starfield.c

#include <stdio.h>
#include <SDL.h>
#define MAX_STARS 100
typedef struct{
	int x,y,speed;
} star_type;
star_type stars[MAX_STARS];

int main(){
	int i;
	Uint8 *p;
	SDL_Surface *screen;
	SDL_Init(SDL_INIT_VIDEO);
	atexit(SDL_Quit);
	screen = SDL_SetVideoMode(640,480,8,SDL_SWSURFACE);
	for (i=0; i< MAX_STARS;i++){
		stars[i].x = rand()%640;
		stars[i].y = rand()%480;
		stars[i].speed = rand()%16;
	}
	for (i=0; i< SDL_NUMEVENTS;i++){
		if (i != SDL_QUIT)
			SDL_EventState(i,SDL_IGNORE);
	}
	while(SDL_PollEvent(NULL) == 0){
		SDL_FillRect(screen,NULL,SDL_MapRGB(screen->format,0,0,0));
		for (i=0; i < MAX_STARS; i++){
			stars[i].x -= stars[i].speed;
			if (stars[i].x <= 0){
				stars[i].x = 640;
			}
			p = (Uint8 *) screen->pixels + stars[i].y * screen->pitch + stars[i].x * screen->format->BytesPerPixel;
			*p = 255;
		}
		SDL_UpdateRect(screen,0,0,0,0);
		SDL_Delay(30);
	}
	return 0;
}