###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_MouseWheelEvent Mouse wheel event structure (event.wheel.*) ## Header File Defined in [](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_events.h) ## Syntax ```c typedef struct SDL_MouseWheelEvent { SDL_EventType type; /**< SDL_EVENT_MOUSE_WHEEL */ Uint32 reserved; Uint64 timestamp; /**< In nanoseconds, populated using SDL_GetTicksNS() */ SDL_WindowID windowID; /**< The window with mouse focus, if any */ SDL_MouseID which; /**< The mouse instance id, SDL_TOUCH_MOUSEID */ float x; /**< The amount scrolled horizontally, positive to the right and negative to the left */ float y; /**< The amount scrolled vertically, positive away from the user and negative toward the user */ SDL_MouseWheelDirection direction; /**< Set to one of the SDL_MOUSEWHEEL_* defines. When FLIPPED the values in X and Y will be opposite. Multiply by -1 to change them back */ float mouse_x; /**< X coordinate, relative to window */ float mouse_y; /**< Y coordinate, relative to window */ } SDL_MouseWheelEvent; ``` ## Version This struct is available since SDL 3.1.3. ---- [CategoryAPI](CategoryAPI), [CategoryAPIStruct](CategoryAPIStruct), [CategoryEvents](CategoryEvents)