include/SDL_hints.h
author Sam Lantinga <slouken@libsdl.org>
Thu, 30 Jan 2014 12:30:40 -0800
changeset 8144 855b1d6d7d8e
parent 8071 1ac2db4abe11
child 8149 681eb46b8ac4
permissions -rw-r--r--
Add a new hint SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT that allows SDL_CreateWindowFrom() to set the pixel format of another SDL_Window (and also will set the SDL_WINDOW_OPENGL flag on the window created with SDL_CreateWindowFrom()).

The reasoning behind this change is that source2 in -tools mode has a single OpenGL context that is used with multiple different windows. Some of those windows are created outside the engine (i.e. with Qt) and therefore we need to use SDL_CreateWindowFrom() to get an SDL_Window for those. The requirement for sharing an OpenGL context across multiple different windows is that each window has the same pixel format. To facilitate this, I now set SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT for the main window before calling SDL_CreateWindowFrom(). When I do this, SDL_CreateWindowFrom() will:

1. Set the pixel format of the returned window to the same pixel format as this SDL_Window passed in with the hint
2. The flag SDL_WINDOW_OPENGL will be set on the new window so it can be used for OpenGL rendering.

I only currently implemented this for Win32/WGL so implementing it for other platforms (i.e. X11) remains a TODO.

CR: SamL

Some pseudocode that shows how this is used in Source2:

HWND hExternalHwnd; // HWND that was established outside of SDL

// Create main window (happens inside platwindow.cpp)
SDL_Window *mainWindow = SDL_CreateWindow( , SDL_WINDOW_OPENGL .. );
// Create GL context, happens inside rendersystemgl
SDL_GLContext onlyContext = SDL_GL_CreateContext( mainWindow );

// Now I need to create another window from hEternalHwnd for my swap chain that will have the same pixel format as mainWindow, so set the hint
SDL_SetHint( SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT, CFmtStr( %p, mainWindow) );

// Create the secondary window. This returned window will have SDL_WINDOW_OPENGL set and share a pixel format with mainWindow from the hint
SDL_Window *secondaryWindow = SDL_CreateWindowFrom( hExternalHwnd );

// To render to the main window:
SDL_GL_MakeCurrent( mainWindow, onlyContext );
// Do some rendering to main window

