A variable controlling how 3D acceleration is used to accelerate the SDL screen surface.

SDL can try to accelerate the SDL screen surface by using streaming textures with a 3D rendering engine. This variable controls whether and how this is done.

This variable can be set to the following values:

• "0" - Disable 3D acceleration
• "1" - Enable 3D acceleration, using the default renderer.
• "X" - Enable 3D acceleration, using X where X is one of the valid

rendering drivers. (e.g. "direct3d", "opengl", etc.)

By default SDL tries to make a best guess for each platform whether to use acceleration or not.

A variable specifying which render driver to use.

If the application doesn't pick a specific renderer to use, this variable specifies the name of the preferred renderer. If the preferred renderer can't be initialized, the normal default renderer is used.

This variable is case insensitive and can be set to the following values:

• "direct3d"
• "opengl"
• "opengles2"
• "opengles"
• "software"

The default varies by platform, but it's the first one in the list that is available on the current platform.

A variable controlling whether the OpenGL render driver uses shaders if they are available.

This variable can be set to the following values:

• "0" - Disable shaders
• "1" - Enable shaders

By default shaders are used if OpenGL supports them.

A variable controlling whether the Direct3D device is initialized for thread-safe operations.

This variable can be set to the following values:

• "0" - Thread-safety is not enabled (faster)
• "1" - Thread-safety is enabled

By default the Direct3D device is created with thread-safety disabled.

A variable controlling whether to enable Direct3D 11+'s Debug Layer.

This variable does not have any effect on the Direct3D 9 based renderer.

This variable can be set to the following values:

• "0" - Disable Debug Layer use
• "1" - Enable Debug Layer use

By default, SDL does not use Direct3D Debug Layer.

A variable controlling the scaling quality

This variable can be set to the following values:

• "0" or "nearest" - Nearest pixel sampling
• "1" or "linear" - Linear filtering (supported by OpenGL and Direct3D)
• "2" or "best" - Currently this is the same as "linear"

By default nearest pixel sampling is used.

A variable controlling whether updates to the SDL screen surface should be synchronized with the vertical refresh, to avoid tearing.

This variable can be set to the following values:

• "0" - Disable vsync
• "1" - Enable vsync

By default SDL does not sync screen surface updates with vertical refresh.

A variable controlling whether the screensaver is enabled.

This variable can be set to the following values:

• "0" - Disable screensaver
• "1" - Enable screensaver

By default SDL will disable the screensaver.

A variable controlling whether the X11 VidMode extension should be used.

This variable can be set to the following values:

• "0" - Disable XVidMode
• "1" - Enable XVidMode

By default SDL will use XVidMode if it is available.

A variable controlling whether the X11 Xinerama extension should be used.

This variable can be set to the following values:

• "0" - Disable Xinerama
• "1" - Enable Xinerama

By default SDL will use Xinerama if it is available.

A variable controlling whether the X11 XRandR extension should be used.

This variable can be set to the following values:

• "0" - Disable XRandR
• "1" - Enable XRandR

By default SDL will not use XRandR because of window manager issues.

A variable controlling whether the X11 _NET_WM_PING protocol should be supported.

This variable can be set to the following values:

• "0" - Disable _NET_WM_PING
• "1" - Enable _NET_WM_PING

By default SDL will use _NET_WM_PING, but for applications that know they will not always be able to respond to ping requests in a timely manner they can turn it off to avoid the window manager thinking the app is hung.

The hint is checked in createWindow().

A variable controlling whether the window frame and title bar are interactive when the cursor is hidden.

This variable can be set to the following values:

• "0" - The window frame is not interactive when the cursor is hidden (no move, resize, etc)
• "1" - The window frame is interactive when the cursor is hidden

By default SDL will allow interaction with the window frame when the cursor is hidden.

A variable controlling whether the windows message loop is processed by SDL

This variable can be set to the following values:

• "0" - The window message loop is not run
• "1" - The window message loop is processed in pumpEvents()

By default SDL will process the windows message loop.

A variable controlling whether grabbing input grabs the keyboard

This variable can be set to the following values:

• "0" - Grab will affect only the mouse
• "1" - Grab will affect mouse and keyboard

By default SDL will not grab the keyboard so system shortcuts still work.

