include/SDL_video.h

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/**
 *  \file SDL_video.h
 *  
 *  Header file for SDL video functions.
 */

#ifndef _SDL_video_h
#define _SDL_video_h

#include "SDL_stdinc.h"
#include "SDL_pixels.h"
#include "SDL_rect.h"
#include "SDL_surface.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif

/**
 *  \brief  The structure that defines a display mode
 *  
 *  \sa SDL_GetNumDisplayModes()
 *  \sa SDL_GetDisplayMode()
 *  \sa SDL_GetDesktopDisplayMode()
 *  \sa SDL_GetCurrentDisplayMode()
 *  \sa SDL_GetClosestDisplayMode()
 *  \sa SDL_SetWindowDisplayMode()
 *  \sa SDL_GetWindowDisplayMode()
 */
typedef struct
{
    Uint32 format;              /**< pixel format */
    int w;                      /**< width */
    int h;                      /**< height */
    int refresh_rate;           /**< refresh rate (or zero for unspecified) */
    void *driverdata;           /**< driver-specific data, initialize to 0 */
} SDL_DisplayMode;

/**
 *  \brief The type used to identify a window
 *  
 *  \sa SDL_CreateWindow()
 *  \sa SDL_CreateWindowFrom()
 *  \sa SDL_DestroyWindow()
 *  \sa SDL_GetWindowData()
 *  \sa SDL_GetWindowFlags()
 *  \sa SDL_GetWindowGrab()
 *  \sa SDL_GetWindowPosition()
 *  \sa SDL_GetWindowSize()
 *  \sa SDL_GetWindowTitle()
 *  \sa SDL_HideWindow()
 *  \sa SDL_MaximizeWindow()
 *  \sa SDL_MinimizeWindow()
 *  \sa SDL_RaiseWindow()
 *  \sa SDL_RestoreWindow()
 *  \sa SDL_SetWindowData()
 *  \sa SDL_SetWindowFullscreen()
 *  \sa SDL_SetWindowGrab()
 *  \sa SDL_SetWindowIcon()
 *  \sa SDL_SetWindowPosition()
 *  \sa SDL_SetWindowSize()
 *  \sa SDL_SetWindowTitle()
 *  \sa SDL_ShowWindow()
 */
typedef struct SDL_Window SDL_Window;

/**
 *  \brief The flags on a window
 *  
 *  \sa SDL_GetWindowFlags()
 */
typedef enum
{
    SDL_WINDOW_FULLSCREEN = 0x00000001,         /**< fullscreen window, implies borderless */
    SDL_WINDOW_OPENGL = 0x00000002,             /**< window usable with OpenGL context */
    SDL_WINDOW_SHOWN = 0x00000004,              /**< window is visible */
    SDL_WINDOW_BORDERLESS = 0x00000008,         /**< no window decoration */
    SDL_WINDOW_RESIZABLE = 0x00000010,          /**< window can be resized */
    SDL_WINDOW_MINIMIZED = 0x00000020,          /**< window is minimized */
    SDL_WINDOW_MAXIMIZED = 0x00000040,          /**< window is maximized */
    SDL_WINDOW_INPUT_GRABBED = 0x00000100,      /**< window has grabbed input focus */
    SDL_WINDOW_INPUT_FOCUS = 0x00000200,        /**< window has input focus */
    SDL_WINDOW_MOUSE_FOCUS = 0x00000400,        /**< window has mouse focus */
    SDL_WINDOW_FOREIGN = 0x00000800             /**< window not created by SDL */
} SDL_WindowFlags;

/**
 *  \brief Used to indicate that you don't care what the window position is.
 */
#define SDL_WINDOWPOS_UNDEFINED 0x7FFFFFF

/**
 *  \brief Used to indicate that the window position should be centered.
 */
#define SDL_WINDOWPOS_CENTERED  0x7FFFFFE

