include/SDL_hints.h
author David Ludwig <dludwig@pobox.com>
Sun, 26 Jan 2014 08:06:36 -0500
changeset 8577 462760a8b82e
parent 8576 8dd593afe2d7
child 8583 fb2933ca805f
permissions -rw-r--r--
WinRT: simulate keyboard events on Windows Phone 8 back-button presses

Pressing the hardware back button on a Windows Phone 8 device will now cause SDL to emit a pair of key-down and key-up events, with the SDL scancode, SDL_SCANCODE_AC_BACK.

By default, if WinRT's native back-button-press events are not explicitly marked as 'handled', then Windows Phone will terminate the app. More details on Microsoft's reasoning behind this can be found on MSDN, at http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj247550(v=vs.105).aspx

To mark back-button-press events as 'handled', set SDL_HINT_WINRT_HANDLE_BACK_BUTTON to 1. Setting it to anything else will cause these events to not be marked as 'handled'.

Due to limitations in Windows Phone's APIs, SDL will emit a virtual key-up event immediately after the back button's key-down event is registered. Unfortunately, Windows Phone 8 only allows one to register for back-button-press events, and not back-button-release events.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 /**
    23  *  \file SDL_hints.h
    24  *
    25  *  Official documentation for SDL configuration variables
    26  *
    27  *  This file contains functions to set and get configuration hints,
    28  *  as well as listing each of them alphabetically.
    29  *
    30  *  The convention for naming hints is SDL_HINT_X, where "SDL_X" is
    31  *  the environment variable that can be used to override the default.
    32  *
    33  *  In general these hints are just that - they may or may not be
    34  *  supported or applicable on any given platform, but they provide
    35  *  a way for an application or user to give the library a hint as
    36  *  to how they would like the library to work.
    37  */
    38 
    39 #ifndef _SDL_hints_h
    40 #define _SDL_hints_h
    41 
    42 #include "SDL_stdinc.h"
    43 
    44 #include "begin_code.h"
    45 /* Set up for C function definitions, even when using C++ */
    46 #ifdef __cplusplus
    47 extern "C" {
    48 #endif
    49 
    50 /**
    51  *  \brief  A variable controlling how 3D acceleration is used to accelerate the SDL screen surface.
    52  *
    53  *  SDL can try to accelerate the SDL screen surface by using streaming
    54  *  textures with a 3D rendering engine.  This variable controls whether and
    55  *  how this is done.
    56  *
    57  *  This variable can be set to the following values:
    58  *    "0"       - Disable 3D acceleration
    59  *    "1"       - Enable 3D acceleration, using the default renderer.
    60  *    "X"       - Enable 3D acceleration, using X where X is one of the valid rendering drivers.  (e.g. "direct3d", "opengl", etc.)
    61  *
    62  *  By default SDL tries to make a best guess for each platform whether
    63  *  to use acceleration or not.
    64  */
    65 #define SDL_HINT_FRAMEBUFFER_ACCELERATION   "SDL_FRAMEBUFFER_ACCELERATION"
    66 
    67 /**
    68  *  \brief  A variable specifying which render driver to use.
    69  *
    70  *  If the application doesn't pick a specific renderer to use, this variable
    71  *  specifies the name of the preferred renderer.  If the preferred renderer
    72  *  can't be initialized, the normal default renderer is used.
    73  *
    74  *  This variable is case insensitive and can be set to the following values:
    75  *    "direct3d"
    76  *    "opengl"
    77  *    "opengles2"
    78  *    "opengles"
    79  *    "software"
    80  *
    81  *  The default varies by platform, but it's the first one in the list that
    82  *  is available on the current platform.
    83  */
    84 #define SDL_HINT_RENDER_DRIVER              "SDL_RENDER_DRIVER"
    85 
    86 /**
    87  *  \brief  A variable controlling whether the OpenGL render driver uses shaders if they are available.
    88  *
    89  *  This variable can be set to the following values:
    90  *    "0"       - Disable shaders
    91  *    "1"       - Enable shaders
    92  *
    93  *  By default shaders are used if OpenGL supports them.
    94  */
    95 #define SDL_HINT_RENDER_OPENGL_SHADERS      "SDL_RENDER_OPENGL_SHADERS"
    96 
    97 /**
    98  *  \brief  A variable controlling whether the Direct3D device is initialized for thread-safe operations.