A variable controlling whether relative mouse mode is implemented using mouse warping

This variable can be set to the following values:

• "0" - Relative mouse mode uses raw input
• "1" - Relative mouse mode uses mouse warping

By default SDL will use raw input for relative mouse mode.

A variable controlling whether the idle timer is disabled on iOS.

When an iOS app does not receive touches for some time, the screen is dimmed automatically. For games where the accelerometer is the only input this is problematic. This functionality can be disabled by setting this hint.

As of SDL 2.0.4, enableScreenSaver() and disableScreenSaver() accomplish the same thing on iOS. They should be preferred over this hint.

This variable can be set to the following values:

• "0" - Enable idle timer
• "1" - Disable idle timer

A variable controlling which orientations are allowed on iOS.

In some circumstances it is necessary to be able to explicitly control which UI orientations are allowed.

This variable is a space delimited list of the following values:

• "LandscapeLeft"
• "LandscapeRight"
• "Portrait"
• "PortraitUpsideDown"

A variable controlling whether an Android / iOS built-in accelerometer should be listed as a joystick device, rather than listing actual joysticks only.

This variable can be set to the following values:

• "0" - List only real joysticks and accept input from them
• "1" - List real joysticks along with the accelerometer as if it were a 3 axis joystick (the default).

A variable that lets you disable the detection and use of Xinput gamepad devices

The variable can be set to the following values:

• "0" - Disable XInput detection (only uses direct input)
• "1" - Enable XInput detection (the default)

A variable that causes SDL to use the old axis and button mapping for XInput devices.

This hint is for backwards compatibility only and will be removed in SDL 2.1.

The default value is 0. This hint must be set before sdl.init().

A variable that lets you manually hint extra gamecontroller db entries

The variable should be newline delimited rows of gamecontroller config data, see gamecontroller.nim

This hint must be set before calling init(INIT_GAMECONTROLLER) You can update mappings after the system is initialized with gameControllerMappingForGUID() and gameControllerAddMapping()

A variable that lets you enable joystick (and gamecontroller) events even when your app is in the background.

The variable can be set to the following values:

• "0" - Disable joystick & gamecontroller input events when the application is in the background.
• "1" - Enable joystick & gamecontroller input events when the application is in the background.

The default value is "0". This hint may be set at any time.

If set to 0 then never set the top most bit on a Window, even if the video mode expects it.

This is a debugging aid for developers and not expected to be used by end users. The default is "1"

This variable can be set to the following values:

• "0" - don't allow topmost
• "1" - allow topmost

A variable that controls the timer resolution, in milliseconds.

The higher resolution the timer, the more frequently the CPU services timer interrupts, and the more precise delays are, but this takes up power and CPU time. This hint is only used on Windows 7 and earlier.

See this blog post for more information: http://randomascii.wordpress.com/2013/07/08/windows-timer-resolution-megawatts-wasted/

If this variable is set to "0", the system timer resolution is not set.

The default value is "1". This hint may be set at any time.

A string specifying SDL's threads stack size in bytes or 0 for the backend's default size.

Use this hint in case you need to set SDL's threads stack size to other than the default.

This is specially useful if you build SDL against a non glibc libc library (such as musl) which provides a relatively small default thread stack size (a few kilobytes versus the default 8MB glibc uses).

Support for this hint is currently available only in the pthread backend.

A variable that determines whether ctrl+click should generate a right-click event on Mac

If present, holding ctrl while left clicking will generate a right click event when on Mac.

A variable specifying which shader compiler to preload when using the Chrome ANGLE binaries

SDL has EGL and OpenGL ES2 support on Windows via the ANGLE project. It can use two different sets of binaries, those compiled by the user from source or those provided by the Chrome browser. In the later case, these binaries require that SDL loads a DLL providing the shader compiler.

This variable can be set to the following values:

• "d3dcompiler_46.dll" - default, best for Vista or later.
• "d3dcompiler_43.dll" - for XP support.
• "none" - do not load any library, useful if you compiled ANGLE from source and included the compiler in your binaries.