/**
 *  \brief Event subtype for window events
 */
typedef enum
{
    SDL_WINDOWEVENT_NONE,           /**< Never used */
    SDL_WINDOWEVENT_SHOWN,          /**< Window has been shown */
    SDL_WINDOWEVENT_HIDDEN,         /**< Window has been hidden */
    SDL_WINDOWEVENT_EXPOSED,        /**< Window has been exposed and should be 
                                         redrawn */
    SDL_WINDOWEVENT_MOVED,          /**< Window has been moved to data1, data2 
                                     */
    SDL_WINDOWEVENT_RESIZED,        /**< Window size changed to data1xdata2 */
    SDL_WINDOWEVENT_MINIMIZED,      /**< Window has been minimized */
    SDL_WINDOWEVENT_MAXIMIZED,      /**< Window has been maximized */
    SDL_WINDOWEVENT_RESTORED,       /**< Window has been restored to normal size
                                         and position */
    SDL_WINDOWEVENT_ENTER,          /**< Window has gained mouse focus */
    SDL_WINDOWEVENT_LEAVE,          /**< Window has lost mouse focus */
    SDL_WINDOWEVENT_FOCUS_GAINED,   /**< Window has gained keyboard focus */
    SDL_WINDOWEVENT_FOCUS_LOST,     /**< Window has lost keyboard focus */
    SDL_WINDOWEVENT_CLOSE           /**< The window manager requests that the 
                                         window be closed */
} SDL_WindowEventID;

/**
 *  \brief An opaque handle to an OpenGL context.
 */
typedef void *SDL_GLContext;

/**
 *  \brief OpenGL configuration attributes
 */
typedef enum
{
    SDL_GL_RED_SIZE,
    SDL_GL_GREEN_SIZE,
    SDL_GL_BLUE_SIZE,
    SDL_GL_ALPHA_SIZE,
    SDL_GL_BUFFER_SIZE,
    SDL_GL_DOUBLEBUFFER,
    SDL_GL_DEPTH_SIZE,
    SDL_GL_STENCIL_SIZE,
    SDL_GL_ACCUM_RED_SIZE,
    SDL_GL_ACCUM_GREEN_SIZE,
    SDL_GL_ACCUM_BLUE_SIZE,
    SDL_GL_ACCUM_ALPHA_SIZE,
    SDL_GL_STEREO,
    SDL_GL_MULTISAMPLEBUFFERS,
    SDL_GL_MULTISAMPLESAMPLES,
    SDL_GL_ACCELERATED_VISUAL,
    SDL_GL_RETAINED_BACKING,
    SDL_GL_CONTEXT_MAJOR_VERSION,
    SDL_GL_CONTEXT_MINOR_VERSION
} SDL_GLattr;


/* Function prototypes */

/**
 *  \brief Get the number of video drivers compiled into SDL
 *  
 *  \sa SDL_GetVideoDriver()
 */
extern DECLSPEC int SDLCALL SDL_GetNumVideoDrivers(void);

/**
 *  \brief Get the name of a built in video driver.
 *  
 *  \note The video drivers are presented in the order in which they are
 *        normally checked during initialization.
 *  
 *  \sa SDL_GetNumVideoDrivers()
 */
extern DECLSPEC const char *SDLCALL SDL_GetVideoDriver(int index);

/**
 *  \brief Initialize the video subsystem, optionally specifying a video driver.
 *  
 *  \param driver_name Initialize a specific driver by name, or NULL for the 
 *                     default video driver.
 *  
 *  \return 0 on success, -1 on error
 *  
 *  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.
 *  
 *  \sa SDL_VideoQuit()
 */
extern DECLSPEC int SDLCALL SDL_VideoInit(const char *driver_name);

/**
 *  \brief Shuts down the video subsystem.
 *  
 *  This function closes all windows, and restores the original video mode.
 *  
 *  \sa SDL_VideoInit()
 */
extern DECLSPEC void SDLCALL SDL_VideoQuit(void);

/**
 *  \brief Returns the name of the currently initialized video driver.
 *  
 *  \return The name of the current video driver or NULL if no driver
 *          has been initialized
 *  
 *  \sa SDL_GetNumVideoDrivers()
 *  \sa SDL_GetVideoDriver()
 */
extern DECLSPEC const char *SDLCALL SDL_GetCurrentVideoDriver(void);

/**
 *  \brief Returns the number of available video displays.
 *  
 *  \sa SDL_GetDisplayBounds()
 *  \sa SDL_SelectVideoDisplay()
 */
extern DECLSPEC int SDLCALL SDL_GetNumVideoDisplays(void);

/**
 *  \brief Get the desktop area represented by a display, with the primary
 *         display located at 0,0
 *  
 *  \return 0 on success, or -1 if the index is out of range.
 *  
 *  \sa SDL_GetNumVideoDisplays()
 */
extern DECLSPEC int SDLCALL SDL_GetDisplayBounds(int index, SDL_Rect * rect);

