include/SDL_hints.h
author Sam Lantinga <slouken@libsdl.org>
Tue, 10 Jan 2017 08:54:33 -0800
changeset 10806 36f40b8cc979
parent 10737 3406a0f8b041
child 10812 a2d6288be599
permissions -rw-r--r--
Fixed bugs 2570, 3145, improved OpenGL ES context support on Windows and X11

Mark Callow

The attached patch does the following for the X11 and Windows platforms, the only ones where SDL attempts to use context_create_es_profile:

- Adds SDL_HINT_OPENGL_ES_DRIVER by which the application can
say to use the OpenGL ES driver & EGL rather than the Open GL
driver. (For bug #2570)
- Adds code to {WIN,X11}_GL_InitExtensions to determine the maximum
OpenGL ES version supported by the OpenGL driver (for bug #3145)
- Modifies the test that determines whether to use the OpenGL
driver or the real OpenGL ES driver to take into account the
hint, the requested and supported ES version and whether ES 1.X
is being requested. (For bug #2570 & bug #3145)
- Enables the testgles2 test for __WINDOWS__ and __LINUX__ and adds
the test to the VisualC projects.

With the fix in place I have run testdraw2, testgl and testgles2 without any issues and have run my own apps that use OpenGL, OpenGL ES 3 and OpenGL ES 1.1.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2017 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 whether to enable Direct3D 11+'s Debug Layer.
   110  *
   111  *  This variable does not have any effect on the Direct3D 9 based renderer.
   112  *
   113  *  This variable can be set to the following values:
   114  *    "0"       - Disable Debug Layer use
   115  *    "1"       - Enable Debug Layer use
   116  *
   117  *  By default, SDL does not use Direct3D Debug Layer.
   118  */
   119 #define SDL_HINT_RENDER_DIRECT3D11_DEBUG    "SDL_RENDER_DIRECT3D11_DEBUG"
   120 
   121 /**
   122  *  \brief  A variable controlling the scaling quality
   123  *
   124  *  This variable can be set to the following values:
   125  *    "0" or "nearest" - Nearest pixel sampling
   126  *    "1" or "linear"  - Linear filtering (supported by OpenGL and Direct3D)
   127  *    "2" or "best"    - Currently this is the same as "linear"
   128  *
   129  *  By default nearest pixel sampling is used
   130  */
   131 #define SDL_HINT_RENDER_SCALE_QUALITY       "SDL_RENDER_SCALE_QUALITY"
   132 
   133 /**
   134  *  \brief  A variable controlling whether updates to the SDL screen surface should be synchronized with the vertical refresh, to avoid tearing.
   135  *
   136  *  This variable can be set to the following values:
   137  *    "0"       - Disable vsync
   138  *    "1"       - Enable vsync
   139  *
   140  *  By default SDL does not sync screen surface updates with vertical refresh.
   141  */
   142 #define SDL_HINT_RENDER_VSYNC               "SDL_RENDER_VSYNC"
   143 
   144 /**
   145  *  \brief  A variable controlling whether the screensaver is enabled. 
   146  *
   147  *  This variable can be set to the following values:
   148  *    "0"       - Disable screensaver
   149  *    "1"       - Enable screensaver
   150  *
   151  *  By default SDL will disable the screensaver.
   152  */
   153 #define SDL_HINT_VIDEO_ALLOW_SCREENSAVER    "SDL_VIDEO_ALLOW_SCREENSAVER"
   154 
   155 /**
   156  *  \brief  A variable controlling whether the X11 VidMode extension should be used.
   157  *
   158  *  This variable can be set to the following values:
   159  *    "0"       - Disable XVidMode
   160  *    "1"       - Enable XVidMode
   161  *
   162  *  By default SDL will use XVidMode if it is available.
   163  */
   164 #define SDL_HINT_VIDEO_X11_XVIDMODE         "SDL_VIDEO_X11_XVIDMODE"
   165 
   166 /**
   167  *  \brief  A variable controlling whether the X11 Xinerama extension should be used.
   168  *
   169  *  This variable can be set to the following values:
   170  *    "0"       - Disable Xinerama
   171  *    "1"       - Enable Xinerama
   172  *
   173  *  By default SDL will use Xinerama if it is available.
   174  */
   175 #define SDL_HINT_VIDEO_X11_XINERAMA         "SDL_VIDEO_X11_XINERAMA"
   176 
   177 /**
   178  *  \brief  A variable controlling whether the X11 XRandR extension should be used.
   179  *
   180  *  This variable can be set to the following values:
   181  *    "0"       - Disable XRandR
   182  *    "1"       - Enable XRandR
   183  *
   184  *  By default SDL will not use XRandR because of window manager issues.
   185  */
   186 #define SDL_HINT_VIDEO_X11_XRANDR           "SDL_VIDEO_X11_XRANDR"
   187 
   188 /**
   189  *  \brief  A variable controlling whether the X11 _NET_WM_PING protocol should be supported.
