Mercurial > sdl-ios-xcode

<HTML
><HEAD
><TITLE
>Event Examples</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Examples"
HREF="guideexamples.html"><LINK
REL="PREVIOUS"
TITLE="Examples"
HREF="guideexamples.html"><LINK
REL="NEXT"
TITLE="Audio Examples"
HREF="guideaudioexamples.html"></HEAD
><BODY
CLASS="SECT1"
BGCOLOR="#FFF8DC"
TEXT="#000000"
LINK="#0000ee"
VLINK="#551a8b"
ALINK="#ff0000"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>SDL Library Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="guideexamples.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 4. Examples</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="guideaudioexamples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="GUIDEEVENTEXAMPLES"
></A
>Event Examples</H1
><P
></P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN375"
></A
>Filtering and Handling Events</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>#include &#60;stdio.h&#62;
#include &#60;stdlib.h&#62;

#include "SDL.h"

/* This function may run in a separate event thread */
int FilterEvents(const SDL_Event *event) {
    static int boycott = 1;

    /* This quit event signals the closing of the window */
    if ( (event-&#62;type == SDL_QUIT) &#38;&#38; boycott ) {
        printf("Quit event filtered out -- try again.\n");
        boycott = 0;
        return(0);
    }
    if ( event-&#62;type == SDL_MOUSEMOTION ) {
        printf("Mouse moved to (%d,%d)\n",
                event-&#62;motion.x, event-&#62;motion.y);
        return(0);    /* Drop it, we've handled it */
    }
    return(1);
}

int main(int argc, char *argv[])
{
    SDL_Event event;

    /* Initialize the SDL library (starts the event loop) */
    if ( SDL_Init(SDL_INIT_VIDEO) &#60; 0 ) {
        fprintf(stderr,
                "Couldn't initialize SDL: %s\n", SDL_GetError());
        exit(1);
    }

    /* Clean up on exit, exit on window close and interrupt */
    atexit(SDL_Quit);

    /* Ignore key events */
    SDL_EventState(SDL_KEYDOWN, SDL_IGNORE);
    SDL_EventState(SDL_KEYUP, SDL_IGNORE);

    /* Filter quit and mouse motion events */
    SDL_SetEventFilter(FilterEvents);

    /* The mouse isn't much use unless we have a display for reference */
    if ( SDL_SetVideoMode(640, 480, 8, 0) == NULL ) {
        fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
                        SDL_GetError());
        exit(1);
    }

    /* Loop waiting for ESC+Mouse_Button */
    while ( SDL_WaitEvent(&#38;event) &#62;= 0 ) {
        switch (event.type) {
            case SDL_ACTIVEEVENT: {
                if ( event.active.state &#38; SDL_APPACTIVE ) {
                    if ( event.active.gain ) {
                        printf("App activated\n");
                    } else {
                        printf("App iconified\n");
                    }
                }
            }
            break;

            case SDL_MOUSEBUTTONDOWN: {
                Uint8 *keys;

                keys = SDL_GetKeyState(NULL);
                if ( keys[SDLK_ESCAPE] == SDL_PRESSED ) {
                    printf("Bye bye...\n");
                    exit(0);
                }
                printf("Mouse button pressed\n");
            }
            break;

            case SDL_QUIT: {
                printf("Quit requested, quitting.\n");
                exit(0);
            }
            break;
        }
    }
    /* This should never happen */
    printf("SDL_WaitEvent error: %s\n", SDL_GetError());
    exit(1);
}</PRE
></P
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="guideexamples.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="guideaudioexamples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Examples</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="guideexamples.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Audio Examples</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
author	Sam Lantinga <slouken@libsdl.org>
date	Mon, 13 Apr 2009 08:44:48 +0000
parents	355632dca928
children