SDL学习入门



1、搭建开发平台
    （1）sudo apt-get install libsdl1.2-dev
        最基本的开发包
    （2）sudo apt-get install libsdl-image1.2-dev
        关于图像的开发包
    （3）sudo apt-get install libsdl-mixer1.2-dev
        关于音频的开发包
    （4）sudo apt-get install libsdl-ttf2.0-dev
        关于文字的开发包
    安装好以上四个开发包，开发平台算是搭建好了
    
2、最有代表性的简单程序，包括图像，文字，音乐，注释如下：

[cpp] view plaincopyprint?

1. #include <stdio.h>  
2. #include <stdlib.h>  
3. #include <SDL/SDL.h>  
4. #include <SDL/SDL_image.h>  
5. #include <SDL/SDL_mixer.h>  
6. #include <SDL/SDL_ttf.h>  
7.   
8. static SDL_Surface* screen;//SDL窗口  
9.   
10. int main(int argc, char *argv[])  
11. {  
12.   
13.     int quit = 0;  
14.     SDL_Surface *text_sur;//文字容器  
15.     SDL_Surface *background;//图像容器  
16.     SDL_Event event;  
17.     SDL_Color color;  
18.     SDL_Rect srect, drect;  
19.     Mix_Music *bgsound;  
20.     TTF_Font *font;  
21.       
22.     //初始化SDL  
23.     if (SDL_Init(SDL_INIT_VIDEO||SDL_INIT_AUDIO) < 0)  
24.     {  
25.         fprintf(stderr, "SDL init error:%s\n", SDL_GetError());  
26.         exit(0);  
27.     }  
28.     atexit(SDL_Quit);//注册退出时调用的操作  
29.       
30.       
31.     //设置SDL屏幕大小  
32.     screen = SDL_SetVideoMode(600, 400, 24, SDL_HWSURFACE);  
33.     if (screen == NULL)  
34.     {  
35.         fprintf(stderr, "Set video mode failure:%s\n", SDL_GetError());  
36.         exit(0);  
37.     }  
38.       
39.     //设置SDL窗口标题  
40.     SDL_WM_SetCaption("test", NULL);  
41.    
42.     /*显示图像*/  
43.     background = IMG_Load("background.jpg");//导入图像文件，并将图像放入文字容器  
44.     srect.x = 0;  
45.     srect.y = 0;  
46.     srect.w = background->w;  
47.     srect.h = background->h;  
48.     drect = srect;//设置截取范围  
49.     SDL_BlitSurface(background, &srect, screen, &drect);//将图像容器放入SDL窗口  
50.   
51.     /*显示文字*/  
52.     //初始化TTF  
53.     if (TTF_Init() < 0)  
54.     {  
55.         fprintf(stderr, "TTF init error:%s\n", SDL_GetError());  
56.         return;  
57.     }  
58.       
59.     font = TTF_OpenFont("test.ttf", 40);//导入字体文件  
60.     color.r = 255;  
61.     color.g = 0;  
62.     color.b = 0;//设置文字颜色  
63.     text_sur=TTF_RenderText_Solid(font, "Hello, Welcome to GAME!!", color);//将文字放入文字容器  
64.       
65.     srect.x = 0;  
66.     srect.y = 0;  
67.     srect.w = text_sur->w;  
68.     srect.h = text_sur->h;  
69.       
70.     drect.x = (600 - text_sur->w) / 2;  
71.     drect.y = (400 - text_sur->h) / 2;  
72.     drect.w = text_sur->w;  
73.     drect.h = text_sur->h;//设置截取范围  
74.     SDL_BlitSurface(text_sur, &srect, screen, &drect);//将文字容器放入SDL窗口  
75.       
76.     SDL_UpdateRect(screen, 0, 0, 600, 400);//更新SDL窗口，让新添加的容器显示  
77.   
78.     /*播放声音*/  
79.     Mix_OpenAudio(44100, AUDIO_S16, 2, 4096);//打开音频  
80.     bgsound = Mix_LoadMUS("bgsound.mp3");//导入声音文件  
81.     Mix_PlayMusic(bgsound, -1);//播放音频  
82.     while (quit == 0)  
83.     {  
84.         while (SDL_PollEvent(&event))  
85.         {  
86.             switch (event.type)  
87.             {  
88.              case SDL_QUIT:  
89.                 Mix_CloseAudio();//关闭音频  
90.                 quit = 1;  
91.                 break;  
92.              default:  
93.                 break;  
94.             }  
95.         }  
96.         SDL_Delay(100);  
97.     }  
98.       
99.     return 0;  
100. }  

