Mercurial > sdl-ios-xcode
view src/main/win32/SDL_win32_main.c @ 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 | 3c068a8c016f |
children | 8b8314cc34a6 |
line wrap: on
line source
/* SDL_main.c, placed in the public domain by Sam Lantinga 4/13/98 The WinMain function -- calls your program's main() function */ #include <stdio.h> #include <stdlib.h> #define WIN32_LEAN_AND_MEAN #include <windows.h> #ifdef _WIN32_WCE # define DIR_SEPERATOR TEXT("\\") # undef _getcwd # define _getcwd(str,len) wcscpy(str,TEXT("")) # define setbuf(f,b) # define setvbuf(w,x,y,z) # define fopen _wfopen # define freopen _wfreopen # define remove(x) DeleteFile(x) #else # define DIR_SEPERATOR TEXT("/") # include <direct.h> #endif /* Include the SDL main definition header */ #include "SDL.h" #include "SDL_main.h" #ifdef main # ifndef _WIN32_WCE_EMULATION # undef main # endif /* _WIN32_WCE_EMULATION */ #endif /* main */ /* The standard output files */ #define STDOUT_FILE TEXT("stdout.txt") #define STDERR_FILE TEXT("stderr.txt") #ifndef NO_STDIO_REDIRECT # ifdef _WIN32_WCE static wchar_t stdoutPath[MAX_PATH]; static wchar_t stderrPath[MAX_PATH]; # else static char stdoutPath[MAX_PATH]; static char stderrPath[MAX_PATH]; # endif #endif #if defined(_WIN32_WCE) && _WIN32_WCE < 300 /* seems to be undefined in Win CE although in online help */ #define isspace(a) (((CHAR)a == ' ') || ((CHAR)a == '\t')) #endif /* _WIN32_WCE < 300 */ static void UnEscapeQuotes( char *arg ) { char *last = NULL; while( *arg ) { if( *arg == '"' && *last == '\\' ) { char *c_curr = arg; char *c_last = last; while( *c_curr ) { *c_last = *c_curr; c_last = c_curr; c_curr++; } *c_last = '\0'; } last = arg; arg++; } } /* Parse a command line buffer into arguments */ static int ParseCommandLine(char *cmdline, char **argv) { char *bufp; char *lastp = NULL; int argc, last_argc; argc = last_argc = 0; for ( bufp = cmdline; *bufp; ) { /* Skip leading whitespace */ while ( isspace(*bufp) ) { ++bufp; } /* Skip over argument */ if ( *bufp == '"' ) { ++bufp; if ( *bufp ) { if ( argv ) { argv[argc] = bufp; } ++argc; } /* Skip over word */ while ( *bufp && ( *bufp != '"' || *lastp == '\\' ) ) { lastp = bufp; ++bufp; } } else { if ( *bufp ) { if ( argv ) { argv[argc] = bufp; } ++argc; } /* Skip over word */ while ( *bufp && ! isspace(*bufp) ) { ++bufp; } } if ( *bufp ) { if ( argv ) { *bufp = '\0'; } ++bufp; } /* Strip out \ from \" sequences */ if( argv && last_argc != argc ) { UnEscapeQuotes( argv[last_argc] ); } last_argc = argc; } if ( argv ) { argv[argc] = NULL; } return(argc); } /* Show an error message */ static void ShowError(const char *title, const char *message) { /* If USE_MESSAGEBOX is defined, you need to link with user32.lib */ #ifdef USE_MESSAGEBOX MessageBox(NULL, message, title, MB_ICONEXCLAMATION|MB_OK); #else fprintf(stderr, "%s: %s\n", title, message); #endif } /* Pop up an out of memory message, returns to Windows */ static BOOL OutOfMemory(void) { ShowError("Fatal Error", "Out of memory - aborting"); return FALSE; } /* SDL_Quit() shouldn't be used with atexit() directly because calling conventions may differ... */ static void cleanup(void) { SDL_Quit(); } /* Remove the output files if there was no output written */ static void cleanup_output(void) { #ifndef NO_STDIO_REDIRECT FILE *file; int empty; #endif /* Flush the output in case anything is queued */ fclose(stdout); fclose(stderr); #ifndef NO_STDIO_REDIRECT /* See if the files have any output in them */ if ( stdoutPath[0] ) { file = fopen(stdoutPath, TEXT("rb")); if ( file ) { empty = (fgetc(file) == EOF) ? 1 : 0; fclose(file); if ( empty ) { remove(stdoutPath); } } } if ( stderrPath[0] ) { file = fopen(stderrPath, TEXT("rb")); if ( file ) { empty = (fgetc(file) == EOF) ? 