NAME

SDL2::FFI - FFI Wrapper for SDL (Simple DirectMedia Layer) Development Library

SYNOPSIS

use SDL2::FFI qw[:all];
die 'Error initializing SDL: ' . SDL_GetError() unless SDL_Init(SDL_INIT_VIDEO) == 0;
my $win = SDL_CreateWindow( 'Example window!',
    SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, SDL_WINDOW_RESIZABLE );
die 'Could not create window: ' . SDL_GetError() unless $win;
my $event = SDL2::Event->new;
SDL_Init(SDL_INIT_VIDEO);
my $renderer = SDL_CreateRenderer( $win, -1, 0 );
SDL_SetRenderDrawColor( $renderer, 242, 242, 242, 255 );
do {
    SDL_WaitEventTimeout( $event, 10 );
    SDL_RenderClear($renderer);
    SDL_RenderPresent($renderer);
} until $event->type == SDL_QUIT;
SDL_DestroyRenderer($renderer);
SDL_DestroyWindow($win);
SDL_Quit();

DESCRIPTION

SDL2::FFI is an FFI::Platypus backed bindings to the Simple DirectMedia Layer - a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware.

Initialization and Shutdown

The functions in this category are used to set SDL up for use and generally have global effects in your program. These functions may be imported with the :init or :default tag.

`SDL_Init( ... )`

Initializes the SDL library. This must be called before using most other SDL functions.

SDL_Init( SDL_INIT_TIMER | SDL_INIT_VIDEO | SDL_INIT_EVENTS );

SDL_Init( ... ) simply forwards to calling SDL_InitSubSystem( ... ). Therefore, the two may be used interchangeably. Though for readability of your code SDL_InitSubSystem( ... ) might be preferred.

The file I/O (for example: SDL_RWFromFile( ... )) and threading (SDL_CreateThread( ... )) subsystems are initialized by default. Message boxes ( SDL_ShowSimpleMessageBox( ... ) ) also attempt to work without initializing the video subsystem, in hopes of being useful in showing an error dialog when SDL_Init fails. You must specifically initialize other subsystems if you use them in your application.

Logging (such as SDL_Log( ... ) ) works without initialization, too.

Expected parameters include:

flags which may be any be imported with the :init tag and may be OR'd together

Subsystem initialization is ref-counted, you must call SDL_QuitSubSystem( ... ) for each SDL_InitSubSystem( ... ) to correctly shutdown a subsystem manually (or call SDL_Quit( ) to force shutdown). If a subsystem is already loaded then this call will increase the ref-count and return.

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_InitSubSystem( ... )`

Compatibility function to initialize the SDL library.

In SDL2, this function and SDL_Init( ... ) are interchangeable.

SDL_InitSubSystem( SDL_INIT_TIMER | SDL_INIT_VIDEO | SDL_INIT_EVENTS );

Expected parameters include:

flags which may be any be imported with the :init tag and may be OR'd together.

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_Quit( )`

Clean up all initialized subsystems.

SDL_Quit( );

You should call this function even if you have already shutdown each initialized subsystem with SDL_QuitSubSystem( ). It is safe to call this function even in the case of errors in initialization.

If you start a subsystem using a call to that subsystem's init function (for example SDL_VideoInit( )) instead of SDL_Init( ... ) or SDL_InitSubSystem( ... ), then you must use that subsystem's quit function (SDL_VideoQuit( )) to shut it down before calling SDL_Quit( ). But generally, you should not be using those functions directly anyhow; use SDL_Init( ... ) instead.

You can use this function in an END { ... } block to ensure that it is run when your application is shutdown.

`SDL_QuitSubSystem( ... )`

Shut down specific SDL subsystems.

SDL_QuitSubSystem( SDL_INIT_VIDEO );

If you start a subsystem using a call to that subsystem's init function (for example SDL_VideoInit( ) ) instead of SDL_Init( ... ) or SDL_InitSubSystem( ... ), SDL_QuitSubSystem( ... ) and SDL_WasInit( ... ) will not work. You will need to use that subsystem's quit function ( SDL_VideoQuit( ) directly instead. But generally, you should not be using those functions directly anyhow; use SDL_Init( ... ) instead.

You still need to call SDL_Quit( ) even if you close all open subsystems with SDL_QuitSubSystem( ... ).

Expected parameters include:

flags which may be any be imported with the :init tag and may be OR'd together.

`SDL_WasInit( ... )`

Get a mask of the specified subsystems which are currently initialized.

SDL_Init( SDL_INIT_VIDEO | SDL_INIT_AUDIO );
warn SDL_WasInit( SDL_INIT_TIMER ); # false
warn SDL_WasInit( SDL_INIT_VIDEO ); # true (32 == SDL_INIT_VIDEO)
my $mask = SDL_WasInit( );
warn 'video init!'  if ($mask & SDL_INIT_VIDEO); # yep
warn 'video timer!' if ($mask & SDL_INIT_TIMER); # nope

Expected parameters include:

flags which may be any be imported with the :init tag and may be OR'd together.

If flags is 0, it returns a mask of all initialized subsystems, otherwise it returns the initialization status of the specified subsystems.

The return value does not include SDL_INIT_NOPARACHUTE.

Configuration Variables

This category contains functions to set and get configuration hints, as well as listing each of them alphabetically.

The convention for naming hints is SDL_HINT_X, where SDL_X is the environment variable that can be used to override the default. You may import those recognised by SDL2 with the :hints tag.

In general these hints are just that - they may or may not be supported or applicable on any given platform, but they provide a way for an application or user to give the library a hint as to how they would like the library to work.

`SDL_SetHintWithPriority( ... )`

Set a hint with a specific priority.

SDL_SetHintWithPriority( SDL_EVENT_LOGGING, 2, SDL_HINT_OVERRIDE );

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.

Expected parameters include:

name: the hint to set
value: the value of the hint variable
priority: the priority level for the hint

Returns a true if the hint was set, untrue otherwise.

`SDL_SetHint( ... )`

Set a hint with normal priority.

SDL_SetHint( SDL_HINT_XINPUT_ENABLED, 1 );

Hints will not be set if there is an existing override hint or environment variable that takes precedence. You can use SDL_SetHintWithPriority( ) to set the hint with override priority instead.

Expected parameters:

name: the hint to set
value: the value of the hint variable

Returns a true value if the hint was set, untrue otherwise.

`SDL_GetHint( ... )`

Get the value of a hint.

SDL_GetHint( SDL_HINT_XINPUT_ENABLED );

Expected parameters:

name: the hint to query

Returns the string value of a hint or an undefined value if the hint isn't set.

`SDL_GetHintBoolean( ... )`

Get the boolean value of a hint variable.

SDL_GetHintBoolean( SDL_HINT_XINPUT_ENABLED, 0);

Expected parameters:

name: the name of the hint to get the boolean value from
default_value: the value to return if the hint does not exist

Returns the boolean value of a hint or the provided default value if the hint does not exist.

`SDL_AddHintCallback( ... )`

Add a function to watch a particular hint.

my $cb = SDL_AddHintCallback(
	SDL_HINT_XINPUT_ENABLED,
	sub {
		my ($userdata, $name, $oldvalue, $newvalue) = @_;
		...;
	},
	{ time => time( ), clicks => 3 }
);

Expected parameters:

name: the hint to watch
callback: a code reference that will be called when the hint value changes
userdata: a pointer to pass to the callback function

Returns a pointer to a FFI::Platypus::Closure which you may pass to SDL_DelHintCallback( ... ).

`SDL_DelHintCallback( ... )`

Remove a callback watching a particular hint.

SDL_AddHintCallback(
	SDL_HINT_XINPUT_ENABLED,
	$cb,
	{ time => time( ), clicks => 3 }
);

Expected parameters:

name: the hint to watch
callback: FFI::Platypus::Closure object returned by SDL_AddHintCallback( ... )
userdata: a pointer to pass to the callback function

`SDL_ClearHints( )`

Clear all hints.

SDL_ClearHints( );

This function is automatically called during SDL_Quit( ).

Error Handling

Functions in this category provide simple error message routines for SDL. SDL_GetError( ) can be called for almost all SDL functions to determine what problems are occurring. Check the wiki page of each specific SDL function to see whether SDL_GetError( ) is meaningful for them or not. These functions may be imported with the :error tag.

The SDL error messages are in English.

`SDL_SetError( ... )`

Set the SDL error message for the current thread.

Calling this function will replace any previous error message that was set.

This function always returns -1, since SDL frequently uses -1 to signify an failing result, leading to this idiom:

if ($error_code) {
	return SDL_SetError( 'This operation has failed: %d', $error_code );
}

Expected parameters:

fmt: a printf( )-style message format string
@params: additional parameters matching % tokens in the fmt string, if any

`SDL_GetError( )`

Retrieve a message about the last error that occurred on the current thread.

warn SDL_GetError( );

It is possible for multiple errors to occur before calling SDL_GetError( ). Only the last error is returned.

The message is only applicable when an SDL function has signaled an error. You must check the return values of SDL function calls to determine when to appropriately call SDL_GetError( ). You should not use the results of SDL_GetError( ) to decide if an error has occurred! Sometimes SDL will set an error string even when reporting success.

SDL will not clear the error string for successful API calls. You must check return values for failure cases before you can assume the error string applies.

Error strings are set per-thread, so an error set in a different thread will not interfere with the current thread's operation.

The returned string is internally allocated and must not be freed by the application.

Returns a message with information about the specific error that occurred, or an empty string if there hasn't been an error message set since the last call to SDL_ClearError( ). The message is only applicable when an SDL function has signaled an error. You must check the return values of SDL function calls to determine when to appropriately call SDL_GetError( ).

`SDL_GetErrorMsg( ... )`

Get the last error message that was set for the current thread.

my $x;
warn SDL_GetErrorMsg($x, 300);

This allows the caller to copy the error string into a provided buffer, but otherwise operates exactly the same as SDL_GetError( ).

errstr: A buffer to fill with the last error message that was set for the current thread
maxlen: The size of the buffer pointed to by the errstr parameter

Returns the pointer passed in as the errstr parameter.

`SDL_ClearError( )`

Clear any previous error message for this thread.

Log Handling

Simple log messages with categories and priorities. These functions may be imported with the :logging tag.

By default, logs are quiet but if you're debugging SDL you might want:

SDL_LogSetAllPriority( SDL_LOG_PRIORITY_WARN );

Here's where the messages go on different platforms:

Windows		debug output stream
Android		log output
Others		standard error output (STDERR)

Messages longer than the maximum size (4096 bytes) will be truncated.

`SDL_LogSetAllPriority( ... )`

Set the priority of all log categories.

SDL_LogSetAllPriority( SDL_LOG_PRIORITY_WARN );

Expected parameters:

priority: The SDL_LogPriority to assign. These may be imported with the :logpriority tag.

`SDL_LogSetPriority( ... )`

Set the priority of all log categories.

SDL_LogSetPriority( SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_WARN );

Expected parameters:

category: The category to assign a priority to. These may be imported with the :logcategory tag.
priority: The SDL_LogPriority to assign. These may be imported with the :logpriority tag.

`SDL_LogGetPriority( ... )`

Get the priority of a particular log category.

SDL_LogGetPriority( SDL_LOG_CATEGORY_ERROR );

Expected parameters:

category: The SDL_LogCategory to query. These may be imported with the :logcategory tag.

`SDL_LogGetPriority( ... )`

Get the priority of a particular log category.

SDL_LogGetPriority( SDL_LOG_CATEGORY_ERROR );

Expected parameters:

category: The SDL_LogCategory to query. These may be imported with the :logcategory tag.

`SDL_LogResetPriorities( )`

Reset all priorities to default.

SDL_LogResetPriorities( );

This is called by SDL_Quit( ).

`SDL_Log( ... )`

Log a message with SDL_LOG_CATEGORY_APPLICATION and SDL_LOG_PRIORITY_INFO.

SDL_Log( 'HTTP Status: %s', $http->status );

Expected parameters:

fmt: A sprintf( ) style message format string.
...: Any additional parameters matching % tokens in the fmt string, if any.

`SDL_LogVerbose( ... )`

Log a message with SDL_LOG_PRIORITY_VERBOSE.