#include <stdio.h>#include <stdlib.h>#include <SDL/SDL.h>#include <SDL/SDL_image.h>#include <SDL/SDL_mixer.h>#include <SDL/SDL_ttf.h>static SDL_Surface* screen;//SDL窗口int main(int argc, char *argv[]){    int quit = 0;    SDL_Surface *text_sur;//文字容器    SDL_Surface *background;//图像容器    SDL_Event event;    SDL_Color color;    SDL_Rect srect, drect;    Mix_Music *bgsound;    TTF_Font *font;        //初始化SDL    if (SDL_Init(SDL_INIT_VIDEO||SDL_INIT_AUDIO) < 0)    {        fprintf(stderr, "SDL init error:%s\n", SDL_GetError());        exit(0);    }    atexit(SDL_Quit);//注册退出时调用的操作            //设置SDL屏幕大小    screen = SDL_SetVideoMode(600, 400, 24, SDL_HWSURFACE);    if (screen == NULL)    {        fprintf(stderr, "Set video mode failure:%s\n", SDL_GetError());        exit(0);    }        //设置SDL窗口标题    SDL_WM_SetCaption("test", NULL);     /*显示图像*/    background = IMG_Load("background.jpg");//导入图像文件，并将图像放入文字容器    srect.x = 0;    srect.y = 0;    srect.w = background->w;    srect.h = background->h;    drect = srect;//设置截取范围    SDL_BlitSurface(background, &srect, screen, &drect);//将图像容器放入SDL窗口    /*显示文字*/    //初始化TTF    if (TTF_Init() < 0)    {        fprintf(stderr, "TTF init error:%s\n", SDL_GetError());        return;    }        font = TTF_OpenFont("test.ttf", 40);//导入字体文件    color.r = 255;    color.g = 0;    color.b = 0;//设置文字颜色    text_sur=TTF_RenderText_Solid(font, "Hello, Welcome to GAME!!", color);//将文字放入文字容器        srect.x = 0;    srect.y = 0;    srect.w = text_sur->w;    srect.h = text_sur->h;        drect.x = (600 - text_sur->w) / 2;    drect.y = (400 - text_sur->h) / 2;    drect.w = text_sur->w;    drect.h = text_sur->h;//设置截取范围    SDL_BlitSurface(text_sur, &srect, screen, &drect);//将文字容器放入SDL窗口        SDL_UpdateRect(screen, 0, 0, 600, 400);//更新SDL窗口，让新添加的容器显示    /*播放声音*/    Mix_OpenAudio(44100, AUDIO_S16, 2, 4096);//打开音频    bgsound = Mix_LoadMUS("bgsound.mp3");//导入声音文件    Mix_PlayMusic(bgsound, -1);//播放音频    while (quit == 0)    {        while (SDL_PollEvent(&event))        {            switch (event.type)            {             case SDL_QUIT:                Mix_CloseAudio();//关闭音频                quit = 1;                break;             default:                break;            }        }        SDL_Delay(100);    }        return 0;}

问题：gcc main.c -o main编译时可能会出现如下错误：

[cpp] view plaincopyprint?

1. main.c:(.text+0x19): undefined reference to `SDL_Init'  
2. main.c:(.text+0x22): undefined reference to `SDL_GetError'  
3. main.c:(.text+0x50): undefined reference to `SDL_Quit'  
4. main.c:(.text+0x79): undefined reference to `SDL_SetVideoMode'  
5. main.c:(.text+0x8c): undefined reference to `SDL_GetError'  
6. main.c:(.text+0xc7): undefined reference to `SDL_WM_SetCaption'  
7. main.c:(.text+0xd3): undefined reference to `IMG_Load'  
8. main.c:(.text+0x132): undefined reference to `SDL_UpperBlit'  
9. main.c:(.text+0x137): undefined reference to `TTF_Init'  
10. main.c:(.text+0x140): undefined reference to `SDL_GetError'  
11. main.c:(.text+0x174): undefined reference to `TTF_OpenFont'  
12. main.c:(.text+0x1a3): undefined reference to `TTF_RenderText_Solid'  
13. main.c:(.text+0x24c): undefined reference to `SDL_UpperBlit'  
14. main.c:(.text+0x279): undefined reference to `SDL_UpdateRect'  
15. main.c:(.text+0x29d): undefined reference to `Mix_OpenAudio'  
16. main.c:(.text+0x2a9): undefined reference to `Mix_LoadMUS'  
17. main.c:(.text+0x2c1): undefined reference to `Mix_PlayMusic'  
18. main.c:(.text+0x2d5): undefined reference to `Mix_CloseAudio'  
19. main.c:(.text+0x2ec): undefined reference to `SDL_PollEvent'  
20. main.c:(.text+0x2fc): undefined reference to `SDL_Delay'  
21. collect2: ld returned 1 exit status  

main.c:(.text+0x19): undefined reference to `SDL_Init'main.c:(.text+0x22): undefined reference to `SDL_GetError'main.c:(.text+0x50): undefined reference to `SDL_Quit'main.c:(.text+0x79): undefined reference to `SDL_SetVideoMode'main.c:(.text+0x8c): undefined reference to `SDL_GetError'main.c:(.text+0xc7): undefined reference to `SDL_WM_SetCaption'main.c:(.text+0xd3): undefined reference to `IMG_Load'main.c:(.text+0x132): undefined reference to `SDL_UpperBlit'main.c:(.text+0x137): undefined reference to `TTF_Init'main.c:(.text+0x140): undefined reference to `SDL_GetError'main.c:(.text+0x174): undefined reference to `TTF_OpenFont'main.c:(.text+0x1a3): undefined reference to `TTF_RenderText_Solid'main.c:(.text+0x24c): undefined reference to `SDL_UpperBlit'main.c:(.text+0x279): undefined reference to `SDL_UpdateRect'main.c:(.text+0x29d): undefined reference to `Mix_OpenAudio'main.c:(.text+0x2a9): undefined reference to `Mix_LoadMUS'main.c:(.text+0x2c1): undefined reference to `Mix_PlayMusic'main.c:(.text+0x2d5): undefined reference to `Mix_CloseAudio'main.c:(.text+0x2ec): undefined reference to `SDL_PollEvent'main.c:(.text+0x2fc): undefined reference to `SDL_Delay'collect2: ld returned 1 exit status

原因：那是因为该程序用到四个静态库，分别为：
（1）SDL
（2）SDL_image
（3）SDL_ttf
（4）SDL_mixer
需用-l参数连起来才能编译得过，如：gcc main.c -lSDL -lSDL_image -lSDL_ttf -lSDL_mixer -o main