A variable that is the address of another Window (as a hex string formatted with "%p").

If this hint is set before createWindowFrom() and the Window it is set to has WINDOW_OPENGL set (and running on WGL only, currently), then two things will occur on the newly created Window:

1. Its pixel format will be set to the same pixel format as this Window. This is needed for example when sharing an OpenGL context across multiple windows.

2. The flag WINDOW_OPENGL will be set on the new window so it can be used for OpenGL rendering.

This variable can be set to the following values:

The address (as a string "%p") of the Window that new windows created with createWindowFrom() should share a pixel format with.

A URL to a WinRT app's privacy policy

All network-enabled WinRT apps must make a privacy policy available to its users. On Windows 8, 8.1, and RT, Microsoft mandates that this policy be be available in the Windows Settings charm, as accessed from within the app. SDL provides code to add a URL-based link there, which can point to the app's privacy policy.

To setup a URL to an app's privacy policy, set HINT_WINRT_PRIVACY_POLICY_URL before calling any init() procedures. The contents of the hint should be a valid URL. For example, "http://www.example.com".

The default value is "", which will prevent SDL from adding a privacy policy link to the Settings charm. This hint should only be set during app init.

The label text of an app's "Privacy Policy" link may be customized via another hint, HINT_WINRT_PRIVACY_POLICY_LABEL.

Please note that on Windows Phone, Microsoft does not provide standard UI for displaying a privacy policy link, and as such, HINT_WINRT_PRIVACY_POLICY_URL will not get used on that platform. Network-enabled phone apps should display their privacy policy through some other, in-app means.

Label text for a WinRT app's privacy policy link

Network-enabled WinRT apps must include a privacy policy. On Windows 8, 8.1, and RT, Microsoft mandates that this policy be available via the Windows Settings charm. SDL provides code to add a link there, with its label text being set via the optional hint, HINT_WINRT_PRIVACY_POLICY_LABEL.

Please note that a privacy policy's contents are not set via this hint. A separate hint, HINT_WINRT_PRIVACY_POLICY_URL, is used to link to the actual text of the policy.

The contents of this hint should be encoded as a UTF8 string.

The default value is "Privacy Policy". This hint should only be set during app initialization, preferably before any calls to init().

For additional information on linking to a privacy policy, see the documentation for HINT_WINRT_PRIVACY_POLICY_URL.

Allows back-button-press events on Windows Phone to be marked as handled.

Windows Phone devices typically feature a Back button. When pressed, the OS will emit back-button-press events, which apps are expected to handle in an appropriate manner. If apps do not explicitly mark these events as 'Handled', then the OS will invoke its default behavior for unhandled back-button-press events, which on Windows Phone 8 and 8.1 is to terminate the app (and attempt to switch to the previous app, or to the device's home screen).

Setting the HINT_WINRT_HANDLE_BACK_BUTTON hint to 1 will cause SDL to mark back-button-press events as 'Handled', if and when one is sent to the app.

Internally, Windows Phone sends back button events as parameters to special back-button-press callback procedures. Apps that need to respond to back-button-press events are expected to register one or more callback procedures for such, shortly after being launched (during the app's initialization phase). After the back button is pressed, the OS will invoke these callbacks. If the app's callback(s) do not explicitly mark the event as handled by the time they return, or if the app never registers one of these callback, the OS will consider the event un-handled, and it will apply its default back button behavior (terminate the app).

SDL registers its own back-button-press callback with the Windows Phone OS. This callback will emit a pair of SDL key-press events (sdl.KEYDOWN and sdl.KEYUP), each with a scancode of SCANCODE_AC_BACK, after which it will check the contents of the hint, HINT_WINRT_HANDLE_BACK_BUTTON.

If the hint's value is set to 1, the back button event's 'Handled' property will get set to true. If the hint's value is set to something else, or if it is unset, SDL will leave the event's 'Handled' property alone. (By default, the OS sets this property to false, to note.)

SDL apps can either set HINT_WINRT_HANDLE_BACK_BUTTON well before a back button is pressed, or can set it in direct-response to a back button being pressed.