SDL_LogVerbose( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogDebug( ... )`

Log a message with SDL_LOG_PRIORITY_DEBUG.

SDL_LogDebug( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogInfo( ... )`

Log a message with SDL_LOG_PRIORITY_INFO.

SDL_LogInfo( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogWarn( ... )`

Log a message with SDL_LOG_PRIORITY_WARN.

SDL_LogWarn( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogError( ... )`

Log a message with SDL_LOG_PRIORITY_ERROR.

SDL_LogError( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogCritical( ... )`

Log a message with SDL_LOG_PRIORITY_CRITICAL.

SDL_LogCritical( 'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogMessage( ... )`

Log a message with the specified category and priority.

SDL_LogMessage( SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_CRITICAL,
				'Current time: %s [%ds exec]', +localtime( ), time - $^T );

Expected parameters:

category: The category of the message.
priority: The priority of the message.
fmt: A sprintf( ) style message format string.
...: Additional parameters matching % tokens in the fmt string, if any.

`SDL_LogSetOutputFunction( ... )`

Replace the default log output function with one of your own.

my $cb = SDL_LogSetOutputFunction( sub { ... }, {} );

Expected parameters:

callback

A coderef to call instead of the default callback.

This coderef should expect the following parameters:

userdata: What was passed as userdata to SDL_LogSetOutputFunction( ).
category: The category of the message.
priority: The priority of the message.
message: The message being output.

userdata

Data passed to the callback.

Querying SDL Version

These functions are used to collect or display information about the version of SDL that is currently being used by the program or that it was compiled against.

The version consists of three segments (X.Y.Z)

X - Major Version, which increments with massive changes, additions, and enhancements
Y - Minor Version, which increments with backwards-compatible changes to the major revision
Z - Patchlevel, which increments with fixes to the minor revision

Example: The first version of SDL 2 was 2.0.0

The version may also be reported as a 4-digit numeric value where the thousands place represents the major version, the hundreds place represents the minor version, and the tens and ones places represent the patchlevel (update version).

Example: The first version number of SDL 2 was 2000

`SDL_GetVersion( ... )`

Get the version of SDL that is linked against your program.

my $ver = SDL2::Version->new;
SDL_GetVersion( $ver );

This function may be called safely at any time, even before SDL_Init( ).

Expected parameters include:

version - An SDL2::Version object which will be filled with the proper values

Display and Window Management

This category contains functions for handling display and window actions.

These functions may be imported with the :video tag.

`SDL_GetNumVideoDrivers( )`

my $num = SDL_GetNumVideoDrivers( );

Get the number of video drivers compiled into SDL.

Returns a number >= 1 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetVideoDriver( ... )`

Get the name of a built in video driver.

CORE::say SDL_GetVideoDriver($_) for 0 .. SDL_GetNumVideoDrivers( ) - 1;

The video drivers are presented in the order in which they are normally checked during initialization.

Expected parameters include:

index - the index of a video driver

Returns the name of the video driver with the given index.

`SDL_VideoInit( ... )`

Initialize the video subsystem, optionally specifying a video driver.

SDL_VideoInit( 'x11' );

This function initializes the video subsystem, setting up a connection to the window manager, etc, and determines the available display modes and pixel formats, but does not initialize a window or graphics mode.

If you use this function and you haven't used the SDL_INIT_VIDEO flag with either SDL_Init( ) or SDL_InitSubSystem( ), you should call SDL_VideoQuit( ) before calling SDL_Quit( ).

It is safe to call this function multiple times. SDL_VideoInit( ) will call SDL_VideoQuit( ) itself if the video subsystem has already been initialized.

You can use SDL_GetNumVideoDrivers( ) and SDL_GetVideoDriver( ) to find a specific `driver_name`.

Expected parameters include:

driver_name - the name of a video driver to initialize, or undef for the default driver

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_VideoQuit( )`

Shut down the video subsystem, if initialized with SDL_VideoInit( ).

SDL_VideoQuit( );

This function closes all windows, and restores the original video mode.

`SDL_GetCurrentVideoDriver( )`

Get the name of the currently initialized video driver.

my $driver = SDL_GetCurrentVideoDriver( );

Returns the name of the current video driver or NULL if no driver has been initialized.

`SDL_GetNumVideoDisplays( )`

Get the number of available video displays.

my $screens = SDL_GetNumVideoDisplays( );

Returns a number >= 1 or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetDisplayName( ... )`

Get the name of a display in UTF-8 encoding.

my $screen = SDL_GetDisplayName( 0 );

Expected parameters include:

displayIndex - the index of display from which the name should be queried

Returns the name of a display or undefined for an invalid display index or failure; call SDL_GetError( ) for more information.

`SDL_GetDisplayBounds( ... )`

Get the desktop area represented by a display.

my $rect = SDL_GetDisplayBounds( 0 );

The primary display (displayIndex == 0) is always located at 0,0.

Expected parameters include:

displayIndex - the index of the display to query

Returns the SDL2::Rect structure filled in with the display bounds on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetDisplayUsableBounds( ... )`

Get the usable desktop area represented by a display.

my $rect = SDL_GetDisplayUsableBounds( 0 );

The primary display (displayIndex == 0) is always located at 0,0.

This is the same area as SDL_GetDisplayBounds( ... ) reports, but with portions reserved by the system removed. For example, on Apple's macOS, this subtracts the area occupied by the menu bar and dock.

Setting a window to be fullscreen generally bypasses these unusable areas, so these are good guidelines for the maximum space available to a non-fullscreen window.

Expected parameters include:

displayIndex - the index of the display to query

Returns the SDL2::Rect structure filled in with the display bounds on success or a negative error code on failure; call SDL_GetError( ) for more information. This function also returns -1 if the parameter displayIndex is out of range.

`SDL_GetDisplayDPI( ... )`

Get the dots/pixels-per-inch for a display.

my ( $ddpi, $hdpi, $vdpi ) = SDL_GetDisplayDPI( 0 );

Diagonal, horizontal and vertical DPI can all be optionally returned if the appropriate parameter is non-NULL.

A failure of this function usually means that either no DPI information is available or the displayIndex is out of range.

Expected parameters include:

displayIndex - the index of the display from which DPI information should be queried

Returns [ddpi, hdpi, vdip] on success or a negative error code on failure; call SDL_GetError( ) for more information.

ddpi is the diagonal DPI of the display, hdpi is the horizontal DPI of the display, vdpi is the vertical DPI of the display.

`SDL_GetDisplayOrientation( ... )`

Get the orientation of a display.

my $orientation = SDL_GetDisplayOrientation( 0 );

Expected parameters include:

displayIndex - the index of the display to query

Returns a value which may be imported with :displayOrientation or SDL_ORIENTATION_UNKNOWN if it isn't available.

`SDL_GetNumDisplayModes( ... )`

Get the number of available display modes.

my $modes = SDL_GetNumDisplayModes( 0 );

The displayIndex needs to be in the range from 0 to SDL_GetNumVideoDisplays( ) - 1.

Expected parameters include:

displayIndex - the index of the display to query

Returns a number >= 1 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetDisplayMode( ... )`

Get information about a specific display mode.

my $mode = SDL_GetDisplayMode( 0, 0 );

The display modes are sorted in this priority:

width - largest to smallest
height - largest to smallest
bits per pixel - more colors to fewer colors
packed pixel layout - largest to smallest
refresh rate - highest to lowest

Expected parameters include:

displayIndex - the index of the display to query
modeIndex - the index of the display mode to query

Returns an SDL2::DisplayMode structure filled in with the mode at modeIndex on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetDesktopDisplayMode( ... )`

Get information about the desktop's display mode.

my $mode = SDL_GetDesktopDisplayMode( 0 );

There's a difference between this function and SDL_GetCurrentDisplayMode( ... ) when SDL runs fullscreen and has changed the resolution. In that case this function will return the previous native display mode, and not the current display mode.

Expected parameters include:

displayIndex - the index of the display to query

Returns an SDL2::DisplayMode structure filled in with the current display mode on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetCurrentDisplayMode( ... )`

my $mode = SDL_GetCurrentDisplayMode( 0 );

There's a difference between this function and SDL_GetDesktopDisplayMode( ... ) when SDL runs fullscreen and has changed the resolution. In that case this function will return the current display mode, and not the previous native display mode.

Expected parameters include:

displayIndex - the index of the display to query

Returns an SDL2::DisplayMode structure filled in with the current display mode on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetClosestDisplayMode( ... )`

Get the closes match to the requested display mode.

$mode = SDL_GetClosestDisplayMode( 0, $mode );

The available display modes are scanned and he closest mode matching the requested mode is returned. The mode format and refresh rate default to the desktop mode if they are set to 0. The modes are scanned with size being first priority, format being second priority, and finally checking the refresh rate. If all the available modes are too small, then an undefined value is returned.

Expected parameters include:

displayIndex - index of the display to query
mode - an SDL2::DisplayMode structure containing the desired display mode
closest - an SDL2::DisplayMode structure filled in with the closest match of the available display modes

Returns the passed in value closest or an undefined value if no matching video mode was available; call SDL_GetError( ) for more information.

`SDL_GetWindowDisplayIndex( ... )`

Get the index of the display associated with a window.

my $index = SDL_GetWindowDisplayIndex( $window );

Expected parameters include:

window - the window to query

Returns the index of the display containing the center of the window on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_SetWindowDisplayMode( ... )`

Set the display mode to use when a window is visible at fullscreen.

my $ok = !SDL_SetWindowDisplayMode( $window, $mode );

This only affects the display mode used when the window is fullscreen. To change the window size when the window is not fullscreen, use SDL_SetWindowSize( ... ).

`SDL_GetWindowDisplayMode( ... )`

Query the display mode to use when a window is visible at fullscreen.

my $mode = SDL_GetWindowDisplayMode( $window );

Expected parameters include:

window - the window to query

Returns a SDL2::DisplayMode structure on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetWindowPixelFormat( ... )`

Get the pixel format associated with the window.

my $format = SDL_GetWindowPixelFormat( $window );

Expected parameters include:

window - the window to query

Returns the pixel format of the window on success or SDL_PIXELFORMAT_UNKNOWN on failure; call SDL_GetError( ) for more information.

`SDL_CreateWindow( ... )`

Create a window with the specified position, dimensions, and flags.

my $window = SDL_CreateWindow( 'Example',
    SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
    1280, 720,
  	SDL_WINDOW_SHOWN
);

flags may be any of the following OR'd together:

SDL_WINDOW_FULLSCREEN - fullscreen window
SDL_WINDOW_FULLSCREEN_DESKTOP - fullscreen window at desktop resolution
SDL_WINDOW_OPENGL - window usable with an OpenGL context
SDL_WINDOW_VULKAN - window usable with a Vulkan instance
SDL_WINDOW_METAL - window usable with a Metal instance
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_INPUT_GRABBED - window has grabbed input focus
SDL_WINDOW_ALLOW_HIGHDPI - window should be created in high-DPI mode if supported (>= SDL 2.0.1)

SDL_WINDOW_SHOWN is ignored by SDL_CreateWindow( ... ). The SDL_Window is implicitly shown if SDL_WINDOW_HIDDEN is not set. SDL_WINDOW_SHOWN may be queried later using SDL_GetWindowFlags( ... ).

On Apple's macOS, you must set the NSHighResolutionCapable Info.plist property to YES, otherwise you will not receive a High-DPI OpenGL canvas.

If the window is created with the SDL_WINDOW_ALLOW_HIGHDPI flag, its size in pixels may differ from its size in screen coordinates on platforms with high-DPI support (e.g. iOS and macOS). Use SDL_GetWindowSize( ... ) to query the client area's size in screen coordinates, and SDL_GL_GetDrawableSize( ) or SDL_GetRendererOutputSize( ) to query the drawable size in pixels.

If the window is set fullscreen, the width and height parameters w and h will not be used. However, invalid size parameters (e.g. too large) may still fail. Window size is actually limited to 16384 x 16384 for all platforms at window creation.

If the window is created with any of the SDL_WINDOW_OPENGL or SDL_WINDOW_VULKAN flags, then the corresponding LoadLibrary function (SDL_GL_LoadLibrary or SDL_Vulkan_LoadLibrary) is called and the corresponding UnloadLibrary function is called by SDL_DestroyWindow( ... ).

