from %s! SDL Error: %s\n", path.c_str(), SDL_GetError() ); }
        else {
            pWidth = lSurface->w;
            pHeight = lSurface->h;
        }

        SDL_FreeSurface( lSurface ); // Surface no longer needed
    }

    pSprite = nTexture;
    return pSprite != NULL;
}

void Paddle::free() {
    if ( pSprite != NULL ) {
        SDL_DestroyTexture( pSprite );
        pWidth = 0; pHeight = 0;
    }
}

// Getter methods
int Paddle::getXPos() { return xPos; }      int Paddle::getYPos() { return yPos; }
int Paddle::getWidth() { return pWidth; }   int Paddle::getHeight() { return pHeight; }

我还包含了 Makefile，因为那里也很容易出错。

生成文件

OBJS = breakout.cpp
DEPS = paddle.h core.h

CC = g++

COMPILER_FLAGS = -w

LINKER_FLAGS = -lSDL2 -lSDL2_image

OBJ_NAME = breakout

%.o: %.cpp $(DEPS)
    $(CC) -c -o $@ $< $(COMPILER_FLAGS)

all : $(OBJS)
    $(CC) $(OBJS) $(COMPILER_FLAGS) $(LINKER_FLAGS) paddle.cpp core.cpp -o $(OBJ_NAME)

错误日志

g++ breakout.cpp -w -lSDL2 -lSDL2_image paddle.cpp core.cpp -o breakout
/tmp/cc0H2fKM.o: In function `Paddle::loadFromFile(SDL_Renderer*, std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
paddle.cpp:(.text+0x111): undefined reference to `IMG_Load'
paddle.cpp:(.text+0x121): undefined reference to `SDL_GetError'
paddle.cpp:(.text+0x15a): undefined reference to `SDL_CreateTextureFromSurface'
paddle.cpp:(.text+0x16a): undefined reference to `SDL_GetError'
paddle.cpp:(.text+0x1b8): undefined reference to `SDL_FreeSurface'
/tmp/cc0H2fKM.o: In function `Paddle::free()':
paddle.cpp:(.text+0x203): undefined reference to `SDL_DestroyTexture'
/tmp/ccDHGaLY.o: In function `Core::Core()':
core.cpp:(.text+0x12): undefined reference to `SDL_Init'
core.cpp:(.text+0x1e): undefined reference to `SDL_GetError'
core.cpp:(.text+0x44): undefined reference to `SDL_SetHint'
core.cpp:(.text+0x86): undefined reference to `SDL_CreateWindow'
core.cpp:(.text+0xa1): undefined reference to `SDL_GetError'
core.cpp:(.text+0xd1): undefined reference to `SDL_CreateRenderer'
core.cpp:(.text+0xee): undefined reference to `SDL_GetError'
core.cpp:(.text+0x127): undefined reference to `SDL_SetRenderDrawColor'
core.cpp:(.text+0x138): undefined reference to `IMG_Init'
core.cpp:(.text+0x149): undefined reference to `SDL_GetError'
/tmp/ccDHGaLY.o: In function `Core::~Core()':
core.cpp:(.text+0x17a): undefined reference to `SDL_DestroyRenderer'
core.cpp:(.text+0x195): undefined reference to `SDL_DestroyWindow'
core.cpp:(.text+0x1a5): undefined reference to `IMG_Quit'
core.cpp:(.text+0x1aa): undefined reference to `SDL_Quit'
/tmp/ccDHGaLY.o: In function `Core::runGame()':
core.cpp:(.text+0x1ea): undefined reference to `SDL_PollEvent'
core.cpp:(.text+0x218): undefined reference to `SDL_SetRenderDrawColor'
core.cpp:(.text+0x228): undefined reference to `SDL_RenderClear'
core.cpp:(.text+0x244): undefined reference to `SDL_RenderPresent'
/tmp/ccDHGaLY.o: In function `Core::render()':
core.cpp:(.text+0x2d1): undefined reference to `SDL_RenderCopy'
collect2: ld returned 1 exit status
make: *** [all] Error 1

我非常感谢您的支持，而不仅仅是手头的问题。但也可以对我的代码提出任何一般性建议。

谢谢

25 4 0
文章推荐： c++ - 如何用资源中没有的其他图像替换 QML (Qt) 文件中的图像
文章推荐： java - 将图像附加到 JLabel 的边框
文章推荐： c++如何访问父类中的函数？
文章推荐： c++ - 使用外部二进制资源
行者123
个人简介

我是一名优秀的程序员,十分优秀！

滴滴打车优惠券免费领取
滴滴打车优惠券
全站热门文章
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com