// To render to the secondary window:
SDL_GLMakeCurrent( secondaryWindow, onlyContext );
// Do some rendering to secondary window
     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 the X11 VidMode extension should be used.
   133  *
   134  *  This variable can be set to the following values:
   135  *    "0"       - Disable XVidMode
   136  *    "1"       - Enable XVidMode
   137  *
   138  *  By default SDL will use XVidMode if it is available.
   139  */
   140 #define SDL_HINT_VIDEO_X11_XVIDMODE         "SDL_VIDEO_X11_XVIDMODE"
   141 
   142 /**
   143  *  \brief  A variable controlling whether the X11 Xinerama extension should be used.
   144  *
   145  *  This variable can be set to the following values:
   146  *    "0"       - Disable Xinerama
   147  *    "1"       - Enable Xinerama
   148  *
   149  *  By default SDL will use Xinerama if it is available.
   150  */
   151 #define SDL_HINT_VIDEO_X11_XINERAMA         "SDL_VIDEO_X11_XINERAMA"
   152 
   153 /**
   154  *  \brief  A variable controlling whether the X11 XRandR extension should be used.
   155  *
   156  *  This variable can be set to the following values:
   157  *    "0"       - Disable XRandR
   158  *    "1"       - Enable XRandR
   159  *
   160  *  By default SDL will not use XRandR because of window manager issues.
   161  */
   162 #define SDL_HINT_VIDEO_X11_XRANDR           "SDL_VIDEO_X11_XRANDR"
   163 
   164 /**
   165  *  \brief  A variable controlling whether grabbing input grabs the keyboard
   166  *
   167  *  This variable can be set to the following values:
   168  *    "0"       - Grab will affect only the mouse
   169  *    "1"       - Grab will affect mouse and keyboard
   170  *
   171  *  By default SDL will not grab the keyboard so system shortcuts still work.
   172  */
   173 #define SDL_HINT_GRAB_KEYBOARD              "SDL_GRAB_KEYBOARD"
   174 
   175 /**
   176 *  \brief  A variable controlling whether relative mouse mode is implemented using mouse warping
   177 *
   178 *  This variable can be set to the following values:
   179 *    "0"       - Relative mouse mode uses raw input
   180 *    "1"       - Relative mouse mode uses mouse warping
   181 *
   182 *  By default SDL will use raw input for relative mouse mode
   183 */
   184 #define SDL_HINT_MOUSE_RELATIVE_MODE_WARP    "SDL_MOUSE_RELATIVE_MODE_WARP"
   185 
   186 /**
   187  *  \brief Minimize your SDL_Window if it loses key focus when in fullscreen mode. Defaults to true.
   188  *
   189  */
   190 #define SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS   "SDL_VIDEO_MINIMIZE_ON_FOCUS_LOSS"
   191 
   192 /**
   193  *  \brief Set whether windows go fullscreen in their own spaces on Mac OS X
   194  *
   195  *  This variable can be set to the following values:
   196  *    "0"       - Fullscreen windows will use the classic fullscreen mode
   197  *    "1"       - Fullscreen windows will use fullscreen spaces
   198  *
   199  *  By default SDL will use the classic fullscreen mode.
   200  */
   201 #define SDL_HINT_VIDEO_FULLSCREEN_SPACES   "SDL_VIDEO_FULLSCREEN_SPACES"
   202 
   203 /**
   204  *  \brief  A variable controlling whether the idle timer is disabled on iOS.
   205  *
   206  *  When an iOS app does not receive touches for some time, the screen is
   207  *  dimmed automatically. For games where the accelerometer is the only input
   208  *  this is problematic. This functionality can be disabled by setting this
   209  *  hint.
   210  *
   211  *  This variable can be set to the following values:
   212  *    "0"       - Enable idle timer
   213  *    "1"       - Disable idle timer
   214  */
   215 #define SDL_HINT_IDLE_TIMER_DISABLED "SDL_IOS_IDLE_TIMER_DISABLED"
   216 
   217 /**
   218  *  \brief  A variable controlling which orientations are allowed on iOS.
   219  *
   220  *  In some circumstances it is necessary to be able to explicitly control
   221  *  which UI orientations are allowed.
   222  *
   223  *  This variable is a space delimited list of the following values:
   224  *    "LandscapeLeft", "LandscapeRight", "Portrait" "PortraitUpsideDown"
   225  */
   226 #define SDL_HINT_ORIENTATIONS "SDL_IOS_ORIENTATIONS"
   227     
   228 /**
   229  *  \brief  A variable controlling whether an Android built-in accelerometer should be
   230  *  listed as a joystick device, rather than listing actual joysticks only.
   231  *
   232  *  This variable can be set to the following values:
   233  *    "0"       - List only real joysticks and accept input from them
   234  *    "1"       - List real joysticks along with the accelerometer as if it were a 3 axis joystick (the default).
   235  */
   236 #define SDL_HINT_ACCEL_AS_JOY "SDL_ACCEL_AS_JOY"
   237 
   238 
   239 /**
   240  *  \brief  A variable that lets you disable the detection and use of Xinput gamepad devices
   241  *
   242  *  The variable can be set to the following values:
   243  *    "0"       - Disable XInput timer (only uses direct input)
   244  *    "1"       - Enable XInput timer (the default)
   245  */
   246 #define SDL_HINT_XINPUT_ENABLED "SDL_XINPUT_ENABLED"
   247 
   248 
   249 /**
   250  *  \brief  A variable that lets you manually hint extra gamecontroller db entries
   251  *
   252  *  The variable should be newline delimited rows of gamecontroller config data, see SDL_gamecontroller.h
   253  *
   254  *  This hint must be set before calling SDL_Init(SDL_INIT_GAMECONTROLLER)
   255  *  You can update mappings after the system is initialized with SDL_GameControllerMappingForGUID() and SDL_GameControllerAddMapping()
   256  */
   257 #define SDL_HINT_GAMECONTROLLERCONFIG "SDL_GAMECONTROLLERCONFIG"
   258 
   259 
   260 /**
   261  *  \brief  A variable that lets you enable joystick (and gamecontroller) events even when your app is in the background.
   262  *
   263  *  The variable can be set to the following values:
   264  *    "0"       - Disable joystick & gamecontroller input events when the
   265  *                application is in the background.
   266  *    "1"       - Enable joystick & gamecontroller input events when the
   267  *                application is in the backgroumd.
   268  *
   269  *  The default value is "0".  This hint may be set at any time.
   270  */
   271 #define SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS "SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS"
   272 
   273 
   274 /**
   275  *  \brief If set to 0 then never set the top most bit on a SDL Window, even if the video mode expects it.