If SDL_WINDOW_VULKAN is specified and there isn't a working Vulkan driver, SDL_CreateWindow( ... ) will fail because SDL_Vulkan_LoadLibrary( ) will fail.

If SDL_WINDOW_METAL is specified on an OS that does not support Metal, SDL_CreateWindow( ... ) will fail.

On non-Apple devices, SDL requires you to either not link to the Vulkan loader or link to a dynamic library version. This limitation may be removed in a future version of SDL.

Expected parameters include:

title - the title of the window, in UTF-8 encoding
x - the x position of the window, SDL_WINDOWPOS_CENTERED, or SDL_WINDOWPOS_UNDEFINED
y - the y position of the window, SDL_WINDOWPOS_CENTERED, or SDL_WINDOWPOS_UNDEFINED
w - the width of the window, in screen coordinates
h - the height of the window, in screen coordinates
flags - 0, or one or more :windowFlags OR'd together

Returns the window that was created or an undefined value on failure; call SDL_GetError( ) for more information.

`SDL_CreateWindowFrom( ... )`

Create an SDL window from an existing native window.

my $window = SDL_CreateWindowFrom( $data );

In some cases (e.g. OpenGL) and on some platforms (e.g. Microsoft Windows) the hint SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT needs to be configured before using SDL_CreateWindowFrom( ... ).

Expected parameters include:

data - driver-dependant window creation data, typically your native window

Returns the window that was created or an undefined value on failure; call SDL_GetError( ) for more information.

`SDL_GetWindowID( ... )`

Get the numeric ID of a window.

my $id = SDL_GetWindowID( $window );

The numeric ID is what SDL2::WindowEvent references, and is necessary to map these events to specific SDL2::Window objects.

Expected parameters include:

window - the window to query

Returns the ID of the window on success or 0 on failure; call SDL_GetError( ) for more information.

`SDL_GetWindowFromID( ... )`

Get a window from a stored ID.

my $window = SDL_GetWindowFromID( 2 );

The numeric ID is what SDL2::WindowEvent references, and is necessary to map these events to specific SDL2::Window objects.

Expected parameters include:

id - the ID of the window

Returns the window associated with id or an undefined value if it doesn't exist; call SDL_GetError( ) for more information.

`SDL_GetWindowFlags( ... )`

Get the window flags.

my $id = SDL_GetWindowFlags( $window );

The numeric ID is what SDL2::WindowEvent references, and is necessary to map these events to specific SDL2::Window objects.

Expected parameters include:

window - the window to query

Returns a mask of the :windowFlags associated with window.

`SDL_SetWindowTitle( ... )`

Set the title of a window.

SDL_SetWindowTitle( $window, 'Untitle file *' );

This string is expected to be in UTF-8 encoding.

Expected parameters include:

window - the window to change
title - the desired window title in UTF-8 format

`SDL_GetWindowTitle( ... )`

Get the title of a window.

my $title = SDL_GetWindowTitle( $window );

Expected parameters include:

window - the window to query

Returns the title of the window in UTF-8 format or "" (an empty string) if there is no title.

`SDL_SetWindowIcon( ... )`

Set the icon for a window.

SDL_SetWindowIcon( $window, $icon );

Expected parameters include:

window - the window to change
icon - an SDL2::Surface structure containing the icon for the window

`SDL_SetWindowData( ... )`

Associate an arbitrary named pointer with a window.

my $prev = SDL_SetWindowData( $window, 'test', $data );

Expected parameters include:

window - the window to change
name - the name of the pointer
userdata - the associated pointer

Returns the previous value associated with name.

`SDL_GetWindowData( ... )`

Retrieve the data pointer associated with a window.

my $data = SDL_SetWindowData( $window, 'test' );

Expected parameters include:

window - the window to query
name - the name of the pointer

Returns the value associated with name.

`SDL_SetWindowPosition( ... )`

Set the position of a window.

SDL_SetWindowPosition( $window, 100, 100 );

The window coordinate origin is the upper left of the display.

Expected parameters include:

window - the window to reposition
x - the x coordinate of the window in screen coordinates, or SDL_WINDOWPOS_CENTERED or SDL_WINDOWPOS_UNDEFINED
y - the y coordinate of the window in screen coordinates, or SDL_WINDOWPOS_CENTERED or SDL_WINDOWPOS_UNDEFINED

`SDL_GetWindowPosition( ... )`

Get the position of a window.

my ($x, $y) = SDL_GetWindowPosition( $window );

Expected parameters include:

window - the window to query

Returns the x and y positions of the window, in screen coordinates, either of which may be undefined.

`SDL_SetWindowSize( ... )`

Set the size of a window's client area.

SDL_SetWindowSize( $window, 100, 100 );

The window size in screen coordinates may differ from the size in pixels, if the window was created with SDL_WINDOW_ALLOW_HIGHDPI on a platform with high-dpi support (e.g. iOS or macOS). Use SDL_GL_GetDrawableSize( ... ) or SDL_GetRendererOutputSize( ... ) to get the real client area size in pixels.

Fullscreen windows automatically match the size of the display mode, and you should use SDL_SetWindowDisplayMode( ... ) to change their size.

Expected parameters include:

window - the window to change
w - the width of the window in pixels, in screen coordinates, must be > 0
h - the height of the window in pixels, in screen coordinates, must be > 0

`SDL_GetWindowSize( ... )`

Get the position of a window.

my ($w, $h) = SDL_GetWindowSize( $window );

The window size in screen coordinates may differ from the size in pixels, if the window was created with SDL_WINDOW_ALLOW_HIGHDPI on a platform with high-dpi support (e.g. iOS or macOS). Use SDL_GL_GetDrawableSize( ... ), SDL_Vulkan_GetDrawableSize( ... ), or SDL_GetRendererOutputSize( ... ) to get the real client area size in pixels.

Expected parameters include:

window - the window to query the width and height from

Returns the width and height of the window, in screen coordinates, either of which may be undefined.

`SDL_GetWindowBordersSize( ... )`

Get the size of a window's borders (decorations) around the client area.

my ($top, $left, $bottom, $right) = SDL_GetWindowBorderSize( $window );

Expected parameters include:

window - the window to query the size values of the border (decorations) from

Returns the top, left, bottom, and right size values, any of which may be undefined.

Note: If this function fails (returns -1), the size values will be initialized to 0, 0, 0, 0, as if the window in question was borderless.

Note: This function may fail on systems where the window has not yet been decorated by the display server (for example, immediately after calling SDL_CreateWindow( ... ) ). It is recommended that you wait at least until the window has been presented and composited, so that the window system has a chance to decorate the window and provide the border dimensions to SDL.

This function also returns -1 if getting the information is not supported.

`SDL_SetWindowMinimumSize( ... )`

Set the minimum size of a window's client area.

SDL_SetWindowMinimumSize( $window, 100, 100 );

Expected parameters include:

window - the window to change
w - the minimum width of the window in pixels
h - the minimum height of the window in pixels

`SDL_GetWindowMinimumSize( ... )`

Get the minimum size of a window's client area.

my ($w, $h) = SDL_GetWindowMinimumSize( $window );

Expected parameters include:

window - the window to query the minimum width and minimum height from

Returns the minimum width and minimum height of the window, either of which may be undefined.

`SDL_SetWindowMaximumSize( ... )`

Set the maximum size of a window's client area.

SDL_SetWindowMaximumSize( $window, 100, 100 );

Expected parameters include:

window - the window to change
w - the maximum width of the window in pixels
h - the maximum height of the window in pixels

`SDL_GetWindowMaximumSize( ... )`

Get the maximum size of a window's client area.

my ($w, $h) = SDL_GetWindowMaximumSize( $window );

Expected parameters include:

window - the window to query the maximum width and maximum height from

Returns the maximum width and maximum height of the window, either of which may be undefined.

`SDL_SetWindowBordered( ... )`

Set the border state of a window.

SDL_SetWindowBordered( $window, 1 );

This will add or remove the window's SDL_WINDOW_BORDERLESS flag and add or remove the border from the actual window. This is a no-op if the window's border already matches the requested state.

You can't change the border state of a fullscreen window.

Expected parameters include:

window - the window of which to change the border state
bordered - false value to remove border, true value to add border

`SDL_SetWindowResizable( ... )`

Set the user-resizable state of a window.

SDL_SetWindowResizable( $window, 1 );

This will add or remove the window's SDL_WINDOW_RESIZABLE flag and allow/disallow user resizing of the window. This is a no-op if the window's resizable state already matches the requested state.

You can't change the resizable state of a fullscreen window.

Expected parameters include:

window - the window of which to change the border state
bordered - true value to allow resizing, false value to disallow

`SDL_ShowWindow( ... )`

Show a window.

SDL_ShowWindow( $window );

Expected parameters include:

window - the window to show

`SDL_HideWindow( ... )`

Hide a window.

SDL_HideWindow( $window );

Expected parameters include:

window - the window to hide

`SDL_RaiseWindow( ... )`

Raise a window above other windows and set the input focus.

SDL_RaiseWindow( $window );

Expected parameters include:

window - the window to raise

`SDL_MaximizeWindow( ... )`

Make a window as large as possible.

SDL_MaximizeWindow( $window );

Expected parameters include:

window - the window to maximize

`SDL_MinimizeWindow( ... )`

Minimize a window to an iconic representation.

SDL_MinimizeWindow( $window );

Expected parameters include:

window - the window to minimize

`SDL_RestoreWindow( ... )`

Restore the size and position of a minimized or maximized window.

SDL_RestoreWindow( $window );

Expected parameters include:

window - the window to restore

`SDL_SetWindowFullscreen( ... )`

Set a window's fullscreen state.

SDL_SetWindowFullscreen( $window, SDL_WINDOW_FULLSCREEN );

Expected parameters include:

window - the window to change
flags - SDL_WINDOW_FULLSCREEN, SDL_WINDOW_FULLSCREEN_DESKTOP or 0

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_GetWindowSurface( ... )`

Get the SDL surface associated with the window.

my $surface = SDL_GetWindowSurface( $window );

A new surface will be created with the optimal format for the window, if necessary. This surface will be freed when the window is destroyed. Do not free this surface.

This surface will be invalidated if the window is resized. After resizing a window this function must be called again to return a valid surface.

You may not combine this with 3D or the rendering API on this window.

This function is affected by SDL_HINT_FRAMEBUFFER_ACCELERATION.

Expected parameters include:

window - the window to query

Returns the surface associated with the window, or an undefined on failure; call SDL_GetError( ) for more information.

`SDL_UpdateWindowSurface( ... )`

Copy the window surface to the screen.

my $ok = !SDL_UpdateWindowSurface( $window );

This is the function you use to reflect any changes to the surface on the screen.

Expected parameters include:

window - the window to query

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_UpdateWindowSurfaceRects( ... )`

Copy areas of the window surface to the screen.

SDL_UpdateWindowSurfaceRects( $window, @recs );

This is the function you use to reflect changes to portions of the surface on the screen.

Expected parameters include:

window - the window to update
rects - an array of SDL2::Rect structures representing areas of the surface to copy

Returns 0 on success or a negative error code on failure; call SDL_GetError( ) for more information.

`SDL_SetWindowGrab( ... )`

Set a window's input grab mode.

SDL_SetWindowGrab( $window, 1 );

When input is grabbed the mouse is confined to the window.

If the caller enables a grab while another window is currently grabbed, the other window loses its grab in favor of the caller's window.

Expected parameters include:

window - the window for which the input grab mode should be set
grabbed - a true value to grab input or a false value to release input

`SDL_SetWindowKeyboardGrab( ... )`

Set a window's keyboard grab mode.

SDL_SetWindowKeyboardGrab( $window, 1 );

If the caller enables a grab while another window is currently grabbed, the other window loses its grab in favor of the caller's window.

Expected parameters include:

window - The window for which the keyboard grab mode should be set.
grabbed - This is true to grab keyboard, and false to release.

`SDL_SetWindowMouseGrab( ... )`

Set a window's mouse grab mode.

SDL_SetWindowMouseGrab( $window, 1 );

Expected parameters include:

window - The window for which the mouse grab mode should be set.
grabbed - This is true to grab mouse, and false to release.