/**
 *  \brief Set the index of the currently selected display.
 *  
 *  \return 0 on success, or -1 if the index is out of range.
 *  
 *  \sa SDL_GetNumVideoDisplays()
 *  \sa SDL_GetCurrentVideoDisplay()
 */
extern DECLSPEC int SDLCALL SDL_SelectVideoDisplay(int index);

/**
 *  \brief Get the index of the currently selected display.
 *  
 *  \return The index of the currently selected display.
 *  
 *  \sa SDL_GetNumVideoDisplays()
 *  \sa SDL_SelectVideoDisplay()
 */
extern DECLSPEC int SDLCALL SDL_GetCurrentVideoDisplay(void);

/**
 *  \brief Returns the number of available display modes for the current display.
 *  
 *  \sa SDL_GetDisplayMode()
 */
extern DECLSPEC int SDLCALL SDL_GetNumDisplayModes(void);

/**
 *  \brief Fill in information about a specific display mode.
 *  
 *  \note The display modes are sorted in this priority:
 *        \li bits per pixel -> more colors to fewer colors
 *        \li width -> largest to smallest
 *        \li height -> largest to smallest
 *        \li refresh rate -> highest to lowest
 *  
 *  \sa SDL_GetNumDisplayModes()
 */
extern DECLSPEC int SDLCALL SDL_GetDisplayMode(int index,
                                               SDL_DisplayMode * mode);

/**
 *  \brief Fill in information about the desktop display mode for the current 
 *         display.
 */
extern DECLSPEC int SDLCALL SDL_GetDesktopDisplayMode(SDL_DisplayMode * mode);

/**
 *  \brief Fill in information about the current display mode.
 */
extern DECLSPEC int SDLCALL SDL_GetCurrentDisplayMode(SDL_DisplayMode * mode);


/**
 *  \brief Get the closest match to the requested display mode.
 *  
 *  \param mode The desired display mode
 *  \param closest A pointer to a display mode to be filled in with the closest 
 *                 match of the available display modes.
 *  
 *  \return The passed in value \c closest, or NULL if no matching video mode 
 *          was available.
 *  
 *  The available display modes are scanned, and \c closest is filled in with the
 *  closest mode matching the requested mode and returned.  The mode format and 
 *  refresh_rate default to the desktop mode if they are 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 NULL is returned.
 *  
 *  \sa SDL_GetNumDisplayModes()
 *  \sa SDL_GetDisplayMode()
 */
extern DECLSPEC SDL_DisplayMode *SDLCALL SDL_GetClosestDisplayMode(const
                                                                   SDL_DisplayMode
                                                                   * mode,
                                                                   SDL_DisplayMode
                                                                   * closest);

/**
 *  \brief Set the display mode used when a fullscreen window is visible
 *         on the currently selected display.  By default the window's
 *         dimensions and the desktop format and refresh rate are used.
 *  
 *  \param mode The mode to use, or NULL for the default mode.
 *  
 *  \return 0 on success, or -1 if setting the display mode failed.
 *  
 *  \sa SDL_GetWindowDisplayMode()
 *  \sa SDL_SetWindowFullscreen()
 */
extern DECLSPEC int SDLCALL SDL_SetWindowDisplayMode(SDL_Window * window,
                                                     const SDL_DisplayMode
                                                         * mode);

/**
 *  \brief Fill in information about the display mode used when a fullscreen
 *         window is visible on the currently selected display.
 *
 *  \sa SDL_SetWindowDisplayMode()
 *  \sa SDL_SetWindowFullscreen()
 */
extern DECLSPEC int SDLCALL SDL_GetWindowDisplayMode(SDL_Window * window,
                                                     SDL_DisplayMode * mode);

/**
 *  \brief Get the pixel format associated with the window.
 */
extern DECLSPEC Uint32 SDLCALL SDL_GetWindowPixelFormat(SDL_Window * window);

/**
 *  \brief Set the gamma correction for each of the color channels on the 
 *         currently selected display.
 *  
 *  \return 0 on success, or -1 if setting the gamma isn't supported.
 *  
 *  \sa SDL_SetGammaRamp()
 */
extern DECLSPEC int SDLCALL SDL_SetGamma(float red, float green, float blue);

/**
 *  \brief Set the gamma ramp for the currently selected display.
 *  
 *  \param red The translation table for the red channel, or NULL.
 *  \param green The translation table for the green channel, or NULL.
 *  \param blue The translation table for the blue channel, or NULL.
 *  
 *  \return 0 on success, or -1 if gamma ramps are unsupported.
 *  
 *  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.
 *  
 *  \sa SDL_GetGammaRamp()
 */
extern DECLSPEC int SDLCALL SDL_SetGammaRamp(const Uint16 * red,
                                             const Uint16 * green,
                                             const Uint16 * blue);

