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"
• "metal"
• "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 policy for renderSetLogicalSize.

This variable can be set to the following values:

• "0" or "letterbox" - Uses letterbox/sidebars to fit the entire rendering on screen
• "1" or "overscan" - Will zoom the rendering so it fills the entire screen, allowing edges to be drawn offscreen

By default letterbox is used.

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 graphics context is externally managed.

This variable can be set to the following values:

• "0" - SDL will manage graphics contexts that are attached to windows.
• "1" - Disable graphics context management on windows.

By default SDL will manage OpenGL contexts in certain situations. For example, on Android the context will be automatically saved and restored when pausing the application. Additionally, some platforms will assume usage of OpenGL if Vulkan isn't used. Setting this to "1" will prevent this behavior, which is desireable when the application manages the graphics context, such as an externally managed OpenGL context or attaching a Vulkan surface to the window.

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 X11 _NET_WM_BYPASS_COMPOSITOR hint should be used.

This variable can be set to the following values:

• "0" - Disable _NET_WM_BYPASS_COMPOSITOR
• "1" - Enable _NET_WM_BYPASS_COMPOSITOR

By default SDL will use _NET_WM_BYPASS_COMPOSITOR.

A variable controlling whether X11 should use GLX or EGL by default.

This variable can be set to the following values:

• "0" - Use GLX
• "1" - Use EGL

By default SDL will use GLX when both are present.

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 motion is affected by renderer scaling

This variable can be set to the following values:

• "0" - Relative motion is unaffected by DPI or renderer's logical size
• "1" - Relative motion is scaled according to DPI scaling and logical size

By default relative mouse deltas are affected by DPI and renderer scaling

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.

Allow mouse click events when clicking to focus an SDL window

This variable can be set to the following values:

• "0" - Ignore mouse clicks that activate a window
• "1" - Generate events for mouse clicks that activate a window

By default SDL will ignore mouse clicks that activate a window.

A variable controlling whether touch events should generate synthetic mouse events.

This variable can be set to the following values:

• "0" - Touch events will not generate mouse events
• "1" - Touch events will generate mouse events

By default SDL will generate mouse events for touch events.

A variable controlling whether mouse events should generate synthetic touch events.

This variable can be set to the following values:

• "0" - Mouse events will not generate touch events (default for desktop platforms)
• "1" - Mouse events will generate touch events (default for mobile platforms, such as Android and iOS)

Minimize your Window if it loses key focus when in fullscreen mode. Defaults to "false".

WARNING: Before SDL 2.0.14, this defaulted to "true"! In 2.0.14, we're seeing if "true" causes more problems than it solves in modern times.

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, sdl.enableScreenSaver() and sdl.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/Android.

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 controllers used with the Apple TV generate UI events.

When UI events are generated by controller input, the app will be backgrounded when the Apple TV remote's menu button is pressed, and when the pause or B buttons on gamepads are pressed.

More information about properly making use of controllers for the Apple TV can be found here: https://developer.apple.com/tvos/human-interface-guidelines/remote-and-controllers/

This variable can be set to the following values:

• "0" - Controller input does not generate UI events (the default).
• "1" - Controller input generates UI events.

A variable controlling whether the Apple TV remote's joystick axes will automatically match the rotation of the remote.

This variable can be set to the following values:

• "0" - Remote orientation does not affect joystick axes (the default).
• "1" - Joystick axes are based on the orientation of the remote.

A variable controlling whether the home indicator bar on iPhone X should be hidden.

This variable can be set to the following values:

• "0" - The indicator bar is not hidden (default for windowed applications)
• "1" - The indicator bar is hidden and is shown when the screen is touched (useful for movie playback applications)
• "2" - The indicator bar is dim and the first swipe makes it visible and the second swipe performs the "home" action (default for fullscreen applications)

A variable controlling whether an Android / iOS built-in accelerometer should be listed as a joystick device.

This variable can be set to the following values:

• "0" - The accelerometer is not listed as a joystick
• "1" - The accelerometer is available as a 3 axis joystick (the default) as if it were a 3 axis joystick (the default).