   190  *
   191  *  This variable can be set to the following values:
   192  *    "0"       - Disable _NET_WM_PING
   193  *    "1"       - Enable _NET_WM_PING
   194  *
   195  *  By default SDL will use _NET_WM_PING, but for applications that know they
   196  *  will not always be able to respond to ping requests in a timely manner they can
   197  *  turn it off to avoid the window manager thinking the app is hung.
   198  *  The hint is checked in CreateWindow.
   199  */
   200 #define SDL_HINT_VIDEO_X11_NET_WM_PING      "SDL_VIDEO_X11_NET_WM_PING"
   201 
   202 /**
   203  *  \brief  A variable controlling whether the window frame and title bar are interactive when the cursor is hidden 
   204  *
   205  *  This variable can be set to the following values:
   206  *    "0"       - The window frame is not interactive when the cursor is hidden (no move, resize, etc)
   207  *    "1"       - The window frame is interactive when the cursor is hidden
   208  *
   209  *  By default SDL will allow interaction with the window frame when the cursor is hidden
   210  */
   211 #define SDL_HINT_WINDOW_FRAME_USABLE_WHILE_CURSOR_HIDDEN    "SDL_WINDOW_FRAME_USABLE_WHILE_CURSOR_HIDDEN"
   212 
   213 /**
   214  *  \brief  A variable controlling whether the windows message loop is processed by SDL 
   215  *
   216  *  This variable can be set to the following values:
   217  *    "0"       - The window message loop is not run
   218  *    "1"       - The window message loop is processed in SDL_PumpEvents()
   219  *
   220  *  By default SDL will process the windows message loop
   221  */
   222 #define SDL_HINT_WINDOWS_ENABLE_MESSAGELOOP "SDL_WINDOWS_ENABLE_MESSAGELOOP"
   223 
   224 /**
   225  *  \brief  A variable controlling whether grabbing input grabs the keyboard
   226  *
   227  *  This variable can be set to the following values:
   228  *    "0"       - Grab will affect only the mouse
   229  *    "1"       - Grab will affect mouse and keyboard
   230  *
   231  *  By default SDL will not grab the keyboard so system shortcuts still work.
   232  */
   233 #define SDL_HINT_GRAB_KEYBOARD              "SDL_GRAB_KEYBOARD"
   234 
   235 /**
   236  *  \brief  A variable setting the speed scale for mouse motion, in floating point, when the mouse is not in relative mode
   237  */
   238 #define SDL_HINT_MOUSE_NORMAL_SPEED_SCALE    "SDL_MOUSE_NORMAL_SPEED_SCALE"
   239 
   240 /**
   241  *  \brief  A variable setting the scale for mouse motion, in floating point, when the mouse is in relative mode
   242  */
   243 #define SDL_HINT_MOUSE_RELATIVE_SPEED_SCALE    "SDL_MOUSE_RELATIVE_SPEED_SCALE"
   244 
   245 /**
   246  *  \brief  A variable controlling whether relative mouse mode is implemented using mouse warping
   247  *
   248  *  This variable can be set to the following values:
   249  *    "0"       - Relative mouse mode uses raw input
   250  *    "1"       - Relative mouse mode uses mouse warping
   251  *
   252  *  By default SDL will use raw input for relative mouse mode
   253  */
   254 #define SDL_HINT_MOUSE_RELATIVE_MODE_WARP    "SDL_MOUSE_RELATIVE_MODE_WARP"
   255 
   256 /**
   257  *  \brief Allow mouse click events when clicking to focus an SDL window
   258  *
   259  *  This variable can be set to the following values:
   260  *    "0"       - Ignore mouse clicks that activate a window
   261  *    "1"       - Generate events for mouse clicks that activate a window
   262  *
   263  *  By default SDL will ignore mouse clicks that activate a window
   264  */
   265 #define SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH "SDL_MOUSE_FOCUS_CLICKTHROUGH"
   266 
   267 /**
   268  *  \brief Minimize your SDL_Window if it loses key focus when in fullscreen mode. Defaults to true.
   269  *
   270  */
   271 #define SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS   "SDL_VIDEO_MINIMIZE_ON_FOCUS_LOSS"
   272 
   273 /**
   274  *  \brief  A variable controlling whether the idle timer is disabled on iOS.
   275  *
   276  *  When an iOS app does not receive touches for some time, the screen is
   277  *  dimmed automatically. For games where the accelerometer is the only input
   278  *  this is problematic. This functionality can be disabled by setting this
   279  *  hint.
   280  *
   281  *  As of SDL 2.0.4, SDL_EnableScreenSaver() and SDL_DisableScreenSaver()
   282  *  accomplish the same thing on iOS. They should be preferred over this hint.
