Mercurial > sdl-ios-xcode
view docs/html/guidebasicsinit.html @ 2842:97ba0be8b565
Date: Sat, 06 Dec 2008 15:27:00 +0100
From: Couriersud
Subject: SDL: Relative mouse movements
The patch below will reenable processing of relative mouse movements.
The DirectFB drivers generates those in "grabbed" mode. These ensure,
that even in fullscreen mode relative movements are reported. SDLMAME
depends on this for games with trackballs.
Looking at the code I ask myself whether relative movements should be
handled in the drivers (x11, directfb). Both x11 and directfb are able
to report relative movements. This would leave it to the driver to use
the most appropriate method for relative movements when at the border of
a fullscreen window or being "grabbed".
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sat, 06 Dec 2008 17:50:50 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >Initializing SDL</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="The Basics" HREF="guidethebasics.html"><LINK REL="PREVIOUS" TITLE="The Basics" HREF="guidethebasics.html"><LINK REL="NEXT" TITLE="Graphics and Video" HREF="guidevideo.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="guidethebasics.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 1. The Basics</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="guidevideo.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="GUIDEBASICSINIT" ></A >Initializing SDL</H1 ><P >SDL is composed of eight subsystems - Audio, CDROM, Event Handling, File I/O, Joystick Handling, Threading, Timers and Video. Before you can use any of these subsystems they must be initialized by calling <A HREF="sdlinit.html" ><TT CLASS="FUNCTION" >SDL_Init</TT ></A > (or <A HREF="sdlinitsubsystem.html" ><TT CLASS="FUNCTION" >SDL_InitSubSystem</TT ></A >). <TT CLASS="FUNCTION" >SDL_Init</TT > must be called before any other SDL function. It automatically initializes the Event Handling, File I/O and Threading subsystems and it takes a parameter specifying which other subsystems to initialize. So, to initialize the default subsystems and the Video subsystems you would call: <PRE CLASS="PROGRAMLISTING" > SDL_Init ( SDL_INIT_VIDEO );</PRE > To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call: <PRE CLASS="PROGRAMLISTING" > SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE ></P ><P ><TT CLASS="FUNCTION" >SDL_Init</TT > is complemented by <A HREF="sdlquit.html" ><TT CLASS="FUNCTION" >SDL_Quit</TT ></A > (and <A HREF="sdlquitsubsystem.html" ><TT CLASS="FUNCTION" >SDL_QuitSubSystem</TT ></A >). <TT CLASS="FUNCTION" >SDL_Quit</TT > shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P ><P >With <TT CLASS="FUNCTION" >SDL_Init</TT > and <TT CLASS="FUNCTION" >SDL_Quit</TT > firmly embedded in your programmers toolkit you can write your first and most basic SDL application. However, we must be prepare to handle errors. Many SDL functions return a value and indicates whether the function has succeeded or failed, <TT CLASS="FUNCTION" >SDL_Init</TT >, for instance, returns -1 if it could not initialize a subsystem. SDL provides a useful facility that allows you to determine exactly what the problem was, every time an error occurs within SDL an error message is stored which can be retrieved using <TT CLASS="FUNCTION" >SDL_GetError</TT >. Use this often, you can never know too much about an error.</P ><DIV CLASS="EXAMPLE" ><A NAME="AEN60" ></A ><P ><B >Example 1-1. Initializing SDL</B ></P ><PRE CLASS="PROGRAMLISTING" >#include "SDL.h" /* All SDL App's need this */ #include <stdio.h> int main(int argc, char *argv[]) { printf("Initializing SDL.\n"); /* Initialize defaults, Video and Audio */ if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) { printf("Could not initialize SDL: %s.\n", SDL_GetError()); exit(-1); } printf("SDL initialized.\n"); printf("Quiting SDL.\n"); /* Shutdown all subsystems */ SDL_Quit(); printf("Quiting....\n"); exit(0); } </PRE ></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="guidethebasics.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="guidevideo.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >The Basics</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="guidethebasics.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Graphics and Video</TD ></TR ></TABLE ></DIV ></BODY ></HTML >