/ 
SDL2-FFI-0.04
River stage zero No dependents
/ SDL2::Enum

NAME

SDL2::Enum - Enumerations and Defined Constants Related to SDL

SYNOPSIS

use SDL2::FFI qw[:all]; # Yep, you import from SDL2::FFI

DESCRIPTION

:init

These are the flags which may be passed to SDL_Init( ... ). You should specify the subsystems which you will be using in your application.

SDL_INIT_TIMER - Timer subsystem
SDL_INIT_AUDIO - Audio subsystem
SDL_INIT_VIDEO - Video subsystem. Automatically initializes the events subsystem
SDL_INIT_JOYSTICK - Joystick subsystem. Automatically initializes the events subsystem
SDL_INIT_HAPTIC - Haptic (force feedback) subsystem
SDL_INIT_GAMECONTROLLER - Controller subsystem. Automatically initializes the joystick subsystem
SDL_INIT_EVENTS - Events subsystem
SDL_INIT_SENSOR - Sensor subsystem
SDL_INIT_EVERYTHING - All of the above subsystems
SDL_INIT_NOPARACHUTE - Compatibility; this flag is ignored

:audioformat

Audio format flags.

These are what the 16 bits in SDL_AudioFormat currently mean... (Unspecified bits are always zero).

++-----------------------sample is signed if set
||
||       ++-----------sample is bigendian if set
||       ||
||       ||          ++---sample is float if set
||       ||          ||
||       ||          || +---sample bit size---+
||       ||          || |                     |
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
SDL_AUDIO_MASK_BITSIZE
SDL_AUDIO_MASK_DATATYPE
SDL_AUDIO_MASK_ENDIAN
SDL_AUDIO_MASK_SIGNED
SDL_AUDIO_BITSIZE( ...
SDL_AUDIO_ISFLOAT( ... )
SDL_AUDIO_ISBIGENDIAN( ... )
SDL_AUDIO_ISSIGNED( ... )
SDL_AUDIO_ISINT( ... )
SDL_AUDIO_ISLITTLEENDIAN( ... )
SDL_AUDIO_ISUNSIGNED( ... )

Defaults to LSB byte order.

AUDIO_U8 - Unsigned 8-bit samples
AUDIO_S8 - Signed 8-bit samples
AUDIO_U16LSB - Unsigned 16-bit samples
AUDIO_S16LSB - Signed 16-bit samples
AUDIO_U16MSB - As above, but big-endian byte order
AUDIO_S16MSB - As above, but big-endian byte order
AUDIO_U16 - AUDIO_U16LSB
AUDIO_S16 - AUDIO_S16LSB

int32 support.

AUDIO_S32LSB - 32-bit integer samples
AUDIO_S32MSB - As above, but big-endian byte order
AUDIO_S32 - AUDIO_S32LSB

float 32 support.

AUDIO_F32LSB - 32-bit floating point samples
AUDIO_F32MSB - As above, but big-endian byte order
AUDIO_F32 - AUDIO_F32LSB

Native audio byte ordering.

AUDIO_U16SYS
AUDIO_S16SYS
AUDIO_S32SYS
AUDIO_F32SYS

Which audio format changes are allowed when opening a device.

SDL_AUDIO_ALLOW_FREQUENCY_CHANGE
SDL_AUDIO_ALLOW_FORMAT_CHANGE
SDL_AUDIO_ALLOW_CHANNELS_CHANGE
SDL_AUDIO_ALLOW_SAMPLES_CHANGE
SDL_AUDIO_ALLOW_ANY_CHANGE

Upper limit of filters in SDL_AudioCVT

    SDL_AUDIOCVT_MAX_FILTERS - The maximum number of SDL_AudioFilter functions in SDL_AudioCVT is currently limited to 9. The SDL2::AudioCVT-filters( )> array has 10 pointers, one of which is the terminating NULL pointer.

:audiostatus

Get the current audio state.

SDL_AUDIO_STOPPED
SDL_AUDIO_PLAYING
SDL_AUDIO_PAUSED

:blendmode

The blend mode used in SDL_RenderCopy( ... ) and drawing operations.

SDL_BLENDMODE_NONE - no blending
dstRGBA = srcRGBA
SDL_BLENDMODE_BLEND - alpha blending
dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA))
dstA = srcA + (dstA * (1-srcA))
SDL_BLENDMODE_ADD - additive blending
dstRGB = (srcRGB * srcA) + dstRGB
dstA = dstA
SDL_BLENDMODE_MOD - color modulate
dstRGB = srcRGB * dstRGB
dstA = dstA
SDL_BLENDMODE_MUL - color multiply
dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
dstA = (srcA * dstA) + (dstA * (1-srcA))
SDL_BLENDMODE_INVALID

Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode( ... ).

:blendoperation

The blend operation used when combining source and destination pixel components.

SDL_BLENDOPERATION_ADD - supported by all renderers
dst + src
SDL_BLENDOPERATION_SUBTRACT - supported by D3D9, D3D11, OpenGL, OpenGLES
dst - src
SDL_BLENDOPERATION_REV_SUBTRACT - supported by D3D9, D3D11, OpenGL, OpenGLES
src - dst
SDL_BLENDOPERATION_MINIMUM - supported by D3D11
min(dst, src)
SDL_BLENDOPERATION_MAXIMUM - supported by D3D11
max(dst, src)

:blendfactor

The normalized factor used to multiply pixel components.