If the caller enables a grab while another window is currently grabbed, the other window loses its grab in favor of the caller's window.

`SDL_GetWindowGrab( ... )`

Get a window's input grab mode.

my $grabbing = SDL_GetWindowGrab( $window );

Expected parameters include:

window - the window to query

Returns true if input is grabbed, false otherwise.

`SDL_GetWindowKeyboardGrab( ... )`

Get a window's keyboard grab mode.

my $keyboard = SDL_GetWindowKeyboardGrab( $window );

Expected parameters include:

window - the window to query

Returns true if keyboard is grabbed, and false otherwise.

`SDL_GetWindowMouseGrab( ... )`

Get a window's mouse grab mode.

my $mouse = SDL_GetWindowMouseGrab( $window );

Expected parameters include:

window - the window to query

This returns true if mouse is grabbed, and false otherwise.

`SDL_GetGrabbedWindow( )`

Get the window that currently has an input grab enabled.

my $window = SDL_GetGrabbedWindow( );

Returns the window if input is grabbed or undefined otherwise.

`SDL_SetWindowBrightness( ... )`

Set the brightness (gamma multiplier) for a given window's display.

my $ok = !SDL_SetWindowBrightness( $window, 2 );

Despite the name and signature, this method sets the brightness of the entire display, not an individual window. A window is considered to be owned by the display that contains the window's center pixel. (The index of this display can be retrieved using SDL_GetWindowDisplayIndex( ... ).) The brightness set will not follow the window if it is moved to another display.

Many platforms will refuse to set the display brightness in modern times. You are better off using a shader to adjust gamma during rendering, or something similar.

Expected parameters includes:

window - the window used to select the display whose brightness will be changed
brightness - the brightness (gamma multiplier) value to set where 0.0 is completely dark and 1.0 is normal brightness

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetWindowBrightness( ... )`

Get the brightness (gamma multiplier) for a given window's display.

my $gamma = SDL_GetWindowBrightness( $window );

Despite the name and signature, this method retrieves the brightness of the entire display, not an individual window. A window is considered to be owned by the display that contains the window's center pixel. (The index of this display can be retrieved using SDL_GetWindowDisplayIndex( ... ).)

Expected parameters include:

window - the window used to select the display whose brightness will be queried

Returns the brightness for the display where 0.0 is completely dark and 1.0 is normal brightness.

`SDL_SetWindowOpacity( ... )`

Set the opacity for a window.

SDL_SetWindowOpacity( $window, .5 );

The parameter opacity will be clamped internally between 0.0 (transparent) and 1.0 (opaque).

This function also returns -1 if setting the opacity isn't supported.

Expected parameters include:

window - the window which will be made transparent or opaque
opacity - the opacity value (0.0 - transparent, 1.0 - opaque)

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetWindowOpacity( ... )`

Get the opacity of a window.

my $opacity = SDL_GetWindowOpacity( $window );

If transparency isn't supported on this platform, opacity will be reported as 1.0 without error.

The parameter opacity is ignored if it is undefined.

This function also returns -1 if an invalid window was provided.

Expected parameters include:

window - the window to get the current opacity value from

Returns the current opacity on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetWindowModalFor( ... )`

Set the window as a modal for another window.

my $ok = !SDL_SetWindowModalFor( $winodw, $parent );

Expected parameters include:

modal_window - the window that should be set modal
parent_window - the parent window for the modal window

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetWindowInputFocus( ... )`

Explicitly set input focus to the window.

SDL_SetWindowInputFocus( $window );

You almost certainly want SDL_RaiseWindow( ... ) instead of this function. Use this with caution, as you might give focus to a window that is completely obscured by other windows.

Expected parameters include:

window - the window that should get the input focus

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetWindowGammaRamp( ... )`

Set the gamma ramp for the display that owns a given window.

my $ok = !SDL_SetWindowGammaRamp( $window, \@red, \@green, \@blue );

Set the gamma translation table for the red, green, and blue channels of the video hardware. Each table is an array of 256 16-bit quantities, representing a mapping between the input and output for that channel. The input is the index into the array, and the output is the 16-bit gamma value at that index, scaled to the output color precision. Despite the name and signature, this method sets the gamma ramp of the entire display, not an individual window. A window is considered to be owned by the display that contains the window's center pixel. (The index of this display can be retrieved using SDL_GetWindowDisplayIndex( ... ).) The gamma ramp set will not follow the window if it is moved to another display.

Expected parameters include:

window - the window used to select the display whose gamma ramp will be changed
red - a 256 element array of 16-bit quantities representing the translation table for the red channel, or NULL
green - a 256 element array of 16-bit quantities representing the translation table for the green channel, or NULL
blue - a 256 element array of 16-bit quantities representing the translation table for the blue channel, or NULL

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetWindowGammaRamp( ... )`

Get the gamma ramp for a given window's display.

my ($red, $green, $blue) = SDL_GetWindowGammaRamp( $window );

Despite the name and signature, this method retrieves the gamma ramp of the entire display, not an individual window. A window is considered to be owned by the display that contains the window's center pixel. (The index of this display can be retrieved using SDL_GetWindowDisplayIndex( ... ).)

Expected parameters include:

window - the window used to select the display whose gamma ramp will be queried

Returns three 256 element arrays of 16-bit quantities filled in with the translation table for the red, gree, and blue channels on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetWindowHitTest( ... )`

Provide a callback that decides if a window region has special properties.

	SDL_SetWindowHitTest( $window, sub ($win, $point, $data) {
    	warn sprintf 'Click at x:%d y:%d', $point->x, $point->y;
    	...;
	});

Normally, windows are dragged and resized by decorations provided by the system window manager (a title bar, borders, etc), but for some apps, it makes sense to drag them from somewhere else inside the window itself; for example, one might have a borderless window that wants to be draggable from any part, or simulate its own title bar, etc.

This function lets the app provide a callback that designates pieces of a given window as special. This callback is run during event processing if we need to tell the OS to treat a region of the window specially; the use of this callback is known as "hit testing."

Mouse input may not be delivered to your application if it is within a special area; the OS will often apply that input to moving the window or resizing the window and not deliver it to the application.

Specifying undef for a callback disables hit-testing. Hit-testing is disabled by default.

Platforms that don't support this functionality will return -1 unconditionally, even if you're attempting to disable hit-testing.

Your callback may fire at any time, and its firing does not indicate any specific behavior (for example, on Windows, this certainly might fire when the OS is deciding whether to drag your window, but it fires for lots of other reasons, too, some unrelated to anything you probably care about and when the mouse isn't actually at the location it is testing). Since this can fire at any time, you should try to keep your callback efficient, devoid of allocations, etc.

Expected parameters include:

window - the window to set hit-testing on
callback - the function to call when doing a hit-test
callback_data - an app-defined void pointer passed to callback

Returns 0 on success or -1 on error (including unsupported); call SDL_GetError( )( ) for more information.

`SDL_FlashWindow( ... )`

Request a window to give a signal, e.g. a visual signal, to demand attention from the user.

SDL_FlashWindow( $window, 10 );

Expected parameters include:

window - the window to request the flashing for
flash_count - number of times the window gets flashed on systems that support flashing the window multiple times, like Windows, else it is ignored

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_DestroyWindow( ... )`

Destroy a window.

SDL_DestoryWindow( $window );

If window is undefined, this function will return immediately after setting the SDL error message to "Invalid window". See SDL_GetError( )( ).

Expected parameters include:

window - the window to destroy

`SDL_IsScreenSaverEnabled( ... )`

Check whether the screensaver is currently enabled.

my $enabled = SDL_IsScreenSaverEnabled( );

The screensaver is disabled by default since SDL 2.0.2. Before SDL 2.0.2 the screensaver was enabled by default.

The default can also be changed using SDL_HINT_VIDEO_ALLOW_SCREENSAVER.

Returns true if the screensaver is enabled, false if it is disabled.

`SDL_EnableScreenSaver( ... )`

Allow the screen to be blanked by a screen saver.

SDL_EnableScreenSaver( );

`SDL_DisableScreenSaver( ... )`

Prevent the screen from being blanked by a screen saver.

SDL_DisableScreenSaver( );

If you disable the screensaver, it is automatically re-enabled when SDL quits.

OpenGL Support Functions

These may be imported with the :opengl tag.

`SDL_GL_LoadLibrary( ... )`

Dynamically load an OpenGL library.

my $ok = SDL_GL_LoadLibrary( );

This should be done after initializing the video driver, but before creating any OpenGL windows. If no OpenGL library is loaded, the default library will be loaded upon creation of the first OpenGL window.

If you do this, you need to retrieve all of the GL functions used in your program from the dynamic library using SDL_GL_GetProcAddress( ).

Expected parameters include:

path - the platform dependent OpenGL library name, or undef to open the default OpenGL library

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_GetProcAddress( ... )`

Get an OpenGL function by name.

my $ptr = SDL_GL_GetProcAddress( 'glGenBuffers' );
...; # TODO
# TODO: In the future, this should return an XSUB loaded with FFI.

If the GL library is loaded at runtime with SDL_GL_LoadLibrary( ... ), then all GL functions must be retrieved this way. Usually this is used to retrieve function pointers to OpenGL extensions.

There are some quirks to looking up OpenGL functions that require some extra care from the application. If you code carefully, you can handle these quirks without any platform-specific code, though:

On Windows, function pointers are specific to the current GL context; this means you need to have created a GL context and made it current before calling SDL_GL_GetProcAddress( ). If you recreate your context or create a second context, you should assume that any existing function pointers aren't valid to use with it. This is (currently) a Windows-specific limitation, and in practice lots of drivers don't suffer this limitation, but it is still the way the wgl API is documented to work and you should expect crashes if you don't respect it. Store a copy of the function pointers that comes and goes with context lifespan.
On X11, function pointers returned by this function are valid for any context, and can even be looked up before a context is created at all. This means that, for at least some common OpenGL implementations, if you look up a function that doesn't exist, you'll get a non-NULL result that is _NOT_ safe to call. You must always make sure the function is actually available for a given GL context before calling it, by checking for the existence of the appropriate extension with SDL_GL_ExtensionSupported( ... ), or verifying that the version of OpenGL you're using offers the function as core functionality.
Some OpenGL drivers, on all platforms, will return undef if a function isn't supported, but you can't count on this behavior. Check for extensions you use, and if you get an undef anyway, act as if that extension wasn't available. This is probably a bug in the driver, but you can code defensively for this scenario anyhow.
Just because you're on Linux/Unix, don't assume you'll be using X11. Next-gen display servers are waiting to replace it, and may or may not make the same promises about function pointers.
OpenGL function pointers must be declared APIENTRY as in the example code. This will ensure the proper calling convention is followed on platforms where this matters (Win32) thereby avoiding stack corruption.

Expected parameters include:

proc - the name of an OpenGL function

Returns a pointer to the named OpenGL function. The returned pointer should be cast to the appropriate function signature.

`SDL_GL_UnloadLibrary( )`

Unload the OpenGL library previously loaded by SDL_GL_LoadLibrary( ... ).

`SDL_GL_ExtensionSupported( ... )`

Check if an OpenGL extension is supported for the current context.

my $ok = SDL_GL_ExtensionSupported( 'GL_ARB_texture_rectangle' );

This function operates on the current GL context; you must have created a context and it must be current before calling this function. Do not assume that all contexts you create will have the same set of extensions available, or that recreating an existing context will offer the same extensions again.

While it's probably not a massive overhead, this function is not an O(1) operation. Check the extensions you care about after creating the GL context and save that information somewhere instead of calling the function every time you need to know.

Expected parameters include:

extension - the name of the extension to check

Returns true if the extension is supported, false otherwise.

`SDL_GL_ResetAttributes( )`

Reset all previously set OpenGL context attributes to their default values.

SDL_GL_ResetAttributes( );

`SDL_GL_SetAttribute( ... )`

Set an OpenGL window attribute before window creation.

SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

This function sets the OpenGL attribute attr to value. The requested attributes should be set before creating an OpenGL window. You should use SDL_GL_GetAttribute( ... ) to check the values after creating the OpenGL context, since the values obtained can differ from the requested ones.

