整合sdl的定时器及事件机制的样例

SDL（Simple DirectMedia Layer）是一套开放源代码的跨平台多媒体开发库.有利于多媒体及游戏的开发,具体详见维基百科:http://zh.wikipedia.org/wiki/SDL
此样例是对sdl事件机制和定时器的简单整合, 自ffmpeg的tutorial04.c了解的

你需要先安装sdl
编译,生成: gcc -o testevent2 testevent2.c  `sdl-config --cflags --libs`

#include "SDL.h"

#include <stdio.h>
#include <time.h>

#define FF_0_EVENT   (SDL_USEREVENT)
#define FF_1_EVENT (SDL_USEREVENT + 1)
#define FF_2_EVENT (SDL_USEREVENT + 2)
#define FF_3_EVENT (SDL_USEREVENT + 3)
#define FF_4_EVENT (SDL_USEREVENT + 4)

#define random(x) (rand()%x)

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) {
	
	SDL_Event event;
	srand((int)time(0));
	int ffrand;
	ffrand = random(5);
	printf("ffrand = %d \n", ffrand);
	
	switch (ffrand) {
			case 0:
			    event.type = FF_0_EVENT;
				break;
			case 1:
				event.type = FF_1_EVENT;
				break;
			case 2:
				event.type = FF_2_EVENT;
				break;
			case 3:
				event.type = FF_3_EVENT;
				break;
			case 4:
				event.type = FF_4_EVENT;
				break;
			default:
				break;
		}
	SDL_PushEvent(&event);
	return interval; /* 0 means stop timer */
}


static void schedule_refresh(int delay) {
	SDL_AddTimer(delay, sdl_refresh_timer_cb, NULL);
}

int main(int argc, char *argv[]) {
	
	SDL_Event       event;
	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
		fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
		exit(1);
	}
	
	schedule_refresh(1000);
	
	while(1) {
		SDL_WaitEvent(&event);
		
		switch(event.type) {
			case FF_0_EVENT:
				printf("0 \n");
				break;
			case FF_1_EVENT:
				printf("1 \n");
				break;
			case FF_2_EVENT:
				printf("2 \n");
				break;
			case FF_3_EVENT:
				printf("3 \n");
				SDL_Quit();
				return 0;
				break;
			case FF_4_EVENT:
				printf("4 \n");
				break;
			default:
				break;
		}
	}
	
	return 0;
}

notice:
1, SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)
sdl初始化一定要全部初始化,如果仅仅初始化SDL_INIT_TIMER, 事件机制将不起任何作用
因为sdl_event的有mouse,key等界面元素