A variable controlling whether the Android / tvOS remotes should be listed as joystick devices, instead of sending keyboard events.

This variable can be set to the following values:

• "0" - Remotes send enter/escape/arrow key events
• "1" - Remotes are available as 2 axis, 2 button joysticks (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 overrides the automatic controller type detection.

The variable should be comma separated entries, in the form: VID/PID=type

The VID and PID should be hexadecimal with exactly 4 digits, e.g. 0x00fd

The type should be one of:

• Xbox360
• XboxOne
• PS3
• PS4
• PS5
• SwitchPro

This hint affects what driver is used, and must be set before calling sdl.init(sdl.INIT_GAMECONTROLLER).

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 provide a file with extra gamecontroller db entries.

The file should contain lines of gamecontroller config data, see gamecontroller.nim

This hint must be set before calling sdl.init(sdl.INIT_GAMECONTROLLER)

You can update mappings after the system is initialized with sdl.gameControllerMappingForGUID() and sdl.gameControllerAddMapping().

A variable containing a list of devices to skip when scanning for game controllers.

The format of the string is a comma separated list of USB VID/PID pairs in hexadecimal form, e.g.

0xAAAA/0xBBBB,0xCCCC/0xDDDD

The variable can also take the form of @file, in which case the named file will be loaded and interpreted as the value of the variable.

If set, all devices will be skipped when scanning for game controllers except for the ones listed in this variable.

The format of the string is a comma separated list of USB VID/PID pairs in hexadecimal form, e.g.

0xAAAA/0xBBBB,0xCCCC/0xDDDD

The variable can also take the form of @file, in which case the named file will be loaded and interpreted as the value of the variable.

If set, game controller face buttons report their values according to their labels instead of their positional layout.

For example, on Nintendo Switch controllers, normally you'd get:

‎
    (Y)
(X)     (B)
    (A)
‎

but if this hint is set, you'll get:

‎
    (X)
(Y)     (A)
    (B)
‎

The variable can be set to the following values:

• "0" - Report the face buttons by position, as though they were on an Xbox controller.
• "1" - Report the face buttons by label instead of position

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

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.

A variable controlling whether the HIDAPI joystick drivers should be used.

This variable can be set to the following values:

• "0" - HIDAPI drivers are not used
• "1" - HIDAPI drivers are used (the default)

This variable is the default for all drivers, but can be overridden by the hints for specific drivers below.

A variable controlling whether the HIDAPI driver for PS4 controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is the value of HINT_JOYSTICK_HIDAPI.

A variable controlling whether the HIDAPI driver for PS5 controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is the value of SDL_HINT_JOYSTICK_HIDAPI.

A variable controlling whether extended input reports should be used for PS4 controllers when using the HIDAPI driver.

This variable can be set to the following values:

• "0" - extended reports are not enabled (the default)
• "1" - extended reports

Extended input reports allow rumble on Bluetooth PS4 controllers, but break DirectInput handling for applications that don't use SDL.

Once extended reports are enabled, they can not be disabled without power cycling the controller.

A variable controlling whether the HIDAPI driver for Steam Controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is the value of HINT_JOYSTICK_HIDAPI.

A variable controlling whether the HIDAPI driver for Nintendo Switch controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is the value of HINT_JOYSTICK_HIDAPI.

A variable controlling whether the HIDAPI driver for XBox controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is the value of HINT_JOYSTICK_HIDAPI.

A variable controlling whether the HIDAPI driver for XBox controllers on Windows should pull correlated data from XInput.

This variable can be set to the following values:

• "0" - HIDAPI Xbox driver will only use HIDAPI data
• "1" - HIDAPI Xbox driver will also pull data from XInput, providing better trigger axes, guide button presses, and rumble support

The default is "1". This hint applies to any joysticks opened after setting the hint.

A variable controlling whether the HIDAPI driver for Nintendo GameCube controllers should be used.

This variable can be set to the following values:

• "0" - HIDAPI driver is not used
• "1" - HIDAPI driver is used

The default is "0" on Windows, otherwise the value of HINT_JOYSTICK_HIDAPI.