Expected parameters include:

attr - an SDL_GLattr enum value specifying the OpenGL attribute to set
value - the desired value for the attribute

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_GetAttribute( ... )`

Get the actual value for an attribute from the current context.

my $value = SDL_GL_GetAttribute(SDL_GL_DOUBLEBUFFER);

Expected parameters include:

attr - an SDL_GLattr enum value specifying the OpenGL attribute to get

Returns the value on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_CreateContext( ... )`

Create an OpenGL context for an OpenGL window, and make it current.

	# Window mode MUST include SDL_WINDOW_OPENGL for use with OpenGL.
	my $window = SDL_CreateWindow(
    	'SDL2/OpenGL Demo', 0, 0, 640, 480,
    	SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);

	# Create an OpenGL context associated with the window
	my $glcontext = SDL_GL_CreateContext( $window );

	# now you can make GL calls.
	glClearColor( 0, 0, 0 ,1 );
	glClear( GL_COLOR_BUFFER_BIT );
	SDL_GL_SwapWindow( $window );

	# Once finished with OpenGL functions, the SDL_GLContext can be deleted.
	SDL_GL_DeleteContext( $glcontext );

Windows users new to OpenGL should note that, for historical reasons, GL functions added after OpenGL version 1.1 are not available by default. Those functions must be loaded at run-time, either with an OpenGL extension-handling library or with SDL_GL_GetProcAddress( ... ) and its related functions.

SDL2::GLContext is opaque to the application.

Expected parameters include:

window - the window to associate with the context

Returns the OpenGL context associated with window or undef on error; call SDL_GetError( )( ) for more details.

`SDL_GL_MakeCurrent( ... )`

Set up an OpenGL context for rendering into an OpenGL window.

SDL_GL_MakeCurrent( $window, $gl );

The context must have been created with a compatible window.

Expected parameters include:

window - the window to associate with the context
context - the OpenGL context to associate with the window

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_GetCurrentWindow( )`

Get the currently active OpenGL window.

my $window = SDL_GL_GetCurrentWindow( );

Returns the currently active OpenGL window on success or undef on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_GetCurrentContext( )`

Get the currently active OpenGL context.

my $gl = SDL_GL_GetCurrentContext( );

Returns the currently active OpenGL context or NULL on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_GetDrawableSize( ... )`

Get the size of a window's underlying drawable in pixels.

my ($w, $h) = SDL_GL_GetDrawableSize( $window );

This returns info useful for calling glViewport( ... ).

This may differ from SDL_GetWindowSize( ... ) if we're rendering to a high-DPI drawable, i.e. the window was created with SDL_WINDOW_ALLOW_HIGHDPI on a platform with high-DPI support (Apple calls this "Retina"), and not disabled by the SDL_HINT_VIDEO_HIGHDPI_DISABLED hint.

Expected parameters include:

window - the window from which the drawable size should be queried

Returns the width and height in pixels, either of which may be undefined.

`SDL_GL_SetSwapInterval( ... )`

Set the swap interval for the current OpenGL context.

my $ok = !SDL_GL_SetSwapInterval( 1 );

Some systems allow specifying -1 for the interval, to enable adaptive vsync. Adaptive vsync works the same as vsync, but if you've already missed the vertical retrace for a given frame, it swaps buffers immediately, which might be less jarring for the user during occasional framerate drops. If application requests adaptive vsync and the system does not support it, this function will fail and return -1. In such a case, you should probably retry the call with 1 for the interval.

Adaptive vsync is implemented for some glX drivers with GLX_EXT_swap_control_tear: https://www.opengl.org/registry/specs/EXT/glx_swap_control_tear.txt and for some Windows drivers with WGL_EXT_swap_control_tear: https://www.opengl.org/registry/specs/EXT/wgl_swap_control_tear.txt

Read more on the Khronos wiki: https://www.khronos.org/opengl/wiki/Swap_Interval#Adaptive_Vsync

Expected parameters include:

interval - 0 for immediate updates, 1 for updates synchronized with the vertical retrace, -1 for adaptive vsync

Returns 0 on success or -1 if setting the swap interval is not supported; call SDL_GetError( )( ) for more information.

`SDL_GL_GetSwapInterval( )`

Get the swap interval for the current OpenGL context.

my $interval = SDL_GL_GetSwapInterval( );

If the system can't determine the swap interval, or there isn't a valid current context, this function will return 0 as a safe default.

Returns 0 if there is no vertical retrace synchronization, 1 if the buffer swap is synchronized with the vertical retrace, and -1 if late swaps happen immediately instead of waiting for the next retrace; call SDL_GetError( )( ) for more information.

`SDL_GL_SwapWindow( ... )`

Update a window with OpenGL rendering.

SDL_GL_SwapWindow( $window );

This is used with double-buffered OpenGL contexts, which are the default.

On macOS, make sure you bind 0 to the draw framebuffer before swapping the window, otherwise nothing will happen. If you aren't using glBindFramebuffer( ), this is the default and you won't have to do anything extra.

Expected parameters include:

window - the window to change

`SDL_GL_DeleteContext( ... )`

Delete an OpenGL context.

SDL_GL_DeleteContext( $context );

Expected parameters include:

context - the OpenGL context to be deleted

2D Accelerated Rendering

This category contains functions for 2D accelerated rendering. You may import these functions with the :render tag.

This API supports the following features:

single pixel points
single pixel lines
filled rectangles
texture images

All of these may be drawn in opaque, blended, or additive modes.

The texture images can have an additional color tint or alpha modulation applied to them, and may also be stretched with linear interpolation, rotated or flipped/mirrored.

For advanced functionality like particle effects or actual 3D you should use SDL's OpenGL/Direct3D support or one of the many available 3D engines.

This API is not designed to be used from multiple threads, see SDL issue #986 for details.

`SDL_GetNumRenderDrivers( )`

Get the number of 2D rendering drivers available for the current display.

my $drivers = SDL_GetNumRenderDrivers( );

A render driver is a set of code that handles rendering and texture management on a particular display. Normally there is only one, but some drivers may have several available with different capabilities.

There may be none if SDL was compiled without render support.

Returns a number >= 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRenderDriverInfo( ... )`

Get info about a specific 2D rendering driver for the current display.

my $info = !SDL_GetRendererDriverInfo( );

Expected parameters include:

index - the index of the driver to query information about

Returns an SDL2::RendererInfo structure on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_CreateWindowAndRenderer( ... )`

Create a window and default renderer.

my ($window, $renderer) = SDL_CreateWindowAndRenderer(640, 480, 0);

Expected parameters include:

width - the width of the window
height - the height of the window
window_flags - the flags used to create the window (see SDL_CreateWindow( ... ))

Returns a SDL2::Window and SDL2::Renderer objects on success, or -1 on error; call SDL_GetError( )( ) for more information.

`SDL_CreateRenderer( ... )`

Create a 2D rendering context for a window.

my $renderer = SDL_CreateRenderer( $window, -1, 0);

Expected parameters include:

window - the window where rendering is displayed
index - the index of the rendering driver to initialize, or -1 to initialize the first one supporting the requested flags
flags - 0, or one or more SDL_RendererFlags OR'd together

Returns a valid rendering context or undefined if there was an error; call SDL_GetError( )( ) for more information.

`SDL_CreateSoftwareRenderer( ... )`

Create a 2D software rendering context for a surface.

my $renderer = SDL_CreateSoftwareRenderer( $surface );

Two other API which can be used to create SDL_Renderer:

SDL_CreateRenderer( ... ) and SDL_CreateWindowAndRenderer( ... ). These can also create a software renderer, but they are intended to be used with an SDL2::Window as the final destination and not an SDL2::Surface.

Expected parameters include:

surface - the SDL2::Surface structure representing the surface where rendering is done

Returns a valid rendering context or undef if there was an error; call SDL_GetError( )( ) for more information.

`SDL_GetRenderer( ... )`

Get the renderer associated with a window.

my $renderer = SDL_GetRenderer( $window );

Expected parameters include:

window - the window to query

Returns the rendering context on success or undef on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRendererInfo( ... )`

Get information about a rendering context.

my $info = !SDL_GetRendererInfo( $renderer );

Expected parameters include:

renderer - the rendering context

Returns an SDL2::RendererInfo structure on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRendererOutputSize( ... )`

Get the output size in pixels of a rendering context.

my ($w, $h) = SDL_GetRendererOutputSize( $renderer );

Due to high-dpi displays, you might end up with a rendering context that has more pixels than the window that contains it, so use this instead of SDL_GetWindowSize( ... ) to decide how much drawing area you have.

Expected parameters include:

renderer - the rendering context

Returns the width and height on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_CreateTexture( ... )`

Create a texture for a rendering context.

my $texture = SDL_CreateTexture( $renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, 1024, 768);

You can set the texture scaling method by setting SDL_HINT_RENDER_SCALE_QUALITY before creating the texture.

Expected parameters include:

renderer - the rendering context
format - one of the enumerated values in :pixelFormatEnum
access - one of the enumerated values in :textureAccess
w - the width of the texture in pixels
h - the height of the texture in pixels

Returns a pointer to the created texture or undefined if no rendering context was active, the format was unsupported, or the width or height were out of range; call SDL_GetError( )( ) for more information.

`SDL_CreateTextureFromSurface( ... )`

Create a texture from an existing surface.

	use Config;
	my ($rmask, $gmask, $bmask, $amask) =
	$Config{byteorder} == 4321 ? (0xff000000,0x00ff0000,0x0000ff00,0x000000ff) :
    							 (0x000000ff,0x0000ff00,0x00ff0000,0xff000000);
	my $surface = SDL_CreateRGBSurface( 0, 640, 480, 32, $rmask, $gmask, $bmask, $amask );
	my $texture = SDL_CreateTextureFromSurface( $renderer, $surface );

The surface is not modified or freed by this function.

The SDL_TextureAccess hint for the created texture is SDL_TEXTUREACCESS_STATIC.

The pixel format of the created texture may be different from the pixel format of the surface. Use SDL_QueryTexture( ... ) to query the pixel format of the texture.

Expected parameters include:

renderer - the rendering context
surface - the SDL2::Surface structure containing pixel data used to fill the texture

Returns the created texture or undef on failure; call SDL_GetError( )( ) for more information.

`SDL_QueryTexture( ... )`

Query the attributes of a texture.

my ( $format, $access, $w, $h ) = SDL_QueryTexture( $texture );

Expected parameters include:

texture - the texture to query

Returns the following on success...

format - a pointer filled in with the raw format of the texture; the actual format may differ, but pixel transfers will use this format (one of the :pixelFormatEnum values)
access - a pointer filled in with the actual access to the texture (one of the :textureAccess values)
w - a pointer filled in with the width of the texture in pixels
h - a pointer filled in with the height of the texture in pixels

...or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetTextureColorMod( ... )`

Set an additional color value multiplied into render copy operations.

my $ok = !SDL_SetTextureColorMod( $texture, 64, 64, 64 );

When this texture is rendered, during the copy operation each source color channel is modulated by the appropriate color value according to the following formula:

srcC = srcC * (color / 255)

Color modulation is not always supported by the renderer; it will return -1 if color modulation is not supported.

Expected parameters include:

texture - the texture to update
r - the red color value multiplied into copy operations
g - the green color value multiplied into copy operations
b - the blue color value multiplied into copy operations

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetTextureColorMod( ... )`

Get the additional color value multiplied into render copy operations.

my ( $r, $g, $b ) = SDL_GetTextureColorMod( $texture );

Expected parameters include:

texture - the texture to query

Returns the current red, green, and blue color values on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetTextureAlphaMod( ... )`

Set an additional alpha value multiplied into render copy operations.

SDL_SetTextureAlphaMod( $texture, 100 );

When this texture is rendered, during the copy operation the source alpha

value is modulated by this alpha value according to the following formula:

srcA = srcA * (alpha / 255)

Alpha modulation is not always supported by the renderer; it will return -1 if alpha modulation is not supported.

Expected parameters include:

texture - the texture to update
alpha - the source alpha value multiplied into copy operations

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetTextureAlphaMod( ... )`

Get the additional alpha value multiplied into render copy operations.

my $alpha = SDL_GetTextureAlphaMod( $texture );

Expected parameters include:

texture - the texture to query

Returns the current alpha value on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetTextureBlendMode( ... )`

Set the blend mode for a texture, used by SDL_RenderCopy( ... ).

If the blend mode is not supported, the closest supported mode is chosen and this function returns -1.

Expected parameters include:

texture - the texture to update
blendMode - the :blendMode to use for texture blending

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetTextureBlendMode( ... )`

Get the blend mode used for texture copy operations.

SDL_GetTextureBlendMode( $texture, SDL_BLENDMODE_ADD );

Expected parameters include:

texture - the texture to query

Returns the current :blendMode on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetTextureScaleMode( ... )`

Set the scale mode used for texture scale operations.

SDL_SetTextureScaleMode( $texture, $scaleMode );

If the scale mode is not supported, the closest supported mode is chosen.

Expected parameters include:

texture - The texture to update.
scaleMode - the SDL_ScaleMode to use for texture scaling.

Returns 0 on success, or -1 if the texture is not valid.

`SDL_GetTextureScaleMode( ... )`

Get the scale mode used for texture scale operations.

my $ok = SDL_GetTextureScaleMode( $texture );

Expected parameters include:

texture - the texture to query.

Returns the current scale mode on success, or -1 if the texture is not valid.

`SDL_UpdateTexture( ... )`

Update the given texture rectangle with new pixel data.

my $rect = SDL2::Rect->new( { x => 0, y => ..., w => $surface->w, h => $surface->h } );
SDL_UpdateTexture( $texture, $rect, $surface->pixels, $surface->pitch );

The pixel data must be in the pixel format of the texture. Use SDL_QueryTexture( ... ) to query the pixel format of the texture.

This is a fairly slow function, intended for use with static textures that do not change often.

If the texture is intended to be updated often, it is preferred to create the texture as streaming and use the locking functions referenced below. While this function will work with streaming textures, for optimization reasons you may not get the pixels back if you lock the texture afterward.

Expected parameters include:

texture - the texture to update
rect - an SDL2::Rect structure representing the area to update, or undef to update the entire texture
pixels - the raw pixel data in the format of the texture
pitch - the number of bytes in a row of pixel data, including padding between lines

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_UpdateYUVTexture( ... )`

Update a rectangle within a planar YV12 or IYUV texture with new pixel data.

SDL_UpdateYUVTexture( $texture, $rect, $yPlane, $yPitch, $uPlane, $uPitch, $vPlane, $vPitch );

You can use SDL_UpdateTexture( ... ) as long as your pixel data is a contiguous block of Y and U/V planes in the proper order, but this function is available if your pixel data is not contiguous.

Expected parameters include:

texture - the texture to update
rect - a pointer to the rectangle of pixels to update, or undef to update the entire texture
Yplane - the raw pixel data for the Y plane
Ypitch - the number of bytes between rows of pixel data for the Y plane
Uplane - the raw pixel data for the U plane
Upitch - the number of bytes between rows of pixel data for the U plane
Vplane - the raw pixel data for the V plane
Vpitch - the number of bytes between rows of pixel data for the V plane

Returns 0 on success or -1 if the texture is not valid; call SDL_GetError( )( ) for more information.

`SDL_UpdateNVTexture( ... )`

Update a rectangle within a planar NV12 or NV21 texture with new pixels.

SDL_UpdateNVTexture( $texture, $rect, $yPlane, $yPitch, $uPlane, $uPitch );

You can use SDL_UpdateTexture( ... ) as long as your pixel data is a contiguous block of NV12/21 planes in the proper order, but this function is available if your pixel data is not contiguous.

Expected parameters include:

texture - the texture to update
rect - a pointer to the rectangle of pixels to update, or undef to update the entire texture.
Yplane - the raw pixel data for the Y plane.
Ypitch - the number of bytes between rows of pixel data for the Y plane.
UVplane - the raw pixel data for the UV plane.
UVpitch - the number of bytes between rows of pixel data for the UV plane.

Returns 0 on success, or -1 if the texture is not valid.

`SDL_LockTexture( ... )`

Lock a portion of the texture for write-only pixel access.

SDL_LockTexture( $texture, $rect, $pixels, $pitch );

As an optimization, the pixels made available for editing don't necessarily contain the old texture data. This is a write-only operation, and if you need to keep a copy of the texture data you should do that at the application level.

You must use SDL_UpdateTexture( ... ) to unlock the pixels and apply any changes.

Expected parameters include:

texture - the texture to lock for access, which was created with SDL_TEXTUREACCESS_STREAMING
rect - an SDL2::Rect structure representing the area to lock for access; undef to lock the entire texture
pixels - this is filled in with a pointer to the locked pixels, appropriately offset by the locked area
pitch - this is filled in with the pitch of the locked pixels; the pitch is the length of one row in bytes

Returns 0 on success or a negative error code if the texture is not valid or was not created with `SDL_TEXTUREACCESS_STREAMING`; call SDL_GetError( )( ) for more information.

`SDL_LockTextureToSurface( ... )`

Lock a portion of the texture for write-only pixel access, and expose it as a SDL surface.

my $surface = SDL_LockTextureSurface( $texture, $rect );

Besides providing an SDL2::Surface instead of raw pixel data, this function operates like SDL2::LockTexture.

You must use SDL_UnlockTexture( ... ) to unlock the pixels and apply any changes.

The returned surface is freed internally after calling SDL_UnlockTexture( ... ) or SDL_DestroyTexture( ... ). The caller should not free it.

Expected parameters include:

texture - the texture to lock for access, which was created with SDL_TEXTUREACCESS_STREAMING
rect - a pointer to the rectangle to lock for access. If the rect is undef, the entire texture will be locked

Returns the SDL2::Surface structure on success, or -1 if the texture is not valid or was not created with SDL_TEXTUREACCESS_STREAMING.

`SDL_UnlockTexture( ... )`

Unlock a texture, uploading the changes to video memory, if needed.

SDL_UnlockTexture( $texture );

Warning: Please note that SDL_LockTexture( ... ) is intended to be write-only; it will not guarantee the previous contents of the texture will be provided. You must fully initialize any area of a texture that you lock before unlocking it, as the pixels might otherwise be uninitialized memory.

Which is to say: locking and immediately unlocking a texture can result in corrupted textures, depending on the renderer in use.

Expected parameters include:

texture - a texture locked by SDL_LockTexture( ... )

`SDL_RenderTargetSupported( ... )`

Determine whether a renderer supports the use of render targets.

my $bool = SDL_RenderTargetSupported( $renderer );

Expected parameters include:

renderer - the renderer that will be checked

Returns true if supported or false if not.

`SDL_SetRenderTarget( ... )`

Set a texture as the current rendering target.

SDL_SetRenderTarget( $renderer, $texture );

Before using this function, you should check the SDL_RENDERER_TARGETTEXTURE bit in the flags of SDL2::RendererInfo to see if render targets are supported.

The default render target is the window for which the renderer was created. To stop rendering to a texture and render to the window again, call this function with a undefined texture.

Expected parameters include:

renderer - the rendering context
texture - the targeted texture, which must be created with the SDL_TEXTUREACCESS_TARGET flag, or undef to render to the window instead of a texture.

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRenderTarget( ... )`

Get the current render target.

my $texture = SDL_GetRenderTarget( $renderer );

The default render target is the window for which the renderer was created, and is reported an undefined value here.

Expected parameters include:

renderer - the rendering context

Returns the current render target or undef for the default render target.

`SDL_RenderSetLogicalSize( ... )`

Set a device independent resolution for rendering.

SDL_RenderSetLogicalSize( $renderer, 100, 100 );

This function uses the viewport and scaling functionality to allow a fixed logical resolution for rendering, regardless of the actual output resolution. If the actual output resolution doesn't have the same aspect ratio the output rendering will be centered within the output display.

If the output display is a window, mouse and touch events in the window will be filtered and scaled so they seem to arrive within the logical resolution.

If this function results in scaling or subpixel drawing by the rendering backend, it will be handled using the appropriate quality hints.

Expected parameters include:

renderer - the renderer for which resolution should be set
w - the width of the logical resolution
h - the height of the logical resolution

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderGetLogicalSize( ... )`

Get device independent resolution for rendering.

my ($w, $h) = SDL_RenderGetLogicalSize( $renderer );

This may return 0 for w and h if the SDL2::Renderer has never had its logical size set by SDL_RenderSetLogicalSize( ... ) and never had a render target set.

Expected parameters include:

renderer - a rendering context

Returns the width and height.

`SDL_RenderSetIntegerScale( ... )`

Set whether to force integer scales for resolution-independent rendering.

SDL_RenderSetIntegerScale( $renderer, 1 );

This function restricts the logical viewport to integer values - that is, when a resolution is between two multiples of a logical size, the viewport size is rounded down to the lower multiple.

Expected parameters include:

renderer - the renderer for which integer scaling should be set
enable - enable or disable the integer scaling for rendering

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderGetIntegerScale( ... )`

Get whether integer scales are forced for resolution-independent rendering.

SDL_RenderGetIntegerScale( $renderer );

Expected parameters include:

renderer - the renderer from which integer scaling should be queried

Returns true if integer scales are forced or false if not and on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderSetViewport( ... )`

Set the drawing area for rendering on the current target.

SDL_RenderSetViewport( $renderer, $rect );

When the window is resized, the viewport is reset to fill the entire new window size.

Expected parameters include:

renderer - the rendering context
rect - the SDL2::Rect structure representing the drawing area, or undef to set the viewport to the entire target

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderGetViewport( ... )`

Get the drawing area for the current target.

my $rect = SDL_RenderGetViewport( $renderer );

Expected parameters include:

renderer - the rendering context

Returns an SDL2::Rect structure filled in with the current drawing area.

`SDL_RenderSetClipRect( ... )`

Set the clip rectangle for rendering on the specified target.

SDL_RenderSetClipRect( $renderer, $rect );

Expected parameters include:

renderer - the rendering context for which clip rectangle should be set
rect - an SDL2::Rect structure representing the clip area, relative to the viewport, or undef to disable clipping

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderGetClipRect( ... )`

Get the clip rectangle for the current target.

my $rect = SDL_RenderGetClipRect( $renderer );

Expected parameters include:

renderer - the rendering context from which clip rectangle should be queried

Returns an SDL2::Rect structure filled in with the current clipping area or an empty rectangle if clipping is disabled.

`SDL_RenderIsClipEnabled( ... )`

Get whether clipping is enabled on the given renderer.

my $tf = SDL_RenderIsClipEnabled( $renderer );

Expected parameters include:

renderer - the renderer from which clip state should be queried

Returns true if clipping is enabled or false if not; call SDL_GetError( )( ) for more information.

`SDL_RenderSetScale( ... )`

Set the drawing scale for rendering on the current target.

SDL_RenderSetScale( $renderer, .5, 1 );

The drawing coordinates are scaled by the x/y scaling factors before they are used by the renderer. This allows resolution independent drawing with a single coordinate system.

If this results in scaling or subpixel drawing by the rendering backend, it will be handled using the appropriate quality hints. For best results use integer scaling factors.

Expected parameters include:

renderer - a rendering context
scaleX - the horizontal scaling factor
scaleY - the vertical scaling factor

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderGetScale( ... )`

Get the drawing scale for the current target.

my ($scaleX, $scaleY) = SDL_RenderGetScale( $renderer );

Expected parameters include:

renderer - the renderer from which drawing scale should be queried

Returns the horizonal and vertical scaling factors.

`SDL_SetRenderDrawColor( ... )`

Set the color used for drawing operations (Rect, Line and Clear).

SDL_SetRenderDrawColor( $renderer, 0, 0, 128, SDL_ALPHA_OPAQUE );

Set the color for drawing or filling rectangles, lines, and points, and for SDL_RenderClear( ... ).

Expected parameters include:

renderer - the rendering context
r - the red value used to draw on the rendering target
g - the green value used to draw on the rendering target
b - the blue value used to draw on the rendering target
a - the alpha value used to draw on the rendering target; usually SDL_ALPHA_OPAQUE (255). Use SDL_SetRenderDrawBlendMode to specify how the alpha channel is used

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRenderDrawColor( ... )`

Get the color used for drawing operations (Rect, Line and Clear).

my ($r, $g, $b, $a) = SDL_GetRenderDrawColor( $renderer );

Expected parameters include:

renderer - the rendering context

Returns red, green, blue, and alpha values on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_SetRenderDrawBlendMode( ... )`

Set the blend mode used for drawing operations (Fill and Line).