SDL_BLENDFACTOR_ZERO - 0, 0, 0, 0
SDL_BLENDFACTOR_ONE - 1, 1, 1, 1
SDL_BLENDFACTOR_SRC_COLOR - srcR, srcG, srcB, srcA
SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR - 1-srcR, 1-srcG, 1-srcB, 1-srcA
SDL_BLENDFACTOR_SRC_ALPHA - srcA, srcA, srcA, srcA
SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA - 1-srcA, 1-srcA, 1-srcA, 1-srcA
SDL_BLENDFACTOR_DST_COLOR - dstR, dstG, dstB, dstA
SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR - 1-dstR, 1-dstG, 1-dstB, 1-dstA
SDL_BLENDFACTOR_DST_ALPHA - dstA, dstA, dstA, dstA
SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA - 1-dstA, 1-dstA, 1-dstA, 1-dstA

:errorcode

SDL_ENOMEM - Out of memory
SDL_EFREAD - Error reading file
SDL_EFWRITE - Error writing file
SDL_EFSEEK - Error seeking in file
SDL_UNSUPPORTED
SDL_LASTERROR

:eventstate

General keyboard/mouse state definitions

SDL_RELEASED
SDL_PRESSED

:eventtype

The types of events that can be delivered.

SDL_FIRSTEVENT - Unused
SDL_QUIT - User-requested quit
SDL_APP_TERMINATING - The application is being terminated by the OS

Called on iOS in applicationWillTerminate()

Called on Android in onDestroy()

SDL_APP_LOWMEMORY - The application is low on memory, free memory if possible

Called on iOS in applicationDidReceiveMemoryWarning()

Called on Android in onLowMemory()

SDL_APP_WILLENTERBACKGROUND - The application is about to enter the background

Called on iOS in applicationWillResignActive()

Called on Android in onPause()

SDL_APP_DIDENTERBACKGROUND - The application did enter the background and may not get CPU for some time

Called on iOS in applicationDidEnterBackground()

Called on Android in onPause()

SDL_APP_WILLENTERFOREGROUND - The application is about to enter the foreground

Called on iOS in applicationWillEnterForeground()

Called on Android in onResume()

SDL_APP_DIDENTERFOREGROUND - The application is now interactive

Called on iOS in applicationDidBecomeActive()

Called on Android in onResume()

SDL_LOCALECHANGED - The user's locale preferences have changed
SDL_DISPLAYEVENT - Display state change
SDL_WINDOWEVENT - Window state change
SDL_SYSWMEVENT - System specific event
SDL_KEYDOWN - Key pressed
SDL_KEYUP - Key released
SDL_TEXTEDITING - Keyboard text editing (composition)
SDL_TEXTINPUT - Keyboard text input
SDL_KEYMAPCHANGED - Keymap changed due to a system event such as an input language or keyboard layout change
SDL_MOUSEMOTION - Mouse moved
SDL_MOUSEBUTTONDOWN - Mouse button pressed
SDL_MOUSEBUTTONUP - Mouse button released
SDL_MOUSEWHEEL - Mouse wheel motion
SDL_JOYAXISMOTION - Joystick axis motion
SDL_JOYBALLMOTION - Joystick trackball motion
SDL_JOYHATMOTION - Joystick hat position change
SDL_JOYBUTTONDOWN - Joystick button pressed
SDL_JOYBUTTONUP - Joystick button released
SDL_JOYDEVICEADDED - A new joystick has been inserted into the system
SDL_JOYDEVICEREMOVED - An opened joystick has been removed
SDL_CONTROLLERAXISMOTION - Game controller axis motion
SDL_CONTROLLERBUTTONDOWN - Game controller button pressed
SDL_CONTROLLERBUTTONUP - Game controller button released
SDL_CONTROLLERDEVICEADDED - A new Game controller has been inserted into the system
SDL_CONTROLLERDEVICEREMOVED - An opened Game controller has been removed
SDL_CONTROLLERDEVICEREMAPPED - The controller mapping was updated
SDL_CONTROLLERTOUCHPADDOWN - Game controller touchpad was touched
SDL_CONTROLLERTOUCHPADMOTION - Game controller touchpad finger was moved
SDL_CONTROLLERTOUCHPADUP - Game controller touchpad finger was lifted
SDL_CONTROLLERSENSORUPDATE - Game controller sensor was updated
SDL_FINGERDOWN
SDL_FINGERUP
SDL_FINGERMOTION
SDL_DOLLARGESTURE
SDL_DOLLARRECORD
SDL_MULTIGESTURE
SDL_CLIPBOARDUPDATE - The clipboard changed
SDL_DROPFILE - The system requests a file open
SDL_DROPTEXT - text/plain drag-and-drop event
SDL_DROPBEGIN - A new set of drops is beginning (NULL filename)
SDL_DROPCOMPLETE - Current set of drops is now complete (NULL filename)
SDL_AUDIODEVICEADDED - A new audio device is available
SDL_AUDIODEVICEREMOVED - An audio device has been removed
SDL_SENSORUPDATE - A sensor was updated
SDL_RENDER_TARGETS_RESET - The render targets have been reset and their contents need to be updated
SDL_RENDER_DEVICE_RESET - The device has been reset and all textures need to be recreated
SDL_USEREVENT
SDL_LASTEVENT - This last event is only for bounding internal arrays

Events SDL_USEREVENT through SDL_LASTEVENT are for your use and should be allocated with SDL_RegisterEvents( ... ).

:hints

SDL_HINT_DEFAULT - low priority, used for default values
SDL_HINT_NORMAL - medium priority
SDL_HINT_OVERRIDE - high priority

SDL_Hint

These enum values can be passed to Configuration Variable related functions.

SDL_HINT_ACCELEROMETER_AS_JOYSTICK

A hint that specifies whether the Android / iOS built-in accelerometer should be listed as a joystick device, rather than listing actual joysticks only.

Values:

0   list only real joysticks and accept input from them
1   list real joysticks along with the accelorometer as if it were a 3 axis joystick (the default)

Example:

# This disables the use of gyroscopes as axis device
SDL_SetHint(SDL_HINT_ACCELEROMETER_AS_JOYSTICK, "0");
SDL_HINT_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION

A hint that specifies the Android APK expansion main file version.

Values:

X   the Android APK expansion main file version (should be a string number like "1", "2" etc.)

This hint must be set together with the hint SDL_HINT_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION.

If both hints were set then SDL_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.

SDL_HINT_ANDROID_APK_EXPANSION_PATCH_FILE_VERSION

A hint that specifies the Android APK expansion patch file version.

