SDL事件处理（一些数据类型）

SDL1.2中的定义：

typedef enum {       SDL_NOEVENT = 0,/**< Unused (do not remove) */       SDL_ACTIVEEVENT,/**< Application loses/gains visibility */       SDL_KEYDOWN,/**< Keys pressed */       SDL_KEYUP,/**< Keys released */       SDL_MOUSEMOTION,/**< Mouse moved */       SDL_MOUSEBUTTONDOWN,/**< Mouse button pressed */       SDL_MOUSEBUTTONUP,/**< Mouse button released */       SDL_JOYAXISMOTION,/**< Joystick axis motion */       SDL_JOYBALLMOTION,/**< Joystick trackball motion */       SDL_JOYHATMOTION,/**< Joystick hat position change */       SDL_JOYBUTTONDOWN,/**< Joystick button pressed */       SDL_JOYBUTTONUP,/**< Joystick button released */       SDL_QUIT,/**< User-requested quit */       SDL_SYSWMEVENT,/**< System specific event */       SDL_EVENT_RESERVEDA,/**< Reserved for future use.. */       SDL_EVENT_RESERVEDB,/**< Reserved for future use.. */       SDL_VIDEORESIZE,/**< User resized video mode */       SDL_VIDEOEXPOSE,/**< Screen needs to be redrawn */       SDL_EVENT_RESERVED2,/**< Reserved for future use.. */       SDL_EVENT_RESERVED3,/**< Reserved for future use.. */       SDL_EVENT_RESERVED4,/**< Reserved for future use.. */       SDL_EVENT_RESERVED5,/**< Reserved for future use.. */       SDL_EVENT_RESERVED6,/**< Reserved for future use.. */       SDL_EVENT_RESERVED7,/**< Reserved for future use.. */       /** Events SDL_USEREVENT through SDL_MAXEVENTS-1 are for your use */       SDL_USEREVENT = 24,       /** This last event is only for bounding internal arrays*  It is the number of bits in the event mask datatype -- Uint32        */       SDL_NUMEVENTS = 32} SDL_EventType;

SDL2.0中的定义：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.txt 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() */    /* 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 */    /* 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 */    /* Render events */    SDL_RENDER_TARGETS_RESET = 0x2000, /**< The render targets have been reset */    /** 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;

SDL2.0中的事件类型明显比SDL1.2中的多！

SDL采用int SDL_PollEvent(SDL_Event* event);来从底层抽取事件。每一个事件都有一个独立的数据结构来定义，但是第一个成员都是int type.
例如：SDL1.2中的：

typedef struct SDL_JoyBallEvent {Uint8 type;Uint8 which;Uint8 ball;Sint16 xrel;Sint16 yrel;} SDL_JoyBallEvent;/** Joystick hat position change event structure */typedef struct SDL_JoyHatEvent {Uint8 type;Uint8 which;Uint8 hat;Uint8 value;} SDL_JoyHatEvent;SDL2.0中的：typedef struct SDL_JoyBallEvent{    Uint32 type;           Uint32 timestamp;    SDL_JoystickID which;     Uint8 ball;             Uint8 padding1;    Uint8 padding2;    Uint8 padding3;    Sint16 xrel;            Sint16 yrel;     } SDL_JoyBallEvent;/** *  \brief Joystick hat position change event structure (event.jhat.*) */typedef struct SDL_JoyHatEvent{    Uint32 type;          Uint32 timestamp;    SDL_JoystickID which;     Uint8 hat;             Uint8 value;           Uint8 padding1;    Uint8 padding2;} SDL_JoyHatEvent;从上面也可以看出SDL2.0相对于SDL1.2事件类型的改变而SDL_Event是各种事件的联合：SDL1.2：typedef union SDL_Event {Uint8 type;SDL_ActiveEvent active;SDL_KeyboardEvent key;SDL_MouseMotionEvent motion;SDL_MouseButtonEvent button;SDL_JoyAxisEvent jaxis;SDL_JoyBallEvent jball;SDL_JoyHatEvent jhat;SDL_JoyButtonEvent jbutton;SDL_ResizeEvent resize;SDL_ExposeEvent expose;SDL_QuitEvent quit;SDL_UserEvent user;SDL_SysWMEvent syswm;} SDL_Event;SDL2.0：typedef union SDL_Event{    Uint32 type;                    /**< Event type, shared with all events */SDL_EventType中定义的。具体的去看SDL源码    SDL_CommonEvent common;         /**< Common 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_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 */    Uint8 padding[56];} SDL_Event;