In order to get notified when a back button is pressed, SDL apps should register a callback procedure with addEventWatch(), and have it listen for sdl.KEYDOWN events that have a scancode of SCANCODE_AC_BACK.

(Alternatively, sdl.KEYUP events can be listened-for. Listening for either event type is suitable.) Any value of HINT_WINRT_HANDLE_BACK_BUTTON set by such a callback, will be applied to the OS' current back-button-press event.

More details on back button behavior in Windows Phone apps can be found at the following page, on Microsoft's developer site:

http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj247550(v=vs.105).aspx

A variable that dictates policy for fullscreen Spaces on Mac OS X.

This hint only applies to Mac OS X.

The variable can be set to the following values:

• "0" - Disable Spaces support (FULLSCREEN_DESKTOP won't use them and WINDOW_RESIZABLE windows won't offer the "fullscreen" button on their titlebars).
• "1" - Enable Spaces support (FULLSCREEN_DESKTOP will use them and WINDOW_RESIZABLE windows will offer the "fullscreen" button on their titlebars).

The default value is "1". Spaces are disabled regardless of this hint if the OS isn't at least Mac OS X Lion (10.7). This hint must be set before any windows are created.

When set don't force the SDL app to become a foreground process

This hint only applies to Mac OS X.

Android APK expansion main file version. Should be a string number like "1", "2" etc.

Must be set together with HINT_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION.

If both hints were set then rwFromFile() will look into expansion files after a given relative path was not found in the internal storage and assets.

By default this hint is not set and the APK expansion files are not searched.

Android APK expansion patch file version. Should be a string number like "1", "2" etc.

Must be set together with HINT_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION.

If both hints were set then rwFromFile() will look into expansion files after a given relative path was not found in the internal storage and assets.

By default this hint is not set and the APK expansion files are not searched.

A variable to control whether certain IMEs should handle text editing internally instead of sending sdl.TEXTEDITING events.

The variable can be set to the following values:

• "0" - sdl.TEXTEDITING events are sent, and it is the application's responsibility to render the text from these events and differentiate it somehow from committed text. (default)
• "1" - If supported by the IME then sdl.TEXTEDITING events are not sent, and text that is being composed will be rendered in its own UI.

A variable to control whether mouse and touch events are to be treated together or separately.

The variable can be set to the following values:

• "0" - Mouse events will be handled as touch events, and touch will raise fake mouse events. This is the behaviour of SDL <= 2.0.3. (default)
• "1" - Mouse events will be handled separately from pure touch events.

The value of this hint is used at runtime, so it can be changed at any time.

Override the binding element for keyboard inputs for Emscripten builds.

This hint only applies to the emscripten platform

The variable can be one of

• "#window" - The javascript window object (this is the default)
• "#document" - The javascript document object
• "#screen" - the javascript window.screen object
• "#canvas" - the WebGL canvas element
• any other string without a leading # sign applies to the element on the page with that ID.

Tell SDL not to catch the SIGINT or SIGTERM signals.

This hint only applies to Unix-like platforms.

The variable can be set to the following values:

• "0" - SDL will install a SIGINT and SIGTERM handler, and when it catches a signal, convert it into an sdl.QUIT event.
• "1" - SDL will not install a signal handler at all.

Tell SDL not to generate window-close events for Alt+F4 on Windows.

The variable can be set to the following values:

• "0" - SDL will generate a window-close event when it sees Alt+F4.
• "1" - SDL will only do normal key handling for Alt+F4.

Set a hint with a specific priority.

The priority controls the behavior when setting a hint that already has a value. Hints will replace existing hints of their priority and lower. Environment variables are considered to have override priority.

Return true if the hint was set, false otherwise.

Set a hint with normal priority.

Return true if the hint was set, false otherwise.

Get a hint.

Return the string value of a hint variable.

Add a procedure to watch a particular hint.

name The hint to watch.

callback The procedure to call when the hint value changes.

userdata A pointer to pass to the callback procedure.

Remove a procedure watching a particular hint.

name The hint being watched.

callback The procedure being called when the hint value changes.

userdata A pointer being passed to the callback procedure.

Clear all hints.

This procedure is called during quit() to free stored hints.