Values:

X   the Android APK expansion patch file version (should be a string number like "1", "2" etc.)

This hint must be set together with the hint SDL_HINT_ANDROID_APK_EXPANSION_MAIN_FILE_VERSION.

If both hints were set then SDL_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.

SDL_HINT_ANDROID_SEPARATE_MOUSE_AND_TOUCH

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

Values:

0   mouse events will be handled as touch events and touch will raise fake mouse events (default)
1   mouse events will be handled separately from pure touch events

By default mouse events will be handled as touch events and touch will raise fake mouse events.

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

SDL_HINT_APPLE_TV_CONTROLLER_UI_EVENTS

A hint that specifies whether controllers used with the Apple TV generate UI events.

Values:

0   controller input does not gnerate UI events (default)
1   controller input generates 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/

SDL_HINT_APPLE_TV_REMOTE_ALLOW_ROTATION

A hint that specifies whether the Apple TV remote's joystick axes will automatically match the rotation of the remote.

Values:

0   remote orientation does not affect joystick axes (default)
1   joystick axes are based on the orientation of the remote
SDL_HINT_BMP_SAVE_LEGACY_FORMAT

A hint that specifies whether SDL should not use version 4 of the bitmap header when saving BMPs.

Values:

0   version 4 of the bitmap header will be used when saving BMPs (default)
1   version 4 of the bitmap header will not be used 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.

If the hint is not set then 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. This is the default behavior since SDL 2.0.5.

If the hint is set then 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. This was the default behavior before SDL 2.0.5.

SDL_HINT_EMSCRIPTEN_ASYNCIFY

A hint that specifies if SDL should give back control to the browser automatically when running with asyncify.

Values:

0   disable emscripten_sleep calls (if you give back browser control manually or use asyncify for other purposes)
1   enable emscripten_sleep calls (default)

This hint only applies to the Emscripten platform.

SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT

A hint that specifies a value to override the binding element for keyboard inputs for Emscripten builds.

Values:

#window     the JavaScript window object (default)
#document   the JavaScript document object
#screen     the JavaScript window.screen object
#canvas     the default WebGL canvas element

Any other string without a leading # sign applies to the element on the page with that ID.

This hint only applies to the Emscripten platform.

SDL_HINT_FRAMEBUFFER_ACCELERATION

A hint that specifies how 3D acceleration is used with SDL_GetWindowSurface( ... ).

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 whether to use acceleration or not on each platform.

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

SDL_HINT_GAMECONTROLLERCONFIG

A variable that lets you provide a file with extra gamecontroller db entries.

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( ).

SDL_HINT_GRAB_KEYBOARD

A variable setting the double click time, in milliseconds.

SDL_HINT_IDLE_TIMER_DISABLED

A hint that specifies a variable controlling whether the idle timer is disabled on iOS.

Values:

0   enable idle timer (default)
1   disable idle timer

When an iOS application 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.

SDL_HINT_IME_INTERNAL_EDITING

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.

SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS

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 (default)

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

SDL_HINT_MAC_BACKGROUND_APP

A hint that specifies if the SDL app should not be forced to become a foreground process on Mac OS X.

Values:

0   force the SDL app to become a foreground process (default)
1   do not force the SDL app to become a foreground process

This hint only applies to Mac OSX.

SDL_HINT_MAC_CTRL_CLICK_EMULATE_RIGHT_CLICK

A hint that specifies whether ctrl+click should generate a right-click event on Mac.

Values:

0   disable emulating right click (default)
1   enable emulating right click
SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH

A hint that specifies if mouse click events are sent when clicking to focus an SDL window.

Values:

0   no mouse click events are sent when clicking to focus (default)
1   mouse click events are sent when clicking to focus
SDL_HINT_MOUSE_RELATIVE_MODE_WARP

A hint that specifies whether relative mouse mode is implemented using mouse warping.

Values:

0   relative mouse mode uses the raw input (default)
1   relative mouse mode uses mouse warping
SDL_HINT_NO_SIGNAL_HANDLERS

A hint that specifies not to catch the SIGINT or SIGTERM signals.

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
SDL_HINT_ORIENTATIONS

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
SDL_HINT_RENDER_DIRECT3D11_DEBUG

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 (default)
1   Enable Debug Layer use
SDL_HINT_RENDER_DIRECT3D_THREADSAFE

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; default)
1   Thread-safety is enabled
SDL_HINT_RENDER_DRIVER

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.

SDL_HINT_RENDER_OPENGL_SHADERS

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 (default)
SDL_HINT_RENDER_SCALE_QUALITY

A variable controlling the scaling quality

This variable can be set to the following values: 0 or nearest Nearest pixel sampling (default) 1 or linear Linear filtering (supported by OpenGL and Direct3D) 2 or best Currently this is the same as linear

SDL_HINT_RENDER_VSYNC

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.

SDL_HINT_RPI_VIDEO_LAYER

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.

SDL_HINT_THREAD_STACK_SIZE

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.

Instead of this hint, in 2.0.9 and later, you can use SDL_CreateThreadWithStackSize( ). This hint only works with the classic SDL_CreateThread( ).

SDL_HINT_TIMER_RESOLUTION

A variable that controls the timer resolution, in milliseconds.

he 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.

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.

SDL_HINT_VIDEO_ALLOW_SCREENSAVER

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.

SDL_HINT_VIDEO_HIGHDPI_DISABLED

If set to 1, then do not allow high-DPI windows. ("Retina" on Mac and iOS)

SDL_HINT_VIDEO_MAC_FULLSCREEN_SPACES

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
    SDL_WINDOW_RESIZABLE windows won't offer the "fullscreen"
    button on their titlebars).
1   Enable Spaces support (FULLSCREEN_DESKTOP will use them and
    SDL_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.

SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS

Minimize your SDL_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.

SDL_HINT_VIDEO_WIN_D3DCOMPILER

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.

SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT

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

If this hint is set before SDL_CreateWindowFrom( ) and the SDL_Window* it is set to has SDL_WINDOW_OPENGL set (and running on WGL only, currently), then two things will occur on the newly created SDL_Window:

1. Its pixel format will be set to the same pixel format as this SDL_Window. This is needed for example when sharing an OpenGL context across multiple windows.
2. The flag SDL_WINDOW_OPENGL will be set on the new window so it can be used for OpenGL rendering.

This variable can be set to the address (as a string %p) of the SDL_Window* that new windows created with SDL_CreateWindowFrom( ... )should share a pixel format with.

SDL_HINT_VIDEO_X11_NET_WM_PING

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.

SDL_HINT_VIDEO_X11_XINERAMA

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.

SDL_HINT_VIDEO_X11_XRANDR

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.

SDL_HINT_VIDEO_X11_XVIDMODE

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.

SDL_HINT_WINDOW_FRAME_USABLE_WHILE_CURSOR_HIDDEN

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.

SDL_HINT_WINDOWS_DISABLE_THREAD_NAMING

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.
SDL_HINT_WINDOWS_INTRESOURCE_ICON

A variable to specify custom icon resource id from RC file on Windows platform.

SDL_HINT_WINDOWS_INTRESOURCE_ICON_SMALL

A variable to specify custom icon resource id from RC file on Windows platform.

SDL_HINT_WINDOWS_ENABLE_MESSAGELOOP

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 SDL_PumpEvents( )

By default SDL will process the windows message loop.

SDL_HINT_WINDOWS_NO_CLOSE_ON_ALT_F4

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.
SDL_HINT_WINRT_HANDLE_BACK_BUTTON

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 SDL_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 functions. Apps that need to respond to back-button-press events are expected to register one or more callback functions 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 SDL_SCANCODE_AC_BACK, after which it will check the contents of the hint, SDL_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 a true value. 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 SDL_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 function with SDL_AddEventWatch( ), and have it listen for SDL_KEYDOWN events that have a scancode of SDL_SCANCODE_AC_BACK. (Alternatively, SDL_KEYUP events can be listened-for. Listening for either event type is suitable.) Any value of SDL_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

SDL_HINT_WINRT_PRIVACY_POLICY_LABEL

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, SDL_HINT_WINRT_PRIVACY_POLICY_LABEL.

Please note that a privacy policy's contents are not set via this hint. A separate hint, SDL_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 SDL_HINT_WINRT_PRIVACY_POLICY_URL.

SDL_HINT_WINRT_PRIVACY_POLICY_URL

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 SDL_HINT_WINRT_PRIVACY_POLICY_URL before calling any SDL_Init( ... ) functions. The contents of the hint should be a valid URL. For example, http://www.example.com.

The default value is an empty string (), 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, SDL_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, SDL_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.

SDL_HINT_XINPUT_ENABLED

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 (default)
SDL_HINT_XINPUT_USE_OLD_JOYSTICK_MAPPING

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( ... )

SDL_HINT_QTWAYLAND_WINDOW_FLAGS

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
SDL_HINT_QTWAYLAND_CONTENT_ORIENTATION

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
SDL_HINT_RENDER_LOGICAL_SIZE_MODE

A variable controlling the scaling policy for SDL_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.

SDL_HINT_VIDEO_EXTERNAL_CONTEXT

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 desirable when the application manages the graphics context, such as an externally managed OpenGL context or attaching a Vulkan surface to the window.

<SDL_HINT_VIDEO_X11_WINDOW_VISUALID>

A variable forcing the visual ID chosen for new X11 windows.

SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR

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.

SDL_HINT_VIDEO_X11_FORCE_EGL

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.

SDL_HINT_MOUSE_DOUBLE_CLICK_TIME

A variable setting the double click time, in milliseconds.

SDL_HINT_MOUSE_DOUBLE_CLICK_RADIUS

A variable setting the double click radius, in pixels.

SDL_HINT_MOUSE_NORMAL_SPEED_SCALE

A variable setting the speed scale for mouse motion, in floating point, when the mouse is not in relative mode.

SDL_HINT_MOUSE_RELATIVE_SPEED_SCALE

A variable setting the scale for mouse motion, in floating point, when the mouse is in relative mode.

SDL_HINT_MOUSE_RELATIVE_SCALING

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.

SDL_HINT_TOUCH_MOUSE_EVENTS

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.

SDL_HINT_MOUSE_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)
SDL_HINT_IOS_HIDE_HOME_INDICATOR

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)
SDL_HINT_TV_REMOTE_AS_JOYSTICK

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).
SDL_HINT_GAMECONTROLLERTYPE

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).

SDL_HINT_GAMECONTROLLERCONFIG_FILE

A variable that lets you provide a file with extra gamecontroller db entries.

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

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( ).

SDL_HINT_GAMECONTROLLER_IGNORE_DEVICES

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.

SDL_HINT_GAMECONTROLLER_IGNORE_DEVICES_EXCEPT

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.

SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS

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.

SDL_HINT_JOYSTICK_HIDAPI

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.

SDL_HINT_JOYSTICK_HIDAPI_PS4

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 SDL_HINT_JOYSTICK_HIDAPI

SDL_HINT_JOYSTICK_HIDAPI_PS4_RUMBLE

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 (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.

For compatibility with applications written for versions of SDL prior to the introduction of PS5 controller support, this value will also control the state of extended reports on PS5 controllers when the SDL_HINT_JOYSTICK_HIDAPI_PS5_RUMBLE hint is not explicitly set.

SDL_HINT_JOYSTICK_HIDAPI_PS5

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.

SDL_HINT_JOYSTICK_HIDAPI_PS5_RUMBLE

A variable controlling whether extended input reports should be used for PS5 controllers when using the HIDAPI driver.

This variable can be set to the following values:

0   extended reports are not enabled (default)
1   extended reports

Extended input reports allow rumble on Bluetooth PS5 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.

For compatibility with applications written for versions of SDL prior to the introduction of PS5 controller support, this value defaults to the value of SDL_HINT_JOYSTICK_HIDAPI_PS4_RUMBLE.

