Mercurial > sdl-ios-xcode
view docs/html/guidebasicsinit.html @ 1643:51038e80ae59
More general fix for bug #189
The clipping is done at a higher level, and the low level functions are
passed clipped rectangles. Drivers which don't support source clipping
have not been changed, so the image will be squished instead of clipped,
but at least they will no longer crash when the destination rect was out
of bounds.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 17 Apr 2006 06:47:23 +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 >