1 : 0; fclose(file); if ( empty ) { remove(stderrPath); } } } #endif } #if defined(_MSC_VER) && !defined(_WIN32_WCE) /* The VC++ compiler needs main defined */ #define console_main main #endif /* This is where execution begins [console apps] */ int console_main(int argc, char *argv[]) { size_t n; char *bufp, *appname; int status; /* Get the class name from argv[0] */ appname = argv[0]; if ( (bufp=SDL_strrchr(argv[0], '\\')) != NULL ) { appname = bufp+1; } else if ( (bufp=SDL_strrchr(argv[0], '/')) != NULL ) { appname = bufp+1; } if ( (bufp=SDL_strrchr(appname, '.')) == NULL ) n = SDL_strlen(appname); else n = (bufp-appname); bufp = SDL_stack_alloc(char, n+1); if ( bufp == NULL ) { return OutOfMemory(); } SDL_strlcpy(bufp, appname, n+1); appname = bufp; /* Load SDL dynamic link library */ if ( SDL_Init(SDL_INIT_NOPARACHUTE) < 0 ) { ShowError("WinMain() error", SDL_GetError()); return(FALSE); } atexit(cleanup_output); atexit(cleanup); /* Sam: We still need to pass in the application handle so that DirectInput will initialize properly when SDL_RegisterApp() is called later in the video initialization. */ SDL_SetModuleHandle(GetModuleHandle(NULL)); /* Run the application main() code */ status = SDL_main(argc, argv); /* Exit cleanly, calling atexit() functions */ exit(status); /* Hush little compiler, don't you cry... */ return 0; } /* This is where execution begins [windowed apps] */ #ifdef _WIN32_WCE int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPWSTR szCmdLine, int sw) #else int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw) #endif { HINSTANCE handle; char **argv; int argc; char *cmdline; #ifdef _WIN32_WCE wchar_t *bufp; int nLen; #else char *bufp; size_t nLen; #endif #ifndef NO_STDIO_REDIRECT DWORD pathlen; #ifdef _WIN32_WCE wchar_t path[MAX_PATH]; #else char path[MAX_PATH]; #endif FILE *newfp; #endif /* Start up DDHELP.EXE before opening any files, so DDHELP doesn't keep them open. This is a hack.. hopefully it will be fixed someday. DDHELP.EXE starts up the first time DDRAW.DLL is loaded. */ handle = LoadLibrary(TEXT("DDRAW.DLL")); if ( handle != NULL ) { FreeLibrary(handle); } #ifndef NO_STDIO_REDIRECT pathlen = GetModuleFileName(NULL, path, SDL_arraysize(path)); while ( pathlen > 0 && path[pathlen] != '\\' ) { --pathlen; } path[pathlen] = '\0'; #ifdef _WIN32_WCE wcsncpy( stdoutPath, path, SDL_arraysize(stdoutPath) ); wcsncat( stdoutPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) ); #else SDL_strlcpy( stdoutPath, path, SDL_arraysize(stdoutPath) ); SDL_strlcat( stdoutPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) ); #endif /* Redirect standard input and standard output */ newfp = freopen(stdoutPath, TEXT("w"), stdout); #ifndef _WIN32_WCE if ( newfp == NULL ) { /* This happens on NT */ #if !defined(stdout) stdout = fopen(stdoutPath, TEXT("w")); #else newfp = fopen(stdoutPath, TEXT("w")); if ( newfp ) { *stdout = *newfp; } #endif } #endif /* _WIN32_WCE */ #ifdef _WIN32_WCE wcsncpy( stderrPath, path, SDL_arraysize(stdoutPath) ); wcsncat( stderrPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) ); #else SDL_strlcpy( stderrPath, path, SDL_arraysize(stderrPath) ); SDL_strlcat( stderrPath, DIR_SEPERATOR STDERR_FILE, SDL_arraysize(stderrPath) ); #endif newfp = freopen(stderrPath, TEXT("w"), stderr); #ifndef _WIN32_WCE if ( newfp == NULL ) { /* This happens on NT */ #if !defined(stderr) stderr = fopen(stderrPath, TEXT("w")); #else newfp = fopen(stderrPath, TEXT("w")); if ( newfp ) { *stderr = *newfp; } #endif } #endif /* _WIN32_WCE */ setvbuf(stdout, NULL, _IOLBF, BUFSIZ); /* Line buffered */ setbuf(stderr, NULL); /* No buffering */ #endif /* !NO_STDIO_REDIRECT */ #ifdef _WIN32_WCE nLen = wcslen(szCmdLine)+128+1; bufp = SDL_stack_alloc(wchar_t, nLen*2); wcscpy (bufp, TEXT("\"")); GetModuleFileName(NULL, bufp+1, 128-3); wcscpy (bufp+wcslen(bufp), TEXT("\" ")); wcsncpy(bufp+wcslen(bufp), szCmdLine,nLen-wcslen(bufp)); nLen = wcslen(bufp)+1; cmdline = SDL_stack_alloc(char, nLen); if ( cmdline == NULL ) { return OutOfMemory(); } WideCharToMultiByte(CP_ACP, 0, bufp, -1, cmdline, nLen, NULL, NULL); #else /* Grab the command line */ bufp = GetCommandLine(); nLen = SDL_strlen(bufp)+1; cmdline = SDL_stack_alloc(char, nLen); if ( cmdline == NULL ) { return OutOfMemory(); } SDL_strlcpy(cmdline, bufp, nLen); #endif /* Parse it into argv and argc */ argc = ParseCommandLine(cmdline, NULL); argv = SDL_stack_alloc(char*, argc+1); if ( argv == NULL ) { return OutOfMemory(); } ParseCommandLine(cmdline, argv); /* Run the main program (after a little SDL initialization) */ console_main(argc, argv); /* Hush little compiler, don't you cry... */ return 0; }