/**
 *  \brief Get the gamma ramp for the currently selected display.
 *  
 *  \param red   A pointer to a 256 element array of 16-bit quantities to hold 
 *               the translation table for the red channel, or NULL.
 *  \param green A pointer to a 256 element array of 16-bit quantities to hold 
 *               the translation table for the green channel, or NULL.
 *  \param blue  A pointer to a 256 element array of 16-bit quantities to hold 
 *               the translation table for the blue channel, or NULL.
 *   
 *  \return 0 on success, or -1 if gamma ramps are unsupported.
 *  
 *  \sa SDL_SetGammaRamp()
 */
extern DECLSPEC int SDLCALL SDL_GetGammaRamp(Uint16 * red, Uint16 * green,
                                             Uint16 * blue);


/**
 *  \brief Create a window with the specified position, dimensions, and flags.
 *  
 *  \param title The title of the window, in UTF-8 encoding.
 *  \param x     The x position of the window, ::SDL_WINDOWPOS_CENTERED, or 
 *               ::SDL_WINDOWPOS_UNDEFINED.
 *  \param y     The y position of the window, ::SDL_WINDOWPOS_CENTERED, or 
 *               ::SDL_WINDOWPOS_UNDEFINED.
 *  \param w     The width of the window.
 *  \param h     The height of the window.
 *  \param flags The flags for the window, a mask of any of the following: 
 *               ::SDL_WINDOW_FULLSCREEN, ::SDL_WINDOW_OPENGL, 
 *               ::SDL_WINDOW_SHOWN,      ::SDL_WINDOW_BORDERLESS, 
 *               ::SDL_WINDOW_RESIZABLE,  ::SDL_WINDOW_MAXIMIZED, 
 *               ::SDL_WINDOW_MINIMIZED,  ::SDL_WINDOW_INPUT_GRABBED.
 *  
 *  \return The id of the window created, or zero if window creation failed.
 *  
 *  \sa SDL_DestroyWindow()
 */
extern DECLSPEC SDL_Window * SDLCALL SDL_CreateWindow(const char *title,
                                                      int x, int y, int w,
                                                      int h, Uint32 flags);

/**
 *  \brief Create an SDL window from an existing native window.
 *  
 *  \param data A pointer to driver-dependent window creation data
 *  
 *  \return The id of the window created, or zero if window creation failed.
 *  
 *  \sa SDL_DestroyWindow()
 */
extern DECLSPEC SDL_Window * SDLCALL SDL_CreateWindowFrom(const void *data);

/**
 *  \brief Get the numeric ID of a window, for logging purposes.
 */
extern DECLSPEC Uint32 SDLCALL SDL_GetWindowID(SDL_Window * window);

/**
 *  \brief Get a window from a stored ID, or NULL if it doesn't exist.
 */
extern DECLSPEC SDL_Window * SDLCALL SDL_GetWindowFromID(Uint32 id);

/**
 *  \brief Get the window flags.
 */
extern DECLSPEC Uint32 SDLCALL SDL_GetWindowFlags(SDL_Window * window);

/**
 *  \brief Set the title of a window, in UTF-8 format.
 *  
 *  \sa SDL_GetWindowTitle()
 */
extern DECLSPEC void SDLCALL SDL_SetWindowTitle(SDL_Window * window,
                                                const char *title);

/**
 *  \brief Get the title of a window, in UTF-8 format.
 *  
 *  \sa SDL_SetWindowTitle()
 */
extern DECLSPEC const char *SDLCALL SDL_GetWindowTitle(SDL_Window * window);

/**
 *  \brief Set the icon for a window.
 *  
 *  \param icon The icon for the window.
 */
extern DECLSPEC void SDLCALL SDL_SetWindowIcon(SDL_Window * window,
                                               SDL_Surface * icon);

/**
 *  \brief Associate an arbitrary pointer with a window.
 *  
 *  \sa SDL_GetWindowData()
 */
extern DECLSPEC void SDLCALL SDL_SetWindowData(SDL_Window * window,
                                               void *userdata);

/**
 *  \brief Retrieve the data pointer associated with a window.
 *  
 *  \sa SDL_SetWindowData()
 */
extern DECLSPEC void *SDLCALL SDL_GetWindowData(SDL_Window * window);