SDL_HINT_JOYSTICK_HIDAPI_PS5_PLAYER_LED

A variable controlling whether the player LEDs should be lit to indicate which player is associated with a PS5 controller.

This variable can be set to the following values:

0   player LEDs are not enabled
1   player LEDs are enabled (default)
SDL_HINT_JOYSTICK_HIDAPI_STADIA

A variable controlling whether the HIDAPI driver for Google Stadia 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.

SDL_HINT_JOYSTICK_HIDAPI_STEAM

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 SDL_HINT_JOYSTICK_HIDAPI.

SDL_HINT_JOYSTICK_HIDAPI_SWITCH

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 SDL_HINT_JOYSTICK_HIDAPI.

SDL_HINT_JOYSTICK_HIDAPI_SWITCH_HOME_LED

A variable controlling whether the Home button LED should be turned on when a Nintendo Switch controller is opened

This variable can be set to the following values:

0   home button LED is left off
1   home button LED is turned on (default)
SDL_HINT_JOYSTICK_HIDAPI_JOY_CONS

A variable controlling whether Switch Joy-Cons should be treated the same as Switch Pro Controllers when using the HIDAPI driver.

This variable can be set to the following values:

0   basic Joy-Con support with no analog input (default)
1   Joy-Cons treated as half full Pro Controllers with analog inputs and sensors

This does not combine Joy-Cons into a single controller. That's up to the user.

SDL_HINT_JOYSTICK_HIDAPI_XBOX

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 0 on Windows, otherwise the value of SDL_HINT_JOYSTICK_HIDAPI.

SDL_HINT_JOYSTICK_HIDAPI_CORRELATE_XINPUT

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.

SDL_HINT_JOYSTICK_HIDAPI_GAMECUBE

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 the value of SDL_HINT_JOYSTICK_HIDAPI.

SDL_HINT_ENABLE_STEAM_CONTROLLERS

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 (default)

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

SDL_HINT_JOYSTICK_RAWINPUT

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 (default)
SDL_HINT_JOYSTICK_THREAD

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 (default)
1   A separate thread is used for handling raw input messages
SDL_HINT_LINUX_JOYSTICK_DEADZONES

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 (default)
1   Return axis values with deadzones taken into account
SDL_HINT_ALLOW_TOPMOST

If set to 0 then never set the top most bit on a SDL 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 (default)
SDL_HINT_THREAD_PRIORITY_POLICY

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( ).

SDL_HINT_THREAD_FORCE_REALTIME_TIME_CRITICAL

Specifies whether SDL_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 SDL_THREAD_PRIORITY_TIME_CRITICAL to a realtime scheduling policy
SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT

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

If this hint is set before SDL_CreateWindowFrom( ) and the SDL_Window* it is set to has SDL_WINDOW_OPENGL set (and running on WGL only, currently), then two things will occur on the newly created SDL_Window:

1. Its pixel format will be set to the same pixel format as this SDL_Window. This is needed for example when sharing an OpenGL context across multiple windows.
2. The flag SDL_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 SDL_Window* that new windows created with SDL_CreateWindowFrom( ... ) should share a pixel format with.
SDL_HINT_ANDROID_TRAP_BACK_BUTTON

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.

SDL_HINT_ANDROID_BLOCK_ON_PAUSE

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.

SDL_HINT_ANDROID_BLOCK_ON_PAUSE_PAUSEAUDIO

A variable to control whether SDL will pause audio in background (Requires SDL_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.

SDL_HINT_RETURN_KEY_HIDES_IME

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.

SDL_HINT_WINDOWS_FORCE_MUTEX_CRITICAL_SECTIONS

Force SDL to use Critical Sections for mutexes on Windows. On Windows 7 and newer, Slim Reader/Writer Locks are available. They offer better performance, allocate no kernel resources and use less memory. SDL will fall back to Critical Sections on older OS versions or if forced to by this hint.

This also affects Condition Variables. When SRW mutexes are used, SDL will use Windows Condition Variables as well. Else, a generic SDL_cond implementation will be used that works with all mutexes.

This variable can be set to the following values:

0

Use SRW Locks when available. If not, fall back to Critical Sections. (default)

1

Force the use of Critical Sections in all cases.

SDL_HINT_WINDOWS_FORCE_SEMAPHORE_KERNEL

Force SDL to use Kernel Semaphores on Windows. Kernel Semaphores are inter-process and require a context switch on every interaction. On Windows 8 and newer, the WaitOnAddress API is available. Using that and atomics to implement semaphores increases performance. SDL will fall back to Kernel Objects on older OS versions or if forced to by this hint.

This variable can be set to the following values:

0

Use Atomics and WaitOnAddress API when available. If not, fall back to Kernel Objects. (default)

1

Force the use of Kernel Objects in all cases.

SDL_HINT_WINDOWS_USE_D3D9EX

Use the D3D9Ex API introduced in Windows Vista, instead of normal D3D9. Direct3D 9Ex contains changes to state management that can eliminate device loss errors during scenarios like Alt+Tab or UAC prompts. D3D9Ex may require some changes to your application to cope with the new behavior, so this is disabled by default.

This hint must be set before initializing the video subsystem.

For more information on Direct3D 9Ex, see:

https://docs.microsoft.com/en-us/windows/win32/direct3darticles/graphics-apis-in-windows-vista#direct3d-9ex
https://docs.microsoft.com/en-us/windows/win32/direct3darticles/direct3d-9ex-improvements

This variable can be set to the following values:

0

Use the original Direct3D 9 API (default)

1

Use the Direct3D 9Ex API on Vista and later (and fall back if D3D9Ex is unavailable)

SDL_HINT_VIDEO_DOUBLE_BUFFER

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 function.

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

KMSDRM (kmsdrm)
Raspberry Pi (raspberrypi)
SDL_HINT_KMSDRM_REQUIRE_DRM_MASTER

Determines whether SDL enforces that DRM master is required in order to initialize the KMSDRM video backend.