   283  *
   284  *  This variable can be set to the following values:
   285  *    "0"       - Enable idle timer
   286  *    "1"       - Disable idle timer
   287  */
   288 #define SDL_HINT_IDLE_TIMER_DISABLED "SDL_IOS_IDLE_TIMER_DISABLED"
   289 
   290 /**
   291  *  \brief  A variable controlling which orientations are allowed on iOS.
   292  *
   293  *  In some circumstances it is necessary to be able to explicitly control
   294  *  which UI orientations are allowed.
   295  *
   296  *  This variable is a space delimited list of the following values:
   297  *    "LandscapeLeft", "LandscapeRight", "Portrait" "PortraitUpsideDown"
   298  */
   299 #define SDL_HINT_ORIENTATIONS "SDL_IOS_ORIENTATIONS"
   300 
   301 /**
   302  *  \brief  A variable controlling whether controllers used with the Apple TV
   303  *  generate UI events.
   304  *
   305  * When UI events are generated by controller input, the app will be
   306  * backgrounded when the Apple TV remote's menu button is pressed, and when the
   307  * pause or B buttons on gamepads are pressed.
   308  *
   309  * More information about properly making use of controllers for the Apple TV
   310  * can be found here:
   311  * https://developer.apple.com/tvos/human-interface-guidelines/remote-and-controllers/
   312  *
   313  *  This variable can be set to the following values:
   314  *    "0"       - Controller input does not generate UI events (the default).
   315  *    "1"       - Controller input generates UI events.
   316  */
   317 #define SDL_HINT_APPLE_TV_CONTROLLER_UI_EVENTS "SDL_APPLE_TV_CONTROLLER_UI_EVENTS"
   318 
   319 /**
   320  * \brief  A variable controlling whether the Apple TV remote's joystick axes
   321  *         will automatically match the rotation of the remote.
   322  *
   323  *  This variable can be set to the following values:
   324  *    "0"       - Remote orientation does not affect joystick axes (the default).
   325  *    "1"       - Joystick axes are based on the orientation of the remote.
   326  */
   327 #define SDL_HINT_APPLE_TV_REMOTE_ALLOW_ROTATION "SDL_APPLE_TV_REMOTE_ALLOW_ROTATION"
   328 
   329 /**
   330  *  \brief  A variable controlling whether the Android / iOS built-in
   331  *  accelerometer should be listed as a joystick device, rather than listing
   332  *  actual joysticks only.
   333  *
   334  *  This variable can be set to the following values:
   335  *    "0"       - List only real joysticks and accept input from them
   336  *    "1"       - List real joysticks along with the accelerometer as if it were a 3 axis joystick (the default).
   337  */
   338 #define SDL_HINT_ACCELEROMETER_AS_JOYSTICK "SDL_ACCELEROMETER_AS_JOYSTICK"
   339 
   340 
   341 /**
   342  *  \brief  A variable that lets you disable the detection and use of Xinput gamepad devices
   343  *
   344  *  The variable can be set to the following values:
   345  *    "0"       - Disable XInput detection (only uses direct input)
   346  *    "1"       - Enable XInput detection (the default)
   347  */
   348 #define SDL_HINT_XINPUT_ENABLED "SDL_XINPUT_ENABLED"
   349 
   350 
   351 /**
   352  *  \brief  A variable that causes SDL to use the old axis and button mapping for XInput devices.
   353  *
   354  *  This hint is for backwards compatibility only and will be removed in SDL 2.1
   355  *
   356  *  The default value is "0".  This hint must be set before SDL_Init()
   357  */
   358 #define SDL_HINT_XINPUT_USE_OLD_JOYSTICK_MAPPING "SDL_XINPUT_USE_OLD_JOYSTICK_MAPPING"
   359 
   360 
   361 /**
   362  *  \brief  A variable that lets you manually hint extra gamecontroller db entries
   363  *
   364  *  The variable should be newline delimited rows of gamecontroller config data, see SDL_gamecontroller.h
   365  *
   366  *  This hint must be set before calling SDL_Init(SDL_INIT_GAMECONTROLLER)
   367  *  You can update mappings after the system is initialized with SDL_GameControllerMappingForGUID() and SDL_GameControllerAddMapping()
   368  */
   369 #define SDL_HINT_GAMECONTROLLERCONFIG "SDL_GAMECONTROLLERCONFIG"
   370 
   371 
   372 /**
   373  *  \brief  A variable that lets you enable joystick (and gamecontroller) events even when your app is in the background.
   374  *
   375  *  The variable can be set to the following values:
   376  *    "0"       - Disable joystick & gamecontroller input events when the
   377  *                application is in the background.
   378  *    "1"       - Enable joystick & gamecontroller input events when the
   379  *                application is in the background.
   380  *
   381  *  The default value is "0".  This hint may be set at any time.