SDL_SetRenderDrawBlendMode( $renderer, SDL_BLENDMODE_BLEND );

If the blend mode is not supported, the closest supported mode is chosen.

Expected parameters include:

renderer - the rendering context
blendMode - the :blendMode to use for blending

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GetRenderDrawBlendMode( ... )`

Get the blend mode used for drawing operations.

my $blendMode = SDL_GetRenderDrawBlendMode( $rendering );

Expected parameters include:

renderer - the rendering context

Returns the current :blendMode on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderClear( ... )`

Clear the current rendering target with the drawing color.

SDL_RenderClear( $renderer );

This function clears the entire rendering target, ignoring the viewport and the clip rectangle.

renderer - the rendering context

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawPoint( ... )`

Draw a point on the current rendering target.

SDL_RenderDrawPoint( $renderer, 100, 100 );

SDL_RenderDrawPoint( ... ) draws a single point. If you want to draw multiple, use SDL_RenderDrawPoints( ... ) instead.

Expected parameters include:

renderer - the rendering context
x - the x coordinate of the point
y - the y coordinate of the point

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawPoints( ... )`

Draw multiple points on the current rendering target.

my @points = map { SDL2::Point->new( {x => int rand, y => int rand } ) } 1..1024;
SDL_RenderDrawPoints( $renderer, @points );

renderer - the rendering context
points - an array of SDL2::Point structures that represent the points to draw

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawLine( ... )`

Draw a line on the current rendering target.

SDL_RenderDrawLine( $renderer, 300, 240, 340, 240 );

SDL_RenderDrawLine( ... ) draws the line to include both end points. If you want to draw multiple, connecting lines use SDL_RenderDrawLines( ... ) instead.

Expected parameters include:

renderer - the rendering context
x1 - the x coordinate of the start point
y1 - the y coordinate of the start point
x2 - the x coordinate of the end point
y2 - the y coordinate of the end point

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawLines( ... )`

Draw a series of connected lines on the current rendering target.

SDL_RenderDrawLines( $renderer, @points);

Expected parameters include:

renderer - the rendering context
points - an array of SDL2::Point structures representing points along the lines

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawRect( ... )`

Draw a rectangle on the current rendering target.

SDL_RenderDrawRect( $renderer, SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ) );

Expected parameters include:

renderer - the rendering context
rect - an SDL2::Rect structure representing the rectangle to draw

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawRects( ... )`

Draw some number of rectangles on the current rendering target.

	SDL_RenderDrawRects( $renderer,
		SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ),
        SDL2::Rect->new( { x => 75,  y => 75,  w => 50,  h => 50 } )
    );

Expected parameters include:

renderer - the rendering context
rects - an array of SDL2::Rect structures representing the rectangles to be drawn

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderFillRect( ... )`

Fill a rectangle on the current rendering target with the drawing color.

SDL_RenderFillRect( $renderer, SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ) );

The current drawing color is set by SDL_SetRenderDrawColor( ... ), and the color's alpha value is ignored unless blending is enabled with the appropriate call to SDL_SetRenderDrawBlendMode( ... ).

Expected parameters include:

renderer - the rendering context
rect - the SDL2::Rect structure representing the rectangle to fill

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderFillRects( ... )`

Fill some number of rectangles on the current rendering target with the drawing color.

	SDL_RenderFillRects( $renderer,
		SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ),
        SDL2::Rect->new( { x => 75,  y => 75,  w => 50,  h => 50 } )
    );

Expected parameters include:

renderer - the rendering context
rects - an array of SDL2::Rect structures representing the rectangles to be filled

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderCopy( ... )`

Copy a portion of the texture to the current rendering target.

SDL_RenderCopy( $renderer, $blueShapes, $srcR, $destR );

The texture is blended with the destination based on its blend mode set with SDL_SetTextureBlendMode( ... ).

The texture color is affected based on its color modulation set by SDL_SetTextureColorMod( ... ).

The texture alpha is affected based on its alpha modulation set by SDL_SetTextureAlphaMod( ... ).

Expected parameters include:

renderer - the rendering context
texture - the source texture
srcrect - the source SDL2::Rect structure
dstrect - the destination SDL2::Rect structure; the texture will be stretched to fill the given rectangle

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderCopyEx( ... )`

Copy a portion of the texture to the current rendering, with optional rotation and flipping.

Copy a portion of the texture to the current rendering target, optionally rotating it by angle around the given center and also flipping it top-bottom and/or left-right.

The texture is blended with the destination based on its blend mode set with SDL_SetTextureBlendMode( ... ).

The texture color is affected based on its color modulation set by SDL_SetTextureColorMod( ... ).

The texture alpha is affected based on its alpha modulation set by SDL_SetTextureAlphaMod( ... ).

Expected parameters include:

renderer - the rendering context
texture - the source texture
srcrect - the source SDL2::Rect structure
dstrect - the destination SDL_Rect structure
angle - an angle in degrees that indicates the rotation that will be applied to dstrect, rotating it in a clockwise direction
center - a pointer to a point indicating the point around which dstrect will be rotated (if NULL, rotation will be done around dstrect.w / 2, dstrect.h / 2)
flip - a :rendererFlip value stating which flipping actions should be performed on the texture

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawPointF( ... )`

Draw a point on the current rendering target at subpixel precision.

SDL_RenderDrawPointF( $renderer, 25.5, 100.25 );

Expected parameters include:

renderer - The renderer which should draw a point.
x - The x coordinate of the point.
y - The y coordinate of the point.

Returns 0 on success, or -1 on error

`SDL_RenderDrawPointsF( ... )`

Draw multiple points on the current rendering target at subpixel precision.

my @points = map { SDL2::Point->new( {x => int rand, y => int rand } ) } 1..1024;
SDL_RenderDrawPointsF( $renderer, @points );

Expected parameters include:

renderer - The renderer which should draw multiple points
points - The points to draw

Returns 0 on success, or -1 on error; call SDL_GetError( )( ) for more information.

`SDL_RenderDrawLineF( ... )`

Draw a line on the current rendering target at subpixel precision.

SDL_RenderDrawLineF( $renderer, 100, 100, 250, 100);

Expected parameters include:

renderer - The renderer which should draw a line.
x1 - The x coordinate of the start point.
y1 - The y coordinate of the start point.
x2 - The x coordinate of the end point.
y2 - The y coordinate of the end point.

Returns 0 on success, or -1 on error.

`SDL_RenderDrawLinesF( ... )`

Draw a series of connected lines on the current rendering target at subpixel precision.

SDL_RenderDrawLines( $renderer, @points);

Expected parameters include:

renderer - The renderer which should draw multiple lines.
points - The points along the lines

Return 0 on success, or -1 on error.

`SDL_RenderDrawRectF( ... )`

Draw a rectangle on the current rendering target at subpixel precision.

SDL_RenderDrawRectF( $renderer, $point);

Expected parameters include:

renderer - The renderer which should draw a rectangle.
rect - A pointer to the destination rectangle

Returns 0 on success, or -1 on error

`SDL_RenderDrawRectsF( ... )`

Draw some number of rectangles on the current rendering target at subpixel precision.

	SDL_RenderDrawRectsF( $renderer,
		SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ),
        SDL2::Rect->new( { x => 75,  y => 75,  w => 50,  h => 50 } )
    );

Expected parameters include:

renderer - The renderer which should draw multiple rectangles.
rects - A pointer to an array of destination rectangles.

Returns 0 on success, or -1 on error.

`SDL_RenderFillRectF( ... )`

Fill a rectangle on the current rendering target with the drawing color at subpixel precision.

	SDL_RenderFillRectF( $renderer,
        SDL2::Rect->new( { x => 75,  y => 75,  w => 50,  h => 50 } )
    );

Expected parameters include:

renderer - The renderer which should fill a rectangle.
rect - A pointer to the destination rectangle

Returns 0 on success, or -1 on error.

`SDL_RenderFillRectsF( ... )`

Fill some number of rectangles on the current rendering target with the drawing color at subpixel precision.

	SDL_RenderFillRectsF( $renderer,
		SDL2::Rect->new( { x => 100, y => 100, w => 100, h => 100 } ),
        SDL2::Rect->new( { x => 75,  y => 75,  w => 50,  h => 50 } )
    );

Expected parameters include:

renderer - The renderer which should fill multiple rectangles.
rects - A pointer to an array of destination rectangles.

Returns 0 on success, or -1 on error.

`SDL_RenderCopyF( ... )`

Copy a portion of the texture to the current rendering target at subpixel precision.

Expected parameters include:

renderer - The renderer which should copy parts of a texture
texture - The source texture
srcrect - A pointer to the source rectangle
dstrect - A pointer to the destination rectangle

Returns 0 on success, or -1 on error.

`SDL_RenderCopyExF( ... )`

Copy a portion of the source texture to the current rendering target, with rotation and flipping, at subpixel precision.

renderer - The renderer which should copy parts of a texture
texture - The source texture
srcrect - A pointer to the source rectangle
dstrect - A pointer to the destination rectangle
angle - An angle in degrees that indicates the rotation that will be applied to dstrect, rotating it in a clockwise direction
center - A pointer to a point indicating the point around which dstrect will be rotated (if NULL, rotation will be done around dstrect.w/2, dstrect.h/2)
flip - A :rendererFlip value stating which flipping actions should be performed on the texture

Returns 0 on success, or -1 on error

`SDL_RenderReadPixels( ... )`

Read pixels from the current rendering target to an array of pixels.

	SDL_RenderReadPixels(
        $renderer,
        SDL2::Rect->new( { x => 0, y => 0, w => 640, h => 480 } ),
        SDL_PIXELFORMAT_RGB888,
        $surface->pixels, $surface->pitch
    );

WARNING: This is a very slow operation, and should not be used frequently.

pitch specifies the number of bytes between rows in the destination pixels data. This allows you to write to a subrectangle or have padded rows in the destination. Generally, pitch should equal the number of pixels per row in the `pixels` data times the number of bytes per pixel, but it might contain additional padding (for example, 24bit RGB Windows Bitmap data pads all rows to multiples of 4 bytes).

Expected parameters include:

renderer - the rendering context
rect - an SDL2::Rect structure representing the area to read
format - an :pixelFormatEnum value of the desired format of the pixel data, or 0 to use the format of the rendering target
pixels - pointer to the pixel data to copy into
pitch - the pitch of the pixels parameter

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_RenderPresent( ... )`

Update the screen with any rendering performed since the previous call.

SDL_RenderPresent( $renderer );

SDL's rendering functions operate on a backbuffer; that is, calling a rendering function such as SDL_RenderDrawLine( ... ) does not directly put a line on the screen, but rather updates the backbuffer. As such, you compose your entire scene and *present* the composed backbuffer to the screen as a complete picture.

Therefore, when using SDL's rendering API, one does all drawing intended for the frame, and then calls this function once per frame to present the final drawing to the user.

The backbuffer should be considered invalidated after each present; do not assume that previous contents will exist between frames. You are strongly encouraged to call SDL_RenderClear( ... ) to initialize the backbuffer before starting each new frame's drawing, even if you plan to overwrite every pixel.

Expected parameters include:

renderer - the rendering context

`SDL_DestroyTexture( ... )`

Destroy the specified texture.

SDL_DestroyTexture( $texture );

Passing undef or an otherwise invalid texture will set the SDL error message to "Invalid texture".

Expected parameters include:

texture - the texture to destroy

`SDL_DestroyRenderer( ... )`

Destroy the rendering context for a window and free associated textures.

SDL_DestroyRenderer( $renderer );

Expected parameters include:

renderer - the rendering context

`SDL_RenderFlush( ... )`

Force the rendering context to flush any pending commands to the underlying rendering API.

SDL_RenderFlush( $renderer );

You do not need to (and in fact, shouldn't) call this function unless you are planning to call into OpenGL/Direct3D/Metal/whatever directly in addition to using an SDL_Renderer.