The DRM subsystem has a concept of a "DRM master" which is a DRM client that has the ability to set planes, set cursor, etc. When SDL is DRM master, it can draw to the screen using the SDL rendering APIs. Without DRM master, SDL is still able to process input and query attributes of attached displays, but it cannot change display state or draw to the screen directly.

In some cases, it can be useful to have the KMSDRM backend even if it cannot be used for rendering. An app may want to use SDL for input processing while using another rendering API (such as an MMAL overlay on Raspberry Pi) or using its own code to render to DRM overlays that SDL doesn't support.

This hint must be set before initializing the video subsystem.

This variable can be set to the following values:

0

SDL will allow usage of the KMSDRM backend without DRM master

1

SDL Will require DRM master to use the KMSDRM backend (default)

SDL_HINT_OPENGL_ES_DRIVER

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.

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 SDL_GL_GetProcAddress( ).

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.

SDL_HINT_AUDIO_RESAMPLING_MODE

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. SDL_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

SDL_HINT_AUDIO_CATEGORY

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

SDL_HINT_RENDER_BATCHING

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.

SDL_HINT_AUTO_UPDATE_JOYSTICKS

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_JoystickUpdate( ) (default)

This hint can be toggled on and off at runtime.

SDL_HINT_AUTO_UPDATE_SENSORS

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.

SDL_HINT_EVENT_LOGGING

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.

SDL_HINT_WAVE_RIFF_CHUNK_SIZE

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)

SDL_HINT_WAVE_TRUNCATION

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)

SDL_HINT_WAVE_FACT_CHUNK

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)

SDL_HINT_DISPLAY_USABLE_BOUNDS

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.

SDL_HINT_AUDIO_DEVICE_APP_NAME

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.

SDL_HINT_AUDIO_DEVICE_STREAM_NAME

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.

SDL_HINT_AUDIO_DEVICE_STREAM_ROLE

Specify an application role for an audio device.

Some audio backends (such as Pipewire) allow you to describe the role of your audio stream. Among other things, this description might show up in a system control panel or software for displaying and manipulating media playback/capture graphs.

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 (Game, Music, Movie, etc...).

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

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

SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED

Specify the behavior of Alt+Tab while the keyboard is grabbed.

By default, SDL emulates Alt+Tab functionality while the keyboard is grabbed and your window is full-screen. This prevents the user from getting stuck in your application if you've enabled keyboard grab.

The variable can be set to the following values:

0

SDL will not handle Alt+Tab. Your application is responsible for handling Alt+Tab while the keyboard is grabbed.

1

SDL will minimize your window when Alt+Tab is pressed (default)

SDL_HINT_PREFERRED_LOCALES

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 SDL_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"

:assertState

SDL_ASSERTION_RETRY - Retry the assert immediately
SDL_ASSERTION_BREAK - Make the debugger trigger a breakpoint
SDL_ASSERTION_ABORT - Terminate the program
SDL_ASSERTION_IGNORE - Ignore the assert
SDL_ASSERTION_ALWAYS_IGNORE - Ignore the assert from now on

:logcategory

The predefined log categories

By default the application category is enabled at the INFO level, the assert category is enabled at the WARN level, test is enabled at the VERBOSE level and all other categories are enabled at the CRITICAL level.

SDL_LOG_CATEGORY_APPLICATION
SDL_LOG_CATEGORY_ERROR
SDL_LOG_CATEGORY_ASSERT
SDL_LOG_CATEGORY_SYSTEM
SDL_LOG_CATEGORY_AUDIO
SDL_LOG_CATEGORY_VIDEO
SDL_LOG_CATEGORY_RENDER
SDL_LOG_CATEGORY_INPUT
SDL_LOG_CATEGORY_TEST
SDL_LOG_CATEGORY_RESERVED1
SDL_LOG_CATEGORY_RESERVED2
SDL_LOG_CATEGORY_RESERVED3
SDL_LOG_CATEGORY_RESERVED4
SDL_LOG_CATEGORY_RESERVED5
SDL_LOG_CATEGORY_RESERVED6
SDL_LOG_CATEGORY_RESERVED7
SDL_LOG_CATEGORY_RESERVED8
SDL_LOG_CATEGORY_RESERVED9
SDL_LOG_CATEGORY_RESERVED10
SDL_LOG_CATEGORY_CUSTOM

:logpriority

The predefined log priorities.

SDL_LOG_PRIORITY_VERBOSE
SDL_LOG_PRIORITY_DEBUG
SDL_LOG_PRIORITY_INFO
SDL_LOG_PRIORITY_WARN
SDL_LOG_PRIORITY_ERROR
SDL_LOG_PRIORITY_CRITICAL
SDL_NUM_LOG_PRIORITIES

:windowflags

The flags on a window.

SDL_WINDOW_FULLSCREEN - Fullscreen window
SDL_WINDOW_OPENGL - Window usable with OpenGL context
SDL_WINDOW_SHOWN - Window is visible
SDL_WINDOW_HIDDEN - Window is not visible
SDL_WINDOW_BORDERLESS - No window decoration
SDL_WINDOW_RESIZABLE - Window can be resized
SDL_WINDOW_MINIMIZED - Window is minimized
SDL_WINDOW_MAXIMIZED - Window is maximized
SDL_WINDOW_MOUSE_GRABBED - Window has grabbed mouse input
SDL_WINDOW_INPUT_FOCUS - Window has input focus
SDL_WINDOW_MOUSE_FOCUS - Window has mouse focus
SDL_WINDOW_FULLSCREEN_DESKTOP - Fullscreen window without frame
SDL_WINDOW_FOREIGN - Window not created by SDL
SDL_WINDOW_ALLOW_HIGHDPI - Window should be created in high-DPI mode if supported.

On macOS NSHighResolutionCapable must be set true in the application's Info.plist for this to have any effect.