/**
 *  \brief Set the position of a window.
 *  
 *  \param window The window to reposition.
 *  \param x        The x coordinate of the window, ::SDL_WINDOWPOS_CENTERED, or
                    ::SDL_WINDOWPOS_UNDEFINED.
 *  \param y        The y coordinate of the window, ::SDL_WINDOWPOS_CENTERED, or
                    ::SDL_WINDOWPOS_UNDEFINED.
 *  
 *  \note The window coordinate origin is the upper left of the display.
 *  
 *  \sa SDL_GetWindowPosition()
 */
extern DECLSPEC void SDLCALL SDL_SetWindowPosition(SDL_Window * window,
                                                   int x, int y);

/**
 *  \brief Get the position of a window.
 *  
 *  \sa SDL_SetWindowPosition()
 */
extern DECLSPEC void SDLCALL SDL_GetWindowPosition(SDL_Window * window,
                                                   int *x, int *y);

/**
 *  \brief Set the size of a window's client area.
 *  
 *  \note You can't change the size of a fullscreen window, it automatically
 *        matches the size of the display mode.
 *  
 *  \sa SDL_GetWindowSize()
 */
extern DECLSPEC void SDLCALL SDL_SetWindowSize(SDL_Window * window, int w,
                                               int h);

/**
 *  \brief Get the size of a window's client area.
 *  
 *  \sa SDL_SetWindowSize()
 */
extern DECLSPEC void SDLCALL SDL_GetWindowSize(SDL_Window * window, int *w,
                                               int *h);

/**
 *  \brief Show a window.
 *  
 *  \sa SDL_HideWindow()
 */
extern DECLSPEC void SDLCALL SDL_ShowWindow(SDL_Window * window);

/**
 *  \brief Hide a window.
 *  
 *  \sa SDL_ShowWindow()
 */
extern DECLSPEC void SDLCALL SDL_HideWindow(SDL_Window * window);

/**
 *  \brief Raise a window above other windows and set the input focus.
 */
extern DECLSPEC void SDLCALL SDL_RaiseWindow(SDL_Window * window);

/**
 *  \brief Make a window as large as possible.
 *  
 *  \sa SDL_RestoreWindow()
 */
extern DECLSPEC void SDLCALL SDL_MaximizeWindow(SDL_Window * window);

/**
 *  \brief Minimize a window to an iconic representation.
 *  
 *  \sa SDL_RestoreWindow()
 */
extern DECLSPEC void SDLCALL SDL_MinimizeWindow(SDL_Window * window);

/**
 *  \brief Restore the size and position of a minimized or maximized window.
 *  
 *  \sa SDL_MaximizeWindow()
 *  \sa SDL_MinimizeWindow()
 */
extern DECLSPEC void SDLCALL SDL_RestoreWindow(SDL_Window * window);

/**
 *  \brief Set a window's fullscreen state.
 *  
 *  \return 0 on success, or -1 if setting the display mode failed.
 *  
 *  \sa SDL_SetWindowDisplayMode()
 *  \sa SDL_GetWindowDisplayMode()
 */
extern DECLSPEC int SDLCALL SDL_SetWindowFullscreen(SDL_Window * window,
                                                    int fullscreen);

/**
 *  \brief Set a window's input grab mode.
 *  
 *  \param mode This is 1 to grab input, and 0 to release input.
 *  
 *  \sa SDL_GetWindowGrab()
 */
extern DECLSPEC void SDLCALL SDL_SetWindowGrab(SDL_Window * window,
                                               int mode);

/**
 *  \brief Get a window's input grab mode.
 *  
 *  \return This returns 1 if input is grabbed, and 0 otherwise.
 *  
 *  \sa SDL_SetWindowGrab()
 */
extern DECLSPEC int SDLCALL SDL_GetWindowGrab(SDL_Window * window);

/**
 *  \brief Get driver specific information about a window.
 *  
 *  \note Include SDL_syswm.h for the declaration of SDL_SysWMinfo.
 */
struct SDL_SysWMinfo;
extern DECLSPEC SDL_bool SDLCALL SDL_GetWindowWMInfo(SDL_Window * window,
                                                     struct SDL_SysWMinfo
                                                     *info);

/**
 *  \brief Destroy a window.
 */
extern DECLSPEC void SDLCALL SDL_DestroyWindow(SDL_Window * window);


