view src/joystick/SDL_sysjoystick.h @ 4216:5b99971a27b4 SDL-1.2

Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
parents a1b03ba2fcd0
children
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is SDL_free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* This is the system specific header for the SDL joystick API */

#include "SDL_joystick.h"

/* The SDL joystick structure */
struct _SDL_Joystick {
	Uint8 index;		/* Device index */
	const char *name;	/* Joystick name - system dependent */

	int naxes;		/* Number of axis controls on the joystick */
	Sint16 *axes;		/* Current axis states */

	int nhats;		/* Number of hats on the joystick */
	Uint8 *hats;		/* Current hat states */
	
	int nballs;		/* Number of trackballs on the joystick */
	struct balldelta {
		int dx;
		int dy;
	} *balls;		/* Current ball motion deltas */
	
	int nbuttons;		/* Number of buttons on the joystick */
	Uint8 *buttons;		/* Current button states */
	
	struct joystick_hwdata *hwdata;	/* Driver dependent information */

	int ref_count;		/* Reference count for multiple opens */
};

/* Function to scan the system for joysticks.
 * Joystick 0 should be the system default joystick.
 * This function should return the number of available joysticks, or -1
 * on an unrecoverable fatal error.
 */
extern int SDL_SYS_JoystickInit(void);

/* Function to get the device-dependent name of a joystick */
extern const char *SDL_SYS_JoystickName(int index);

/* Function to open a joystick for use.
   The joystick to open is specified by the index field of the joystick.
   This should fill the nbuttons and naxes fields of the joystick structure.
   It returns 0, or -1 if there is an error.
 */
extern int SDL_SYS_JoystickOpen(SDL_Joystick *joystick);

/* Function to update the state of a joystick - called as a device poll.
 * This function shouldn't update the joystick structure directly,
 * but instead should call SDL_PrivateJoystick*() to deliver events
 * and update joystick device state.
 */
extern void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick);

/* Function to close a joystick after use */
extern void SDL_SYS_JoystickClose(SDL_Joystick *joystick);

/* Function to perform any system-specific joystick related cleanup */
extern void SDL_SYS_JoystickQuit(void);