mouse-events-sdl.c

Linux游戏编程源码

/* Example of simple mouse input with SDL. */

#include <SDL/SDL.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
    SDL_Surface *screen;
    SDL_Event event;

    /* Initialize SDL's video system and check for errors. */
    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
	printf("Unable to initialize SDL: %s\n", SDL_GetError());
	return 1;
    }

    /* Make sure SDL_Quit gets called when the program exits! */
    atexit(SDL_Quit);

    /* Attempt to set a 256x256 hicolor (16-bit) video mode. */
    screen = SDL_SetVideoMode(256, 256, 16, 0);
    if (screen == NULL) {
	printf("Unable to set video mode: %s\n", SDL_GetError());
	return 1;
    }

    /* Start the event loop. Keep reading events until there
       is an error, or the user presses a mouse button. */
    while (SDL_WaitEvent(&event) != 0) {

	/* SDL_WaitEvent has filled in our event structure
	   with the next event. We check its type field to
	   find out what happened. */
	switch (event.type) {

	    /* The next two event types deal
	       with mouse activity. */
	case SDL_MOUSEMOTION:
	    printf("Mouse motion. ");

	    /* SDL provides the current position. */
	    printf("New position is (%i,%i). ",
		   event.motion.x, event.motion.y);

	    /* We can also get relative motion. */
	    printf("That is a (%i,%i) change.\n",
		   event.motion.xrel, event.motion.yrel);
	    break;

	case SDL_MOUSEBUTTONDOWN:
	    printf("Mouse button pressed. ");

	    printf("Button %i at (%i,%i)\n",
		   event.button.button, event.button.x, event.button.y);
	    break;

	    /* The SDL_QUIT event indicates that
	       the windows "Close" button has been
	       pressed. We can ignore this if we
	       need to, but that tends to make
	       users rather impatient. */
	case SDL_QUIT:
	    printf("Quit event. Bye.\n");
	    exit(0);
	}
    }

    return 0;
}