SDL_WINDOW_MOUSE_CAPTURE - Window has mouse captured (unrelated to MOUSE_GRABBED)
SDL_WINDOW_ALWAYS_ON_TOP - Window should always be above others
SDL_WINDOW_SKIP_TASKBAR - Window should not be added to the taskbar
SDL_WINDOW_UTILITY - Window should be treated as a utility window
SDL_WINDOW_TOOLTIP - Window should be treated as a tooltip
SDL_WINDOW_POPUP_MENU - Window should be treated as a popup menu
SDL_WINDOW_KEYBOARD_GRABBED - Window has grabbed keyboard input
SDL_WINDOW_VULKAN - Window usable for Vulkan surface
SDL_WINDOW_METAL - Window usable for Metal view
SDL_WINDOW_INPUT_GRABBED - Equivalent to SDL_WINDOW_MOUSE_GRABBED for compatibility

:windowEventID

Event subtype for window events.

SDL_WINDOWEVENT_NONE - Never used
SDL_WINDOWEVENT_SHOWN - Window has been shown
SDL_WINDOWEVENT_HIDDEN - Window has been hidden
SDL_WINDOWEVENT_EXPOSED - Window has been exposed and should be redrawn
SDL_WINDOWEVENT_MOVED - Window has been moved to data1, data2
SDL_WINDOWEVENT_RESIZED - Window has been resized to data1 x data2
SDL_WINDOWEVENT_SIZE_CHANGED - The window size has changed, either as a result of an API call or through the system or user changing the window size.
SDL_WINDOWEVENT_MINIMIZED - Window has been minimized
SDL_WINDOWEVENT_MAXIMIZED - Window has been maximized
SDL_WINDOWEVENT_RESTORED - Window has been restored to normal size and position
SDL_WINDOWEVENT_ENTER - Window has gained mouse focus
SDL_WINDOWEVENT_LEAVE - Window has lost mouse focus
SDL_WINDOWEVENT_FOCUS_GAINED - Window has gained keyboard focus
SDL_WINDOWEVENT_FOCUS_LOST - Window has lost keyboard focus
SDL_WINDOWEVENT_CLOSE - The window manager requests that the window be closed
SDL_WINDOWEVENT_TAKE_FOCUS - Window is being offered a focus (should SetWindowInputFocus( ) on itself or a subwindow, or ignore)
SDL_WINDOWEVENT_HIT_TEST - Window had a hit test that wasn't SDL_HITTEST_NORMAL.

:displayEventID

Event subtype for display events.

SDL_DISPLAYEVENT_NONE - Never used
SDL_DISPLAYEVENT_ORIENTATION - Display orientation has changed to data1
SDL_DISPLAYEVENT_CONNECTED - Display has been added to the system
SDL_DISPLAYEVENT_DISCONNECTED - Display has been removed from the system

:displayOrientation

SDL_ORIENTATION_UNKNOWN - The display orientation can't be determined
SDL_ORIENTATION_LANDSCAPE - The display is in landscape mode, with the right side up, relative to portrait mode
SDL_ORIENTATION_LANDSCAPE_FLIPPED - The display is in landscape mode, with the left side up, relative to portrait mode
SDL_ORIENTATION_PORTRAIT - The display is in portrait mode
SDL_ORIENTATION_PORTRAIT_FLIPPED - The display is in portrait mode, upside down

:glAttr

OpenGL configuration attributes.

SDL_GL_RED_SIZE
SDL_GL_GREEN_SIZE
SDL_GL_BLUE_SIZE
SDL_GL_ALPHA_SIZE
SDL_GL_BUFFER_SIZE
SDL_GL_DOUBLEBUFFER
SDL_GL_DEPTH_SIZE
SDL_GL_STENCIL_SIZE
SDL_GL_ACCUM_RED_SIZE
SDL_GL_ACCUM_GREEN_SIZE
SDL_GL_ACCUM_BLUE_SIZE
SDL_GL_ACCUM_ALPHA_SIZE
SDL_GL_STEREO
SDL_GL_MULTISAMPLEBUFFERS
SDL_GL_MULTISAMPLESAMPLES
SDL_GL_ACCELERATED_VISUAL
SDL_GL_RETAINED_BACKING
SDL_GL_CONTEXT_MAJOR_VERSION
SDL_GL_CONTEXT_MINOR_VERSION
SDL_GL_CONTEXT_EGL
SDL_GL_CONTEXT_FLAGS
SDL_GL_CONTEXT_PROFILE_MASK
SDL_GL_SHARE_WITH_CURRENT_CONTEXT
SDL_GL_FRAMEBUFFER_SRGB_CAPABLE
SDL_GL_CONTEXT_RELEASE_BEHAVIOR
SDL_GL_CONTEXT_RESET_NOTIFICATION
SDL_GL_CONTEXT_NO_ERROR

:glProfile

SDL_GL_CONTEXT_PROFILE_CORE
SDL_GL_CONTEXT_PROFILE_COMPATIBILITY
SDL_GL_CONTEXT_PROFILE_ES

:glContextFlag

SDL_GL_CONTEXT_DEBUG_FLAG
SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG
SDL_GL_CONTEXT_ROBUST_ACCESS_FLAG
SDL_GL_CONTEXT_RESET_ISOLATION_FLAG

:glContextReleaseFlag

SDL_GL_CONTEXT_RELEASE_BEHAVIOR_NONE
SDL_GL_CONTEXT_RELEASE_BEHAVIOR_FLUSH

:glContextResetNotification

SDL_GL_CONTEXT_RESET_NO_NOTIFICATION
SDL_GL_CONTEXT_RESET_LOSE_CONTEXT

:rendererFlags

Flags used when creating a rendering context.

SDL_RENDERER_SOFTWARE - The renderer is a software fallback
SDL_RENDERER_ACCELERATED - The renderer uses hardware acceleration
SDL_RENDERER_PRESENTVSYNC - Present is synchronized with the refresh rate
SDL_RENDERER_TARGETTEXTURE - The renderer supports rendering to texture

:scaleMode

The scaling mode for a texture.

SDL_SCALEMODENEAREST - nearest pixel sampling
SDL_SCALEMODELINEAR - linear filtering
SDL_SCALEMODEBEST - anisotropic filtering

:textureAccess

The access pattern allowed for a texture.

