view docs/html/guidebasicsinit.html @ 892:dc29e5907694

Date: Sun, 18 Apr 2004 16:09:53 -0400 (EDT) From: David MacCormack Subject: [SDL] Linux joystick patch I recently got myself a PS2 -> USB converter (a super joybox 5). It accepts 4 PSX/PS2 controllers. It's implemented as a HID, which is nice because it doesn't require its own driver, but the problem is that it's implemented as a *single* HID -- that is, it shows up as a single joystick with 19 axes, 4 hats, and 48 buttons. This poses a problem for a number of apps which use SDL (stella, fce ultra, zsnes, to name a few) and see only a single (physical) joystick even though there are really 4 (logical) joysticks. There are a number of these types of devices on the market, and I've seen others post messages (in the zsnes forum, for example) with the same problem, so I came up with what I think is a pretty generic solution. I patched src/joystick/linux/SDL_sysjoystic.c to include support for logical joysticks; basically, it's a static array and supporting functions that map a single physical joystick to multiple logical joysticks. The attached patch has the new code. It's wrapped inside #ifndef statements so that you can get the old behavior if you want.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 16 May 2004 18:46:24 +0000
parents 355632dca928
children
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>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
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><TT
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></A
> (or <A
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><TT
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>). <TT
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> 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
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>    SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE
></P
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><TT
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><P
>With <TT
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>SDL_Init</TT
> and <TT
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>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
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>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
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>SDL_GetError</TT
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>#include "SDL.h"   /* All SDL App's need this */
#include &#60;stdio.h&#62;

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);
}&#13;</PRE
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