Question

我是C ++和SDL的新手;我正在尝试使用此处的说明添加新的SDL扩展库：http://www.lazyfoo.net/SDL_tutorials/lesson03/windows/devcpp/index.php

但是我得到了这些错误：

3 C：\ Documents and Settings \ Edmund \ My Documents \ C ++ \ myprojects \ SDL \ SDLevent.cpp SDL / SDL_image.h：没有这样的文件或目录。

C：\ Documents and Settings \ Edmund \ My Documents \ C ++ \ myprojects \ SDL \ SDLevent.cpp在函数`SDL_Surface * load_image（std :: string）'：

28 C：\ Documents and Settings \ Edmund \ My Documents \ C ++ \ myprojects \ SDL \ SDLevent.cpp`IMG_Load'unclaclared（首次使用此功能）

然后是一堆不合格的ID。

这是我的代码：

#include "SDL/SDL.h"
#include "SDL/SDL_image.h"

#include <string>

//Screen attributes
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
const int SCREEN_BPP = 32;

//The surfaces
SDL_Surface *image = NULL;
SDL_Surface *screen = NULL;

//The event structure that will be used
SDL_Event event;

SDL_Surface *load_image( std::string filename ) 
{
    //The image that's loaded
    SDL_Surface* loadedImage = NULL;

    //The optimized image that will be used
    SDL_Surface* optimizedImage = NULL;

    //Load the image
    loadedImage = IMG_Load( filename.c_str() );

    //If the image loaded
    if( loadedImage != NULL )
    {
        //Create an optimized image
        optimizedImage = SDL_DisplayFormat( loadedImage );

        //Free the old image
        SDL_FreeSurface( loadedImage );
    }

    //Return the optimized image
    return optimizedImage;
}

void apply_surface( int x, int y, SDL_Surface* source, SDL_Surface* destination )
{
    //Temporary rectangle to hold the offsets
    SDL_Rect offset;

    //Get the offsets
    offset.x = x;
    offset.y = y;

    //Blit the surface
    SDL_BlitSurface( source, NULL, destination, &offset );
}

bool init()
{
    //Initialize all SDL subsystems
    if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 )
    {
        return false;    
    }

    //Set up the screen
    screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE );

    //If there was an error in setting up the screen
    if( screen == NULL )
    {
        return false;    
    }

    //Set the window caption
    SDL_WM_SetCaption( "Event test", NULL );

    //If everything initialized fine
    return true;
}

bool load_files()
{
    //Load the image
    image = load_image( "astyle.bmp" );

    //If there was an error in loading the image
    if( image == NULL )
    {
        return false;    
    }

    //If everything loaded fine
    return true;    
}

void clean_up()
{
    //Free the image
    SDL_FreeSurface( image );

    //Quit SDL
    SDL_Quit();    
}

   //Initialize
    if( init() == false )
    {
        return 1;    
    }

    //Load the files
    if( load_files() == false )
    {
        return 1;    
    }

//Apply the surface to the screen
    apply_surface( 0, 0, image, screen );

    //Update the screen
    if( SDL_Flip( screen ) == -1 )
    {
        return 1;    
    }

 //While the user hasn't quit
    while( quit == false )
    {

 //While there's an event to handle
        while( SDL_PollEvent( &event ) )
        {

    //If the user has Xed out the window
            if( event.type == SDL_QUIT )
            {
                //Quit the program
                quit = true;
            }    
        }
    }

 //Free the surface and quit SDL
    clean_up();

    return 0;    
}

它与教程中的内容完全相同，因此它不应该是代码的问题。我已经按照Lazy foo上的说明写了这封信，我把所有文件放在正确的位置并链接到它们，所以我不知道我做错了什么。

Answer 1

您的编译器找不到SDL/SDL_image.h标头，导致所有这些“未申报”错误。

也许您在链接说明中跳过了Step 2。

Answer 2

你应该使用

#include "SDL.h"
#include "SDL_image.h"

并确保已将sdl include文件夹放在include目录中

Answer 3

你确定你有SDL_Image功能吗？你在用什么IDE？如果它的视觉工作室确保您已链接以下内容：

Linker Input

还要确保已从http://www.libsdl.org/projects/SDL_image/

下载了最新的SDL_Image文件

另一个可能的问题是您没有将SDL_Image DLL文件放在正确的位置。

为什么SDL_image不起作用

3 个答案: