1. 高频枚举值或结构体
1.1 SDL_WindowFlags
/**
* \brief The flags on a window
*
* \sa SDL_GetWindowFlags()
*/
typedef enum
{
/* !!! FIXME: change this to name = (1<<x). */
SDL_WINDOW_FULLSCREEN = 0x00000001, /**< fullscreen window */
SDL_WINDOW_OPENGL = 0x00000002, /**< window usable with OpenGL context */
SDL_WINDOW_SHOWN = 0x00000004, /**< window is visible */
SDL_WINDOW_HIDDEN = 0x00000008, /**< window is not visible */
SDL_WINDOW_BORDERLESS = 0x00000010, /**< no window decoration */
SDL_WINDOW_RESIZABLE = 0x00000020, /**< window can be resized */
SDL_WINDOW_MINIMIZED = 0x00000040, /**< window is minimized */
SDL_WINDOW_MAXIMIZED = 0x00000080, /**< 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_FULLSCREEN_DESKTOP = ( SDL_WINDOW_FULLSCREEN | 0x00001000 ),
SDL_WINDOW_FOREIGN = 0x00000800, /**< window not created by SDL */
SDL_WINDOW_ALLOW_HIGHDPI = 0x00002000, /**< window should be created in high-DPI mode if supported.
On macOS NSHighResolutionCapable must be set true in the
application's Info.plist for this to have any effect. */
SDL_WINDOW_MOUSE_CAPTURE = 0x00004000, /**< window has mouse captured (unrelated to INPUT_GRABBED) */
SDL_WINDOW_ALWAYS_ON_TOP = 0x00008000, /**< window should always be above others */
SDL_WINDOW_SKIP_TASKBAR = 0x00010000, /**< window should not be added to the taskbar */
SDL_WINDOW_UTILITY = 0x00020000, /**< window should be treated as a utility window */
SDL_WINDOW_TOOLTIP = 0x00040000, /**< window should be treated as a tooltip */
SDL_WINDOW_POPUP_MENU = 0x00080000, /**< window should be treated as a popup menu */
SDL_WINDOW_VULKAN = 0x10000000 /**< window usable for Vulkan surface */
} SDL_WindowFlags;
这个枚举值主要是和窗口相关的属性。
1.2 SDL_RendererFlags
typedef enum
{
SDL_RENDERER_SOFTWARE = 0x00000001, /**< The renderer is a software fallback */
SDL_RENDERER_ACCELERATED = 0x00000002, /**< The renderer uses hardware
acceleration */
SDL_RENDERER_PRESENTVSYNC = 0x00000004, /**< Present is synchronized
with the refresh rate */
SDL_RENDERER_TARGETTEXTURE = 0x00000008 /**< The renderer supports
rendering to texture */
} SDL_RendererFlags;
和SDL_Renderer属性相关。
1.3 SDL_EventType
/**
* \brief The types of events that can be delivered.
*/
typedef enum
{
SDL_FIRSTEVENT = 0, /**< Unused (do not remove) */ /* Application events */
SDL_QUIT = 0x100, /**< User-requested quit */ /* These application events have special meaning on iOS, see README-ios.md for details */
SDL_APP_TERMINATING, /**< The application is being terminated by the OS
Called on iOS in applicationWillTerminate()
Called on Android in onDestroy()
*/
SDL_APP_LOWMEMORY, /**< The application is low on memory, free memory if possible.
Called on iOS in applicationDidReceiveMemoryWarning()
Called on Android in onLowMemory()
*/
SDL_APP_WILLENTERBACKGROUND, /**< The application is about to enter the background
Called on iOS in applicationWillResignActive()
Called on Android in onPause()
*/
SDL_APP_DIDENTERBACKGROUND, /**< The application did enter the background and may not get CPU for some time
Called on iOS in applicationDidEnterBackground()
Called on Android in onPause()
*/
SDL_APP_WILLENTERFOREGROUND, /**< The application is about to enter the foreground
Called on iOS in applicationWillEnterForeground()
Called on Android in onResume()
*/
SDL_APP_DIDENTERFOREGROUND, /**< The application is now interactive
Called on iOS in applicationDidBecomeActive()
Called on Android in onResume()
*/ /* Display events */
SDL_DISPLAYEVENT = 0x150, /**< Display state change */ /* Window events */
SDL_WINDOWEVENT = 0x200, /**< Window state change */
SDL_SYSWMEVENT, /**< System specific event */ /* Keyboard events */
SDL_KEYDOWN = 0x300, /**< Key pressed */
SDL_KEYUP, /**< Key released */
SDL_TEXTEDITING, /**< Keyboard text editing (composition) */
SDL_TEXTINPUT, /**< Keyboard text input */
SDL_KEYMAPCHANGED, /**< Keymap changed due to a system event such as an
input language or keyboard layout change.
*/ /* Mouse events */
SDL_MOUSEMOTION = 0x400, /**< Mouse moved */
SDL_MOUSEBUTTONDOWN, /**< Mouse button pressed */
SDL_MOUSEBUTTONUP, /**< Mouse button released */
SDL_MOUSEWHEEL, /**< Mouse wheel motion */ /* Joystick events */
SDL_JOYAXISMOTION = 0x600, /**< Joystick axis motion */
SDL_JOYBALLMOTION, /**< Joystick trackball motion */
SDL_JOYHATMOTION, /**< Joystick hat position change */
SDL_JOYBUTTONDOWN, /**< Joystick button pressed */
SDL_JOYBUTTONUP, /**< Joystick button released */
SDL_JOYDEVICEADDED, /**< A new joystick has been inserted into the system */
SDL_JOYDEVICEREMOVED, /**< An opened joystick has been removed */ /* Game controller events */
SDL_CONTROLLERAXISMOTION = 0x650, /**< Game controller axis motion */
SDL_CONTROLLERBUTTONDOWN, /**< Game controller button pressed */
SDL_CONTROLLERBUTTONUP, /**< Game controller button released */
SDL_CONTROLLERDEVICEADDED, /**< A new Game controller has been inserted into the system */
SDL_CONTROLLERDEVICEREMOVED, /**< An opened Game controller has been removed */
SDL_CONTROLLERDEVICEREMAPPED, /**< The controller mapping was updated */ /* Touch events */
SDL_FINGERDOWN = 0x700,
SDL_FINGERUP,
SDL_FINGERMOTION, /* Gesture events */
SDL_DOLLARGESTURE = 0x800,
SDL_DOLLARRECORD,
SDL_MULTIGESTURE, /* Clipboard events */
SDL_CLIPBOARDUPDATE = 0x900, /**< The clipboard changed */ /* Drag and drop events */
SDL_DROPFILE = 0x1000, /**< The system requests a file open */
SDL_DROPTEXT, /**< text/plain drag-and-drop event */
SDL_DROPBEGIN, /**< A new set of drops is beginning (NULL filename) */
SDL_DROPCOMPLETE, /**< Current set of drops is now complete (NULL filename) */ /* Audio hotplug events */
SDL_AUDIODEVICEADDED = 0x1100, /**< A new audio device is available */
SDL_AUDIODEVICEREMOVED, /**< An audio device has been removed. */ /* Sensor events */
SDL_SENSORUPDATE = 0x1200, /**< A sensor was updated */ /* Render events */
SDL_RENDER_TARGETS_RESET = 0x2000, /**< The render targets have been reset and their contents need to be updated */
SDL_RENDER_DEVICE_RESET, /**< The device has been reset and all textures need to be recreated */ /** Events ::SDL_USEREVENT through ::SDL_LASTEVENT are for your use,
* and should be allocated with SDL_RegisterEvents()
*/
SDL_USEREVENT = 0x8000, /**
* This last event is only for bounding internal arrays
*/
SDL_LASTEVENT = 0xFFFF
} SDL_EventType;
这个就是SDL事件代号，SDL_Event结构体中的type属性。
1.4 SDL_WindowEventID
/**
* \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 has been resized to data1xdata2 */
SDL_WINDOWEVENT_SIZE_CHANGED, /**< The window size has changed, either as
a result of an API call or through the
system or user changing the window size. */
SDL_WINDOWEVENT_MINIMIZED, /**< Window has been minimized */
SDL_WINDOWEVENT_MAXIMIZED, /**< Window has been maximized */
SDL_WINDOWEVENT_RESTORED, /**< Window has been restored to normal size
and position */
SDL_WINDOWEVENT_ENTER, /**< Window has gained mouse focus */
SDL_WINDOWEVENT_LEAVE, /**< Window has lost mouse focus */
SDL_WINDOWEVENT_FOCUS_GAINED, /**< Window has gained keyboard focus */
SDL_WINDOWEVENT_FOCUS_LOST, /**< Window has lost keyboard focus */
SDL_WINDOWEVENT_CLOSE, /**< The window manager requests that the window be closed */
SDL_WINDOWEVENT_TAKE_FOCUS, /**< Window is being offered a focus (should SetWindowInputFocus() on itself or a subwindow, or ignore) */
SDL_WINDOWEVENT_HIT_TEST /**< Window had a hit test that wasn't SDL_HITTEST_NORMAL. */
} SDL_WindowEventID;
窗口事件代码。
1.5 SDL_Event
/**
* \brief General event structure
*/
typedef union SDL_Event
{
Uint32 type; /**< Event type, shared with all events */
SDL_CommonEvent common; /**< Common event data */
SDL_DisplayEvent display; /**< Window event data */
SDL_WindowEvent window; /**< Window event data */
SDL_KeyboardEvent key; /**< Keyboard event data */
SDL_TextEditingEvent edit; /**< Text editing event data */
SDL_TextInputEvent text; /**< Text input event data */
SDL_MouseMotionEvent motion; /**< Mouse motion event data */
SDL_MouseButtonEvent button; /**< Mouse button event data */
SDL_MouseWheelEvent wheel; /**< Mouse wheel event data */
SDL_JoyAxisEvent jaxis; /**< Joystick axis event data */
SDL_JoyBallEvent jball; /**< Joystick ball event data */
SDL_JoyHatEvent jhat; /**< Joystick hat event data */
SDL_JoyButtonEvent jbutton; /**< Joystick button event data */
SDL_JoyDeviceEvent jdevice; /**< Joystick device change event data */
SDL_ControllerAxisEvent caxis; /**< Game Controller axis event data */
SDL_ControllerButtonEvent cbutton; /**< Game Controller button event data */
SDL_ControllerDeviceEvent cdevice; /**< Game Controller device event data */
SDL_AudioDeviceEvent adevice; /**< Audio device event data */
SDL_SensorEvent sensor; /**< Sensor event data */
SDL_QuitEvent quit; /**< Quit request event data */
SDL_UserEvent user; /**< Custom event data */
SDL_SysWMEvent syswm; /**< System dependent window event data */
SDL_TouchFingerEvent tfinger; /**< Touch finger event data */
SDL_MultiGestureEvent mgesture; /**< Gesture event data */
SDL_DollarGestureEvent dgesture; /**< Gesture event data */
SDL_DropEvent drop; /**< Drag and drop event data */ /* This is necessary for ABI compatibility between Visual C++ and GCC
Visual C++ will respect the push pack pragma and use 52 bytes for
this structure, and GCC will use the alignment of the largest datatype
within the union, which is 8 bytes. So... we'll add padding to force the size to be 56 bytes for both.
*/
Uint8 padding[56];
} SDL_Event;
当然SDL2还有很多其他的结构体或枚举值，这里只是列出初学者很常见的几个。
2. 窗口管理相关的函数
初学时，接触比较多的是窗口相关的函数，但是数量也是挺多的。
SDL_Init
说明：初始化SDL库，内部调用了SDL_InitSubSystem()。在进行任何SDL操作前，必须先调用此函数初始化。
参数：falgs标识子系统编号。
返回值：成功返回0,失败返回负值
/* As of version 0.5, SDL is loaded dynamically into the application *//**
* \name SDL_INIT_*
*
* These are the flags which may be passed to SDL_Init(). You should
* specify the subsystems which you will be using in your application.
*/
/* @{ */
#define SDL_INIT_TIMER 0x00000001u
#define SDL_INIT_AUDIO 0x00000010u
#define SDL_INIT_VIDEO 0x00000020u /**< SDL_INIT_VIDEO implies SDL_INIT_EVENTS */
#define SDL_INIT_JOYSTICK 0x00000200u /**< SDL_INIT_JOYSTICK implies SDL_INIT_EVENTS */
#define SDL_INIT_HAPTIC 0x00001000u
#define SDL_INIT_GAMECONTROLLER 0x00002000u /**< SDL_INIT_GAMECONTROLLER implies SDL_INIT_JOYSTICK */
#define SDL_INIT_EVENTS 0x00004000u
#define SDL_INIT_SENSOR 0x00008000u
#define SDL_INIT_NOPARACHUTE 0x00100000u /**< compatibility; this flag is ignored. */
#define SDL_INIT_EVERYTHING ( \
SDL_INIT_TIMER | SDL_INIT_AUDIO | SDL_INIT_VIDEO | SDL_INIT_EVENTS | \
SDL_INIT_JOYSTICK | SDL_INIT_HAPTIC | SDL_INIT_GAMECONTROLLER | SDL_INIT_SENSOR \
)
/* @} *//**
* This function initializes the subsystems specified by \c flags
*/
extern DECLSPEC int SDLCALL SDL_Init(Uint32 flags);
SDL_Quit
说明：清理初始化的子系统
参数：无
返回值：无
* This function cleans up all initialized subsystems. You should
* call it upon all exit conditions.
*/
extern DECLSPEC void SDLCALL SDL_Quit(void);
SDL_CreateWindow
说明：创建一个窗口
参数： title：窗口标题； x：SDL_WINDOWPOS_CENTERED(居中)或SDL_WINDOWPOS_UNDEFINED(未定义)；y：同x； w：窗口宽度； h：窗口高度； flags：即上面的SDL_WindowFlags。
返回值：窗口SDL_window指针
/**
* \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, in screen coordinates.
* \param h The height of the window, in screen coordinates.
* \param flags The flags for the window, a mask of any of the following:
* ::SDL_WINDOW_FULLSCREEN, ::SDL_WINDOW_OPENGL,
* ::SDL_WINDOW_HIDDEN, ::SDL_WINDOW_BORDERLESS,
* ::SDL_WINDOW_RESIZABLE, ::SDL_WINDOW_MAXIMIZED,
* ::SDL_WINDOW_MINIMIZED, ::SDL_WINDOW_INPUT_GRABBED,
* ::SDL_WINDOW_ALLOW_HIGHDPI, ::SDL_WINDOW_VULKAN.
*
* \return The created window, or NULL if window creation failed.
*
* 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 Mac OS X). Use SDL_GetWindowSize() to query
* the client area's size in screen coordinates, and SDL_GL_GetDrawableSize(),
* SDL_Vulkan_GetDrawableSize(), or SDL_GetRendererOutputSize() to query the
* drawable size in pixels.
*
* 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.
*
* \note 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.
*
* \sa SDL_DestroyWindow()
* \sa SDL_GL_LoadLibrary()
* \sa SDL_Vulkan_LoadLibrary()
*/
extern DECLSPEC SDL_Window * SDLCALL SDL_CreateWindow(const char *title,
int x, int y, int w,
int h, Uint32 flags);
SDL_DestroyWindow
说明：销毁一个窗口
参数：窗口指针
返回值：无
SDL_CreateWindowFrom
2.5 SDL_GetWindowID
2.6 SDL_GetWindowFromID
SDL_GetWindowFlags
SDL_SetWindowTitle
SDL_GetWindowTitle
SDL_SetWindowIcon
SDL_SetWindowData
SDL_RaiseWindow
SDL_GetWindowPosition_SDL_GetWindowGrab
SDL_GetWindowSize
SDL_HideWindow
SDL_MaximizeWindow
SDL_MinimizeWindow
SDL_RaiseWindow
SDL_SetWindowFullscreen
SDL_SetWindowGrab
SDL_SetWindowSize
SDL_UpdateWindowSurfaceRects
SDL_CreateRenderer
SDL_GetRenderer
SDL_DestroyRenderer
SDL_CreateTexture
SDL_DestroyTexture
。。。
还有很多，就不一一列出来，要用时可以再去查看头文件说明。