   276  *      This is a debugging aid for developers and not expected to be used by end users. The default is "1"
   277  *
   278  *  This variable can be set to the following values:
   279  *    "0"       - don't allow topmost
   280  *    "1"       - allow topmost
   281  */
   282 #define SDL_HINT_ALLOW_TOPMOST "SDL_ALLOW_TOPMOST"
   283 
   284 
   285 /**
   286  *  \brief A variable that controls the timer resolution, in milliseconds.
   287  *
   288  *  The higher resolution the timer, the more frequently the CPU services
   289  *  timer interrupts, and the more precise delays are, but this takes up
   290  *  power and CPU time.  This hint is only used on Windows 7 and earlier.
   291  *
   292  *  See this blog post for more information:
   293  *  http://randomascii.wordpress.com/2013/07/08/windows-timer-resolution-megawatts-wasted/
   294  *
   295  *  If this variable is set to "0", the system timer resolution is not set.
   296  *
   297  *  The default value is "1". This hint may be set at any time.
   298  */
   299 #define SDL_HINT_TIMER_RESOLUTION "SDL_TIMER_RESOLUTION"
   300 
   301 
   302 /**
   303  *  \brief If set to 1, then do not allow high-DPI windows. ("Retina" on Mac)
   304  */
   305 #define SDL_HINT_VIDEO_HIGHDPI_DISABLED "SDL_VIDEO_HIGHDPI_DISABLED"
   306 
   307 /**
   308  *  \brief A variable that determines whether ctrl+click should generate a right-click event on Mac
   309  *  
   310  *  If present, holding ctrl while left clicking will generate a right click
   311  *  event when on Mac.
   312  */
   313 #define SDL_HINT_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK "SDL_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK"
   314 
   315 /**
   316 *  \brief  A variable specifying which shader compiler to preload when using the Chrome ANGLE binaries
   317 *
   318 *  SDL has EGL and OpenGL ES2 support on Windows via the ANGLE project. It
   319 *  can use two different sets of binaries, those compiled by the user from source
   320 *  or those provided by the Chrome browser. In the later case, these binaries require
   321 *  that SDL loads 
   322 *
   323 *  This variable can be set to the following values:
   324 *    "d3dcompiler_46.dll" - default, best for Vista or later.
   325 *    "d3dcompiler_43.dll" - for XP support.
   326 *    "none" - do not load any library, useful if you compiled ANGLE from source and included the compiler in your binaries.
   327 *
   328 */
   329 #define SDL_HINT_VIDEO_WIN_D3DCOMPILER              "SDL_VIDEO_WIN_D3DCOMPILER"
   330 
   331 /**
   332 *  \brief  A variable that is the address of another SDL_Window* (as a hex string formatted with "%p").
   333 *  
   334 *  If this hint is set before SDL_CreateWindowFrom() and the SDL_Window* it is set to has
   335 *  SDL_WINDOW_OPENGL set (and running on WGL only, currently), then two things will occur on the newly 
   336 *  created SDL_Window:
   337 
   338 *  1. Its pixel format will be set to the same pixel format as this SDL_Window.  This is
   339 *  needed for example when sharing an OpenGL context across multiple windows.
   340 *
   341 *  2. The flag SDL_WINDOW_OPENGL will be set on the new window so it can be used for
   342 *  OpenGL rendering.
   343 *
   344 *  This variable can be set to the following values:
   345 *    The address (as a string "%p") of the SDL_Window* that new windows created with SDL_CreateWindowFrom() should
   346 *    share a pixel format with.
   347 */
   348 #define SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT    "SDL_VIDEO_WINDOW_SHARE_PIXEL_FORMAT"
   349 
   350 /**
   351  *  \brief  An enumeration of hint priorities
   352  */
   353 typedef enum
   354 {
   355     SDL_HINT_DEFAULT,
   356     SDL_HINT_NORMAL,
   357     SDL_HINT_OVERRIDE
   358 } SDL_HintPriority;
   359 
   360 
   361 /**
   362  *  \brief Set a hint with a specific priority
   363  *
   364  *  The priority controls the behavior when setting a hint that already
   365  *  has a value.  Hints will replace existing hints of their priority and
   366  *  lower.  Environment variables are considered to have override priority.
   367  *
   368  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   369  */
   370 extern DECLSPEC SDL_bool SDLCALL SDL_SetHintWithPriority(const char *name,
   371                                                          const char *value,
   372                                                          SDL_HintPriority priority);
   373 
   374 /**
   375  *  \brief Set a hint with normal priority
   376  *
   377  *  \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
   378  */
   379 extern DECLSPEC SDL_bool SDLCALL SDL_SetHint(const char *name,
   380                                              const char *value);
   381 
   382 /**
   383  *  \brief Get a hint
   384  *
   385  *  \return The string value of a hint variable.
   386  */
   387 extern DECLSPEC const char * SDLCALL SDL_GetHint(const char *name);
   388 
   389 /**
   390  *  \brief Add a function to watch a particular hint
   391  *
   392  *  \param name The hint to watch
   393  *  \param callback The function to call when the hint value changes
   394  *  \param userdata A pointer to pass to the callback function
   395  */
   396 typedef void (*SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);
   397 extern DECLSPEC void SDLCALL SDL_AddHintCallback(const char *name,
   398                                                  SDL_HintCallback callback,
   399                                                  void *userdata);
   400 
   401 /**
   402  *  \brief Remove a function watching a particular hint
   403  *
   404  *  \param name The hint being watched
   405  *  \param callback The function being called when the hint value changes
   406  *  \param userdata A pointer being passed to the callback function
   407  */
   408 extern DECLSPEC void SDLCALL SDL_DelHintCallback(const char *name,
   409                                                  SDL_HintCallback callback,
   410                                                  void *userdata);
   411 
   412 /**
   413  *  \brief  Clear all hints
   414  *
   415  *  This function is called during SDL_Quit() to free stored hints.
   416  */
   417 extern DECLSPEC void SDLCALL SDL_ClearHints(void);
   418 
   419 
   420 /* Ends C function definitions when using C++ */
   421 #ifdef __cplusplus
   422 }
   423 #endif
   424 #include "close_code.h"
   425 
   426 #endif /* _SDL_hints_h */
   427 
   428 /* vi: set ts=4 sw=4 expandtab: */