   382  */
   383 #define SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS "SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS"
   384 
   385 
   386 /**
   387  *  \brief If set to "0" then never set the top most bit on a SDL Window, even if the video mode expects it.
   388  *      This is a debugging aid for developers and not expected to be used by end users. The default is "1"
   389  *
   390  *  This variable can be set to the following values:
   391  *    "0"       - don't allow topmost
   392  *    "1"       - allow topmost
   393  */
   394 #define SDL_HINT_ALLOW_TOPMOST "SDL_ALLOW_TOPMOST"
   395 
   396 
   397 /**
   398  *  \brief A variable that controls the timer resolution, in milliseconds.
   399  *
   400  *  The higher resolution the timer, the more frequently the CPU services
   401  *  timer interrupts, and the more precise delays are, but this takes up
   402  *  power and CPU time.  This hint is only used on Windows 7 and earlier.
   403  *
   404  *  See this blog post for more information:
   405  *  http://randomascii.wordpress.com/2013/07/08/windows-timer-resolution-megawatts-wasted/
   406  *
   407  *  If this variable is set to "0", the system timer resolution is not set.
   408  *
   409  *  The default value is "1". This hint may be set at any time.
   410  */
   411 #define SDL_HINT_TIMER_RESOLUTION "SDL_TIMER_RESOLUTION"
   412 
   413 
   414 /**
   415  *  \brief  A variable describing the content orientation on QtWayland-based platforms.
   416  *
   417  *  On QtWayland platforms, windows are rotated client-side to allow for custom
   418  *  transitions. In order to correctly position overlays (e.g. volume bar) and
   419  *  gestures (e.g. events view, close/minimize gestures), the system needs to
   420  *  know in which orientation the application is currently drawing its contents.
   421  *
   422  *  This does not cause the window to be rotated or resized, the application
   423  *  needs to take care of drawing the content in the right orientation (the
   424  *  framebuffer is always in portrait mode).
   425  *
   426  *  This variable can be one of the following values:
   427  *    "primary" (default), "portrait", "landscape", "inverted-portrait", "inverted-landscape"
   428  */
   429 #define SDL_HINT_QTWAYLAND_CONTENT_ORIENTATION "SDL_QTWAYLAND_CONTENT_ORIENTATION"
   430 
   431 /**
   432  *  \brief  Flags to set on QtWayland windows to integrate with the native window manager.
   433  *
   434  *  On QtWayland platforms, this hint controls the flags to set on the windows.
   435  *  For example, on Sailfish OS "OverridesSystemGestures" disables swipe gestures.
   436  *
   437  *  This variable is a space-separated list of the following values (empty = no flags):
   438  *    "OverridesSystemGestures", "StaysOnTop", "BypassWindowManager"
   439  */
   440 #define SDL_HINT_QTWAYLAND_WINDOW_FLAGS "SDL_QTWAYLAND_WINDOW_FLAGS"
   441 
   442 /**
   443 *  \brief  A string specifying SDL's threads stack size in bytes or "0" for the backend's default size
   444 *
   445 *  Use this hint in case you need to set SDL's threads stack size to other than the default.
   446 *  This is specially useful if you build SDL against a non glibc libc library (such as musl) which
   447 *  provides a relatively small default thread stack size (a few kilobytes versus the default 8MB glibc uses).
   448 *  Support for this hint is currently available only in the pthread, Windows, and PSP backend.
   449 */
   450 #define SDL_HINT_THREAD_STACK_SIZE              "SDL_THREAD_STACK_SIZE"
   451 
   452 /**
   453  *  \brief If set to 1, then do not allow high-DPI windows. ("Retina" on Mac and iOS)
   454  */
   455 #define SDL_HINT_VIDEO_HIGHDPI_DISABLED "SDL_VIDEO_HIGHDPI_DISABLED"
   456 
   457 /**
   458  *  \brief A variable that determines whether ctrl+click should generate a right-click event on Mac
   459  *
   460  *  If present, holding ctrl while left clicking will generate a right click
   461  *  event when on Mac.
   462  */
   463 #define SDL_HINT_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK "SDL_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK"
   464 
   465 /**
   466 *  \brief  A variable specifying which shader compiler to preload when using the Chrome ANGLE binaries
   467 *
   468 *  SDL has EGL and OpenGL ES2 support on Windows via the ANGLE project. It
   469 *  can use two different sets of binaries, those compiled by the user from source
   470 *  or those provided by the Chrome browser. In the later case, these binaries require
   471 *  that SDL loads a DLL providing the shader compiler.
   472 *
   473 *  This variable can be set to the following values:
   474 *    "d3dcompiler_46.dll" - default, best for Vista or later.
   475 *    "d3dcompiler_43.dll" - for XP support.
   476 *    "none" - do not load any library, useful if you compiled ANGLE from source and included the compiler in your binaries.
