SDL_JoyBallEvent(3type)

💖 SDL_JoyBallEvent — joystick trackball motion event structure (event.jball.*) 💖

okay bestie, this is a page from the SDL3 DATATYPES corner of the SDL manual, and it's all about the vibe of a trackball on your joystick going brrrr in some direction. It's the struct you get handed when a joystick trackball moves. That's it, that's the whole plot. 🎀

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✨ SYNOPSIS ✨

#include <SDL3/SDL_events.h>

typedef struct SDL_JoyBallEvent
{
    SDL_EventType type; /**< SDL_EVENT_JOYSTICK_BALL_MOTION */
    Uint32 reserved;
    Uint64 timestamp;   /**< In nanoseconds, populated using SDL_GetTicksNS() */
    SDL_JoystickID which; /**< The joystick instance id */
    Uint8 ball;         /**< The joystick trackball index */
    Uint8 padding1;
    Uint8 padding2;
    Uint8 padding3;
    Sint16 xrel;        /**< The relative motion in the X direction */
    Sint16 yrel;        /**< The relative motion in the Y direction */
} SDL_JoyBallEvent;

no cap, let's walk the fields one by one because every single one of them matters 🫶

• type — it's an SDL_EventType, and for this lil guy it's literally SDL_EVENT_JOYSTICK_BALL_MOTION. so like, that's how you know what you're looking at when it shows up in the event queue 💅
• reserved — a Uint32 just chillin'. it's reserved. do not touch. mind your business 🙈
• timestamp — a Uint64, in nanoseconds, populated using SDL_GetTicksNS(). so it's giving when did this happen, precisely. ⭐
• which — an SDL_JoystickID, aka the joystick instance id. which joystick is serving this trackball tea 👑
• ball — a Uint8, the joystick trackball index. because yes, a joystick can have more than one trackball, and this one is telling you which one is the main character here 🌈
• padding1 — Uint8. padding. it's padding bestie. that's the whole job.
• padding2 — Uint8. more padding. slay.
• padding3 — Uint8. the third one. iconique trio honestly ✨
• xrel — a Sint16, the relative motion in the X direction. how far sideways it went, relatively 🦋
• yrel — a Sint16, the relative motion in the Y direction. how far up/down it went, relatively 🦋

fr fr: those are relative motions, not absolute positions. the struct is telling you how much it moved, not where it is. don't get it twisted 💀

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🌸 AVAILABILITY 🌸

this struct is available since SDL 3.2.0. so if you're on anything older, it's simply not giving. upgrade, periodt. 💖

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and that's the whole page, bestie!! go forth and handle your trackball events with main character energy 🧚💜

mwah 💋 — brought to you by the lovely humans at Simple Directmedia Layer, from the SDL 3.4.18 era of the SDL 3 datatypes saga.