A variable that controls whether Steam Controllers should be exposed using the sdl.Joystick and game controller APIs.

The variable can be set to the following values:

• "0" - Do not scan for Steam Controllers
• "1" - Scan for Steam Controllers (the default)

The default value is "1". This hint must be set before initializing the joystick subsystem.

A variable controlling whether the RAWINPUT joystick drivers should be used for better handling XInput-capable devices.

This variable can be set to the following values:

• "0" - RAWINPUT drivers are not used
• "1" - RAWINPUT drivers are used (the default)

A variable controlling whether a separate thread should be used for handling joystick detection and raw input messages on Windows.

This variable can be set to the following values:

• "0" - A separate thread is not used (the default)
• "1" - A separate thread is used for handling raw input messages

A variable controlling whether joysticks on Linux adhere to their HID-defined deadzones or return unfiltered values.

This variable can be set to the following values:

• "0" - Return unfiltered joystick axis values (the default)
• "1" - Return axis values with deadzones taken into account

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 variable describing the content orientation on QtWayland-based platforms.

On QtWayland platforms, windows are rotated client-side to allow for custom transitions. In order to correctly position overlays (e.g. volume bar) and gestures (e.g. events view, close/minimize gestures), the system needs to know in which orientation the application is currently drawing its contents.

This does not cause the window to be rotated or resized, the application needs to take care of drawing the content in the right orientation (the framebuffer is always in portrait mode).

This variable can be one of the following values:

"primary" (default), "portrait", "landscape", "inverted-portrait", "inverted-landscape"

Flags to set on QtWayland windows to integrate with the native window manager.

On QtWayland platforms, this hint controls the flags to set on the windows. For example, on Sailfish OS "OverridesSystemGestures" disables swipe gestures.

This variable is a space-separated list of the following values (empty = no flags):

"OverridesSystemGestures", "StaysOnTop", "BypassWindowManager"

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, Windows, and PSP backend.

Note: Instead of this hint, in 2.0.9 and later you can use sdl.CreateThreadWithStackSize(). This hint only works with the classic sdl.CreateThread().

A string specifying additional information to use with sdl.setThreadPriority().

By default sdl.setThreadPriority() will make appropriate system changes in order to apply a thread priority. For example on systems using pthreads the scheduler policy is changed automatically to a policy that works well with a given priority. Code which has specific requirements can override SDL's default behavior with this hint.

pthread hint values are "current", "other", "fifo" and "rr". Currently no other platform hint values are defined but may be in the future.

Note: On Linux, the kernel may send SIGKILL to realtime tasks which exceed the distro configured execution budget for rtkit. This budget can be queried through RLIMIT_RTTIME after calling sdl.setThreadPriority().

Specifies whether THREAD_PRIORITY_TIME_CRITICAL should be treated as realtime.

On some platforms, like Linux, a realtime priority thread may be subject to restrictions that require special handling by the application. This hint exists to let SDL know that the app is prepared to handle said restrictions.

On Linux, SDL will apply the following configuration to any thread that becomes realtime:

• The SCHED_RESET_ON_FORK bit will be set on the scheduling policy,
• An RLIMIT_RTTIME budget will be configured to the rtkit specified limit. * Exceeding this limit will result in the kernel sending `SIGKILL

  to the app,

  • Refer to the man pages for more information.

This variable can be set to the following values:

• "0" - default platform specific behaviour
• "1" - Force THREAD_PRIORITY_TIME_CRITICAL to a realtime scheduling policy

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 sdl.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 sdl.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.

A variable to control whether we trap the Android back button to handle it manually.

This is necessary for the right mouse button to work on some Android devices, or to be able to trap the back button for use in your code reliably. If set to "true", the back button will show up as an sdl.KEYDOWN / sdl.KEYUP pair with a keycode of sdl.SCANCODE_AC_BACK.

The variable can be set to the following values:

• "0" - Back button will be handled as usual for system.

(default)

• "1" - Back button will be trapped, allowing you to handle

the key press manually. (This will also let right mouse click work on systems where the right mouse button functions as back.)