   477 *
   478 */
   479 #define SDL_HINT_VIDEO_WIN_D3DCOMPILER              "SDL_VIDEO_WIN_D3DCOMPILER"
   480 
   481 /**
   482 *  \brief  A variable that is the address of another SDL_Window* (as a hex string formatted with "%p").
   483 *  
   484 *  If this hint is set before SDL_CreateWindowFrom() and the SDL_Window* it is set to has
   485 *  SDL_WINDOW_OPENGL set (and running on WGL only, currently), then two things will occur on the newly 
   486 *  created SDL_Window:
   487 *
   488 *  1. Its pixel format will be set to the same pixel format as this SDL_Window.  This is
   489 *  needed for example when sharing an OpenGL context across multiple windows.
   490 *
   491 *  2. The flag SDL_WINDOW_OPENGL will be set on the new window so it can be used for
   492 *  OpenGL rendering.
   493 *
   494 *  This variable can be set to the following values:
   495 *    The address (as a string "%p") of the SDL_Window* that new windows created with SDL_CreateWindowFrom() should
   496 *    share a pixel format with.
   497 */
   498 #define SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT    "SDL_VIDEO_WINDOW_SHARE_PIXEL_FORMAT"
   499 
   500 /**
   501  *  \brief A URL to a WinRT app's privacy policy
   502  *
   503  *  All network-enabled WinRT apps must make a privacy policy available to its
   504  *  users.  On Windows 8, 8.1, and RT, Microsoft mandates that this policy be
   505  *  be available in the Windows Settings charm, as accessed from within the app.
   506  *  SDL provides code to add a URL-based link there, which can point to the app's
   507  *  privacy policy.
   508  *
   509  *  To setup a URL to an app's privacy policy, set SDL_HINT_WINRT_PRIVACY_POLICY_URL
   510  *  before calling any SDL_Init() functions.  The contents of the hint should
   511  *  be a valid URL.  For example, "http://www.example.com".
   512  *
   513  *  The default value is "", which will prevent SDL from adding a privacy policy
   514  *  link to the Settings charm.  This hint should only be set during app init.
   515  *
   516  *  The label text of an app's "Privacy Policy" link may be customized via another
   517  *  hint, SDL_HINT_WINRT_PRIVACY_POLICY_LABEL.
   518  *
   519  *  Please note that on Windows Phone, Microsoft does not provide standard UI
   520  *  for displaying a privacy policy link, and as such, SDL_HINT_WINRT_PRIVACY_POLICY_URL
   521  *  will not get used on that platform.  Network-enabled phone apps should display
   522  *  their privacy policy through some other, in-app means.
   523  */
   524 #define SDL_HINT_WINRT_PRIVACY_POLICY_URL "SDL_WINRT_PRIVACY_POLICY_URL"
   525 
   526 /** \brief Label text for a WinRT app's privacy policy link
   527  *
   528  *  Network-enabled WinRT apps must include a privacy policy.  On Windows 8, 8.1, and RT,
   529  *  Microsoft mandates that this policy be available via the Windows Settings charm.
   530  *  SDL provides code to add a link there, with its label text being set via the
   531  *  optional hint, SDL_HINT_WINRT_PRIVACY_POLICY_LABEL.
   532  *
   533  *  Please note that a privacy policy's contents are not set via this hint.  A separate
   534  *  hint, SDL_HINT_WINRT_PRIVACY_POLICY_URL, is used to link to the actual text of the
   535  *  policy.
   536  *
   537  *  The contents of this hint should be encoded as a UTF8 string.
   538  *
   539  *  The default value is "Privacy Policy".  This hint should only be set during app
   540  *  initialization, preferably before any calls to SDL_Init().
   541  *
   542  *  For additional information on linking to a privacy policy, see the documentation for
   543  *  SDL_HINT_WINRT_PRIVACY_POLICY_URL.
   544  */
   545 #define SDL_HINT_WINRT_PRIVACY_POLICY_LABEL "SDL_WINRT_PRIVACY_POLICY_LABEL"
   546 
   547 /** \brief Allows back-button-press events on Windows Phone to be marked as handled
   548  *
   549  *  Windows Phone devices typically feature a Back button.  When pressed,
   550  *  the OS will emit back-button-press events, which apps are expected to
   551  *  handle in an appropriate manner.  If apps do not explicitly mark these
   552  *  events as 'Handled', then the OS will invoke its default behavior for
   553  *  unhandled back-button-press events, which on Windows Phone 8 and 8.1 is to
   554  *  terminate the app (and attempt to switch to the previous app, or to the
   555  *  device's home screen).
   556  *
   557  *  Setting the SDL_HINT_WINRT_HANDLE_BACK_BUTTON hint to "1" will cause SDL
   558  *  to mark back-button-press events as Handled, if and when one is sent to
   559  *  the app.
