Mercurial > sdl-ios-xcode
view src/joystick/os2/joyos2.h @ 4139:568c9b3c0167 SDL-1.2
* Added configure option --enable-screensaver, to allow enabling the screensaver by default.
* Use XResetScreenSaver() instead of disabling screensaver entirely.
Full discussion summary from Erik on the SDL mailing list:
Current behaviour
=================
SDL changes the user's display power management settings without
permission from the user and without telling the user.
The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).
In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).
The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.
The problems that the current behaviour tries to solve
======================================================
1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".
2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.
3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.
How the problems should be solved
=================================
The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).
1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.
2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.
3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 29 Feb 2008 13:55:44 +0000 |
parents | 173c063d4f55 |
children | 782fd950bd46 |
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/*****************************************************************************/ /* */ /* COPYRIGHT Copyright (C) 1995 IBM Corporation */ /* */ /* The following IBM OS/2 source code is provided to you solely for */ /* the purpose of assisting you in your development of OS/2 device */ /* drivers. You may use this code in accordance with the IBM License */ /* Agreement provided in the IBM Device Driver Source Kit for OS/2. This */ /* Copyright statement may not be removed. */ /* */ /*****************************************************************************/ #ifndef JOYOS2_H #define JOYOS2_H /****** GAMEPORT.SYS joystick definitions, start *****************************/ #define GAME_VERSION 0x20 /* 2.0 First IBM version */ #define GAMEPDDNAME "GAME$ " #define IOCTL_CAT_USER 0x80 #define GAME_PORT_GET 0x20 /* read GAMEPORT.SYS values */ #define GAME_PORT_RESET 0x60 /* reset joystick mask with given value */ #pragma pack(1) /* pack structure size is 1 byte */ typedef struct { /* GAMEPORT.SYS structure */ USHORT usJs_AxCnt; /* Joystick_A X position */ USHORT usJs_AyCnt; /* Joystick_A Y position */ USHORT usJs_BxCnt; /* Joystick_B X position */ USHORT usJs_ByCnt; /* Joystick_B Y position */ USHORT usJs_ButtonA1Cnt; /* button A1 press count */ USHORT usJs_ButtonA2Cnt; /* button A2 press count */ USHORT usJs_ButtonB1Cnt; /* button B1 press count */ USHORT usJs_ButtonB2Cnt; /* button B2 press count */ UCHAR ucJs_JoyStickMask; /* mask of connected joystick pots */ UCHAR ucJs_ButtonStatus; /* bits of switches down */ ULONG ulJs_Ticks; /* joystick clock ticks */ } GAME_PORT_STRUCT; #pragma pack() /*reset to normal pack size */ /****** GAMEPORT.SYS joystick definitions, end *******************************/ /****************************************************************************/ #define GAME_GET_VERSION 0x01 #define GAME_GET_PARMS 0x02 #define GAME_SET_PARMS 0x03 #define GAME_GET_CALIB 0x04 #define GAME_SET_CALIB 0x05 #define GAME_GET_DIGSET 0x06 #define GAME_SET_DIGSET 0x07 #define GAME_GET_STATUS 0x10 #define GAME_GET_STATUS_BUTWAIT 0x11 #define GAME_GET_STATUS_SAMPWAIT 0x12 /****************************************************************************/ /****************************************************************************/ // bit masks for each axis #define JOY_AX_BIT 0x01 #define JOY_AY_BIT 0x02 #define JOY_A_BITS (JOY_AX_BIT|JOY_AY_BIT) #define JOY_BX_BIT 0x04 #define JOY_BY_BIT 0x08 #define JOY_B_BITS (JOY_BX_BIT|JOY_BY_BIT) #define JOY_ALLPOS_BITS (JOY_A_BITS|JOY_B_BITS) // bit masks for each button #define JOY_BUT1_BIT 0x10 #define JOY_BUT2_BIT 0x20 #define JOY_BUT3_BIT 0x40 #define JOY_BUT4_BIT 0x80 #define JOY_ALL_BUTS (JOY_BUT1_BIT|JOY_BUT2_BIT|JOY_BUT3_BIT|JOY_BUT4_BIT) /****************************************************************************/ /****************************************************************************/ // 1-D position struct used for each axis typedef SHORT GAME_POS; /* some data formats require signed values */ // simple 2-D position for each joystick typedef struct { GAME_POS x; GAME_POS y; } GAME_2DPOS_STRUCT; // struct defining the instantaneous state of both sticks and all buttons typedef struct { GAME_2DPOS_STRUCT A; GAME_2DPOS_STRUCT B; USHORT butMask; } GAME_DATA_STRUCT; // struct to be used for calibration and digital response on each axis typedef struct { GAME_POS lower; GAME_POS centre; GAME_POS upper; } GAME_3POS_STRUCT; /****************************************************************************/ /****************************************************************************/ // status struct returned to OS/2 applications: // current data for all sticks as well as button counts since last read typedef struct { GAME_DATA_STRUCT curdata; USHORT b1cnt; USHORT b2cnt; USHORT b3cnt; USHORT b4cnt; } GAME_STATUS_STRUCT; /****************************************************************************/ /****************************************************************************/ /* in use bitmasks originating in 0.2b */ #define GAME_USE_BOTH_OLDMASK 0x01 /* for backward compat with bool */ #define GAME_USE_X_NEWMASK 0x02 #define GAME_USE_Y_NEWMASK 0x04 #define GAME_USE_X_EITHERMASK (GAME_USE_X_NEWMASK|GAME_USE_BOTH_OLDMASK) #define GAME_USE_Y_EITHERMASK (GAME_USE_Y_NEWMASK|GAME_USE_BOTH_OLDMASK) #define GAME_USE_BOTH_NEWMASK (GAME_USE_X_NEWMASK|GAME_USE_Y_NEWMASK) /* only timed sampling implemented in version 1.0 */ #define GAME_MODE_TIMED 1 /* timed sampling */ #define GAME_MODE_REQUEST 2 /* request driven sampling */ /* only raw implemented in version 1.0 */ #define GAME_DATA_FORMAT_RAW 1 /* [l,c,r] */ #define GAME_DATA_FORMAT_SIGNED 2 /* [-l,0,+r] */ #define GAME_DATA_FORMAT_BINARY 3 /* {-1,0,+1} */ #define GAME_DATA_FORMAT_SCALED 4 /* [-10,+10] */ // parameters defining the operation of the driver typedef struct { USHORT useA; /* new bitmasks: see above */ USHORT useB; USHORT mode; /* see consts above */ USHORT format; /* see consts above */ USHORT sampDiv; /* samp freq = 32 / n */ USHORT scale; /* scaling factor */ USHORT res1; /* must be 0 */ USHORT res2; /* must be 0 */ } GAME_PARM_STRUCT; /****************************************************************************/ /****************************************************************************/ // calibration values for each axis: // - upper limit on value to be considered in lower range // - centre value // - lower limit on value to be considered in upper range typedef struct { GAME_3POS_STRUCT Ax; GAME_3POS_STRUCT Ay; GAME_3POS_STRUCT Bx; GAME_3POS_STRUCT By; } GAME_CALIB_STRUCT; /****************************************************************************/ /****************************************************************************/ // struct defining the digital response values for all axes typedef struct { GAME_3POS_STRUCT Ax; GAME_3POS_STRUCT Ay; GAME_3POS_STRUCT Bx; GAME_3POS_STRUCT By; } GAME_DIGSET_STRUCT; /****************************************************************************/ #endif