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

A variable to control whether the event loop will block itself when the app is paused.

The variable can be set to the following values:

• "0" - Non blocking.
• "1" - Blocking. (default)

The value should be set before SDL is initialized.

A variable to control whether SDL will pause audio in background (Requires ANDROID_BLOCK_ON_PAUSE as "Non blocking")

The variable can be set to the following values:

• "0" - Non paused.
• "1" - Paused. (default)

The value should be set before SDL is initialized.

A variable to control whether the return key on the soft keyboard should hide the soft keyboard on Android and iOS.

The variable can be set to the following values:

• "0" - The return key will be handled as a key event. This is the behaviour of SDL <= 2.0.3. (default)
• "1" - The return key will hide the keyboard.

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.

Disable giving back control to the browser automatically when running with asyncify.

With -s ASYNCIFY, SDL2 calls emscripten_sleep during operations such as refreshing the screen or polling events.

This hint only applies to the emscripten platform.

The variable can be set to the following values:

• "0" - Disable emscripten_sleep calls (if you give back browser control manually or use asyncify for other purposes)
• "1" - Enable emscripten_sleep calls (the default)

Tell SDL not to catch the SIGINT or SIGTERM signals.

This hint only applies to Unix-like platforms, and should set before any calls to sdl.init().

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.

Prevent SDL from using version 4 of the bitmap header when saving BMPs.

The bitmap header version 4 is required for proper alpha channel support and SDL will use it when required. Should this not be desired, this hint can force the use of the 40 byte header version which is supported everywhere.

The variable can be set to the following values:

• "0" - Surfaces with a colorkey or an alpha channel are saved to a 32-bit BMP file with an alpha mask. SDL will use the bitmap header version 4 and set the alpha mask accordingly.
• "1" - Surfaces with a colorkey or an alpha channel are saved to a 32-bit BMP file without an alpha mask. The alpha channel data will be in the file, but applications are going to ignore it.

The default value is "0".

Tell SDL not to name threads on Windows with the 0x406D1388 Exception. The 0x406D1388 Exception is a trick used to inform Visual Studio of a thread's name, but it tends to cause problems with other debuggers, and the .NET runtime. Note that SDL 2.0.6 and later will still use the (safer) SetThreadDescription API, introduced in the Windows 10 Creators Update, if available.

The variable can be set to the following values:

• "0" - SDL will raise the 0x406D1388 Exception to name threads. This is the default behavior of SDL <= 2.0.4.
• "1" - SDL will not raise this exception, and threads will be unnamed. (default) This is necessary with .NET languages or debuggers that aren't Visual Studio.

Tell SDL which Dispmanx layer to use on a Raspberry PI

Also known as Z-order. The variable can take a negative or positive value. The default is "10000".

Tell the video driver that we only want a double buffer.

By default, most lowlevel 2D APIs will use a triple buffer scheme that wastes no CPU time on waiting for vsync after issuing a flip, but introduces a frame of latency. On the other hand, using a double buffer scheme instead is recommended for cases where low latency is an important factor because we save a whole frame of latency. We do so by waiting for vsync immediately after issuing a flip, usually just after eglSwapBuffers call in the backend's *_SwapWindow procedure.

Since it's driver-specific, it's only supported where possible and implemented. Currently supported the following drivers:

• KMSDRM (kmsdrm)
• Raspberry Pi (raspberrypi)

A variable controlling what driver to use for OpenGL ES contexts.

On some platforms, currently Windows and X11, OpenGL drivers may support creating contexts with an OpenGL ES profile. By default SDL uses these profiles, when available, otherwise it attempts to load an OpenGL ES library, e.g. that provided by the ANGLE project. This variable controls whether SDL follows this default behaviour or will always load an OpenGL ES library.

Circumstances where this is useful include:

• Testing an app with a particular OpenGL ES implementation, e.g ANGLE, or emulator, e.g. those from ARM, Imagination or Qualcomm.
• Resolving OpenGL ES function addresses at link time by linking with the OpenGL ES library instead of querying them at run time with glGetProcAddress().