This is for a very-specific case: if you are using SDL's render API, you asked for a specific renderer backend (OpenGL, Direct3D, etc), you set SDL_HINT_RENDER_BATCHING to "1", and you plan to make OpenGL/D3D/whatever calls in addition to SDL render API calls. If all of this applies, you should call SDL_RenderFlush( ... ) between calls to SDL's render API and the low-level API you're using in cooperation.

In all other cases, you can ignore this function. This is only here to get maximum performance out of a specific situation. In all other cases, SDL will do the right thing, perhaps at a performance loss.

This function is first available in SDL 2.0.10, and is not needed in 2.0.9 and earlier, as earlier versions did not queue rendering commands at all, instead flushing them to the OS immediately.

Expected parameters include:

renderer - the rendering context

Returns 0 on success or a negative error code on failure; call SDL_GetError( )( ) for more information.

`SDL_GL_BindTexture( ... )`

Bind an OpenGL/ES/ES2 texture to the current context.

my ($texw, $texh) = SDL_GL_BindTexture( $texture );

This is for use with OpenGL instructions when rendering OpenGL primitives directly.

If not NULL, the returned width and height values suitable for the provided texture. In most cases, both will be 1.0, however, on systems that support the GL_ARB_texture_rectangle extension, these values will actually be the pixel width and height used to create the texture, so this factor needs to be taken into account when providing texture coordinates to OpenGL.

You need a renderer to create an SDL2::Texture, therefore you can only use this function with an implicit OpenGL context from SDL_CreateRenderer( ... ), not with your own OpenGL context. If you need control over your OpenGL context, you need to write your own texture-loading methods.

Also note that SDL may upload RGB textures as BGR (or vice-versa), and re-order the color channels in the shaders phase, so the uploaded texture may have swapped color channels.

Expected parameters include:

texture - the texture to bind to the current OpenGL/ES/ES2 context

Returns the texture's with and height on success, or -1 if the operation is not supported; call SDL_GetError( )( ) for more information.

`SDL_GL_UnbindTexture( ... )`

Unbind an OpenGL/ES/ES2 texture from the current context.

SDL_GL_UnbindTexture( $texture );

See SDL_GL_BindTexture( ... ) for examples on how to use these functions.

Expected parameters include:

texture - the texture to unbind from the current OpenGL/ES/ES2 context

Returns 0 on success, or -1 if the operation is not supported.

`SDL_RenderGetMetalLayer( ... )`

Get the CAMetalLayer associated with the given Metal renderer.

my $opaque = SDL_RenderGetMetalLayer( $renderer );

This function returns void *, so SDL doesn't have to include Metal's headers, but it can be safely cast to a CAMetalLayer *.

Expected parameters include:

renderer - the renderer to query

Returns CAMetalLayer* on success, or undef if the renderer isn't a Metal renderer.

`SDL_RenderGetMetalCommandEncoder( ... )`

Get the Metal command encoder for the current frame

$opaque = SDL_RenderGetMetalCommandEncoder( $renderer );

This function returns void *, so SDL doesn't have to include Metal's headers, but it can be safely cast to an id<MTLRenderCommandEncoder>.

Expected parameters include:

renderer - the renderer to query

Returns id<MTLRenderCommandEncoder> on success, or undef if the renderer isn't a Metal renderer.

`SDL_ComposeCustomBlendMode( ... )`

Compose a custom blend mode for renderers.

The functions SDL_SetRenderDrawBlendMode and SDL_SetTextureBlendMode accept the SDL_BlendMode returned by this function if the renderer supports it.

A blend mode controls how the pixels from a drawing operation (source) get combined with the pixels from the render target (destination). First, the components of the source and destination pixels get multiplied with their blend factors. Then, the blend operation takes the two products and calculates the result that will get stored in the render target.

Expressed in pseudocode, it would look like this:

	my $dstRGB = colorOperation( $srcRGB * $srcColorFactor, $dstRGB * $dstColorFactor );
 	my $dstA   = alphaOperation( $srcA * $srcAlphaFactor, $dstA * $dstAlphaFactor );

Where the functions colorOperation(src, dst) and alphaOperation(src, dst) can return one of the following:

src + dst
src - dst
dst - src
min(src, dst)
max(src, dst)

The red, green, and blue components are always multiplied with the first, second, and third components of the SDL_BlendFactor, respectively. The fourth component is not used.

The alpha component is always multiplied with the fourth component of the :blendFactor. The other components are not used in the alpha calculation.

Support for these blend modes varies for each renderer. To check if a specific :blendMode is supported, create a renderer and pass it to either SDL_SetRenderDrawBlendMode or SDL_SetTextureBlendMode. They will return with an error if the blend mode is not supported.

This list describes the support of custom blend modes for each renderer in SDL 2.0.6. All renderers support the four blend modes listed in the :blendMode enumeration.

direct3d - Supports SDL_BLENDOPERATION_ADD with all factors.
direct3d11 - Supports all operations with all factors. However, some factors produce unexpected results with SDL_BLENDOPERATION_MINIMUM and SDL_BLENDOPERATION_MAXIMUM.
opengl - Supports the SDL_BLENDOPERATION_ADD operation with all factors. OpenGL versions 1.1, 1.2, and 1.3 do not work correctly with SDL 2.0.6.
opengles - Supports the SDL_BLENDOPERATION_ADD operation with all factors. Color and alpha factors need to be the same. OpenGL ES 1 implementation specific: May also support SDL_BLENDOPERATION_SUBTRACT and SDL_BLENDOPERATION_REV_SUBTRACT. May support color and alpha operations being different from each other. May support color and alpha factors being different from each other.
opengles2 - Supports the SDL_BLENDOPERATION_ADD, SDL_BLENDOPERATION_SUBTRACT, SDL_BLENDOPERATION_REV_SUBTRACT operations with all factors.
psp - No custom blend mode support.
software - No custom blend mode support.

Some renderers do not provide an alpha component for the default render target. The SDL_BLENDFACTOR_DST_ALPHA and SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA factors do not have an effect in this case.

Expected parameters include:

srcColorFactor -the :blendFactor applied to the red, green, and blue components of the source pixels
dstColorFactor - the :blendFactor applied to the red, green, and blue components of the destination pixels
colorOperation - the :blendOperation used to combine the red, green, and blue components of the source and destination pixels
srcAlphaFactor - the :blendFactor applied to the alpha component of the source pixels
dstAlphaFactor - the :blendFactor applied to the alpha component of the destination pixels
alphaOperation - the :blendOperation used to combine the alpha component of the source and destination pixels

Returns a :blendMode that represents the chosen factors and operations.

Time Management Routines

This section contains functions for handling the SDL time management routines. They may be imported with the :timer tag.

`SDL_GetTicks( )`

Get the number of milliseconds since SDL library initialization.

my $time = SDL_GetTicks( );

This value wraps if the program runs for more than ~49 days.

Returns an unsigned 32-bit value representing the number of milliseconds since the SDL library initialized.

`SDL_GetPerformanceCounter( )`

Get the current value of the high resolution counter.

my $high_timer = SDL_GetPerformanceCounter( );

This function is typically used for profiling.

The counter values are only meaningful relative to each other. Differences between values can be converted to times by using SDL_GetPerformanceFrequency( ).

Returns the current counter value.

`SDL_GetPerformanceFrequency( ... )`

Get the count per second of the high resolution counter.

my $hz = SDL_GetPerformanceFrequency( );

Returns a platform-specific count per second.

`SDL_Delay( ... )`

Wait a specified number of milliseconds before returning.

SDL_Delay( 1000 );

This function waits a specified number of milliseconds before returning. It waits at least the specified time, but possibly longer due to OS scheduling.

Expected parameters include:

ms - the number of milliseconds to delay

`SDL_AddTimer( ... )`

Call a callback function at a future time.

my $id = SDL_AddTimer( 1000, sub ( $interval, $data ) { warn 'ping!'; $interval; } );

If you use this function, you must pass SDL_INIT_TIMER to SDL_Init( ... ).

The callback function is passed the current timer interval and returns the next timer interval. If the returned value is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled. If the callback returns 0, the periodic alarm is cancelled.

The callback is run on a separate thread.

Timers take into account the amount of time it took to execute the callback. For example, if the callback took 250 ms to execute and returned 1000 (ms), the timer would only wait another 750 ms before its next iteration.

Timing may be inexact due to OS scheduling. Be sure to note the current time with SDL_GetTicks( ) or SDL_GetPerformanceCounter( ) in case your callback needs to adjust for variances.

Expected parameters include:

interval - the timer delay, in milliseconds, passed to callback
callback - the CODE reference to call when the specified interval elapses
param - a pointer that is passed to callback

Returns a timer ID or 0 if an error occurs; call SDL_GetError( )( ) for more information.

`SDL_RemoveTimer( ... )`

SDL_RemoveTimer( $id );

Remove a timer created with SDL_AddTimer( ... ).

Expected parameters include:

id - the ID of the timer to remove

Returns true if the timer is removed or false if the timer wasn't found.

Raw Audio Mixing

These methods provide access to the raw audio mixing buffer for the SDL library. They may be imported with the :audio tag.

`SDL_GetNumAudioDrivers( )`

Returns a list of built in audio drivers, in the order that they were normally initialized by default.

`SDL_GetAudioDriver( ... )`

Returns an audio driver by name.

my $driver = SDL_GetAudioDriver( 1 );

Expected parameters include:

index - The zero-based index of the desired audio driver

`SDL_AudioInit( ... )`

Audio system initialization.

SDL_AudioInit( 'pulseaudio' );

This method is used internally, and should not be used unless you have a specific need to specify the audio driver you want to use. You should normally use SDL_Init( ... ).

Returns 0 on success.

`SDL_AudioQuit( )`

Cleaning up initialized audio system.

SDL_AudioQuit( );

This method is used internally, and should not be used unless you have a specific need to close the selected audio driver. You should normally use SDL_Quit( ).

`SDL_GetCurrentAudioDriver( )`

Get the name of the current audio driver.

my $driver = SDL_GetCurrentAudioDriver( );

The returned string points to internal static memory and thus never becomes invalid, even if you quit the audio subsystem and initialize a new driver (although such a case would return a different static string from another call to this function, of course). As such, you should not modify or free the returned string.

Returns the name of the current audio driver or undef if no driver has been initialized.

`SDL_OpenAudio( ... )`

This function is a legacy means of opening the audio device.

my $obtained = SDL_OpenAudio(
    SDL2::AudioSpec->new( { freq => 48000, channels => 2, format => AUDIO_F32 } ) );

This function remains for compatibility with SDL 1.2, but also because it's slightly easier to use than the new functions in SDL 2.0. The new, more powerful, and preferred way to do this is SDL_OpenAudioDevice( ... ) .

This function is roughly equivalent to:

SDL_OpenAudioDevice( (), 0, $desired, SDL_AUDIO_ALLOW_ANY_CHANGE );

With two notable exceptions:

- If obtained is undefined, we use desired (and allow no changes), which means desired will be modified to have the correct values for silence, etc, and SDL will convert any differences between your app's specific request and the hardware behind the scenes.
- The return value is always success or failure, and not a device ID, which means you can only have one device open at a time with this function.

* \param desired an SDL_AudioSpec structure representing the desired output
*                format. Please refer to the SDL_OpenAudioDevice documentation
*                for details on how to prepare this structure.
* \param obtained an SDL_AudioSpec structure filled in with the actual
*                 parameters, or NULL.
* \returns This function opens the audio device with the desired parameters,
*          and returns 0 if successful, placing the actual hardware
*          parameters in the structure pointed to by `obtained`.
*
*          If `obtained` is NULL, the audio data passed to the callback
*          function will be guaranteed to be in the requested format, and
*          will be automatically converted to the actual hardware audio
*          format if necessary. If `obtained` is NULL, `desired` will
*          have fields modified.
*
*          This function returns a negative error code on failure to open the
*          audio device or failure to set up the audio thread; call
*          SDL_GetError() for more information.

LICENSE

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>

To install SDL2::Enum, copy and paste the appropriate command in to your terminal.

cpanm

cpanm SDL2::Enum

CPAN shell

perl -MCPAN -e shell
install SDL2::Enum

For more information on module installation, please visit the detailed CPAN module installation guide.

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