   560  *
   561  *  Internally, Windows Phone sends back button events as parameters to
   562  *  special back-button-press callback functions.  Apps that need to respond
   563  *  to back-button-press events are expected to register one or more
   564  *  callback functions for such, shortly after being launched (during the
   565  *  app's initialization phase).  After the back button is pressed, the OS
   566  *  will invoke these callbacks.  If the app's callback(s) do not explicitly
   567  *  mark the event as handled by the time they return, or if the app never
   568  *  registers one of these callback, the OS will consider the event
   569  *  un-handled, and it will apply its default back button behavior (terminate
   570  *  the app).
   571  *
   572  *  SDL registers its own back-button-press callback with the Windows Phone
   573  *  OS.  This callback will emit a pair of SDL key-press events (SDL_KEYDOWN
   574  *  and SDL_KEYUP), each with a scancode of SDL_SCANCODE_AC_BACK, after which
   575  *  it will check the contents of the hint, SDL_HINT_WINRT_HANDLE_BACK_BUTTON.
   576  *  If the hint's value is set to "1", the back button event's Handled
   577  *  property will get set to 'true'.  If the hint's value is set to something
   578  *  else, or if it is unset, SDL will leave the event's Handled property
   579  *  alone.  (By default, the OS sets this property to 'false', to note.)
   580  *
   581  *  SDL apps can either set SDL_HINT_WINRT_HANDLE_BACK_BUTTON well before a
   582  *  back button is pressed, or can set it in direct-response to a back button
   583  *  being pressed.
   584  *
   585  *  In order to get notified when a back button is pressed, SDL apps should
   586  *  register a callback function with SDL_AddEventWatch(), and have it listen
   587  *  for SDL_KEYDOWN events that have a scancode of SDL_SCANCODE_AC_BACK.
   588  *  (Alternatively, SDL_KEYUP events can be listened-for.  Listening for
   589  *  either event type is suitable.)  Any value of SDL_HINT_WINRT_HANDLE_BACK_BUTTON
   590  *  set by such a callback, will be applied to the OS' current
   591  *  back-button-press event.
   592  *
   593  *  More details on back button behavior in Windows Phone apps can be found
   594  *  at the following page, on Microsoft's developer site:
   595  *  http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj247550(v=vs.105).aspx
   596  */
   597 #define SDL_HINT_WINRT_HANDLE_BACK_BUTTON "SDL_WINRT_HANDLE_BACK_BUTTON"
   598 
   599 /**
   600  *  \brief  A variable that dictates policy for fullscreen Spaces on Mac OS X.
   601  *
   602  *  This hint only applies to Mac OS X.
   603  *
   604  *  The variable can be set to the following values:
   605  *    "0"       - Disable Spaces support (FULLSCREEN_DESKTOP won't use them and
   606  *                SDL_WINDOW_RESIZABLE windows won't offer the "fullscreen"
   607  *                button on their titlebars).
   608  *    "1"       - Enable Spaces support (FULLSCREEN_DESKTOP will use them and
   609  *                SDL_WINDOW_RESIZABLE windows will offer the "fullscreen"
   610  *                button on their titlebars).
   611  *
   612  *  The default value is "1". Spaces are disabled regardless of this hint if
   613  *   the OS isn't at least Mac OS X Lion (10.7). This hint must be set before
   614  *   any windows are created.
   615  */
   616 #define SDL_HINT_VIDEO_MAC_FULLSCREEN_SPACES    "SDL_VIDEO_MAC_FULLSCREEN_SPACES"
   617 
   618 /**
   619 *  \brief  When set don't force the SDL app to become a foreground process
   620 *
   621 *  This hint only applies to Mac OS X.
   622 *
   623 */
   624 #define SDL_HINT_MAC_BACKGROUND_APP    "SDL_MAC_BACKGROUND_APP"
   625 
   626 /**
   627  * \brief Android APK expansion main file version. Should be a string number like "1", "2" etc.
   628  *
   629  * Must be set together with SDL_HINT_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION.
   630  *
   631  * If both hints were set then SDL_RWFromFile() will look into expansion files
   632  * after a given relative path was not found in the internal storage and assets.
   633  *
   634  * By default this hint is not set and the APK expansion files are not searched.
   635  */
   636 #define SDL_HINT_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION "SDL_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION"
   637  
   638 /**
   639  * \brief Android APK expansion patch file version. Should be a string number like "1", "2" etc.
   640  *
   641  * Must be set together with SDL_HINT_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION.
   642  *
   643  * If both hints were set then SDL_RWFromFile() will look into expansion files
   644  * after a given relative path was not found in the internal storage and assets.
   645  *
   646  * By default this hint is not set and the APK expansion files are not searched.
   647  */
   648 #define SDL_HINT_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION "SDL_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION"
   649 
   650 /**
   651  * \brief A variable to control whether certain IMEs should handle text editing internally instead of sending SDL_TEXTEDITING events.