Caution: for an application to work with the default behaviour across different OpenGL drivers it must query the OpenGL ES function addresses at run time using glGetProcAddress().

This variable is ignored on most platforms because OpenGL ES is native or not supported.

This variable can be set to the following values:

• "0" - Use ES profile of OpenGL, if available. (Default when not set.)
• "1" - Load OpenGL ES library using the default library names.

A variable controlling speed/quality tradeoff of audio resampling.

If available, SDL can use libsamplerate ( http://www.mega-nerd.com/SRC/ ) to handle audio resampling. There are different resampling modes available that produce different levels of quality, using more CPU.

If this hint isn't specified to a valid setting, or libsamplerate isn't available, SDL will use the default, internal resampling algorithm.

Note that this is currently only applicable to resampling audio that is being written to a device for playback or audio being read from a device for capture. AudioCVT always uses the default resampler (although this might change for SDL 2.1).

This hint is currently only checked at audio subsystem initialization.

This variable can be set to the following values:

• "0" or "default" - Use SDL's internal resampling (Default when not set - low quality, fast)
• "1" or "fast" - Use fast, slightly higher quality resampling, if available
• "2" or "medium" - Use medium quality resampling, if available
• "3" or "best" - Use high quality resampling, if available

A variable controlling the audio category on iOS and Mac OS X

This variable can be set to the following values:

• "ambient" - Use the AVAudioSessionCategoryAmbient audio category, will be muted by the phone mute switch (default)
• "playback" - Use the AVAudioSessionCategoryPlayback category

For more information, see Apple's documentation:

https://developer.apple.com/library/content/documentation/Audio/Conceptual/AudioSessionProgrammingGuide/AudioSessionCategoriesandModes/AudioSessionCategoriesandModes.html

A variable controlling whether the 2D render API is compatible or efficient.

This variable can be set to the following values:

• "0" - Don't use batching to make rendering more efficient.
• "1" - Use batching, but might cause problems if app makes its own direct OpenGL calls.

Up to SDL 2.0.9, the render API would draw immediately when requested. Now it batches up draw requests and sends them all to the GPU only when forced to (during SDL_RenderPresent, when changing render targets, by updating a texture that the batch needs, etc). This is significantly more efficient, but it can cause problems for apps that expect to render on top of the render API's output. As such, SDL will disable batching if a specific render backend is requested (since this might indicate that the app is planning to use the underlying graphics API directly). This hint can be used to explicitly request batching in this instance. It is a contract that you will either never use the underlying graphics API directly, or if you do, you will call SDL_RenderFlush() before you do so any current batch goes to the GPU before your work begins. Not following this contract will result in undefined behavior.

A variable controlling whether SDL updates joystick state when getting input events.

This variable can be set to the following values:

• "0" - You'll call sdl.joystickUpdate() manually
• "1" - SDL will automatically call sdl.hoystickUpdate() (default)

This hint can be toggled on and off at runtime.

A variable controlling whether SDL updates sensor state when getting input events

This variable can be set to the following values:

• "0" - You'll call sdl.sensorUpdate() manually
• "1" - SDL will automatically call sdl.sensorUpdate() (default)

This hint can be toggled on and off at runtime.

A variable controlling whether SDL logs all events pushed onto its internal queue.

This variable can be set to the following values:

• "0" - Don't log any events (default)
• "1" - Log all events except mouse and finger motion, which are pretty spammy.
• "2" - Log all events.

This is generally meant to be used to debug SDL itself, but can be useful for application developers that need better visibility into what is going on in the event queue. Logged events are sent through sdl.log(), which means by default they appear on stdout on most platforms or maybe outputDebugString() on Windows, and can be funneled by the app with sdl.logSetOutputFunction(), etc.

This hint can be toggled on and off at runtime, if you only need to log events for a small subset of program execution.

Controls how the size of the RIFF chunk affects the loading of a WAVE file.

The size of the RIFF chunk (which includes all the sub-chunks of the WAVE file) is not always reliable. In case the size is wrong, it's possible to just ignore it and step through the chunks until a fixed limit is reached.