/**
 *  \brief Returns whether the screensaver is currently enabled (default on).
 *  
 *  \sa SDL_EnableScreenSaver()
 *  \sa SDL_DisableScreenSaver()
 */
extern DECLSPEC SDL_bool SDLCALL SDL_IsScreenSaverEnabled(void);

/**
 *  \brief Allow the screen to be blanked by a screensaver
 *  
 *  \sa SDL_IsScreenSaverEnabled()
 *  \sa SDL_DisableScreenSaver()
 */
extern DECLSPEC void SDLCALL SDL_EnableScreenSaver(void);

/**
 *  \brief Prevent the screen from being blanked by a screensaver
 *  
 *  \sa SDL_IsScreenSaverEnabled()
 *  \sa SDL_EnableScreenSaver()
 */
extern DECLSPEC void SDLCALL SDL_DisableScreenSaver(void);


/**
 *  \name OpenGL support functions
 */
/*@{*/

/**
 *  \brief Dynamically load an OpenGL library.
 *  
 *  \param path The platform dependent OpenGL library name, or NULL to open the 
 *              default OpenGL library.
 *  
 *  \return 0 on success, or -1 if the library couldn't be loaded.
 *  
 *  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.
 *  
 *  \note 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().
 *  
 *  \sa SDL_GL_GetProcAddress()
 *  \sa SDL_GL_UnloadLibrary()
 */
extern DECLSPEC int SDLCALL SDL_GL_LoadLibrary(const char *path);

/**
 *  \brief Get the address of an OpenGL function.
 */
extern DECLSPEC void *SDLCALL SDL_GL_GetProcAddress(const char *proc);

/**
 *  \brief Unload the OpenGL library previously loaded by SDL_GL_LoadLibrary().
 *  
 *  \sa SDL_GL_LoadLibrary()
 */
extern DECLSPEC void SDLCALL SDL_GL_UnloadLibrary(void);

/**
 *  \brief Return true if an OpenGL extension is supported for the current 
 *         context.
 */
extern DECLSPEC SDL_bool SDLCALL SDL_GL_ExtensionSupported(const char
                                                           *extension);

/**
 *  \brief Set an OpenGL window attribute before window creation.
 */
extern DECLSPEC int SDLCALL SDL_GL_SetAttribute(SDL_GLattr attr, int value);

/**
 *  \brief Get the actual value for an attribute from the current context.
 */
extern DECLSPEC int SDLCALL SDL_GL_GetAttribute(SDL_GLattr attr, int *value);

/**
 *  \brief Create an OpenGL context for use with an OpenGL window, and make it 
 *         current.
 *  
 *  \sa SDL_GL_DeleteContext()
 */
extern DECLSPEC SDL_GLContext SDLCALL SDL_GL_CreateContext(SDL_Window *
                                                           window);

/**
 *  \brief Set up an OpenGL context for rendering into an OpenGL window.
 *  
 *  \note The context must have been created with a compatible window.
 */
extern DECLSPEC int SDLCALL SDL_GL_MakeCurrent(SDL_Window * window,
                                               SDL_GLContext context);

/**
 *  \brief Set the swap interval for the current OpenGL context.
 *  
 *  \param interval 0 for immediate updates, 1 for updates synchronized with the
 *                  vertical retrace.
 *  
 *  \return 0 on success, or -1 if setting the swap interval is not supported.
 *  
 *  \sa SDL_GL_GetSwapInterval()
 */
extern DECLSPEC int SDLCALL SDL_GL_SetSwapInterval(int interval);

/**
 *  \brief Get the swap interval for the current OpenGL context.
 *  
 *  \return 0 if there is no vertical retrace synchronization, 1 if the buffer 
 *          swap is synchronized with the vertical retrace, and -1 if getting 
 *          the swap interval is not supported.
 *  
 *  \sa SDL_GL_SetSwapInterval()
 */
extern DECLSPEC int SDLCALL SDL_GL_GetSwapInterval(void);

/**
 * \brief Swap the OpenGL buffers for a window, if double-buffering is 
 *        supported.
 */
extern DECLSPEC void SDLCALL SDL_GL_SwapWindow(SDL_Window * window);

/**
 *  \brief Delete an OpenGL context.
 *  
 *  \sa SDL_GL_CreateContext()
 */
extern DECLSPEC void SDLCALL SDL_GL_DeleteContext(SDL_GLContext context);

/*@}*//*OpenGL support functions*/


/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"

#endif /* _SDL_video_h */

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