SDL_TEXTUREACCESS_STATIC - Changes rarely, not lockable
SDL_TEXTUREACCESS_STREAMING - Changes frequently, lockable
SDL_TEXTUREACCESS_TARGET - Texture can be used as a render target

:textureModulate

The texture channel modulation used in SDL_RenderCopy( ... ).

SDL_TEXTUREMODULATE_NONE - No modulation
SDL_TEXTUREMODULATE_COLOR - srcC = srcC * color
SDL_TEXTUREMODULATE_ALPHA - srcA = srcA * alpha

:renderFlip

Flip constants for SDL_RenderCopyEx( ... ).

SDL_FLIP_NONE - do not flip
SDL_FLIP_HORIZONTAL - flip horizontally
SDL_FLIP_VERTICAL - flip vertically

:blendMode

The blend mode used in SDL_RenderCopy( ... ) and drawing operations.

SDL_BLENDMODE_NONE - no blending
dstRGBA = srcRGBA
SDL_BLENDMODE_BLEND - alpha blending
	dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA))
    dstA = srcA + (dstA * (1-srcA))
SDL_BLENDMODE_ADD - additive blending
dstRGB = (srcRGB * srcA) + dstRGB
dstA = dstA
SDL_BLENDMODE_MOD - color modulate
dstRGB = srcRGB * dstRGB
dstA = dstA
SDL_BLENDMODE_MUL - color multiply
dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
dstA = (srcA * dstA) + (dstA * (1-srcA))
SDL_BLENDMODE_INVALID -

Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode( ... )

:blendOperation

The blend operation used when combining source and destination pixel components.

SDL_BLENDOPERATION_ADD - dst + src: supported by all renderers
SDL_BLENDOPERATION_SUBTRACT - dst - src: supported by D3D9, D3D11, OpenGL, OpenGLES
SDL_BLENDOPERATION_REV_SUBTRACT - src - dst: supported by D3D9, D3D11, OpenGL, OpenGLES
SDL_BLENDOPERATION_MINIMUM - min(dst, src): supported by D3D11
SDL_BLENDOPERATION_MAXIMUM - max(dst, src): supported by D3D11

:blendFactor

The normalized factor used to multiply pixel components.

SDL_BLENDFACTOR_ZERO - 0, 0, 0, 0
SDL_BLENDFACTOR_ONE - 1, 1, 1, 1
SDL_BLENDFACTOR_SRC_COLOR - srcR, srcG, srcB, srcA
SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR - 1-srcR, 1-srcG, 1-srcB, 1-srcA
SDL_BLENDFACTOR_SRC_ALPHA - srcA, srcA, srcA, srcA
SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA - 1-srcA, 1-srcA, 1-srcA, 1-srcA
SDL_BLENDFACTOR_DST_COLOR - dstR, dstG, dstB, dstA
SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR - 1-dstR, 1-dstG, 1-dstB, 1-dstA
SDL_BLENDFACTOR_DST_ALPHA - dstA, dstA, dstA, dstA
SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA - 1-dstA, 1-dstA, 1-dstA, 1-dstA

:audio

Audio format flags.

These are what the 16 bits in SDL_AudioFormat currently mean... (Unspecified bits are always zero).

++-----------------------sample is signed if set
||
||       ++-----------sample is bigendian if set
||       ||
||       ||          ++---sample is float if set
||       ||          ||
||       ||          || +---sample bit size---+
||       ||          || |                     |
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

There are macros in SDL 2.0 and later to query these bits.

Audio flags

SDL_AUDIO_MASK_BITSIZE
SDL_AUDIO_MASK_DATATYPE
SDL_AUDIO_MASK_ENDIAN
SDL_AUDIO_MASK_SIGNED
SDL_AUDIO_BITSIZE
SDL_AUDIO_ISFLOAT
SDL_AUDIO_ISBIGENDIAN
SDL_AUDIO_ISSIGNED
SDL_AUDIO_ISINT
SDL_AUDIO_ISLITTLEENDIAN
SDL_AUDIO_ISUNSIGNED

Audio format flags

Defaults to LSB byte order.

AUDIO_U8 - Unsigned 8-bit samples
AUDIO_S8 - Signed 8-bit samples
AUDIO_U16LSB - Unsigned 16-bit samples
AUDIO_S16LSB - Signed 16-bit samples
AUDIO_U16MSB - As above, but big-endian byte order
AUDIO_S16MSB - As above, but big-endian byte order
AUDIO_U16 - AUDIO_U16LSB
AUDIO_S16 - AUDIO_S16LSB

int32 support

AUDIO_S32LSB - 32-bit integer samples
AUDIO_S32MSB - As above, but big-endian byte order
AUDIO_S32 - AUDIO_S32LSB

float32 support

AUDIO_F32LSB - 32-bit floating point samples
AUDIO_F32MSB - As above, but big-endian byte order
AUDIO_F32 - AUDIO_F32LSB

Native audio byte ordering

AUDIO_U16SYS
AUDIO_S16SYS
AUDIO_S32SYS
AUDIO_F32SYS

Allow change flags

Which audio format changes are allowed when opening a device.

SDL_AUDIO_ALLOW_FREQUENCY_CHANGE
SDL_AUDIO_ALLOW_FORMAT_CHANGE
SDL_AUDIO_ALLOW_CHANNELS_CHANGE
SDL_AUDIO_ALLOW_SAMPLES_CHANGE
SDL_AUDIO_ALLOW_ANY_CHANGE

Development

SDL2 is still in early development: the majority of SDL's functions have yet to be implemented and the interface may also grow to be less sugary leading up to an eventual 1.0 release. If you like stable, well tested software that performs as documented, you should hold off on trying to use SDL2 for a bit.

LICENSE

Copyright (C) Sanko Robinson.

This library is free software; you can redistribute it and/or modify it under the terms found in the Artistic License 2. Other copyrights, terms, and conditions may apply to data transmitted through this module.

AUTHOR

Sanko Robinson <sanko@cpan.org>