Note that files that have trailing data unrelated to the WAVE file or corrupt files may slow down the loading process without a reliable boundary. By default, SDL stops after 10000 chunks to prevent wasting time. Use the environment variable sdl.WAVE_CHUNK_LIMIT to adjust this value.

This variable can be set to the following values:

• "force" - Always use the RIFF chunk size as a boundary for the chunk search
• "ignorezero" - Like "force", but a zero size searches up to 4 GiB (default)
• "ignore" - Ignore the RIFF chunk size and always search up to 4 GiB
• "maximum" - Search for chunks until the end of file (not recommended)

Controls how a truncated WAVE file is handled.

A WAVE file is considered truncated if any of the chunks are incomplete or the data chunk size is not a multiple of the block size. By default, SDL decodes until the first incomplete block, as most applications seem to do.

This variable can be set to the following values:

• "verystrict" - Raise an error if the file is truncated
• "strict" - Like "verystrict", but the size of the RIFF chunk is ignored
• "dropframe" - Decode until the first incomplete sample frame
• "dropblock" - Decode until the first incomplete block (default)

Controls how the fact chunk affects the loading of a WAVE file.

The fact chunk stores information about the number of samples of a WAVE file. The Standards Update from Microsoft notes that this value can be used to 'determine the length of the data in seconds'. This is especially useful for compressed formats (for which this is a mandatory chunk) if they produce multiple sample frames per block and truncating the block is not allowed. The fact chunk can exactly specify how many sample frames there should be in this case.

Unfortunately, most application seem to ignore the fact chunk and so SDL ignores it by default as well.

This variable can be set to the following values:

• "truncate" - Use the number of samples to truncate the wave data if the fact chunk is present and valid
• "strict" - Like "truncate", but raise an error if the fact chunk is invalid, not present for non-PCM formats, or if the data chunk doesn't have that many samples
• "ignorezero" - Like "truncate", but ignore fact chunk if the number of samples is zero
• "ignore" - Ignore fact chunk entirely (default)

Override for sdl.getDisplayUsableBounds().

If set, this hint will override the expected results for sdl.getDisplayUsableBounds() for display index 0. Generally you don't want to do this, but this allows an embedded system to request that some of the screen be reserved for other uses when paired with a well-behaved application.

The contents of this hint must be 4 comma-separated integers, the first is the bounds x, then y, width and height, in that order.

Specify an application name for an audio device.

Some audio backends (such as PulseAudio) allow you to describe your audio stream. Among other things, this description might show up in a system control panel that lets the user adjust the volume on specific audio streams instead of using one giant master volume slider.

This hints lets you transmit that information to the OS. The contents of this hint are used while opening an audio device. You should use a string that describes your program ("My Game 2: The Revenge")

Setting this to "" or leaving it unset will have SDL use a reasonable default: probably the application's name or "SDL Application" if SDL doesn't have any better information.

On targets where this is not supported, this hint does nothing.

Specify an application name for an audio device.

Some audio backends (such as PulseAudio) allow you to describe your audio stream. Among other things, this description might show up in a system control panel that lets the user adjust the volume on specific audio streams instead of using one giant master volume slider.

This hints lets you transmit that information to the OS. The contents of this hint are used while opening an audio device. You should use a string that describes your what your program is playing ("audio stream" is probably sufficient in many cases, but this could be useful for something like "team chat" if you have a headset playing VoIP audio separately).

Setting this to "" or leaving it unset will have SDL use a reasonable default: "audio stream" or something similar.

On targets where this is not supported, this hint does nothing.

Override for sdl.getPreferredLocales().

If set, this will be favored over anything the OS might report for the user's preferred locales. Changing this hint at runtime will not generate a LOCALECHANGED event (but if you can change the hint, you can push your own event, if you want).

The format of this hint is a comma-separated list of language and locale, combined with an underscore, as is a common format: "en_GB". Locale is optional: "en". So you might have a list like this: "en_GB,jp,es_PT"

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.

Get a hint.

Return the boolean 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.