   652  *
   653  * The variable can be set to the following values:
   654  *   "0"       - SDL_TEXTEDITING events are sent, and it is the application's
   655  *               responsibility to render the text from these events and 
   656  *               differentiate it somehow from committed text. (default)
   657  *   "1"       - If supported by the IME then SDL_TEXTEDITING events are not sent, 
   658  *               and text that is being composed will be rendered in its own UI.
   659  */
   660 #define SDL_HINT_IME_INTERNAL_EDITING "SDL_IME_INTERNAL_EDITING"
   661 
   662  /**
   663  * \brief A variable to control whether mouse and touch events are to be treated together or separately
   664  *
   665  * The variable can be set to the following values:
   666  *   "0"       - Mouse events will be handled as touch events, and touch will raise fake mouse
   667  *               events. This is the behaviour of SDL <= 2.0.3. (default)
   668  *   "1"       - Mouse events will be handled separately from pure touch events.
   669  *
   670  * The value of this hint is used at runtime, so it can be changed at any time.
   671  */
   672 #define SDL_HINT_ANDROID_SEPARATE_MOUSE_AND_TOUCH "SDL_ANDROID_SEPARATE_MOUSE_AND_TOUCH"
   673 
   674 /**
   675  *  \brief override the binding element for keyboard inputs for Emscripten builds
   676  *
   677  * This hint only applies to the emscripten platform
   678  *
   679  * The variable can be one of
   680  *    "#window"      - The javascript window object (this is the default)
   681  *    "#document"    - The javascript document object
   682  *    "#screen"      - the javascript window.screen object
   683  *    "#canvas"      - the WebGL canvas element
   684  *    any other string without a leading # sign applies to the element on the page with that ID.
   685  */
   686 #define SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT   "SDL_EMSCRIPTEN_KEYBOARD_ELEMENT"
   687 
   688 /**
   689  *  \brief Tell SDL not to catch the SIGINT or SIGTERM signals.
   690  *
   691  * This hint only applies to Unix-like platforms.
   692  *
   693  * The variable can be set to the following values:
   694  *   "0"       - SDL will install a SIGINT and SIGTERM handler, and when it
   695  *               catches a signal, convert it into an SDL_QUIT event.
   696  *   "1"       - SDL will not install a signal handler at all.
   697  */
   698 #define SDL_HINT_NO_SIGNAL_HANDLERS   "SDL_NO_SIGNAL_HANDLERS"
   699 
   700 /**
   701  *  \brief Tell SDL not to generate window-close events for Alt+F4 on Windows.
   702  *
   703  * The variable can be set to the following values:
   704  *   "0"       - SDL will generate a window-close event when it sees Alt+F4.
   705  *   "1"       - SDL will only do normal key handling for Alt+F4.
   706  */
   707 #define SDL_HINT_WINDOWS_NO_CLOSE_ON_ALT_F4	"SDL_WINDOWS_NO_CLOSE_ON_ALT_F4"
   708 
   709 /**
   710  *  \brief Prevent SDL from using version 4 of the bitmap header when saving BMPs.
   711  *
   712  * The bitmap header version 4 is required for proper alpha channel support and
   713  * SDL will use it when required. Should this not be desired, this hint can
   714  * force the use of the 40 byte header version which is supported everywhere.
   715  *
   716  * The variable can be set to the following values:
   717  *   "0"       - Surfaces with a colorkey or an alpha channel are saved to a
   718  *               32-bit BMP file with an alpha mask. SDL will use the bitmap
   719  *               header version 4 and set the alpha mask accordingly.
   720  *   "1"       - Surfaces with a colorkey or an alpha channel are saved to a
   721  *               32-bit BMP file without an alpha mask. The alpha channel data
   722  *               will be in the file, but applications are going to ignore it.
   723  *
   724  * The default value is "0".
   725  */
   726 #define SDL_HINT_BMP_SAVE_LEGACY_FORMAT "SDL_BMP_SAVE_LEGACY_FORMAT"
   727 
   728 /**
   729  * \brief Tell SDL not to name threads on Windows.
   730  *
   731  * The variable can be set to the following values:
   732  *   "0"       - SDL will raise the 0x406D1388 Exception to name threads.
   733  *               This is the default behavior of SDL <= 2.0.4. (default)
   734  *   "1"       - SDL will not raise this exception, and threads will be unnamed.
   735  *               For .NET languages this is required when running under a debugger.
   736  */
   737 #define SDL_HINT_WINDOWS_DISABLE_THREAD_NAMING "SDL_WINDOWS_DISABLE_THREAD_NAMING"
   738 
   739 /**
   740  * \brief Tell SDL which Dispmanx layer to use on a Raspberry PI
   741  *
   742  * Also known as Z-order. The variable can take a negative or positive value.