    99  *
   100  *  This variable can be set to the following values:
   101  *    "0"       - Thread-safety is not enabled (faster)
   102  *    "1"       - Thread-safety is enabled
   103  *
   104  *  By default the Direct3D device is created with thread-safety disabled.
   105  */
   106 #define SDL_HINT_RENDER_DIRECT3D_THREADSAFE "SDL_RENDER_DIRECT3D_THREADSAFE"
   107 
   108 /**
   109  *  \brief  A variable controlling the scaling quality
   110  *
   111  *  This variable can be set to the following values:
   112  *    "0" or "nearest" - Nearest pixel sampling
   113  *    "1" or "linear"  - Linear filtering (supported by OpenGL and Direct3D)
   114  *    "2" or "best"    - Currently this is the same as "linear"
   115  *
   116  *  By default nearest pixel sampling is used
   117  */
   118 #define SDL_HINT_RENDER_SCALE_QUALITY       "SDL_RENDER_SCALE_QUALITY"
   119 
   120 /**
   121  *  \brief  A variable controlling whether updates to the SDL screen surface should be synchronized with the vertical refresh, to avoid tearing.
   122  *
   123  *  This variable can be set to the following values:
   124  *    "0"       - Disable vsync
   125  *    "1"       - Enable vsync
   126  *
   127  *  By default SDL does not sync screen surface updates with vertical refresh.
   128  */
   129 #define SDL_HINT_RENDER_VSYNC               "SDL_RENDER_VSYNC"
   130 
   131 /**
   132  *  \brief  A variable controlling whether to enable Direct3D 11+'s Debug Layer.
   133  *
   134  *  This variable does not have any effect on the Direct3D 9 based renderer,
   135  *  which is used in Win32-based (aka Windows Desktop) apps.
   136  *
   137  *  This variable can be set to the following values:
   138  *    "0"       - Disable Debug Layer use
   139  *    "1"       - Enable Debug Layer use
   140  *
   141  *  By default, SDL does not use Direct3D Debug Layer.
   142  */
   143 #define SDL_HINT_RENDER_DIRECT3D11_DEBUG    "SDL_HINT_RENDER_DIRECT3D11_DEBUG"
   144 
   145 /**
   146  *  \brief  A variable controlling whether the X11 VidMode extension should be used.
   147  *
   148  *  This variable can be set to the following values:
   149  *    "0"       - Disable XVidMode
   150  *    "1"       - Enable XVidMode
   151  *
   152  *  By default SDL will use XVidMode if it is available.
   153  */
   154 #define SDL_HINT_VIDEO_X11_XVIDMODE         "SDL_VIDEO_X11_XVIDMODE"
   155 
   156 /**
   157  *  \brief  A variable controlling whether the X11 Xinerama extension should be used.
   158  *
   159  *  This variable can be set to the following values:
   160  *    "0"       - Disable Xinerama
   161  *    "1"       - Enable Xinerama
   162  *
   163  *  By default SDL will use Xinerama if it is available.
   164  */
   165 #define SDL_HINT_VIDEO_X11_XINERAMA         "SDL_VIDEO_X11_XINERAMA"
   166 
   167 /**
   168  *  \brief  A variable controlling whether the X11 XRandR extension should be used.
   169  *
   170  *  This variable can be set to the following values:
   171  *    "0"       - Disable XRandR
   172  *    "1"       - Enable XRandR
   173  *
   174  *  By default SDL will not use XRandR because of window manager issues.
   175  */
   176 #define SDL_HINT_VIDEO_X11_XRANDR           "SDL_VIDEO_X11_XRANDR"
   177 
   178 /**
   179  *  \brief  A variable controlling whether grabbing input grabs the keyboard
   180  *
   181  *  This variable can be set to the following values:
   182  *    "0"       - Grab will affect only the mouse
   183  *    "1"       - Grab will affect mouse and keyboard
   184  *
   185  *  By default SDL will not grab the keyboard so system shortcuts still work.
   186  */
   187 #define SDL_HINT_GRAB_KEYBOARD              "SDL_GRAB_KEYBOARD"
   188 
   189 /**
   190  *  \brief Minimize your SDL_Window if it loses key focus when in Fullscreen mode. Defaults to true.
   191  *
   192  */
   193 #define SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS   "SDL_VIDEO_MINIMIZE_ON_FOCUS_LOSS"
   194 
   195 /**
   196  *  \brief Set whether windows go fullscreen in their own spaces on Mac OS X
   197  *
   198  *  This variable can be set to the following values:
   199  *    "0"       - Fullscreen windows will use the classic fullscreen mode
   200  *    "1"       - Fullscreen windows will use fullscreen spaces
   201  *
   202  *  By default SDL will use the classic fullscreen mode.
   203  */
   204 #define SDL_HINT_VIDEO_FULLSCREEN_SPACES   "SDL_VIDEO_FULLSCREEN_SPACES"
   205 
   206 /**
   207  *  \brief  A variable controlling whether the idle timer is disabled on iOS.
   208  *
   209  *  When an iOS app does not receive touches for some time, the screen is
   210  *  dimmed automatically. For games where the accelerometer is the only input
   211  *  this is problematic. This functionality can be disabled by setting this
   212  *  hint.
   213  *
   214  *  This variable can be set to the following values:
   215  *    "0"       - Enable idle timer
   216  *    "1"       - Disable idle timer
   217  */
   218 #define SDL_HINT_IDLE_TIMER_DISABLED "SDL_IOS_IDLE_TIMER_DISABLED"
   219 
   220 /**
   221  *  \brief  A variable controlling which orientations are allowed on iOS.
   222  *
   223  *  In some circumstances it is necessary to be able to explicitly control
   224  *  which UI orientations are allowed.
   225  *
   226  *  This variable is a space delimited list of the following values:
   227  *    "LandscapeLeft", "LandscapeRight", "Portrait" "PortraitUpsideDown"
   228  */
   229 #define SDL_HINT_ORIENTATIONS "SDL_IOS_ORIENTATIONS"
   230     
   231 /**
   232  *  \brief  A variable controlling whether an Android built-in accelerometer should be
   233  *  listed as a joystick device, rather than listing actual joysticks only.
   234  *
   235  *  This variable can be set to the following values:
   236  *    "0"       - List only real joysticks and accept input from them
   237  *    "1"       - List real joysticks along with the accelerometer as if it were a 3 axis joystick (the default).
   238  */
   239 #define SDL_HINT_ACCEL_AS_JOY "SDL_ACCEL_AS_JOY"
   240 
   241 
   242 /**
   243  *  \brief  A variable that lets you disable the detection and use of Xinput gamepad devices
   244  *
   245  *  The variable can be set to the following values:
   246  *    "0"       - Disable XInput timer (only uses direct input)
   247  *    "1"       - Enable XInput timer (the default)
   248  */
   249 #define SDL_HINT_XINPUT_ENABLED "SDL_XINPUT_ENABLED"
   250 
   251 
   252 /**
   253  *  \brief  A variable that lets you manually hint extra gamecontroller db entries
   254  *
   255  *  The variable should be newline delimited rows of gamecontroller config data, see SDL_gamecontroller.h
   256  *
   257  *  This hint must be set before calling SDL_Init(SDL_INIT_GAMECONTROLLER)
   258  *  You can update mappings after the system is initialized with SDL_GameControllerMappingForGUID() and SDL_GameControllerAddMapping()
   259  */
   260 #define SDL_HINT_GAMECONTROLLERCONFIG "SDL_GAMECONTROLLERCONFIG"
   261 
   262 
   263 /**
   264  *  \brief  A variable that lets you enable joystick (and gamecontroller) events even when your app is in the background.
   265  *
   266  *  The variable can be set to the following values:
   267  *    "0"       - Disable joystick & gamecontroller input events when the
   268  *                application is in the background.
   269  *    "1"       - Enable joystick & gamecontroller input events when the
   270  *                application is in the backgroumd.
   271  *
   272  *  The default value is "0".  This hint may be set at any time.
   273  */
   274 #define SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS "SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS"
   275 
   276 
   277 /**
   278  *  \brief If set to 0 then never set the top most bit on a SDL Window, even if the video mode expects it.
   279  *      This is a debugging aid for developers and not expected to be used by end users. The default is "1"
   280  *
   281  *  This variable can be set to the following values:
   282  *    "0"       - don't allow topmost
   283  *    "1"       - allow topmost
   284  */
   285 #define SDL_HINT_ALLOW_TOPMOST "SDL_ALLOW_TOPMOST"
   286 
   287 
   288 /**
   289  *  \brief A variable that controls the timer resolution, in milliseconds.
   290  *
   291  *  The higher resolution the timer, the more frequently the CPU services
   292  *  timer interrupts, and the more precise delays are, but this takes up
   293  *  power and CPU time.  This hint is only used on Windows 7 and earlier.
   294  *
   295  *  See this blog post for more information:
   296  *  http://randomascii.wordpress.com/2013/07/08/windows-timer-resolution-megawatts-wasted/
   297  *
   298  *  If this variable is set to "0", the system timer resolution is not set.
   299  *
   300  *  The default value is "1". This hint may be set at any time.
   301  */
   302 #define SDL_HINT_TIMER_RESOLUTION "SDL_TIMER_RESOLUTION"
   303 
   304 
   305 /**
   306  *  \brief If set to 1, then do not allow high-DPI windows. ("Retina" on Mac)
   307  */
   308 #define SDL_HINT_VIDEO_HIGHDPI_DISABLED "SDL_VIDEO_HIGHDPI_DISABLED"
   309 
   310 /**
   311  *  \brief A variable that determines whether ctrl+click should generate a right-click event on Mac
   312  *  
   313  *  If present, holding ctrl while left clicking will generate a right click
   314  *  event when on Mac.
   315  */
   316 #define SDL_HINT_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK "SDL_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK"
   317 
   318 /**
   319 *  \brief  A variable specifying which shader compiler to preload when using the Chrome ANGLE binaries
   320 *
   321 *  SDL has EGL and OpenGL ES2 support on Windows via the ANGLE project. It
   322 *  can use two different sets of binaries, those compiled by the user from source
   323 *  or those provided by the Chrome browser. In the later case, these binaries require
   324 *  that SDL loads 
   325 *
   326 *  This variable can be set to the following values:
   327 *    "d3dcompiler_46.dll" - default, best for Vista or later.
   328 *    "d3dcompiler_43.dll" - for XP support.
   329 *    "none" - do not load any library, useful if you compiled ANGLE from source and included the compiler in your binaries.
   330 *
   331 */
   332 #define SDL_HINT_VIDEO_WIN_D3DCOMPILER              "SDL_VIDEO_WIN_D3DCOMPILER"
   333 
   334 /**
   335  *  \brief A URL to a WinRT app's privacy policy
   336  *
   337  *  All network-enabled WinRT apps must make a privacy policy available to its
   338  *  users.  On Windows 8, 8.1, and RT, Microsoft mandates that this policy be
   339  *  be available in the Windows Settings charm, as accessed from within the app.
   340  *  SDL provides code to add a URL-based link there, which can point to the app's
   341  *  privacy policy.
   342  *
   343  *  To setup a URL to an app's privacy policy, set SDL_HINT_WINRT_PRIVACY_POLICY_URL
   344  *  before calling any SDL_Init functions.  The contents of the hint should
   345  *  be a valid URL.  For example, "http://www.example.com".
   346  *
   347  *  The default value is "", which will prevent SDL from adding a privacy policy
   348  *  link to the Settings charm.  This hint should only be set during app init.
   349  *
   350  *  The label text of an app's "Privacy Policy" link may be customized via another
   351  *  hint, SDL_HINT_WINRT_PRIVACY_POLICY_LABEL.
   352  *
   353  *  Please note that on Windows Phone, Microsoft does not provide standard UI
   354  *  for displaying a privacy policy link, and as such, SDL_HINT_WINRT_PRIVACY_POLICY_URL
   355  *  will not get used on that platform.  Network-enabled phone apps should display
   356  *  their privacy policy through some other, in-app means.
   357  */
   358 #define SDL_HINT_WINRT_PRIVACY_POLICY_URL "SDL_HINT_WINRT_PRIVACY_POLICY_URL"
   359 
   360 /** \brief Label text for a WinRT app's privacy policy link
   361  *
   362  *  Network-enabled WinRT apps must include a privacy policy.  On Windows 8, 8.1, and RT,
   363  *  Microsoft mandates that this policy be available via the Windows Settings charm.
   364  *  SDL provides code to add a link there, with it's label text being set via the
   365  *  optional hint, SDL_HINT_WINRT_PRIVACY_POLICY_LABEL.
   366  *
   367  *  Please note that a privacy policy's contents are not set via this hint.  A separate
   368  *  hint, SDL_HINT_WINRT_PRIVACY_POLICY_URL, is used to link to the actual text of the
   369  *  policy.
   370  *
   371  *  The contents of this hint should be encoded as a UTF8 string.
   372  *
   373  *  The default value is "Privacy Policy".  This hint should only be set during app
   374  *  initialization, preferably before any calls to SDL_Init.
   375  *
   376  *  For additional information on linking to a privacy policy, see the documentation for
   377  *  SDL_HINT_WINRT_PRIVACY_POLICY_URL.
   378  */
   379 #define SDL_HINT_WINRT_PRIVACY_POLICY_LABEL "SDL_HINT_WINRT_PRIVACY_POLICY_LABEL"
   380 
   381 /** \brief If set to 1, back button press events on Windows Phone 8+ will be marked as handled.
   382  *
   383  *  TODO, WinRT: document SDL_HINT_WINRT_HANDLE_BACK_BUTTON need and use
   384  *  For now, more details on why this is needed can be found at the
   385  *  beginning of the following web page:
   386  *  http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj247550(v=vs.105).aspx
   387  */
   388 #define SDL_HINT_WINRT_HANDLE_BACK_BUTTON "SDL_HINT_WINRT_HANDLE_BACK_BUTTON"
   389 
   390 /**
   391  *  \brief  An enumeration of hint priorities
   392  */
   393 typedef enum
   394 {
   395     SDL_HINT_DEFAULT,
   396     SDL_HINT_NORMAL,
   397     SDL_HINT_OVERRIDE
   398 } SDL_HintPriority;
   399 
   400 
   401 /**
   402  *  \brief Set a hint with a specific priority
   403  *
   404  *  The priority controls the behavior when setting a hint that already
   405  *  has a value.  Hints will replace existing hints of their priority and
   406  *  lower.  Environment variables are considered to have override priority.
   407  *
   408  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   409  */
   410 extern DECLSPEC SDL_bool SDLCALL SDL_SetHintWithPriority(const char *name,
   411                                                          const char *value,
   412                                                          SDL_HintPriority priority);
   413 
   414 /**
   415  *  \brief Set a hint with normal priority
   416  *
   417  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   418  */
   419 extern DECLSPEC SDL_bool SDLCALL SDL_SetHint(const char *name,
   420                                              const char *value);
   421 
   422 /**
   423  *  \brief Get a hint
   424  *
   425  *  \return The string value of a hint variable.
   426  */
   427 extern DECLSPEC const char * SDLCALL SDL_GetHint(const char *name);
   428 
   429 /**
   430  *  \brief Add a function to watch a particular hint
   431  *
   432  *  \param name The hint to watch
   433  *  \param callback The function to call when the hint value changes
   434  *  \param userdata A pointer to pass to the callback function
   435  */
   436 typedef void (*SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);
   437 extern DECLSPEC void SDLCALL SDL_AddHintCallback(const char *name,
   438                                                  SDL_HintCallback callback,
   439                                                  void *userdata);
   440 
   441 /**
   442  *  \brief Remove a function watching a particular hint
   443  *
   444  *  \param name The hint being watched
   445  *  \param callback The function being called when the hint value changes
   446  *  \param userdata A pointer being passed to the callback function
   447  */
   448 extern DECLSPEC void SDLCALL SDL_DelHintCallback(const char *name,
   449                                                  SDL_HintCallback callback,
   450                                                  void *userdata);
   451 
   452 /**
   453  *  \brief  Clear all hints
   454  *
   455  *  This function is called during SDL_Quit() to free stored hints.
   456  */
   457 extern DECLSPEC void SDLCALL SDL_ClearHints(void);
   458 
   459 
   460 /* Ends C function definitions when using C++ */
   461 #ifdef __cplusplus
   462 }
   463 #endif
   464 #include "close_code.h"
   465 
   466 #endif /* _SDL_hints_h */
   467 
   468 /* vi: set ts=4 sw=4 expandtab: */