Mercurial > sdl-ios-xcode
view include/SDL_joystick.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 | 4c4113c2162c |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 Sam Lantinga This library is 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 file for SDL joystick event handling */ #ifndef _SDL_joystick_h #define _SDL_joystick_h #include "SDL_stdinc.h" #include "SDL_error.h" #include "begin_code.h" /* Set up for C function definitions, even when using C++ */ #ifdef __cplusplus extern "C" { #endif /* In order to use these functions, SDL_Init() must have been called with the SDL_INIT_JOYSTICK flag. This causes SDL to scan the system for joysticks, and load appropriate drivers. */ /* The joystick structure used to identify an SDL joystick */ struct _SDL_Joystick; typedef struct _SDL_Joystick SDL_Joystick; /* Function prototypes */ /* * Count the number of joysticks attached to the system */ extern DECLSPEC int SDLCALL SDL_NumJoysticks(void); /* * Get the implementation dependent name of a joystick. * This can be called before any joysticks are opened. * If no name can be found, this function returns NULL. */ extern DECLSPEC const char * SDLCALL SDL_JoystickName(int device_index); /* * Open a joystick for use - the index passed as an argument refers to * the N'th joystick on the system. This index is the value which will * identify this joystick in future joystick events. * * This function returns a joystick identifier, or NULL if an error occurred. */ extern DECLSPEC SDL_Joystick * SDLCALL SDL_JoystickOpen(int device_index); /* * Returns 1 if the joystick has been opened, or 0 if it has not. */ extern DECLSPEC int SDLCALL SDL_JoystickOpened(int device_index); /* * Get the device index of an opened joystick. */ extern DECLSPEC int SDLCALL SDL_JoystickIndex(SDL_Joystick *joystick); /* * Get the number of general axis controls on a joystick */ extern DECLSPEC int SDLCALL SDL_JoystickNumAxes(SDL_Joystick *joystick); /* * Get the number of trackballs on a joystick * Joystick trackballs have only relative motion events associated * with them and their state cannot be polled. */ extern DECLSPEC int SDLCALL SDL_JoystickNumBalls(SDL_Joystick *joystick); /* * Get the number of POV hats on a joystick */ extern DECLSPEC int SDLCALL SDL_JoystickNumHats(SDL_Joystick *joystick); /* * Get the number of buttons on a joystick */ extern DECLSPEC int SDLCALL SDL_JoystickNumButtons(SDL_Joystick *joystick); /* * Update the current state of the open joysticks. * This is called automatically by the event loop if any joystick * events are enabled. */ extern DECLSPEC void SDLCALL SDL_JoystickUpdate(void); /* * Enable/disable joystick event polling. * If joystick events are disabled, you must call SDL_JoystickUpdate() * yourself and check the state of the joystick when you want joystick * information. * The state can be one of SDL_QUERY, SDL_ENABLE or SDL_IGNORE. */ extern DECLSPEC int SDLCALL SDL_JoystickEventState(int state); /* * Get the current state of an axis control on a joystick * The state is a value ranging from -32768 to 32767. * The axis indices start at index 0. */ extern DECLSPEC Sint16 SDLCALL SDL_JoystickGetAxis(SDL_Joystick *joystick, int axis); /* * Get the current state of a POV hat on a joystick * The return value is one of the following positions: */ #define SDL_HAT_CENTERED 0x00 #define SDL_HAT_UP 0x01 #define SDL_HAT_RIGHT 0x02 #define SDL_HAT_DOWN 0x04 #define SDL_HAT_LEFT 0x08 #define SDL_HAT_RIGHTUP (SDL_HAT_RIGHT|SDL_HAT_UP) #define SDL_HAT_RIGHTDOWN (SDL_HAT_RIGHT|SDL_HAT_DOWN) #define SDL_HAT_LEFTUP (SDL_HAT_LEFT|SDL_HAT_UP) #define SDL_HAT_LEFTDOWN (SDL_HAT_LEFT|SDL_HAT_DOWN) /* * The hat indices start at index 0. */ extern DECLSPEC Uint8 SDLCALL SDL_JoystickGetHat(SDL_Joystick *joystick, int hat); /* * Get the ball axis change since the last poll * This returns 0, or -1 if you passed it invalid parameters. * The ball indices start at index 0. */ extern DECLSPEC int SDLCALL SDL_JoystickGetBall(SDL_Joystick *joystick, int ball, int *dx, int *dy); /* * Get the current state of a button on a joystick * The button indices start at index 0. */ extern DECLSPEC Uint8 SDLCALL SDL_JoystickGetButton(SDL_Joystick *joystick, int button); /* * Close a joystick previously opened with SDL_JoystickOpen() */ extern DECLSPEC void SDLCALL SDL_JoystickClose(SDL_Joystick *joystick); /* Ends C function definitions when using C++ */ #ifdef __cplusplus } #endif #include "close_code.h" #endif /* _SDL_joystick_h */