   743  * The default is 10000.
   744  */
   745 #define SDL_HINT_RPI_VIDEO_LAYER           "SDL_RPI_VIDEO_LAYER"
   746 
   747 /**
   748  *  \brief  A variable controlling what driver to use for OpenGL ES contexts.
   749  *
   750  *  On some platforms, currently Windows and X11, OpenGL drivers may support
   751  *  creating contexts with an OpenGL ES profile. By default SDL uses these
   752  *  profiles, when available, otherwise it attempts to load an OpenGL ES
   753  *  library, e.g. that provided by the ANGLE project. This variable controls
   754  *  whether SDL follows this default behaviour or will always load an
   755  *  OpenGL ES library.
   756  *
   757  *  Circumstances where this is useful include
   758  *  - Testing an app with a particular OpenGL ES implementation, e.g ANGLE,
   759  *    or emulator, e.g. those from ARM, Imagination or Qualcomm.
   760  *  - Resolving OpenGL ES function addresses at link time by linking with
   761  *    the OpenGL ES library instead of querying them at run time with
   762  *    SDL_GL_GetProcAddress.
   763  *
   764  *  Caution: for an application to work with the default behaviour across
   765  *  different OpenGL drivers it \i must query the OpenGL ES function
   766  *  addresses at run time using SDL_GL_GetProcAddress.
   767  *
   768  *  This variable is ignored on most platforms because OpenGL ES is native
   769  *  or not supported.
   770  *
   771  *  This variable can be set to the following values:
   772  *    "0"       - Use ES profile of OpenGL, if available. (Default when not set.)
   773  *    "1"       - Load OpenGL ES library using the default library names.
   774  *
   775  */
   776 #define SDL_HINT_OPENGL_ES_DRIVER   "SDL_OPENGL_ES_DRIVER"
   777 
   778 /**
   779  *  \brief  An enumeration of hint priorities
   780  */
   781 typedef enum
   782 {
   783     SDL_HINT_DEFAULT,
   784     SDL_HINT_NORMAL,
   785     SDL_HINT_OVERRIDE
   786 } SDL_HintPriority;
   787 
   788 
   789 /**
   790  *  \brief Set a hint with a specific priority
   791  *
   792  *  The priority controls the behavior when setting a hint that already
   793  *  has a value.  Hints will replace existing hints of their priority and
   794  *  lower.  Environment variables are considered to have override priority.
   795  *
   796  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   797  */
   798 extern DECLSPEC SDL_bool SDLCALL SDL_SetHintWithPriority(const char *name,
   799                                                          const char *value,
   800                                                          SDL_HintPriority priority);
   801 
   802 /**
   803  *  \brief Set a hint with normal priority
   804  *
   805  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   806  */
   807 extern DECLSPEC SDL_bool SDLCALL SDL_SetHint(const char *name,
   808                                              const char *value);
   809 
   810 /**
   811  *  \brief Get a hint
   812  *
   813  *  \return The string value of a hint variable.
   814  */
   815 extern DECLSPEC const char * SDLCALL SDL_GetHint(const char *name);
   816 
   817 /**
   818  *  \brief Get a hint
   819  *
   820  *  \return The boolean value of a hint variable.
   821  */
   822 extern DECLSPEC SDL_bool SDLCALL SDL_GetHintBoolean(const char *name, SDL_bool default_value);
   823 
   824 /**
   825  * \brief type definition of the hint callback function.
   826  */
   827 typedef void (*SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);
   828 
   829 /**
   830  *  \brief Add a function to watch a particular hint
   831  *
   832  *  \param name The hint to watch
   833  *  \param callback The function to call when the hint value changes
   834  *  \param userdata A pointer to pass to the callback function
   835  */
   836 extern DECLSPEC void SDLCALL SDL_AddHintCallback(const char *name,
   837                                                  SDL_HintCallback callback,
   838                                                  void *userdata);
   839 
   840 /**
   841  *  \brief Remove a function watching a particular hint
   842  *
   843  *  \param name The hint being watched
   844  *  \param callback The function being called when the hint value changes
   845  *  \param userdata A pointer being passed to the callback function
   846  */
   847 extern DECLSPEC void SDLCALL SDL_DelHintCallback(const char *name,
   848                                                  SDL_HintCallback callback,
   849                                                  void *userdata);
   850 
   851 /**
   852  *  \brief  Clear all hints
   853  *
   854  *  This function is called during SDL_Quit() to free stored hints.
   855  */
   856 extern DECLSPEC void SDLCALL SDL_ClearHints(void);
   857 
   858 
   859 /* Ends C function definitions when using C++ */
   860 #ifdef __cplusplus
   861 }
   862 #endif
   863 #include "close_code.h"
   864 
   865 #endif /* SDL_hints_h_ */
   866 
   867 /* vi: set ts=4 sw=4 expandtab: */